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Clay Murphy0e4e4082015-02-13 10:22:33 -0800[diff] [blame]1<?xml version="1.0" encoding="UTF-8"?>
2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
4<head>
5<title>Android 4.4 Compatibility Definition</title>
6<link rel="stylesheet" type="text/css" href="cdd.css"/>
7</head>
8<body>
9<div><img src="header.jpg" alt="Android logo"/></div>
10<h1>Android 4.4 Compatibility Definition</h1>
11<!--
12<span style="color: red; font-weight: bold;"><h2>Revision 1</h2></span><br/>
13<span style="color: red;">Last updated: July 23, 2013</span>
14-->
15<p><b><font color="red">Revision 1</font></b><br/>
16Last updated: November 27, 2013
17</p>
18<p>Copyright &copy; 2013, Google Inc. All rights reserved.<br/>
19<a href="mailto:compatibility@android.com">compatibility@android.com</a>
20</p>
21
22<h2>Table of Contents</h2>
23<div style="margin-left: 2em;">
24 <a href="#section-1">1. Introduction</a><br/>
25 <a href="#section-2">2. Resources</a><br/>
26 <a href="#section-3">3. Software</a><br/>
27 <div style="margin-left: 2em;">
28 <a href="#section-3.1">3.1. Managed API Compatibility</a><br/>
29 <a href="#section-3.2">3.2. Soft API Compatibility</a><br/>
30 <div style="margin-left: 2em;">
31 <a href="#section-3.2.1">3.2.1. Permissions</a><br/>
32 <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/>
33 <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/>
34 <div style="margin-left: 2em;">
35 <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/>
36 <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/>
37 <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/>
38 <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/>
39 <a href="#section-3.2.3.5">3.2.3.5. Default App Settings</a><br/>
40 </div>
41 </div>
42 <a href="#section-3.3">3.3. Native API Compatibility</a><br/>
43 <div style="margin-left: 2em;">
44 <a href="#section-3.3.1">3.3.1 Application Binary Interfaces</a><br/>
45 </div>
46 <a href="#section-3.4">3.4. Web Compatibility</a><br/>
47 <div style="margin-left: 2em;">
48 <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/>
49 <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/>
50 </div>
51 <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/>
52 <a href="#section-3.6">3.6. API Namespaces</a><br/>
53 <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/>
54 <a href="#section-3.8">3.8. User Interface Compatibility</a><br/>
55 <div style="margin-left: 2em;">
56 <a href="#section-3.8.1">3.8.1. Launcher (Home Screen)</a><br/>
57 <a href="#section-3.8.2">3.8.2. Widgets</a><br/>
58 <a href="#section-3.8.3">3.8.3. Notifications</a><br/>
59 <a href="#section-3.8.4">3.8.4. Search</a><br/>
60 <a href="#section-3.8.5">3.8.5. Toasts</a><br/>
61 <a href="#section-3.8.6">3.8.6. Themes</a><br/>
62 <a href="#section-3.8.7">3.8.7. Live Wallpapers</a><br/>
63 <a href="#section-3.8.8">3.8.8. Recent Application Display</a><br/>
64 <a href="#section-3.8.9">3.8.9. Input Management</a><br/>
65 <a href="#section-3.8.10">3.8.10. Lock Screen Media Remote Control</a><br/>
66 <a href="#section-3.8.11">3.8.11. Dreams</a><br/>
67 <a href="#section-3.8.12">3.8.12. Location</a><br/>
68 <a href="#section-3.8.13">3.8.13. Unicode</a><br/>
69 </div>
70 <a href="#section-3.9">3.9 Device Administration</a><br/>
71 <a href="#section-3.10">3.10 Accessibility</a><br/>
72 <a href="#section-3.11">3.11 Text-to-Speech</a><br/>
73 </div>
74 <a href="#section-4">4. Application Packaging Compatibility</a><br/>
75 <a href="#section-5">5. Multimedia Compatibility</a><br/>
76 <div style="margin-left: 2em;">
77 <a href="#section-5.1">5.1. Media Codecs</a><br/>
78 <a href="#section-5.2">5.2. Video Encoding</a><br/>
79 <a href="#section-5.3">5.3. Video Decoding</a><br/>
80 <a href="#section-5.4">5.4. Audio Recording</a><br/>
81 <a href="#section-5.5">5.5. Audio Latency</a><br/>
82 <a href="#section-5.6">5.6. Network Protocols</a><br/>
83 </div>
84 <a href="#section-6">6. Developer Tools and Options Compatibility</a><br/>
85 <div style="margin-left: 2em;">
86 <a href="#section-6.1">6.1. Developer Tools</a><br/>
87 <a href="#section-6.2">6.2. Developer Options</a><br/>
88 <a href="#section-6.2.1">6.2.1. Experimental</a><br/>
89 </div>
90 <a href="#section-7">7. Hardware Compatibility</a><br/>
91 <div style="margin-left: 2em;">
92 <a href="#section-7.1">7.1. Display and Graphics</a><br/>
93 <div style="margin-left: 2em;">
94 <a href="#section-7.1.1">7.1.1. Screen Configuration</a><br/>
95 <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/>
96 <a href="#section-7.1.3">7.1.3. Screen Orientation</a><br/>
97 <a href="#section-7.1.4">7.1.4. 2D and 3D Graphics Acceleration</a><br/>
98 <a href="#section-7.1.5">7.1.5. Legacy Application Compatibility Mode</a><br/>
99 <a href="#section-7.1.6">7.1.6. Screen Types</a><br/>
100 <a href="#section-7.1.7">7.1.7. Screen Technology</a><br/>
101 <a href="#section-7.1.8">7.1.8. External Displays</a><br/>
102 </div>
103 <a href="#section-7.2">7.2. Input Devices</a><br/>
104 <div style="margin-left: 2em;">
105 <a href="#section-7.2.1">7.2.1. Keyboard</a><br/>
106 <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/>
107 <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/>
108 <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/>
109 <a href="#section-7.2.5">7.2.5. Fake touch input</a><br/>
110 <a href="#section-7.2.6">7.2.6. Microphone</a><br/>
111 </div>
112 <a href="#section-7.3">7.3. Sensors</a><br/>
113 <div style="margin-left: 2em;">
114 <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/>
115 <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/>
116 <a href="#section-7.3.3">7.3.3. GPS</a><br/>
117 <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/>
118 <a href="#section-7.3.5">7.3.5. Barometer</a><br/>
119 <a href="#section-7.3.6">7.3.6. Thermometer</a><br/>
120 <a href="#section-7.3.7">7.3.7. Photometer</a><br/>
121 <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/>
122 </div>
123 <a href="#section-7.4">7.4. Data Connectivity</a><br/>
124 <div style="margin-left: 2em;">
125 <a href="#section-7.4.1">7.4.1. Telephony</a><br/>
126 <a href="#section-7.4.2">7.4.2. IEEE 802.11 (Wi-Fi)</a><br/>
127 <div style="margin-left: 2em;">
128 <a href="#section-7.4.2.1">7.4.2.1. Wi-Fi Direct</a><br/>
129 <a href="#section-7.4.2.2">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</a><br/>
130 </div>
131 <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/>
132 <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/>
133 <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/>
134 <a href="#section-7.4.6">7.4.6. Sync Settings</a><br/>
135 </div>
136 <a href="#section-7.5">7.5. Cameras</a><br/>
137 <div style="margin-left: 2em;">
138 <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/>
139 <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/>
140 <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/>
141 <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/>
142 </div>
143 <a href="#section-7.6">7.6. Memory and Storage</a><br/>
144 <div style="margin-left: 2em;">
145 <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/>
146 <a href="#section-7.6.2">7.6.2. Shared External Storage</a><br/>
147 </div>
148 <a href="#section-7.7">7.7. USB</a><br/>
149 </div>
150 <a href="#section-8">8. Performance Compatibility</a><br/>
151 <a href="#section-9">9. Security Model Compatibility</a><br/>
152 <div style="margin-left: 2em;">
153 <a href="#section-9.1">9.1. Permissions</a><br/>
154 <a href="#section-9.2">9.2. UID and Process Isolation</a><br/>
155 <a href="#section-9.3">9.3. Filesystem Permissions</a><br/>
156 <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/>
157 <a href="#section-9.5">9.5. Multi-User Support</a><br/>
158 <a href="#section-9.6">9.6. Premium SMS Warning</a><br/>
159 <a href="#section-9.7">9.7. Kernel Security Features</a><br/>
160 <a href="#section-9.8">9.8. Privacy</a><br/>
161 <a href="#section-9.9">9.9. Full-Disk Encryption</a><br/>
162 </div>
163 <a href="#section-10">10. Software Compatibility Testing</a><br/>
164 <div style="margin-left: 2em;">
165 <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/>
166 <a href="#section-10.2">10.2. CTS Verifier</a><br/>
167 <a href="#section-10.3">10.3. Reference Applications</a><br/>
168 </div>
169 <a href="#section-11">11. Updatable Software</a><br/>
170 <a href="#section-12">12. Document Changelog</a><br/>
171 <a href="#section-13">13. Contact Us</a><br/>
172</div>
173
174<div style="page-break-before: always;"></div>
175
176<a name="section-1"></a><h2 id="section-1">1. Introduction</h2>
177<p>This document enumerates the requirements that must be met in order for
178devices to be compatible with Android 4.4.</p>
179<p>The use of "must", "must not", "required", "shall", "shall not", "should",
180"should not", "recommended", "may" and "optional" is per the IETF standard
181defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p>
182<p>As used in this document, a "device implementer" or "implementer" is a
183person or organization developing a hardware/software solution running Android
1844.4. A "device implementation" or "implementation" is the hardware/software
185solution so developed.</p>
186<p>To be considered compatible with Android 4.4, device implementations
187MUST meet the requirements presented in this Compatibility Definition,
188including any documents incorporated via reference.</p>
189<p>Where this definition or the software tests described in <a
190href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is
191the responsibility of the device implementer to ensure compatibility with
192existing implementations.</p>
193<p>For this reason, the Android Open Source Project [<a
194href="#resources03">Resources, 3</a>] is both the reference and preferred
195implementation of Android. Device implementers are strongly encouraged to base
196their implementations to the greatest extent possible on the "upstream" source
197code available from the Android Open Source Project. While some components can
198hypothetically be replaced with alternate implementations this practice is
199strongly discouraged, as passing the software tests will become substantially
200more difficult. It is the implementer's responsibility to ensure full
201behavioral compatibility with the standard Android implementation, including
202and beyond the Compatibility Test Suite. Finally, note that certain component
203substitutions and modifications are explicitly forbidden by this document.</p>
204<a name="section-2"></a><h2 id="section-2">2. Resources</h2>
205<ol>
206<a name="resources01"></a><li id="resources01">IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li>
207<a name="resources02"></a><li id="resources02">Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li>
208<a name="resources03"></a><li id="resources03">Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li>
209<a name="resources04"></a><li id="resources04">API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li>
210<a name="resources05"></a><li id="resources05">Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li>
211<a name="resources06"></a><li id="resources06">android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li>
212<a name="resources07"></a><li id="resources07">Android 4.4 allowed version strings: <a href="http://source.android.com/compatibility/4.4/versions.html">http://source.android.com/compatibility/4.4/versions.html</a></li>
213<a name="resources08"></a><li id="resources08">Renderscript: <a href="http://developer.android.com/guide/topics/graphics/renderscript.html">http://developer.android.com/guide/topics/graphics/renderscript.html</a></li>
214<a name="resources09"></a><li id="resources09">Hardware Acceleration: <a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">http://developer.android.com/guide/topics/graphics/hardware-accel.html</a></li>
215<a name="resources10"></a><li id="resources10">android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li>
216<a name="resources11"></a><li id="resources11">HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li>
217<a name="resources12"></a><li id="resources12">HTML5 offline capabilities: <a href="http://dev.w3.org/html5/spec/Overview.html#offline">http://dev.w3.org/html5/spec/Overview.html#offline</a></li>
218<a name="resources13"></a><li id="resources13">HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></li>
219<a name="resources14"></a><li id="resources14">HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></li>
220<a name="resources15"></a><li id="resources15">HTML5/W3C webstorage API: <a href="http://www.w3.org/TR/webstorage/">http://www.w3.org/TR/webstorage/</a></li>
221<a name="resources16"></a><li id="resources16">HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></li>
222<a name="resources17"></a><li id="resources17">Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li>
223<a name="resources18"></a><li id="resources18">AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li>
224<a name="resources19"></a><li id="resources19">Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li>
225<a name="resources20"></a><li id="resources20">Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li>
226<a name="resources21"></a><li id="resources21">Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html">http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html</a></li>
227<a name="resources22"></a><li id="resources22">Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li>
228<a name="resources23"></a><li id="resources23">Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li>
229<a name="resources24"></a><li id="resources24">Themes: <a href="http://developer.android.com/guide/topics/ui/themes.html">http://developer.android.com/guide/topics/ui/themes.html</a></li>
230<a name="resources25"></a><li id="resources25">R.style class: <a href="http://developer.android.com/reference/android/R.style.html">http://developer.android.com/reference/android/R.style.html</a></li>
231<a name="resources26"></a><li id="resources26">Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li>
232<a name="resources27"></a><li id="resources27">Android Device Administration: <a href="http://developer.android.com/guide/topics/admin/device-admin.html">http://developer.android.com/guide/topics/admin/device-admin.html</a></li>
233<a name="resources28"></a><li id="resources28">DevicePolicyManager reference: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html</a></li>
234<a name="resources29"></a><li id="resources29">Android Accessibility Service APIs: <a href="http://developer.android.com/reference/android/accessibilityservice/package-summary.html">http://developer.android.com/reference/android/accessibilityservice/package-summary.html</a></li>
235<a name="resources30"></a><li id="resources30">Android Accessibility APIs: <a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">http://developer.android.com/reference/android/view/accessibility/package-summary.html</a></li>
236<a name="resources31"></a><li id="resources31">Eyes Free project: <a href="http://http://code.google.com/p/eyes-free">http://code.google.com/p/eyes-free</a></li>
237<a name="resources32"></a><li id="resources32">Text-To-Speech APIs: <a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">http://developer.android.com/reference/android/speech/tts/package-summary.html</a></li>
238<a name="resources33"></a><li id="resources33">Reference tool documentation (for adb, aapt, ddms, systrace): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li>
239<a name="resources34"></a><li id="resources34">Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li>
240<a name="resources35"></a><li id="resources35">Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li>
241<a name="resources36"></a><li id="resources36">Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li>
242<a name="resources37"></a><li id="resources37">Android android.content.pm.PackageManager class and Hardware Features List: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">http://developer.android.com/reference/android/content/pm/PackageManager.html</a></li>
243<a name="resources38"></a><li id="resources38">Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li>
244<a name="resources39"></a><li id="resources39">android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li>
245<a name="resources40"></a><li id="resources40">android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li>
246<a name="resources41"></a><li id="resources41">android.hardware.SensorEvent: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li>
247<a name="resources42"></a><li id="resources42">Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li>
248<a name="resources43"></a><li id="resources43">NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></li>
249<a name="resources44"></a><li id="resources44">MIFARE MF1S503X: <a href="http://www.nxp.com/documents/data_sheet/MF1S503x.pdf">http://www.nxp.com/documents/data_sheet/MF1S503x.pdf</a></li>
250<a name="resources45"></a><li id="resources45">MIFARE MF1S703X: <a href="http://www.nxp.com/documents/data_sheet/MF1S703x.pdf">http://www.nxp.com/documents/data_sheet/MF1S703x.pdf</a></li>
251<a name="resources46"></a><li id="resources46">MIFARE MF0ICU1: <a href="http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf">http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf</a></li>
252<a name="resources47"></a><li id="resources47">MIFARE MF0ICU2: <a href="http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf">http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf</a></li>
253<a name="resources48"></a><li id="resources48">MIFARE AN130511: <a href="http://www.nxp.com/documents/application_note/AN130511.pdf">http://www.nxp.com/documents/application_note/AN130511.pdf</a></li>
254<a name="resources49"></a><li id="resources49">MIFARE AN130411: <a href="http://www.nxp.com/documents/application_note/AN130411.pdf">http://www.nxp.com/documents/application_note/AN130411.pdf</a></li>
255<a name="resources50"></a><li id="resources50">Camera orientation API: <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)</a></li>
256<a name="resources51"></a><li id="resources51">Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li>
257<a name="resources52"></a><li id="resources52">Android Open Accessories: <a href="http://developer.android.com/guide/topics/usb/accessory.html">http://developer.android.com/guide/topics/usb/accessory.html</a></li>
258<a name="resources53"></a><li id="resources53">USB Host API: <a href="http://developer.android.com/guide/topics/usb/host.html">http://developer.android.com/guide/topics/usb/host.html</a></li>
259<a name="resources54"></a><li id="resources54">Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/permissions.html">http://developer.android.com/guide/topics/security/permissions.html</a></li>
260<a name="resources55"></a><li id="resources55">Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li>
261<a name="resources56"></a><li id="resources56">Android DownloadManager: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></li>
262<a name="resources57"></a><li id="resources57">Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></li>
263<a name="resources58"></a><li id="resources58">Android Media Formats: <a href="http://developer.android.com/guide/appendix/media-formats.html">http://developer.android.com/guide/appendix/media-formats.html</a></li>
264<a name="resources59"></a><li id="resources59">HTTP Live Streaming Draft Protocol: <a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">http://tools.ietf.org/html/draft-pantos-http-live-streaming-03</a></li>
265<a name="resources60"></a><li id="resources60">NFC Connection Handover: <a href="http://www.nfc-forum.org/specs/spec_list/#conn_handover/">http://www.nfc-forum.org/specs/spec_list/#conn_handover</a></li>
266<a name="resources61"></a><li id="resources61">Bluetooth Secure Simple Pairing Using NFC: <a href="http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf">http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf</a></li>
267<a name="resources62"></a>
268<li id="resources62">Wi-Fi Multicast API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html</a></li>
269<a name="resources63"></a><li id="resources63">Action Assist: <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST</a></li>
270<a name="resources64"></a><li id="resources64">USB Charging Specification: <a href="http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf">http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf</a></li>
271<a name="resources65"></a><li id="resources65">Android Beam: <a href="http://developer.android.com/guide/topics/nfc/nfc.html">http://developer.android.com/guide/topics/nfc/nfc.html</a></li>
272<a name="resources66"></a><li id="resources66">Android USB Audio: <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO</a></li>
273<a name="resources67"></a><li id="resources67">Android NFC Sharing Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS</a></li>
274<a name="resources68"></a>
275<li id="resources68">Wi-Fi Direct (Wi-Fi P2P): <a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html</a></li>
276<a name="resources69"></a><li id="resources69">Lock and Home Screen Widget: <a href="http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html">http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html</a></li>
277<a name="resources70"></a><li id="resources70">UserManager reference: <a href="http://developer.android.com/reference/android/os/UserManager.html">http://developer.android.com/reference/android/os/UserManager.html</a></li>
278<a name="resources71"></a><li id="resources71">External Storage reference: <a
279href="http://source.android.com/devices/tech/storage">http://source.android.com/devices/tech/storage</a></li>
280<a name="resources72"></a><li id="resources72">External Storage APIs: <a href="http://developer.android.com/reference/android/os/Environment.html">http://developer.android.com/reference/android/os/Environment.html</a></li>
281<a name="resources73"></a><li id="resources73">SMS Short Code: <a href="http://en.wikipedia.org/wiki/Short_code">http://en.wikipedia.org/wiki/Short_code</a></li>
282<a name="resources74"></a><li id="resources74">Media Remote Control Client: <a href="http://developer.android.com/reference/android/media/RemoteControlClient.html">http://developer.android.com/reference/android/media/RemoteControlClient.html</a></li>
283<a name="resources75"></a><li id="resources75">Display Manager: <a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">http://developer.android.com/reference/android/hardware/display/DisplayManager.html</a></li>
284<a name="resources76"></a><li id="resources76">Dreams: <a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">http://developer.android.com/reference/android/service/dreams/DreamService.html</a></li>
285<a name="resources77"></a><li id="resources77">Android Application Development-Related Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS</a></li>
286<a name="resources78"></a><li id="resources78">Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">http://developer.android.com/reference/android/hardware/Camera.Parameters.html</a></li>
287<a name="resources79"></a><li id="resources79">EGL Extension-EGL_ANDROID_RECORDABLE: <a href="http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt</a></li>
288<a name="resources80"></a><li id="resources80">Motion Event API: <a href="http://developer.android.com/reference/android/view/MotionEvent.html">http://developer.android.com/reference/android/view/MotionEvent.html</a></li>
289<a name="resources81"></a><li id="resources81">Touch Input Configuration: <a href="http://source.android.com/devices/tech/input/touch-devices.html">http://source.android.com/devices/tech/input/touch-devices.html</a></li>
290<a name="resources82"></a><li id="resources82">Unicode 6.1.0: <a href="http://www.unicode.org/versions/Unicode6.1.0/">http://www.unicode.org/versions/Unicode6.1.0/</a></li>
291<a name="resources83"></a><li id="resources83">WebView compatibility: <a href="http://www.chromium.org/">http://www.chromium.org/</a></li>
292<a name="resources84"></a><li id="resources84">Android Device Owner App: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)</a></li>
293<a name="resources85"></a><li id="resources85">WifiManager API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.html">http://developer.android.com/reference/android/net/wifi/WifiManager.html</a></li>
294<a name="resources86"></a><li id="resources86">RTC Hardware Coding Requirements: <a href="http://www.webmproject.org/hardware/rtc-coding-requirements/">http://www.webmproject.org/hardware/rtc-coding-requirements/</a></li>
295<a name="resources87"></a><li id="resources87">Settings.Secure LOCATION_MODE: <a
296href="http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE">http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE</a></li>
297<a name="resources88"></a><li id="resources88">Content Resolver: <a href="http://developer.android.com/reference/android/content/ContentResolver.html">http://developer.android.com/reference/android/content/ContentResolver.html</a></li>
298<a name="resources89"></a><li id="resources89">SettingInjectorService: <a
299href="http://developer.android.com/reference/android/location/SettingInjectorService.html">http://developer.android.com/reference/android/location/SettingInjectorService.html</a></li>
300<a name="resources90"></a><li id="resources90">Host-based Card Emulation: <a href="http://developer.android.com/guide/topics/connectivity/nfc/hce.html">http://developer.android.com/guide/topics/connectivity/nfc/hce.html</a></li>
301<a name="resources91"></a><li id="resources91">Telephony Provider: <a href="http://developer.android.com/reference/android/provider/Telephony.html">http://developer.android.com/reference/android/provider/Telephony.html</a></li>
302</ol>
303<p>Many of these resources are derived directly or indirectly from the Android
304SDK, and will be functionally identical to the information in that SDK's
305documentation. In any cases where this Compatibility Definition or the
306Compatibility Test Suite disagrees with the SDK documentation, the SDK
307documentation is considered authoritative. Any technical details provided in
308the references included above are considered by inclusion to be part of this
309Compatibility Definition.</p>
310
311<a name="section-3"></a><h2 id="section-3">3. Software</h2>
312<a name="section-3.1"></a><h3 id="section-3.1">3.1. Managed API Compatibility</h3>
313<p>The managed (Dalvik-based) execution environment is the primary vehicle for
314Android applications. The Android application programming interface (API) is
315the set of Android platform interfaces exposed to applications running in the
316managed VM environment. Device implementations MUST provide complete
317implementations, including all documented behaviors, of any documented API
318exposed by the Android SDK [<a href="#resources04">Resources, 4</a>].</p>
319<p>Device implementations MUST NOT omit any managed APIs, alter API interfaces
320or signatures, deviate from the documented behavior, or include no-ops, except
321where specifically allowed by this Compatibility Definition.</p>
322<p>This Compatibility Definition permits some types of hardware for which
323Android includes APIs to be omitted by device implementations. In such cases,
324the APIs MUST still be present and behave in a reasonable way. See
325<a href="#section-7">Section 7</a> for specific requirements for this scenario.
326</p>
327
328<a name="section-3.2"></a><h3 id="section-3.2">3.2. Soft API Compatibility</h3>
329<p>In addition to the managed APIs from Section 3.1, Android also includes a
330significant runtime-only "soft" API, in the form of such things such as
331Intents, permissions, and similar aspects of Android applications that cannot
332be enforced at application compile time.</p>
333<a name="section-3.2.1"></a><h4 id="section-3.2.1">3.2.1. Permissions</h4>
334<p>Device implementers MUST support and enforce all permission constants as
335documented by the Permission reference page [<a
336href="#resources05">Resources, 5</a>]. Note that Section 9 lists additional
337requirements related to the Android security model.</p>
338<a name="section-3.2.2"></a><h4 id="section-3.2.2">3.2.2. Build Parameters</h4>
339<p>The Android APIs include a number of constants on the <code>android.os.Build</code>
340class [<a href="#resources06">Resources, 6</a>] that are intended to describe
341the current device. To provide consistent, meaningful values across device
342implementations, the table below includes additional restrictions on the
343formats of these values to which device implementations MUST conform.</p>
344<table>
345<tbody>
346<tr>
347<td><b>Parameter</b></td>
348<td><b>Comments</b></td>
349</tr>
350<tr>
351<td>VERSION.RELEASE</td>
352<td>The version of the currently-executing Android system, in human-readable
353format. This field MUST have one of the string values defined in [<a
354href="#resources07">Resources, 7</a>].</td>
355</tr>
356<tr>
357<td>VERSION.SDK</td>
358<td>The version of the currently-executing Android system, in a format
359accessible to third-party application code. For Android 4.4, this
360field MUST have the integer value 19.</td>
361</tr>
362<tr>
363<td>VERSION.SDK_INT</td>
364<td>The version of the currently-executing Android system, in a format
365accessible to third-party application code. For Android 4.4, this
366field MUST have the integer value 19.</td>
367</tr>
368<tr>
369<td>VERSION.INCREMENTAL</td>
370<td>A value chosen by the device implementer designating the specific build of
371the currently-executing Android system, in human-readable format. This value
372MUST NOT be re-used for different builds made available to end users. A typical use
373of this field is to indicate which build number or source-control change
374identifier was used to generate the build. There are no requirements on the
375specific format of this field, except that it MUST NOT be null or the empty
376string ("").</td>
377</tr>
378<tr>
379<td>BOARD</td>
380<td>A value chosen by the device implementer identifying the specific internal
381hardware used by the device, in human-readable format. A possible use of this
382field is to indicate the specific revision of the board powering the device.
383The value of this field MUST be encodable as 7-bit ASCII and match the regular expression
384<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
385</tr>
386<tr>
387<td>BRAND</td>
388<td>A value reflecting the brand name associated with the device as
389known to the end users. MUST be in human-readable format and SHOULD represent
390the manufacturer of the device or the company brand under which the device is
391marketed. The value of this field MUST be encodable as 7-bit ASCII and match the
392regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.
393</td>
394</tr>
395<tr>
396<td>CPU_ABI</td>
397<td>The name of the instruction set (CPU type + ABI convention) of native code.
398See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.
399</td>
400</tr>
401<tr>
402<td>CPU_ABI2</td>
403<td>The name of the second instruction set (CPU type + ABI convention) of native code.
404See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>.
405</td>
406</tr>
407<tr>
408<td>DEVICE</td>
409<td>A value chosen by the device implementer containing the development name or
410code name identifying the configuration of the hardware features and industrial
411design of the device. The value of this field MUST be encodable as 7-bit ASCII
412and match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.
413</td>
414</tr>
415<tr>
416<td>FINGERPRINT</td>
417<td>A string that uniquely identifies this build. It SHOULD be reasonably
418human-readable. It MUST follow this template:
419<br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/>
420For example:
421<br/><code>acme/myproduct/mydevice:4.4/KRT16/3359:userdebug/test-keys</code><br/>
422The fingerprint MUST NOT include whitespace characters. If other fields included in the
423template above have whitespace characters, they MUST be replaced in the build
424fingerprint with another character, such as the underscore ("_") character.
425The value of this field MUST be encodable as 7-bit ASCII.</td>
426</tr>
427<tr>
428<td>HARDWARE</td>
429<td>The name of the hardware (from the kernel command line or /proc). It SHOULD be
430reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and
431match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
432</tr>
433<tr>
434<td>HOST</td>
435<td>A string that uniquely identifies the host the build was built on, in
436human readable format. There are no requirements on the specific format of
437this field, except that it MUST NOT be null or the empty string ("").</td>
438</tr>
439<tr>
440<td>ID</td>
441<td>An identifier chosen by the device implementer to refer to a specific
442release, in human readable format. This field can be the same as
443android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
444meaningful for end users to distinguish between software builds. The value of
445this field MUST be encodable as 7-bit ASCII and match the regular expression
446<code>"^[a-zA-Z0-9.,_-]+$"</code>.
447</td>
448</tr>
449<tr>
450<td>MANUFACTURER</td>
451<td>The trade name of the Original Equipment Manufacturer (OEM) of the product.
452There are no requirements on the specific format of this field, except that it
453MUST NOT be null or the empty string ("").</td>
454</tr>
455<tr>
456<td>MODEL</td>
457<td>A value chosen by the device implementer containing the name of the device
458as known to the end user. This SHOULD be the same name under which the device
459is marketed and sold to end users. There are no requirements on the specific
460format of this field, except that it MUST NOT be null or the empty string
461("").</td>
462</tr>
463<tr>
464<td>PRODUCT</td>
465<td>A value chosen by the device implementer containing the development name or
466code name of the specific product (SKU) that SHOULD be unique within the same
467brand. MUST be human-readable, but is not necessarily intended for view by end
468users. The value of this field MUST be encodable as 7-bit ASCII and match the
469regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.
470</td>
471</tr>
472<tr>
473<td>SERIAL</td>
474<td>A hardware serial number, which MUST be available. The value of this field MUST be encodable
475as 7-bit ASCII and match the regular expression
476<code>"^([a-zA-Z0-9]{6,20})$"</code>.</td>
477</tr>
478<tr>
479<td>TAGS</td>
480<td>A comma-separated list of tags chosen by the device implementer that
481further distinguishes the build. For example, "unsigned,debug". The value of
482this field MUST be encodable as 7-bit ASCII and match the regular expression
483<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
484</tr>
485<tr>
486<td>TIME</td>
487<td>A value representing the timestamp of when the build occurred.</td>
488</tr>
489<tr>
490<td>TYPE</td>
491<td>A value chosen by the device implementer specifying the runtime
492configuration of the build. This field SHOULD have one of the values
493corresponding to the three typical Android runtime configurations: "user",
494"userdebug", or "eng". The value of this field MUST be
495encodable as 7-bit ASCII and match the regular expression
496<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td>
497</tr>
498<tr>
499<td>USER</td>
500<td>A name or user ID of the user (or automated user) that generated the
501build. There are no requirements on the specific format of this field, except
502that it MUST NOT be null or the empty string ("").</td>
503</tr>
504</tbody>
505</table>
506<a name="section-3.2.3"></a><h4 id="section-3.2.3">3.2.3. Intent Compatibility</h4>
507<p>
508Device implementations MUST honor Android's loose-coupling Intent system, as
509described in the sections below. By "honored", it is meant that the device
510implementer MUST provide an Android Activity or Service that specifies a
511matching Intent filter and binds to and implements correct behavior for each
512specified Intent pattern.</p>
513<a name="section-3.2.3.1"></a><h4 id="section-3.2.3.1">3.2.3.1. Core Application Intents</h4>
514<p>The Android upstream project defines a number of core applications, such as
515contacts, calendar, photo gallery, music player, and so on. Device implementers
516MAY replace these applications with alternative versions.</p>
517<p>However, any such alternative versions MUST honor the same Intent patterns
518provided by the upstream project. For example, if a device contains an
519alternative music player, it must still honor the Intent pattern issued by
520third-party applications to pick a song.</p>
521<p>The following applications are considered core Android system
522applications:</p>
523<ul>
524<li>Desk Clock</li>
525<li>Browser</li>
526<li>Calendar</li>
527<li>Contacts</li>
528<!--<li>Email</li>-->
529<li>Gallery</li>
530<li>GlobalSearch</li>
531<li>Launcher</li>
532<!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted
533if the device does not support Live Wallpapers, per Section 3.8.5.)</li> -->
534<!-- <li>Messaging (AKA "Mms")</li> -->
535<li>Music</li>
536<!-- <li>Phone</li> -->
537<li>Settings</li>
538<!-- <li>SoundRecorder</li> -->
539</ul>
540<p>The core Android system applications include various Activity, or Service
541components that are considered "public". That is, the attribute
542"android:exported" may be absent, or may have the value "true".</p>
543<p>For every Activity or Service defined
544in one of the core Android system apps that is not marked as non-public via an
545android:exported attribute with the value "false", device implementations MUST
546include a component of the same type implementing the same Intent filter
547patterns as the core Android system app.</p>
548<p>In other words, a device implementation MAY replace core Android system
549apps; however, if it does, the device implementation MUST support all Intent
550patterns defined by each core Android system app being replaced.</p>
551<a name="section-3.2.3.2"></a><h4 id="section-3.2.3.2">3.2.3.2. Intent Overrides</h4>
552<p>As Android is an extensible platform, device implementations MUST allow each
553Intent pattern referenced in Section 3.2.3.1 to be overridden by third-party
554applications. The upstream Android open source implementation allows this by
555default; device implementers MUST NOT attach special privileges to system
556applications' use of these Intent patterns, or prevent third-party
557applications from binding to and assuming control of these patterns. This
558prohibition specifically includes but is not limited to disabling the
559"Chooser" user interface that allows the user to select between multiple
560applications which all handle the same Intent pattern.</p>
561<p>However, device implementations MAY provide default activities for specific
562URI patterns (eg. http://play.google.com) if the default activity provides a
563more specific filter for the data URI. For example, an intent filter specifying
564the data URI "http://www.android.com" is more specific than the browser filter
565for "http://". Device implementations MUST provide a user interface for users
566to modify the default activity for intents.</p>
567
568<a name="section-3.2.3.3"></a><h4 id="section-3.2.3.3">3.2.3.3. Intent Namespaces</h4>
569<p>Device implementations MUST NOT include any Android component that honors any
570new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other
571key string in the android.* or com.android.* namespace. Device implementers
572MUST NOT include any Android components that honor any new Intent or Broadcast
573Intent patterns using an ACTION, CATEGORY, or other key string in a package
574space belonging to another organization. Device implementers MUST NOT alter or
575extend any of the Intent patterns used by the core apps listed in Section
5763.2.3.1. Device implementations MAY include Intent patterns using
577namespaces clearly and obviously associated with their own organization.</p>
578<p>This prohibition is analogous to that specified for Java language classes
579in Section 3.6.</p>
580
581<a name="section-3.2.3.4"></a><h4 id="section-3.2.3.4">3.2.3.4. Broadcast Intents</h4>
582<p>Third-party applications rely on the platform to broadcast certain Intents
583to notify them of changes in the hardware or software environment.
584Android-compatible devices MUST broadcast the public broadcast Intents in
585response to appropriate system events. Broadcast Intents are described in the
586SDK documentation.</p>
587
588<a name="section-3.2.3.5"></a><h4 id="section-3.2.3.5">3.2.3.5. Default App Settings</h4>
589<p>Android 4.4 adds settings that allow users to select their default Home and
590SMS applications. Device implementations MUST provide a similar user settings
591menu for each, compatible with the Intent filter pattern and API methods
592described in the SDK documentation [<a href="#resources91">Resources, 91</a>].
593</p>
594
595<a name="section-3.3"></a><h3 id="section-3.3">3.3. Native API Compatibility</h3>
596<a name="section-3.3.1"></a><h4 id="section-3.3.1">3.3.1 Application Binary Interfaces</h4>
597<p>Managed code running in Dalvik can call into native code provided in the
598application .apk file as an ELF .so file compiled for the appropriate device
599hardware architecture. As native code is highly dependent on the underlying
600processor technology, Android defines a number of Application Binary
601Interfaces (ABIs) in the Android NDK, in the file
602<code>docs/CPU-ARCH-ABIS.html</code>. If a device implementation is compatible
603with one or more defined ABIs, it SHOULD implement compatibility with the
604Android NDK, as below.</p>
605<p>If a device implementation includes support for an Android ABI, it:</p>
606<ul>
607<li>MUST include support for code running in the managed environment to call
608into native code, using the standard Java Native Interface (JNI)
609semantics</li>
610<li>MUST be source-compatible (i.e. header compatible) and binary-compatible
611(for the ABI) with each required library in the list below</li>
612<li>MUST accurately report the native Application Binary Interface (ABI)
613supported by the device, via the <code>android.os.Build.CPU_ABI</code>
614API and <code>android.os.Build.CPU_ABI2</code> parameters.</li>
615<li>MUST report, via <code>android.os.Build.CPU_ABI2</code>, only those ABIs
616documented in the latest version of the Android NDK, in the file
617<code>docs/CPU-ARCH-ABIS.html</code></li>
618<li>MUST report, via <code>android.os.Build.CPU_ABI</code>, only one of the
619ABIs listed below</li>
620 <ul>
621 <li>armeabi-v7a</li>
622 <li>x86</li>
623 <li>mips</li>
624 </ul>
625<li>SHOULD be built using the source code and header files available in the
626upstream Android Open Source Project</li>
627</ul>
628<p>The following native code APIs MUST be available to apps that include
629native code:</p>
630<ul>
631<li>libc (C library)</li>
632<li>libm (math library)</li>
633<li>Minimal support for C++</li>
634<li>JNI interface</li>
635<li>liblog (Android logging)</li>
636<li>libz (Zlib compression)</li>
637<li>libdl (dynamic linker)</li>
638<li>libGLESv1_CM.so (OpenGL ES 1.0)</li>
639<li>libGLESv2.so (OpenGL ES 2.0)</li>
640<li>libGLESv3.so (OpenGL ES 3.0)</li>
641<li>libEGL.so (native OpenGL surface management)</li>
642<li>libjnigraphics.so</li>
643<li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li>
644<li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li>
645<li>libandroid.so (native Android activity support)</li>
646<li>Support for OpenGL, as described below</li>
647</ul>
648<p>Note that future releases of the Android NDK may introduce support for
649additional ABIs. If a device implementation is not compatible with an existing
650predefined ABI, it MUST NOT report support for any ABI at all.</p>
651<p>Note that device implementations MUST include libGLESv3.so and it MUST symlink (symbolic)
652link to libGLESv2.so. On device implementations that declare support for OpenGL ES 3.0, libGLESv2.so
653MUST export the OpenGL ES 3.0 function symbols in addition to the OpenGL ES 2.0 function symbols.</p>
654<p>Native code compatibility is challenging. For this reason, it should be
655repeated that device implementers are VERY strongly encouraged to use the
656upstream implementations of the libraries listed above to help ensure
657compatibility.</p>
658
659<a name="section-3.4"></a><h3 id="section-3.4">3.4. Web Compatibility</h3>
660<a name="section-3.4.1"></a><h4 id="section-3.4.1">3.4.1. WebView Compatibility</h4>
661<p>The Android Open Source implementation uses code from the Chromium
662Project to implement the <code>android.webkit.WebView</code> [<a href="#resources10">Resources, 10</a>] . Because it is not feasible
663to develop a comprehensive test suite for a web rendering system, device
664implementers MUST use the specific upstream build of Chromium in the WebView
665implementation. Specifically:</p>
666<ul>
667<li>Device <code>android.webkit.WebView</code> implementations MUST be based
668on the Chromium build from the upstream Android Open Source Project for Android 4.4.
669This build includes a specific set of functionality and security fixes for the
670WebView. [<a href="#resources83">Resources, 83</a>]</li>
671<li>The user agent string reported by the WebView MUST be in this format:<br/>
672 <code>Mozilla/5.0 (Linux; Android $(VERSION); $(LOCALE); $(MODEL)
673Build/$(BUILD)) AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0
674$(CHROMIUM_VER) Mobile Safari/537.36</code>
675 <ul>
676 <li>The value of the $(VERSION) string MUST be the same as the value for
677<code>android.os.Build.VERSION.RELEASE</code>.</li>
678 <li>The value of the $(LOCALE) string is optional, SHOULD follow the ISO
679conventions for country code and language, and SHOULD refer to the current
680configured locale of the device. If omitted, the trailing semicolon MUST
681also be removed.</li>
682 <li>The value of the $(MODEL) string MUST be the same as the value for
683<code>android.os.Build.MODEL</code>.</li>
684 <li>The value of the $(BUILD) string MUST be the same as the value for
685<code>android.os.Build.ID</code>.</li>
686 <li>The value of the $(CHROMIUM_VER) string MUST be the version of Chromium in
687the upstream Android Open Source Project.</li>
688 <li>Device implementations MAY omit <code>Mobile</code> in the user agent
689string.</li>
690 </ul>
691</li>
692</ul>
693<p>The WebView component SHOULD include support for as much of HTML5 [<a
694href="#resources11">Resources, 11</a>] as possible.</p>
695<a name="section-3.4.2"></a><h4 id="section-3.4.2">3.4.2. Browser Compatibility</h4>
696<p>Device implementations MUST include a standalone Browser application for
697general user web browsing. The standalone Browser MAY be based on a
698browser technology other than WebKit. However, even if an alternate Browser
699application is used, the <code>android.webkit.WebView</code> component
700provided to third-party applications MUST be based on WebKit, as described in
701Section 3.4.1.</p>
702<p>Implementations MAY ship a custom user agent string in the standalone
703Browser application.</p>
704<p>The standalone Browser application (whether based on the upstream
705WebKit Browser application or a third-party replacement) SHOULD include support
706for as much of HTML5 [<a href="#resources11">Resources, 11</a>] as possible.
707Minimally, device implementations MUST support each of these APIs associated
708with HTML5:</p>
709<ul>
710<li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li>
711<li>the &lt;video&gt; tag [<a href="#resources13">Resources, 13</a>]</li>
712<li>geolocation [<a href="#resources14">Resources, 14</a>]</li>
713</ul>
714<p>Additionally, device implementations MUST support the HTML5/W3C webstorage
715API [<a href="#resources15">Resources, 15</a>], and SHOULD support the
716HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note
717that as the web development standards bodies are transitioning to favor
718IndexedDB over webstorage, IndexedDB is expected to become a required
719component in a future version of Android.</i></p>
720
721<a name="section-3.5"></a><h3 id="section-3.5">3.5. API Behavioral Compatibility</h3>
722<p>The behaviors of each of the API types (managed, soft, native, and web)
723must be consistent with the preferred implementation of the upstream Android
724Open Source Project [<a href="#resources03">Resources, 3</a>]. Some specific areas
725of compatibility are:</p>
726<ul>
727<li>Devices MUST NOT change the behavior or semantics of a standard Intent</li>
728<li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a
729 particular type of system component (such as Service, Activity,
730 ContentProvider, etc.)</li>
731<li>Devices MUST NOT change the semantics of a standard permission</li>
732</ul>
733<p>The above list is not comprehensive. The Compatibility Test Suite (CTS)
734tests significant portions of the platform for behavioral compatibility, but
735not all. It is the responsibility of the implementer to ensure behavioral
736compatibility with the Android Open Source Project. For this reason, device
737implementers SHOULD use the source code available via the Android Open Source
738Project where possible, rather than re-implement significant parts of the
739system.</p>
740
741
742<a name="section-3.6"></a><h3 id="section-3.6">3.6. API Namespaces</h3>
743<p>Android follows the package and class namespace conventions defined by the
744Java programming language. To ensure compatibility with third-party
745applications, device implementers MUST NOT make any prohibited modifications
746(see below) to these package namespaces:</p>
747<ul>
748<li>java.*</li>
749<li>javax.*</li>
750<li>sun.*</li>
751<li>android.*</li>
752<li>com.android.*</li>
753</ul>
754<p>Prohibited modifications include:</p>
755<ul>
756<li>Device implementations MUST NOT modify the publicly exposed APIs on the
757Android platform by changing any method or class signatures, or by removing
758classes or class fields.</li>
759<li>Device implementers MAY modify the underlying implementation of the APIs,
760but such modifications MUST NOT impact the stated behavior and Java-language
761signature of any publicly exposed APIs.</li>
762<li>Device implementers MUST NOT add any publicly exposed elements (such as
763classes or interfaces, or fields or methods to existing classes or interfaces)
764to the APIs above.</li>
765</ul>
766<p>A "publicly exposed element" is any construct which is not decorated with
767the "@hide" marker as used in the upstream Android source code. In other
768words, device implementers MUST NOT expose new APIs or alter existing APIs in
769the namespaces noted above. Device implementers MAY make internal-only
770modifications, but those modifications MUST NOT be advertised or otherwise
771exposed to developers.</p>
772<p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
773namespace owned by or referring to another organization. For instance, device
774implementers MUST NOT add APIs to the com.google.* or similar namespace; only
775Google may do so. Similarly, Google MUST NOT add APIs to other companies'
776namespaces. Additionally, if a device implementation includes custom APIs
777outside the standard Android namespace, those APIs MUST be packaged in an
778Android shared library so that only apps that explicitly use them (via the
779<code>&lt;uses-library&gt;</code> mechanism) are affected by the increased
780memory usage of such APIs.</p>
781<p>If a device implementer proposes to improve one of the package namespaces
782above (such as by adding useful new functionality to an existing API, or
783adding a new API), the implementer SHOULD visit source.android.com and begin
784the process for contributing changes and code, according to the information on
785that site.</p>
786<p>Note that the restrictions above correspond to standard conventions for
787naming APIs in the Java programming language; this section simply aims to
788reinforce those conventions and make them binding through inclusion in this
789compatibility definition.</p>
790
791<a name="section-3.7"></a><h3 id="section-3.7">3.7. Virtual Machine Compatibility</h3>
792<p>Device implementations MUST support the full Dalvik Executable (DEX)
793bytecode specification and Dalvik Virtual Machine semantics [<a
794href="#resources17">Resources, 17</a>].</p>
795<p>Device implementations MUST configure Dalvik to allocate memory in
796accordance with the upstream Android platform, and as specified by the following
797table. (See <a href="#section-7.1.1">Section 7.1.1</a> for screen size and screen
798density definitions.)</p>
799
800<p>Note that memory values specified below are considered minimum values,
801and device implementations MAY allocate more memory per application.</p>
802<table>
803<tbody>
804<tr>
805<td><b>Screen Size</b></td>
806<td><b>Screen Density</b></td>
807<td><b>Application Memory</b></td>
808</tr>
809<tr>
810<td>small / normal / large</td>
811<td>ldpi / mdpi</td>
812<td>16MB</td>
813</tr>
814<tr>
815<td>small / normal / large</td>
816<td>tvdpi / hdpi</td>
817<td>32MB</td>
818</tr>
819<tr>
820<td>small / normal / large</td>
821<td>xhdpi</td>
822<td>64MB</td>
823</tr>
824<tr>
825<td>small / normal / large</td>
826<td>400dpi</td>
827<td>96MB</td>
828</tr>
829<tr>
830<td>small / normal / large</td>
831<td>xxhdpi</td>
832<td>128MB</td>
833</tr>
834<tr>
835<td>small / normal / large</td>
836<td>xxxhdpi</td>
837<td>256MB</td>
838</tr>
839<tr>
840<td>xlarge</td>
841<td>mdpi</td>
842<td>32MB</td>
843</tr>
844<tr>
845<td>xlarge</td>
846<td>tvdpi / hdpi</td>
847<td>64MB</td>
848</tr>
849<tr>
850<td>xlarge</td>
851<td>xhdpi</td>
852<td>128MB</td>
853</tr>
854<tr>
855<td>xlarge</td>
856<td>400dpi</td>
857<td>192MB</td>
858</tr>
859<tr>
860<td>xlarge</td>
861<td>xxhdpi</td>
862<td>256MB</td>
863</tr>
864<tr>
865<td>xlarge</td>
866<td>xxxhdpi</td>
867<td>512MB</td>
868</tr>
869</tbody>
870</table>
871
872<a name="section-3.8"></a><h3 id="section-3.8">3.8. User Interface Compatibility</h3>
873
874<a name="section-3.8.1"></a><h4 id="section-3.8.1">3.8.1. Launcher (Home Screen)</h4>
875<p>Android includes a launcher application (home screen) and support for third party applications to replace the device
876launcher (home screen). Device implementations that allow third party applications to replace the device home screen
877MUST declare the platform feature <code>android.software.home_screen</code>.</p>
878
879<a name="section-3.8.2"></a><h4 id="section-3.8.2">3.8.2. Widgets</h4>
880<p>Android defines a component type and corresponding API and lifecycle that allows applications to expose an "AppWidget"
881to the end user [<a href="#resources18">Resources, 18</a>]. Device implementations that support embedding widgets on the
882home screen MUST meet the following requirements and declare support for platform feature <code>android.software.app_widgets</code>.</p>
883<ul>
884 <li>Device launchers MUST include built-in support for AppWidgets, and expose user
885 interface affordances to add, configure, view, and remove AppWidgets directly within the Launcher.</li>
886 <li>Device implementations MUST be capable of rendering widgets that are 4 x 4 in the standard grid size.
887 (See the App Widget Design Guidelines in the Android SDK documentation [<a href="#resources18">Resources, 18</a>] for details.</li>
888 <li>Device implementations that include support for lock screen MUST support application widgets on the lock screen.</li>
889</ul>
890
891<a name="section-3.8.3"></a><h4 id="section-3.8.3">3.8.3. Notifications</h4>
892<p>Android includes APIs that allow developers to notify users of notable
893events [<a href="#resources19">Resources, 19</a>], using hardware and software
894features of the device.</p>
895<p>Some APIs allow applications to perform notifications or attract attention
896using hardware, specifically sound, vibration, and light. Device implementations
897MUST support notifications that use hardware features, as described in the SDK
898documentation, and to the extent possible with the device implementation
899hardware. For instance, if a device implementation includes a vibrator, it
900MUST correctly implement the vibration APIs. If a device implementation lacks
901hardware, the corresponding APIs MUST be implemented as no-ops. Note that this
902behavior is further detailed in <a href="#section-7">Section 7.</a></p>
903<p>Additionally, the implementation MUST correctly render all resources
904(icons, sound files, etc.) provided for in the APIs [<a
905href="#resources20">Resources, 20</a>], or in the
906Status/System Bar icon style guide [<a href="#resources21">Resources, 21</a>].
907Device implementers MAY provide an alternative user experience for
908notifications than that provided by the reference Android Open Source
909implementation; however, such alternative notification systems MUST support
910existing notification resources, as above.</p>
911<p>Android includes support for rich notifications, such as interactive
912Views for ongoing notifications. Device implementations MUST properly display
913and execute rich notifications, as documented in the Android APIs.</p>
914<a name="section-3.8.4"></a><h4 id="section-3.8.4">3.8.4. Search</h4>
915<p>Android includes APIs [<a href="#resources22">Resources, 22</a>] that allow
916developers to incorporate search into their applications, and expose their
917application's data into the global system search. Generally speaking, this
918functionality consists of a single, system-wide user interface that allows users
919to enter queries, displays suggestions as users type, and displays results. The
920Android APIs allow developers to reuse this interface to provide search within
921their own apps, and allow developers to supply results to the common global
922search user interface.</p>
923<p>Device implementations MUST include a single, shared, system-wide search
924user interface capable of real-time suggestions in response to user input.
925Device implementations MUST implement the APIs that allow developers to reuse
926this user interface to provide search within their own applications. Device
927implementations MUST implement the APIs that allow third-party applications to
928add suggestions to the search box when it is run in global search mode. If no
929third-party applications are installed that make use of this functionality,
930the default behavior SHOULD be to display web search engine results and
931suggestions.</p>
932<a name="section-3.8.5"></a><h4 id="section-3.8.5">3.8.5. Toasts</h4>
933<p>Applications can use the "Toast" API (defined in [<a
934href="#resources23">Resources, 23</a>]) to
935display short non-modal strings to the end user, that disappear after a brief
936period of time. Device implementations MUST display Toasts from applications
937to end users in some high-visibility manner.</p>
938
939<a name="section-3.8.6"></a><h4 id="section-3.8.6">3.8.6. Themes</h4>
940<p>Android provides "themes" as a mechanism for applications to apply styles
941across an entire Activity or application.</p>
942<p>Android includes a "Holo" theme family as a set of defined styles for
943application developers to use if they want to match the Holo theme look and
944feel as defined by the Android SDK [<a href="#resources24">Resources, 24</a>].
945Device implementations MUST NOT alter any of the Holo theme attributes exposed
946to applications [<a href="#resources25">Resources, 25</a>].</p>
947<p>Android also includes a "Device Default" theme family as a set of defined
948styles for application developers to use if they want to match the look and feel
949of the device theme as defined by the device implementer. Device implementations
950MAY modify the DeviceDefault theme attributes exposed to applications
951[<a href="#resources25">Resources, 25</a>].</p>
952<p>From version 4.4, Android now supports a new variant theme with translucent system bars,
953allowing application developers to fill the area behind the status and
954navigation bar with their app content. To enable a consistent developer
955experience in this configuration, it is important the status bar icon style
956is maintained across different device implementations. Therefore, Android
957device implementations MUST use white for system status icons (such as signal
958strength and battery level) and notifications issued by the system, unless the
959icon is indicating a problematic status
960[<a href="#resources25">Resources, 25</a>].</p>
961
962<a name="section-3.8.7"></a><h4 id="section-3.8.7">3.8.7. Live Wallpapers</h4>
963<p>Android defines a component type and corresponding API and lifecycle that
964allows applications to expose one or more "Live Wallpapers" to the end user
965[<a href="#resources26">Resources, 26</a>]. Live Wallpapers are animations,
966patterns, or similar images with limited input capabilities that display as a
967wallpaper, behind other applications.</p>
968<p>Hardware is considered capable of reliably running live wallpapers if it
969can run all live wallpapers, with no limitations on functionality, at a
970reasonable framerate with no adverse affects on other applications. If
971limitations in the hardware cause wallpapers and/or applications to crash,
972malfunction, consume excessive CPU or battery power, or run at unacceptably
973low frame rates, the hardware is considered incapable of running live
974wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0
975context to render their content. Live wallpaper will not run reliably on
976hardware that does not support multiple OpenGL contexts because the live
977wallpaper use of an OpenGL context may conflict with other applications that
978also use an OpenGL context.</p>
979<p>Device implementations capable of running live wallpapers reliably as
980described above SHOULD implement live wallpapers. Device implementations
981determined to not run live wallpapers reliably as described above MUST NOT
982implement live wallpapers.</p>
983<a name="section-3.8.8"></a><h4 id="section-3.8.8">3.8.8. Recent Application Display</h4>
984<p>The upstream Android source code includes a user interface for
985displaying recent applications using a thumbnail image of the application's
986graphical state at the moment the user last left the application. Device
987implementations MAY alter or eliminate this user interface; however, a future
988version of Android is planned to make more extensive use of this
989functionality. Device implementations are strongly encouraged to use the
990upstream Android user interface (or a similar thumbnail-based interface)
991for recent applications, or else they may not be compatible with a future
992version of Android.</p>
993<a name="section-3.8.9"></a><h4 id="section-3.8.9">3.8.9. Input Management</h4>
994<p>Android includes support for Input Management and support for third party input method editors.
995Device implementations that allow users to use third party input methods on the device MUST declare the platform feature
996<code>android.software.input_methods</code> and support IME APIs as defined in the Android SDK documentation.</p>
997<p>Device implementations that declare the <code>android.software.input_methods</code> feature MUST provide a user-accessible mechanism
998to add and configure third party input methods. Device implementations MUST display the settings interface in response to the
999<code>android.settings.INPUT_METHOD_SETTINGS</code> intent.</p>
1000
1001<a name="section-3.8.10"></a><h4 id="section-3.8.10">3.8.10. Lock Screen Media Remote Control</h4>
1002<p>Android includes support for Remote Control API that lets media applications integrate with playback controls
1003that are displayed in a remote view like the device lock screen [<a href="#resources74">Resources, 74</a>]. Device implementations
1004that support lock screen in the device and allow users to add widgets on the home screen MUST
1005include support for embedding remote controls in the device lock screen [<a href="#resources69">Resources, 69</a>].</p>
1006
1007<a name="section-3.8.11"></a><h4 id="section-3.8.11">3.8.11. Dreams</h4>
1008<p>Android includes support for interactive screensavers called Dreams [<a href="#resources76">Resources, 76</a>].
1009Dreams allows users to interact with applications when a charging device is idle, or docked in a desk dock. Device implementations
1010MUST include support for Dreams and provide a settings option for users to configure Dreams.</p>
1011
1012<a name="section-3.8.12"></a><h4 id="section-3.8.12">3.8.12. Location</h4>
1013<p>Location modes MUST be displayed in the Location menu within Settings [<a
1014href="#resources87">Resources, 87</a>]. Location services provided through the
1015<code>SettingInjectorService</code> introduced in Android 4.4 must be displayed
1016in the same Location menu [<a href="#resources89">Resources, 89</a>].</p>
1017
1018<a name="section-3.8.13"></a><h4 id="section-3.8.13">3.8.13. Unicode</h4>
1019<p>Android 4.4 includes support for color emoji characters. Android device
1020implementations MUST provide an input method to the user for the Emoji
1021characters defined in Unicode 6.1 [<a href="#resources82">Resources, 82</a>]
1022and MUST be capable of rendering these emoji characters in color glyph.</p>
1023
1024<a name="section-3.9"></a><h3 id="section-3.9">3.9. Device Administration</h3>
1025<p>Android includes features that allow security-aware applications
1026to perform device administration functions at the system level, such as enforcing
1027password policies or performing remote wipe, through the Android Device
1028Administration API [<a href="#resources27">Resources, 27</a>]. Device
1029implementations MUST provide an implementation of the <code>DevicePolicyManager</code>
1030class [<a href="#resources28">Resources, 28</a>]. Device implementations that include support for lock screen
1031MUST support the full range of device administration policies defined in the Android SDK
1032documentation [<a href="#resources27">Resources, 27</a>].</p>
1033<p>Device implementations MAY have a preinstalled application performing device
1034administration functions but this application MUST NOT be set out-of-the box
1035as the default Device Owner app [<a href="#resources84">Resources, 84</a>].</p>
1036
1037<a name="section-3.10"></a><h3 id="section-3.10">3.10. Accessibility</h3>
1038<p>Android provides an accessibility layer that helps users with disabilities
1039to navigate their devices more easily. In addition, Android provides
1040platform APIs that enable accessibility service implementations to receive
1041callbacks for user and system events and generate alternate feedback mechanisms,
1042such as text-to-speech, haptic feedback, and trackball/d-pad navigation
1043[<a href="#resources29">Resources, 29</a>]. Device implementations MUST provide an
1044implementation of the Android accessibility framework consistent with the
1045default Android implementation. Specifically, device implementations MUST meet
1046the following requirements.</p>
1047<ul>
1048 <li>Device implementations MUST support third party accessibility service
1049 implementations through the <code>android.accessibilityservice</code>
1050 APIs [<a href="#resources30">Resources, 30</a>].</li>
1051 <li>Device implementations MUST generate <code>AccessibilityEvents</code>
1052 and deliver these events to all registered <code>AccessibilityService
1053 </code> implementations in a manner consistent with the default Android
1054 implementation.</li>
1055 <li>Device implementations MUST provide a user-accessible mechanism to enable
1056 and disable accessibility services, and MUST display this interface in
1057 response to the
1058 <code>android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS</code>
1059 intent.</li>
1060</ul>
1061<p>Additionally, device implementations SHOULD provide an implementation
1062of an accessibility service on the device, and SHOULD provide a mechanism
1063for users to enable the accessibility service during device setup. An open
1064source implementation of an accessibility service is available from the Eyes
1065Free project [<a href="#resources31">Resources, 31</a>].</p>
1066
1067<a name="section-3.11"></a><h3 id="section-3.11">3.11. Text-to-Speech</h3>
1068<p>Android includes APIs that allow applications to make use of
1069text-to-speech (TTS) services, and allows service providers to provide
1070implementations of TTS services [<a href="#resources32">Resources, 32</a>].
1071Device implementations MUST meet these requirements related to the Android TTS
1072framework:</p>
1073<ul>
1074 <li>Device implementations MUST support the Android TTS framework APIs and
1075 SHOULD include a TTS engine supporting the languages available on the
1076 device. Note that the upstream Android open source software includes a
1077 full-featured TTS engine implementation.</li>
1078 <li>Device implementations MUST support installation of third-party TTS
1079 engines.</li>
1080 <li>Device implementations MUST provide a user-accessible interface that allows
1081 users to select a TTS engine for use at the system level.</li>
1082</ul>
1083
1084<a name="section-4"></a><h2 id="section-4">4. Application Packaging Compatibility</h2>
1085<p>Device implementations MUST install and run Android ".apk" files as
1086generated by the "aapt" tool included in the official Android SDK [<a
1087href="#resources33">Resources, 33</a>].</p>
1088<p>Devices implementations MUST NOT extend either the .apk [<a
1089href="#resources34">Resources, 34</a>], Android Manifest [<a
1090href="#resources35">Resources, 35</a>],
1091Dalvik bytecode [<a href="#resources17">Resources, 17</a>], or renderscript
1092bytecode formats in such a way that would prevent those files from installing
1093and running correctly on other compatible devices. Device implementers SHOULD
1094use the reference upstream implementation of Dalvik, and the reference
1095implementation's package management system.</p>
1096
1097<a name="section-5"></a><h2 id="section-5">5. Multimedia Compatibility</h2>
1098<p>Device implementations MUST include at least one form of audio output, such as
1099speakers, headphone jack, external speaker connection, etc.</p>
1100<a name="section-5.1"></a><h3 id="section-5.1">5.1. Media Codecs</h3>
1101<p>Device implementations MUST support the core media formats specified
1102in the Android SDK documentation [<a href="#resources58">Resources, 58</a>] except
1103where explicitly permitted in this document. Specifically, device implementations
1104MUST support the media formats, encoders, decoders, file types and container
1105formats defined in the tables below. All of these codecs are provided as
1106software implementations in the preferred Android implementation from the Android
1107Open Source Project.</p>
1108
1109<p><strong>Please note that neither Google nor the Open Handset Alliance make any
1110representation that these codecs are unencumbered by third-party patents.
1111Those intending to use this source code in hardware or software products are
1112advised that implementations of this code, including in open source software
1113or shareware, may require patent licenses from the relevant patent
1114holders.</strong></p>
1115
1116<p>Note that these tables do not list specific bitrate requirements for
1117most video codecs because current device hardware does not necessarily support
1118bitrates that map exactly to the required bitrates specified by the relevant
1119standards. Instead, device implementations SHOULD support the highest bitrate
1120practical on the hardware, up to the limits defined by the specifications.</p>
1121<div style="page-break-before: always;"></div>
1122<table>
1123<tbody>
1124
1125<tr>
1126<th>Type</th>
1127<th>Format / Codec</th>
1128<th>Encoder</th>
1129<th>Decoder</th>
1130<th>Details</th>
1131<th>File Type(s) / Container Formats</th>
1132</tr>
1133
1134<tr>
1135<td rowspan="11">Audio</td>
1136<td>MPEG-4 AAC Profile (AAC LC)</td>
1137<td>REQUIRED for device implementations that include microphone hardware
1138and define <code>android.hardware.microphone</code>.</td>
1139<td style="text-align: center;">REQUIRED</td>
1140<td rowspan="1"> Support for mono/stereo/5.0/5.1* content with standard sampling rates from 8 to 48 kHz.</td>
1141<td rowspan="4">
1142 <ul>
1143 <li>3GPP (.3gp)</li>
1144 <li>MPEG-4 (.mp4, .m4a)</li>
1145 <li>ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)</li>
1146 <li>MPEG-TS (.ts, not seekable, Android 3.0+)</li>
1147 </ul>
1148</td>
1149</tr>
1150
1151<tr>
1152<td>MPEG-4 HE AAC Profile (AAC+)</td>
1153<td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>
1154<td style="text-align: center;">REQUIRED</td>
1155<td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>
1156</tr>
1157
1158<tr>
1159<td>MPEG-4 HE AAC v2 Profile (enhanced AAC+)</td>
1160<td>&nbsp;</td>
1161<td style="text-align: center;">REQUIRED</td>
1162<td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td>
1163</tr>
1164
1165<tr>
1166<td>MPEG-4 Audio Object Type ER AAC ELD (Enhanced Low Delay AAC)</td>
1167<td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td>
1168<td style="text-align: center;">REQUIRED</td>
1169<td>Support for mono/stereo content with standard
1170sampling rates from 16 to 48 kHz.</td>
1171</tr>
1172
1173<tr>
1174<td>AMR-NB</td>
1175<td>REQUIRED for device implementations that include microphone hardware
1176and define <code>android.hardware.microphone</code>.</td>
1177<td style="text-align: center;">REQUIRED</td>
1178<td>4.75 to 12.2 kbps sampled @ 8kHz</td>
1179<td>3GPP (.3gp)
1180</td>
1181</tr>
1182
1183<tr>
1184<td>AMR-WB</td>
1185<td>REQUIRED for device implementations that include microphone hardware
1186and define <code>android.hardware.microphone</code>.</td>
1187<td style="text-align: center;">REQUIRED</td>
1188<td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>
1189<td>3GPP (.3gp)</td>
1190</tr>
1191
1192<tr>
1193<td>FLAC</td>
1194<td>&nbsp;</td>
1195<td style="text-align: center;">REQUIRED<br/><small>(Android 3.1+)</small></td>
1196<td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1
1197kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz
1198downsampler does not include a low-pass filter). 16-bit recommended;
1199no dither applied for 24-bit.
1200</td>
1201<td>FLAC (.flac) only</td>
1202</tr>
1203
1204<tr>
1205<td>MP3</td>
1206<td>&nbsp;</td>
1207<td style="text-align: center;">REQUIRED</td>
1208<td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)
1209</td>
1210<td>MP3 (.mp3)</td>
1211</tr>
1212
1213<tr>
1214<td>MIDI</td>
1215<td>&nbsp;</td>
1216<td style="text-align: center;">REQUIRED</td>
1217<td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody </td>
1218<td>
1219 <ul>
1220 <li>Type 0 and 1 (.mid, .xmf, .mxmf)</li>
1221 <li>RTTTL/RTX (.rtttl, .rtx)</li>
1222 <li>OTA (.ota)</li>
1223 <li>iMelody (.imy)</li>
1224 </ul>
1225</td>
1226</tr>
1227
1228<tr>
1229<td>Vorbis</td>
1230<td>&nbsp;</td>
1231<td style="text-align: center;">REQUIRED</td>
1232<td>&nbsp;</td>
1233<td>
1234 <ul>
1235 <li>Ogg (.ogg)</li>
1236 <li>Matroska (.mkv)</li>
1237 </ul>
1238</td>
1239</tr>
1240
1241<tr>
1242<td>PCM/WAVE</td>
1243<td style="text-align: center;">REQUIRED</td>
1244<td style="text-align: center;">REQUIRED</td>
1245<td>8-bit and 16-bit linear PCM** (rates up to limit of hardware).Devices MUST support sampling rates
1246for raw PCM recording at 8000,16000 and 44100 Hz frequencies</td>
1247<td>WAVE (.wav)</td>
1248</tr>
1249
1250<tr>
1251<td rowspan="5">Image</td>
1252<td>JPEG</td>
1253<td style="text-align: center;">REQUIRED</td>
1254<td style="text-align: center;">REQUIRED</td>
1255<td>Base+progressive</td>
1256<td>JPEG (.jpg)</td>
1257</tr>
1258
1259<tr>
1260<td>GIF</td>
1261<td>&nbsp;</td>
1262<td style="text-align: center;">REQUIRED</td>
1263<td>&nbsp;</td>
1264<td>GIF (.gif)</td>
1265</tr>
1266
1267<tr>
1268<td>PNG</td>
1269<td style="text-align: center;">REQUIRED</td>
1270<td style="text-align: center;">REQUIRED</td>
1271<td>&nbsp;</td>
1272<td>PNG (.png)</td>
1273</tr>
1274
1275<tr>
1276<td>BMP</td>
1277<td>&nbsp;</td>
1278<td style="text-align: center;">REQUIRED</td>
1279<td>&nbsp;</td>
1280<td>BMP (.bmp)</td>
1281</tr>
1282
1283
1284<tr>
1285<td>WEBP</td>
1286<td style="text-align: center;">REQUIRED</td>
1287<td style="text-align: center;">REQUIRED</td>
1288<td>&nbsp;</td>
1289<td>WebP (.webp)</td>
1290</tr>
1291
1292<tr>
1293<td rowspan="5">Video</td>
1294<td>H.263</td>
1295<td>REQUIRED for device implementations that include camera hardware
1296and define <code>android.hardware.camera</code> or
1297<code>android.hardware.camera.front</code>.</td>
1298<td style="text-align: center;">REQUIRED</td>
1299<td>&nbsp;</td>
1300<td>
1301 <ul>
1302 <li>3GPP (.3gp)</li>
1303 <li>MPEG-4 (.mp4)</li>
1304 </ul>
1305</td>
1306</tr>
1307
1308<tr>
1309<td>H.264 AVC</td>
1310<td>REQUIRED for device implementations that include camera hardware
1311and define <code>android.hardware.camera</code> or
1312<code>android.hardware.camera.front</code>.</td>
1313<td style="text-align: center;">REQUIRED</td>
1314<td>Baseline Profile (BP)</td>
1315<td>
1316 <ul>
1317 <li>3GPP (.3gp)</li>
1318 <li>MPEG-4 (.mp4)</li>
1319 <li>MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li>
1320 </ul>
1321</td>
1322</tr>
1323
1324<tr>
1325<td>MPEG-4 SP</td>
1326<td>&nbsp;</td>
1327<td style="text-align: center;">REQUIRED</td>
1328<td>&nbsp;</td>
1329<td>3GPP (.3gp)</td>
1330</tr>
1331
1332<tr>
1333<td>VP8****</td>
1334<td style="text-align: center;">REQUIRED<br/><small>(Android 4.3+)</small></td>
1335<td style="text-align: center;">REQUIRED<br/><small>(Android 2.3.3+)</small></td>
1336<td>&nbsp;</td>
1337<td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv, Android 4.0+)***</td>
1338</tr>
1339
1340<tr>
1341<td>VP9</td>
1342<td>&nbsp;</td>
1343<td style="text-align: center;">REQUIRED<br/><small>(Android 4.4+)</small></td>
1344<td>&nbsp;</td>
1345<td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv,
1346Android 4.0+)***</td>
1347</tr>
1348
1349</tbody></table>
1350<ul>
1351<li>*Note: Only downmix of 5.0/5.1 content is required; recording or rendering more than 2 channels is optional.</li>
1352<li>**Note: 16-bit linear PCM capture is mandatory. 8-bit linear PCM capture is not mandatory.</li>
1353<li>***Note: Device implementations SHOULD support writing Matroska WebM files.</li>
1354<li>****Note: For acceptable quality of web video streaming and video-conference
1355services, device implementations SHOULD use a hardware VP8 codec that meets the
1356requirements in [<a href="#resources86">Resources, 86</a>].</li>
1357</ul>
1358
1359<a name="section-5.2"></a><h3 id="section-5.2">5.2. Video Encoding</h3>
1360<p>Android device implementations that include a rear-facing camera and declare
1361<code>android.hardware.camera</code> SHOULD support the following H.264 video encoding
1362profiles.</p>
1363<table>
1364 <thead>
1365 <tr>
1366 <th>&nbsp;</th>
1367 <th>SD (Low quality)</th>
1368 <th>SD (High quality)</th>
1369 <th>HD (When supported by hardware)</th>
1370 </tr>
1371 </thead>
1372 <tbody>
1373 <tr>
1374 <th>Video resolution</th>
1375 <td>176 x 144 px</td>
1376 <td>480 x 360 px</td>
1377 <td>1280 x 720 px</td>
1378 </tr>
1379 <tr>
1380 <th>Video frame rate</th>
1381 <td>12 fps</td>
1382 <td>30 fps</td>
1383 <td>30 fps</td>
1384 </tr>
1385 <tr>
1386 <th>Video bitrate</th>
1387 <td>56 Kbps</td>
1388 <td>500 Kbps or higher</td>
1389 <td>2 Mbps or higher</td>
1390 </tr>
1391 <tr>
1392 <th>Audio codec</th>
1393 <td>AAC-LC</td>
1394 <td>AAC-LC</td>
1395 <td>AAC-LC</td>
1396 </tr>
1397 <tr>
1398 <th>Audio channels</th>
1399 <td>1 (mono)</td>
1400 <td>2 (stereo)</td>
1401 <td>2 (stereo)</td>
1402 </tr>
1403 <tr>
1404 <th>Audio bitrate</th>
1405 <td>24 Kbps</td>
1406 <td>128 Kbps</td>
1407 <td>192 Kbps</td>
1408 </tr>
1409 </tbody>
1410</table>
1411
1412<p>Android device implementations that include a rear-facing camera and declare
1413<code>android.hardware.camera</code> SHOULD support the following VP8 video encoding profiles</p>
1414<table>
1415 <thead>
1416 <tr>
1417 <th>&nbsp;</th>
1418 <th>SD (Low quality)</th>
1419 <th>SD (High quality)</th>
1420 <th>HD 720p <br/> (When supported by hardware)</th>
1421 <th>HD 1080p <br/>(When supported by hardware)</th>
1422 </tr>
1423 </thead>
1424 <tbody>
1425 <tr>
1426 <th>Video resolution</th>
1427 <td>320 x 180 px</td>
1428 <td>640 x 360 px</td>
1429 <td>1280 x 720 px</td>
1430 <td>1920 x 1080 px</td>
1431 </tr>
1432 <tr>
1433 <th>Video frame rate</th>
1434 <td>30 fps</td>
1435 <td>30 fps</td>
1436 <td>30 fps</td>
1437 <td>30 fps</td>
1438 </tr>
1439 <tr>
1440 <th>Video bitrate</th>
1441 <td>800 Kbps</td>
1442 <td>2 Mbps</td>
1443 <td>4 Mbps</td>
1444 <td>10 Mbps</td>
1445 </tr>
1446 </tbody>
1447</table>
1448
1449<a name="section-5.3"></a><h3 id="section-5.3">5.3. Video Decoding</h3>
1450<p>Android device implementations SHOULD support the following VP8, VP9 and
1451H.264 video decoding profiles. Device implementations SHOULD also support
1452dynamic video resolution switching within the same stream for VP8, VP9 and
1453H.264 codecs.</p>
1454<table>
1455 <thead>
1456 <tr>
1457 <th>&nbsp;</th>
1458 <th>SD (Low quality)</th>
1459 <th>SD (High quality)</th>
1460 <th>HD 720p <br/> (When supported by hardware)</th>
1461 <th>HD 1080p <br/>(When supported by hardware)</th>
1462 </tr>
1463 </thead>
1464 <tbody>
1465 <tr>
1466 <th>Video resolution</th>
1467 <td>320 x 180 px</td>
1468 <td>640 x 360 px</td>
1469 <td>1280 x 720 px</td>
1470 <td>1920 x 1080 px</td>
1471 </tr>
1472 <tr>
1473 <th>Video frame rate</th>
1474 <td>30 fps</td>
1475 <td>30 fps</td>
1476 <td>30 fps</td>
1477 <td>30 fps</td>
1478 </tr>
1479 <tr>
1480 <th>Video bitrate</th>
1481 <td>800 Kbps</td>
1482 <td>2 Mbps</td>
1483 <td>8 Mbps</td>
1484 <td>20 Mbps</td>
1485 </tr>
1486 </tbody>
1487</table>
1488
1489<a name="section-5.4"></a><h3 id="section-5.4">5.4. Audio Recording</h3>
1490<p>When an application has used the <code>android.media.AudioRecord</code> API to
1491start recording an audio stream, device implementations that include microphone
1492hardware and declare <code>android.hardware.microphone</code> MUST sample and
1493record audio with each of these behaviors:</p>
1494<ul>
1495<li>The device SHOULD exhibit approximately flat amplitude versus frequency
1496 characteristics; specifically, &plusmn;3 dB, from 100 Hz to 4000 Hz</li>
1497<li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level
1498 (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li>
1499<li>PCM amplitude levels SHOULD linearly track input SPL changes over at least
1500 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li>
1501<li>Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input level.</li>
1502</ul>
1503<p>In addition to the above recording specifications, when an application has
1504started recording an audio stream using the
1505<code>android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION</code> audio
1506source:</p>
1507<ul>
1508<li>Noise reduction processing, if present, MUST be disabled.</li>
1509<li>Automatic gain control, if present, MUST be disabled.</li>
1510</ul>
1511<p>From Android 4.4, <code>android.media.MediaRecorder.AudioSource</code> class has a new
1512audio source: <code>REMOTE_SUBMIX</code>. Devices MUST properly implement the
1513<code>REMOTE_SUBMIX</code> audio source so that when an application uses the
1514<code>android.media.AudioRecord</code> API to record from this audio source,
1515it can capture a mix of all audio streams except for the following:</p>
1516<ul>
1517<li><code>STREAM_RING</code></li>
1518<li><code>STREAM_ALARM</code></li>
1519<li><code>STREAM_NOTIFICATION</code></li>
1520</ul>
1521<p><b>Note:</b> while some of the requirements outlined above are stated as
1522"SHOULD" since Android 4.3, the Compatibility Definition for a future version
1523is planned to change these to "MUST". That is, these requirements are optional
1524in Android 4.4 but <b>will be required</b> by a future version. Existing and new
1525devices that run Android are <b>very strongly encouraged to meet these
1526requirements</b>, or they will not be able to attain Android
1527compatibility when upgraded to the future version.</p>
1528<p>If the platform supports noise suppression technologies tuned for speech
1529recognition, the effect MUST be controllable from the
1530<code>android.media.audiofx.NoiseSuppressor</code> API. Moreover, the "uuid"
1531field for the noise suppressor's effect descriptor MUST uniquely identify each
1532implementation of the noise suppression technology.</p>
1533
1534<a name="section-5.5"></a><h3 id="section-5.5">5.5. Audio Latency</h3>
1535<p>Audio latency is the time delay as an audio signal passes through a system.
1536Many classes of
1537applications rely on short latencies, to achieve real-time sound effects.</p>
1538<p>For the purposes of this section:</p>
1539<ul>
1540<li>"output latency" is defined as the interval between when an application
1541writes a frame of PCM-coded data and when the corresponding sound can be heard
1542by an external listener or observed by a transducer</li>
1543<li>"cold output latency" is defined as the output latency for the first frame, when
1544 the audio output system has been idle and powered down prior to the request</li>
1545<li>"continuous output latency" is defined as the output latency for subsequent frames,
1546 after the device is already playing audio</li>
1547<li>"input latency" is the interval between when an external sound is presented
1548to the device and when an application reads the corresponding frame of PCM-coded data</li>
1549<li>"cold input latency" is defined as the sum of lost input time
1550 and the input latency for the first frame, when
1551 the audio input system has been idle and powered down prior to the request</li>
1552<li>"continuous input latency" is defined as the input latency for subsequent frames,
1553 while the device is already capturing audio</li>
1554<li>"OpenSL ES PCM buffer queue API" is the set of PCM-related OpenSL ES APIs within Android NDK;
1555see <i>NDK_root</i><code>/docs/opensles/index.html</code></li>
1556</ul>
1557<p>Per <a href="#section-5">Section 5</a>,
1558all compatible device implementations MUST include at least one form of audio output.
1559Device implementations SHOULD meet or exceed these output latency requirements:</p>
1560<ul>
1561<li>cold output latency of 100 milliseconds or less</li>
1562<li>continuous output latency of 45 milliseconds or less</li>
1563</ul>
1564<p>If a device implementation meets the requirements of this section
1565after any initial calibration
1566when using the OpenSL ES PCM buffer queue API,
1567for continuous output latency and cold output latency
1568over at least one supported audio output device, it MAY
1569report support for low-latency audio, by reporting the feature
1570"android.hardware.audio.low-latency" via the
1571<code>android.content.pm.PackageManager</code> class. [<a
1572href="#resources37">Resources, 37</a>] Conversely, if the device
1573implementation does not meet these requirements it MUST NOT report support for
1574low-latency audio.</p>
1575<p>
1576Per <a href="#section-7.2.5">Section 7.2.5</a>,
1577microphone hardware may be omitted by device implementations.</p>
1578<p>
1579Device implementations that include microphone
1580hardware and declare <code>android.hardware.microphone</code> SHOULD
1581meet these input audio latency requirements:</p>
1582<ul>
1583<li>cold input latency of 100 milliseconds or less</li>
1584<li>continuous input latency of 50 milliseconds or less</li>
1585</ul>
1586
1587<a name="section-5.6"></a><h3 id="section-5.6">5.6. Network Protocols</h3>
1588<p>Devices MUST support the media network protocols for audio and video playback
1589as specified in the Android SDK documentation
1590[<a href="#resources58">Resources, 58</a>]. Specifically, devices MUST support
1591the following media network protocols:</p>
1592<ul>
1593<li>RTSP (RTP, SDP)</li>
1594<li>HTTP(S) progressive streaming</li>
1595<li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="#resources59">Resources, 59</a>]</li>
1596</ul>
1597<a name="section-6"></a><h2 id="section-6">6. Developer Tools and Options Compatibility</h2>
1598
1599<a name="section-6.1"></a><h3 id="section-6.1">6.1. Developer Tools</h3>
1600<p>Device implementations MUST support the Android Developer Tools provided in the Android SDK.
1601Specifically, Android-compatible devices MUST be compatible with:</p>
1602<ul>
1603<li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources33">Resources, 33</a>]<br/>
1604Device implementations MUST support all <code>adb</code> functions as
1605documented in the Android SDK. The device-side <code>adb</code> daemon MUST
1606be inactive by default, and there MUST be a user-accessible mechanism to turn
1607on the Android Debug Bridge.</li>
1608<li>Android includes support for secure adb. Secure adb enables adb on known authenticated hosts.
1609Device implementations MUST support secure adb.</li>
1610<li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources33">Resources, 33</a>]<br/>
1611Device implementations MUST support all <code>ddms</code> features as documented in the
1612Android SDK. As <code>ddms</code> uses <code>adb</code>, support for
1613<code>ddms</code> SHOULD be inactive by default,
1614but MUST be supported whenever the user has activated the Android Debug
1615Bridge, as above.</li>
1616<li><b>Monkey</b> [<a href="#resources36">Resources, 36</a>]<br/>
1617Device implementations MUST include the Monkey framework, and make it
1618available for applications to use.</li>
1619<li><b>SysTrace</b> [<a href="#resources33">Resources, 33</a>]<br/>
1620Device implementations MUST support systrace tool as documented in the Android SDK.
1621Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn
1622on Systrace.</li>
1623</ul>
1624<p>Most Linux-based systems and Apple Macintosh systems recognize Android
1625devices using the standard Android SDK tools, without additional support;
1626however Microsoft Windows systems typically require a driver for new Android
1627devices. (For instance, new vendor IDs and sometimes new device IDs require
1628custom USB drivers for Windows systems.) If a device implementation is
1629unrecognized by the <code>adb</code> tool as provided in the standard Android
1630SDK, device implementers MUST provide Windows drivers allowing developers to
1631connect to the device using the <code>adb</code> protocol. These drivers MUST
1632be provided for Windows XP, Windows Vista, Windows 7, and Windows 8, in both 32-bit and
163364-bit versions.</p>
1634
1635<a name="section-6.2"></a><h3 id="section-6.2">6.2. Developer Options</h3>
1636<p>Android includes support for developers to configure application development-related settings.
1637Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show
1638application development-related settings [<a href="#resources77">Resources, 77</a>]. The upstream Android
1639implementation hides the Developer Options menu by default, and enables users to launch Developer Options
1640after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations
1641MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide
1642Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with
1643the upstream Android implementation.</p>
1644
1645<a name="section-6.2.1"></a><h4 id="section-6.2.1">6.2.1. Experimental</h4>
1646<p>Android 4.4 introduces ART, an experimental Android runtime, accessible
1647within the Developer Options menu for preview. Device
1648implementations SHOULD include ART (libart.so) and support dual boot from
1649Developer Options, but MUST keep Dalvik (libdvm.so) as the default runtime.</p>
1650
1651<a name="section-7"></a><h2 id="section-7">7. Hardware Compatibility</h2>
1652<p>If a device includes a particular hardware component that has a
1653corresponding API for third-party developers, the device implementation MUST
1654implement that API as described in the Android SDK documentation. If an API in
1655the SDK interacts with a hardware component that is stated to be optional and
1656the device implementation does not possess that component:</p>
1657<ul>
1658<li>complete class definitions (as documented by the SDK) for the component's
1659APIs MUST still be present</li>
1660<li>the API's behaviors MUST be implemented as no-ops in some reasonable
1661fashion</li>
1662<li>API methods MUST return null values where permitted by the SDK
1663documentation</li>
1664<li>API methods MUST return no-op implementations of classes where null
1665values are not permitted by the SDK documentation</li>
1666<li>API methods MUST NOT throw exceptions not documented by the SDK
1667documentation</li>
1668</ul>
1669<p>A typical example of a scenario where these requirements apply is the
1670telephony API: even on non-phone devices, these APIs must be implemented as
1671reasonable no-ops.</p>
1672<p>Device implementations MUST accurately report accurate hardware configuration
1673information via the <code>getSystemAvailableFeatures()</code> and
1674<code>hasSystemFeature(String)</code> methods on the
1675<code>android.content.pm.PackageManager</code> class. [<a
1676href="#resources37">Resources, 37</a>]</p>
1677
1678<a name="section-7.1"></a><h3 id="section-7.1">7.1. Display and Graphics</h3>
1679<p>Android includes facilities that automatically adjust application
1680assets and UI layouts appropriately for the device, to ensure that third-party
1681applications run well on a variety of hardware configurations [<a
1682href="#resources38">Resources, 38</a>]. Devices MUST properly implement these
1683APIs and behaviors, as detailed in this section.</p>
1684
1685<p>The units referenced by the requirements in this section are defined as follows:</p>
1686<ul>
1687<li>"Physical diagonal size" is the distance in inches between two opposing
1688corners of the illuminated portion of the display.</li>
1689<li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a
1690linear horizontal or vertical span of 1". Where dpi values are listed, both
1691horizontal and vertical dpi must fall within the range.</li>
1692<li>"Aspect ratio" is the ratio of the longer dimension of the screen to the
1693shorter dimension. For example, a display of 480x854 pixels would be 854 / 480
1694= 1.779, or roughly "16:9".</li>
1695<li>A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a
1696160 dpi screen, calculated as:
1697<code>pixels = dps * (density / 160)</code>.</li>
1698</ul>
1699
1700
1701<a name="section-7.1.1"></a><h4 id="section-7.1.1">7.1.1. Screen Configuration</h4>
1702
1703<p style="font-weight:bold;">Screen Size</p>
1704<p>The Android UI framework supports a variety of different screen sizes, and
1705allows applications to query the device screen size (aka "screen layout") via
1706<code>android.content.res.Configuration.screenLayout</code> with the
1707<code>SCREENLAYOUT_SIZE_MASK</code>. Device implementations MUST report the
1708correct screen size as defined in the Android SDK documentation
1709[<a href="#resources38">Resources, 38</a>] and determined by the upstream
1710Android platform. Specifically, device implementations must report the correct
1711screen size according to the following logical density-independent pixel (dp)
1712screen dimensions.</p>
1713<ul>
1714<li>Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')</li>
1715<li>Devices that report screen size 'normal' MUST have screen sizes of at least
1716480 dp x 320 dp</li>
1717<li>Devices that report screen size 'large' MUST have screen sizes of at least
1718640 dp x 480 dp</li>
1719<li>Devices that report screen size 'xlarge' MUST have screen sizes of at least
1720960 dp x 720 dp</li>
1721</ul>
1722<p>In addition, devices MUST have screen sizes of at least 2.5 inches in
1723physical diagonal size.</p>
1724
1725<p>Devices MUST NOT change their reported screen size at any time.</p>
1726<p>Applications optionally indicate which screen sizes they support via the
1727<code>&lt;supports-screens&gt;</code> attribute in the AndroidManifest.xml
1728file. Device implementations MUST correctly honor applications' stated support
1729for small, normal, large, and xlarge screens, as described in the Android
1730SDK documentation.</p>
1731
1732<p style="font-weight:bold;">Screen Aspect Ratio</p>
1733<p>The aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly 16:9)</p>
1734
1735<p style="font-weight:bold;">Screen Density</p>
1736<p>The Android UI framework defines a set of standard logical densities to
1737help application developers target application resources. Device
1738implementations MUST report one of the following logical Android framework
1739densities through the <code>android.util.DisplayMetrics</code> APIs, and MUST
1740execute applications at this standard density.
1741<ul>
1742<li>120 dpi, known as 'ldpi'</li>
1743<li>160 dpi, known as 'mdpi'</li>
1744<li>213 dpi, known as 'tvdpi'</li>
1745<li>240 dpi, known as 'hdpi'</li>
1746<li>320 dpi, known as 'xhdpi'</li>
1747<li>400 dpi, known as '400dpi'</li>
1748<li>480 dpi, known as 'xxhdpi'</li>
1749<li>640 dpi, known as 'xxxhdpi'</li>
1750</ul>
1751Device implementations SHOULD define the standard Android framework density
1752that is numerically closest to the physical density of the screen, unless that
1753logical density pushes the reported screen size below the minimum supported.
1754If the standard Android framework density that is numerically closest to the
1755physical density results in a screen size that is smaller than the smallest
1756supported compatible screen size (320 dp width), device implementations SHOULD
1757report the next lowest standard Android framework density.</p>
1758
1759<a name="section-7.1.2"></a><h4 id="section-7.1.2">7.1.2. Display Metrics</h4>
1760<p>Device implementations MUST report correct values for all display metrics
1761defined in <code>android.util.DisplayMetrics</code> [<a
1762href="#resources39">Resources, 39</a>].</p>
1763
1764<a name="section-7.1.3"></a><h4 id="section-7.1.3">7.1.3. Screen Orientation</h4>
1765<p>Devices MUST support dynamic orientation by applications to
1766either portrait or landscape screen orientation. That is, the device must
1767respect the application's request for a specific screen orientation. Device
1768implementations MAY select either portrait or landscape orientation as the
1769default.</p>
1770<p>Devices MUST report the correct value for the device's current orientation,
1771whenever queried via the android.content.res.Configuration.orientation,
1772android.view.Display.getOrientation(), or other APIs.</p>
1773<p>Devices MUST NOT change the reported screen size or density when changing
1774orientation.</p>
1775<p>Devices MUST report which screen orientations they support (
1776<code>android.hardware.screen.portrait</code> and/or
1777<code>android.hardware.screen.landscape</code>) and MUST report at least one
1778supported orientation. For example, a device with a fixed-orientation
1779landscape screen, such as a television or laptop, MUST only report
1780<code>android.hardware.screen.landscape</code>.</p>
1781
1782<a name="section-7.1.4"></a><h4 id="section-7.1.4">7.1.4. 2D and 3D Graphics Acceleration</h4>
1783<p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied
1784and detailed in the Android SDK documentations. Device implementations SHOULD support
1785OpenGL ES 3.0 on devices capable of supporting OpenGL ES 3.0.
1786Device implementations MUST also support Android Renderscript, as detailed in the Android SDK
1787documentation [<a href="#resources08">Resources, 8</a>].</p>
1788<p>Device implementations MUST also correctly identify themselves as
1789supporting OpenGL ES 1.0, OpenGL ES 2.0, or OpenGL ES 3.0. That is:</p>
1790<ul>
1791<li>The managed APIs (such as via the <code>GLES10.getString()</code> method)
1792MUST report support for OpenGL ES 1.0 and OpenGL ES 2.0 </li>
1793<li>The native C/C++ OpenGL APIs (that is, those available to apps via
1794libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for
1795OpenGL ES 1.0 and OpenGL ES 2.0.</li>
1796<li>Device implementations that declare support for OpenGL ES 3.0 MUST support
1797OpenGL ES 3.0 managed APIs and include support for native C/C++ APIs. On device
1798implementations that declare support for OpenGL ES 3.0, libGLESv2.so MUST export the OpenGL ES 3.0
1799function symbols in addition to the OpenGL ES 2.0 function symbols.
1800</li>
1801</ul>
1802
1803<p>Device implementations MAY implement any desired OpenGL ES extensions.
1804However, device implementations MUST report via the OpenGL ES managed and
1805native APIs all extension strings that they do support, and conversely MUST
1806NOT report extension strings that they do not support.</p>
1807<p>Note that Android includes support for applications to optionally
1808specify that they require specific OpenGL texture compression formats. These
1809formats are typically vendor-specific. Device implementations are not required
1810by Android to implement any specific texture compression format. However,
1811they SHOULD accurately report any texture compression formats that they do
1812support, via the <code>getString()</code> method in the OpenGL API.</p>
1813
1814<p>Android includes a mechanism for applications to declare that they
1815wanted to enable hardware acceleration for 2D graphics at the Application,
1816Activity, Window or View level through the use of a manifest tag
1817<code>android:hardwareAccelerated</code> or direct API calls
1818[<a href="#resources09">Resources, 9</a>].</p>
1819<p>In Android 4.4, device implementations MUST enable hardware acceleration by
1820default, and MUST disable hardware acceleration if the developer so requests
1821by setting <code>android:hardwareAccelerated="false"</code> or disabling
1822hardware acceleration directly through the Android View APIs.</p>
1823<p>In addition, device implementations MUST exhibit behavior consistent with the
1824Android SDK documentation on hardware acceleration
1825[<a href="#resources09">Resources, 9</a>].</p>
1826<p>Android includes a <code>TextureView</code> object that lets developers
1827directly integrate hardware-accelerated OpenGL ES textures as rendering targets
1828in a UI hierarchy. Device implementations MUST support the <code>TextureView
1829</code> API, and MUST exhibit consistent behavior with the upstream Android
1830implementation.</p>
1831<p>Android includes support for <code>EGL_ANDROID_RECORDABLE</code>, a EGLConfig attribute
1832that indicates whether the EGLConfig supports rendering to an ANativeWindow that records images to a video.
1833Device implementations MUST support <code>EGL_ANDROID_RECORDABLE</code> extension [<a href="#resources79">Resources, 79</a>].</p>
1834
1835<a name="section-7.1.5"></a><h4 id="section-7.1.5">7.1.5. Legacy Application Compatibility Mode</h4>
1836<p>Android specifies a "compatibility mode" in which the framework
1837operates in an 'normal' screen size equivalent (320dp width) mode for the benefit
1838of legacy applications not developed for old versions of Android that pre-date
1839screen-size independence. Device implementations MUST include support for legacy
1840application compatibility mode as implemented by the upstream Android open source
1841code. That is, device implementations MUST NOT alter the triggers or thresholds at
1842which compatibility mode is activated, and MUST NOT alter the behavior of the
1843compatibility mode itself.</p>
1844
1845<a name="section-7.1.6"></a><h4 id="section-7.1.6">7.1.6. Screen Types</h4>
1846<p>Device implementation screens are classified as one of two types:</p>
1847<ul>
1848<li>Fixed-pixel display implementations: the screen is a single panel that supports only a
1849single pixel width and height. Typically the screen is physically integrated with
1850the device. Examples include mobile phones, tablets, and so on.</li>
1851<li>Variable-pixel display implementations: the device implementation either has no
1852embedded screen and includes a video output port such as VGA, HDMI or a wireless port
1853for display, or has an embedded screen that can change pixel dimensions. Examples
1854include televisions, set-top boxes, and so on.</li>
1855</ul>
1856<p style="font-weight: bold;">Fixed-Pixel Device Implementations</p>
1857<p>Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided
1858that they meet the requirements defined this Compatibility Definition.</p>
1859<p>Fixed-pixel implementations MAY include a video output port for use with an
1860external display. However, if that display is ever used for running apps, the
1861device MUST meet the following requirements:</p>
1862<ul>
1863<li>The device MUST report the same screen configuration and display metrics, as detailed
1864in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.</li>
1865<li>The device MUST report the same logical density as the fixed-pixel display.</li>
1866<li>The device MUST report screen dimensions that are the same as, or very close to,
1867the fixed-pixel display.</li>
1868</ul>
1869<p>For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is
1870considered a fixed-pixel large mdpi display implementation. If it contains a video
1871output port that displays at 720p or 1080p the device implementation MUST scale the output so that
1872applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display
1873or video output port is in use.</p>
1874
1875<p style="font-weight: bold;">Variable-Pixel Device Implementations</p>
1876<p>Variable-pixel device implementations MUST support at least one of 1280x720,
18771920x1080, or 3840x2160 (that is, 720p, 1080p, or 4K). Device implementations with
1878variable-pixel displays MUST NOT support any other screen configuration or
1879mode. Device implementations with variable-pixel screens MAY change screen
1880configuration or mode at runtime or boot-time. For example, a user of a
1881set-top box may replace a 720p display with a 1080p display, and the device
1882implementation may adjust accordingly.</p>
1883
1884<p>Additionally, variable-pixel device implementations MUST report the following
1885configuration buckets for these pixel dimensions:</p>
1886<ul>
1887<li>1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi)
1888density</li>
1889<li>1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi)
1890density</li>
1891<li>3840x2160 (also known as 4K): 'large' screen size, 'xxxhdpi' (640 dpi)
1892density</li>
1893</ul>
1894<p>For clarity, device implementations with variable pixel dimensions are
1895restricted to 720p, 1080p, or 4K in Android 4.4, and MUST be configured to report
1896screen size and density buckets as noted above.</p>
1897
1898<a name="section-7.1.7"></a><h4 id="section-7.1.7">7.1.7. Screen Technology</h4>
1899<p>The Android platform includes APIs that allow applications to render rich
1900graphics to the display. Devices MUST support all of these APIs as defined by
1901the Android SDK unless specifically allowed in this document. Specifically:</p>
1902<ul>
1903<li>Devices MUST support displays capable of rendering 16-bit color graphics and
1904SHOULD support displays capable of 24-bit color graphics.</li>
1905<li>Devices MUST support displays capable of rendering animations.</li>
1906<li>The display technology used MUST have a pixel aspect ratio (PAR) between
1907 0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with
1908 a 10% tolerance.</li>
1909</ul>
1910<a name="section-7.1.8"></a><h4 id="section-7.1.8">7.1.8. External Displays</h4>
1911<p>Android includes support for secondary display to enable media sharing capabilities and
1912developer APIs for accessing external displays. If a device supports an external display either via
1913a wired, wireless or an embedded additional display connection then the device implementation MUST
1914implement the display manager API as described in the Android SDK documentation [<a href="#resources75">Resources, 75</a>].
1915Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support
1916for <code>Display.FLAG_SECURE</code>. Specifically, device implementations that declare support for <code>Display.FLAG_SECURE</code>,
1917MUST support <b>HDCP 2.x or higher</b> for Miracast wireless displays or <b>HDCP 1.2 or higher</b> for wired displays. The upstream
1918Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.</p>
1919
1920<a name="section-7.2"></a><h3 id="section-7.2">7.2. Input Devices</h3>
1921<a name="section-7.2.1"></a><h4 id="section-7.2.1">7.2.1. Keyboard</h4>
1922<p>Device implementations:</p>
1923<ul>
1924<li>MUST include support for the Input Management Framework (which allows third
1925party developers to create Input Management Engines - i.e. soft keyboard) as
1926detailed at <a href="http://developer.android.com">http://developer.android.com</a>
1927</li>
1928<li>MUST provide at least one soft keyboard implementation (regardless of whether
1929a hard keyboard is present)</li>
1930<li>MAY include additional soft keyboard implementations</li>
1931<li>MAY include a hardware keyboard</li>
1932<li>MUST NOT include a hardware keyboard that does not match one of the
1933formats specified in <code>android.content.res.Configuration.keyboard</code>
1934[<a href="#resources40">Resources, 40</a>] (that is, QWERTY, or 12-key)</li>
1935</ul>
1936<a name="section-7.2.2"></a><h4 id="section-7.2.2">7.2.2. Non-touch Navigation</h4>
1937<p>Device implementations:</p>
1938<ul>
1939<li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad,
1940or wheel)</li>
1941<li>MUST report the correct value for
1942<code>android.content.res.Configuration.navigation</code>
1943[<a href="#resources40">Resources, 40</a>]</li>
1944<li>MUST provide a reasonable alternative user interface mechanism for the
1945selection and editing of text, compatible with Input Management Engines. The
1946upstream Android open source implementation includes a selection mechanism suitable
1947for use with devices that lack non-touch navigation inputs.</li>
1948</ul>
1949<a name="section-7.2.3"></a><h4 id="section-7.2.3">7.2.3. Navigation keys</h4>
1950<p>The Home, Recents and Back functions are essential to the Android navigation
1951paradigm. Device implementations MUST make these functions available to the user
1952at all times when running applications. These functions MAY be implemented via
1953dedicated physical buttons (such as mechanical or capacitive touch buttons), or
1954MAY be implemented using dedicated software keys on a distinct portion of the
1955screen, gestures, touch panel, etc. Android supports both implementations. All
1956of these functions MUST be accessible with a single action (e.g. tap,
1957double-click or gesture) when visible.</p>
1958<p>The Back and Recents functions SHOULD have a visible button or icon unless
1959hidden together with other navigation functions in full-screen mode. The Home
1960function MUST have a visible button or icon unless hidden together with other
1961navigation functions in full-screen mode.</p>
1962<p>The Menu function is deprecated in favor of action bar since Android 4.0.
1963Device implementations SHOULD NOT implement a dedicated physical button for
1964the Menu function. If the physical Menu button is implemented and the device
1965is running applications with <code>targetSdkVersion</code> &gt; 10, the device
1966implementation:</p>
1967<ul>
1968 <li>for a device launching with Android 4.4, MUST display the action overflow
1969 button on the action bar when the action bar is visible and the resulting action
1970 overflow menu popu is not empty.</li>
1971 <li>for an existing device launched with an earlier version but upgrading to
1972 Android 4.4, SHOULD display the action overflow button on the action bar
1973 when the action bar is visible and the resulting action overflow menu popup
1974 is not empty.</li>
1975 <li>MUST NOT modify the position of the action overflow popup displayed by
1976 selecting the overflow button in the action bar.</li>
1977 <li>MAY render the action overflow popup at a modified position on the screen
1978 when it is displayed by selecting the physical menu button.</li>
1979</ul>
1980<p>For backwards compatibility, device implementations MUST make available the
1981Menu function to applications when <code>targetSdkVersion</code> &lt;= 10,
1982either by a phsyical button, a software key or gestures. This Menu function
1983should be presented unless hidden together with other navigation functions.</p>
1984<p>Android supports Assist action [<a href="#resources63">Resources, 63</a>].
1985Device implementations MUST make the Assist action available to the user at all
1986times when running applications. The Assist action SHOULD be implemented as a
1987long-press on the Home button or a swipe-up gesture on the software Home key.
1988This function MAY be implemented via another physical button, software key or
1989gestures, but MUST be accessible with a single action (e.g. tap, double-click or
1990gesture) when other navigation keys are visible.</p>
1991<p>Device implementations MAY use a distinct portion of the screen to display
1992the navigation keys, but if so, MUST meet these requirements:</p>
1993<ul>
1994 <li>Device implementation navigation keys MUST use a distinct portion of the
1995 screen, not available to applications, and MUST NOT obscure or otherwise
1996 interfere with the portion of the screen available to applications.</li>
1997 <li>Device implementations MUST make available a portion of the display to
1998 applications that meets the requirements defined in
1999 <a href="section-7.1.1">Section 7.1.1</a>.</li>
2000 <li>Device implementations MUST display the navigation keys when applications
2001 do not specify a system UI mode, or specify
2002 <code>SYSTEM_UI_FLAG_VISIBLE</code>.</li>
2003 <li>Device implementations MUST present the navigation keys in an unobtrusive
2004 "low profile" (eg. dimmed) mode when applications specify
2005 <code>SYSTEM_UI_FLAG_LOW_PROFILE</code>.</li>
2006 <li>Device implementations MUST hide the navigation keys when applications
2007 specify <code>SYSTEM_UI_FLAG_HIDE_NAVIGATION</code>.</li>
2008</ul>
2009<a name="section-7.2.4"></a><h4 id="section-7.2.4">7.2.4. Touchscreen input</h4>
2010<p>Device implementations SHOULD have a pointer input system of some kind (either mouse-like, or touch). However, if a device
2011implementation does not support a pointer input system, it MUST NOT report the <code>android.hardware.touchscreen</code> or
2012<code>android.hardware.faketouch</code> feature constant. Device implementations that do include a pointer input system:</p>
2013<ul>
2014<li>SHOULD support fully independently tracked pointers, if the device input system supports multiple pointers</li>
2015<li>MUST report the value of <code>android.content.res.Configuration.touchscreen</code> [<a href="#resources40">Resources, 40</a>]
2016corresponding to the type of the specific touchscreen on the device</li>
2017</ul>
2018
2019<p>Android includes support for a variety of touch screens, touch pads, and fake touch input devices.
2020Touch screen based device implementations are associated with a display [<a href="#resources81">Resources, 81</a>]
2021such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen,
2022the system does not require any additional affordances to indicate the objects being manipulated.
2023In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities.
2024For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first
2025point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick,
2026and multi-touch trackpad can support fake touch interactions. Android 4.0 includes the feature constant <code>android.hardware.faketouch</code>,
2027which corresponds to a high-fidelity non-touch (that is, pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based
2028input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen
2029functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p>
2030
2031<p>Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that
2032include a touchscreen (single-touch or better) MUST report the platform feature constant <code>android.hardware.touchscreen</code>.
2033Device implementations that report the platform feature constant <code>android.hardware.touchscreen</code> MUST also report the platform feature constant
2034<code>android.hardware.faketouch</code>. Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any
2035touchscreen feature, and MUST report only <code>android.hardware.faketouch</code> if they meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p>
2036
2037<a name="section-7.2.5"></a><h4 id="section-7.2.5">7.2.5. Fake touch input</h4>
2038<p>Device implementations that declare support for <code>android.hardware.faketouch</code></p>
2039<ul>
2040<li> MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen [<a href="#resources80">Resources, 80</a>] </li>
2041<li> MUST report touch event with the action code [<a href="#resources80">Resources, 80</a>] that specifies the state change
2042that occurs on the pointer going <code>down</code> or <code>up</code> on the screen [<a href="#resources80">Resources, 80</a>] </li>
2043<li> MUST support pointer <code>down</code> and <code>up</code> on an object on the screen, which allows users to emulate tap on an object on the screen</li>
2044<li> MUST support pointer <code>down</code>, pointer <code>up</code>, pointer <code>down</code> then pointer <code>up</code> in the same place on an object on the screen
2045within a time threshold, which allows users to emulate double tap on an object on the screen [<a href="#resources80">Resources, 80</a>]</li>
2046<li>MUST support pointer <code>down</code> on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen,
2047followed by a pointer <code>up</code>, which allows users to emulate a touch drag</li>
2048<li> MUST support pointer <code>down</code> then allow users to quickly move the object to a different position on the screen
2049and then pointer <code>up</code> on the screen, which allows users to fling an object on the screen</li>
2050</ul>
2051
2052<p>Devices that declare support for <code>android.hardware.faketouch.multitouch.distinct</code> MUST meet the requirements for
2053faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.</p>
2054
2055<a name="section-7.2.6"></a><h4 id="section-7.2.6">7.2.6. Microphone</h4>
2056<p>Device implementations MAY omit a microphone. However, if a device
2057implementation omits a microphone, it MUST NOT report the
2058<code>android.hardware.microphone</code> feature constant, and must implement
2059the audio recording API as no-ops, per <a href="section-7">Section 7</a>.
2060Conversely, device implementations that do possess a microphone:</p>
2061<ul>
2062<li>MUST report the <code>android.hardware.microphone</code> feature constant</li>
2063<li>SHOULD meet the audio quality requirements in <a href="section-5.4">Section 5.4</a></li>
2064<li>SHOULD meet the audio latency requirements in <a href="section-5.5">Section 5.5</a></li>
2065</ul>
2066
2067<a name="section-7.3"></a><h3 id="section-7.3">7.3. Sensors</h3>
2068<p>Android includes APIs for accessing a variety of sensor types. Devices
2069implementations generally MAY omit these sensors, as provided for in the
2070following subsections. If a device includes a particular sensor type that has a
2071corresponding API for third-party developers, the device implementation MUST
2072implement that API as described in the Android SDK documentation. For example,
2073device implementations:</p>
2074<ul>
2075<li>MUST accurately report the presence or absence of sensors per the
2076<code>android.content.pm.PackageManager</code> class. [<a
2077href="#resources37">Resources, 37</a>]</li>
2078<li>MUST return an accurate list of supported sensors via the
2079<code>SensorManager.getSensorList()</code> and similar methods</li>
2080<li>MUST behave reasonably for all other sensor APIs (for example, by
2081returning true or false as appropriate when applications attempt to register
2082listeners, not calling sensor listeners when the corresponding sensors are not
2083present; etc.)</li>
2084<li>MUST report all sensor measurements using the relevant International System
2085of Units (i.e. metric) values for each sensor type as defined in the Android SDK
2086documentation [<a href="#resources41">Resources, 41</a>]</li>
2087</ul>
2088<p>The list above is not comprehensive; the documented behavior of the Android
2089SDK is to be considered authoritative.</p>
2090<p>Some sensor types are synthetic, meaning they can be derived from data
2091provided by one or more other sensors. (Examples include the orientation
2092sensor, and the linear acceleration sensor.) Device implementations SHOULD
2093implement these sensor types, when they include the prerequisite physical
2094sensors.</p>
2095<p>Android includes a notion of a "streaming" sensor, which is
2096one that returns data continuously, rather than only when the data changes.
2097Device implementations MUST continuously provide periodic data samples for any
2098API indicated by the Android SDK documentation to be a streaming
2099sensor. Note that the device implementations MUST ensure that the sensor stream must not
2100prevent the device CPU from entering a suspend state or waking up from a suspend state.</p>
2101
2102<a name="section-7.3.1"></a><h4 id="section-7.3.1">7.3.1. Accelerometer</h4>
2103<p>Device implementations SHOULD include a 3-axis accelerometer. If a device
2104implementation does include a 3-axis accelerometer, it:</p>
2105<ul>
2106<li>SHOULD be able to deliver events at 120 Hz or greater. Note that while the
2107accelerometer frequency above is stated as "SHOULD" for Android 4.4, the Compatibility Definition
2108for a future version is planned to change these to "MUST". That is, these standards are
2109optional in Android but <b>will be required</b> in future versions. Existing and
2110new devices that run Android are <b>very strongly encouraged to meet these requirements
2111in Android</b> so they will be able to upgrade to the future platform releases
2112</li>
2113<li>MUST comply with the Android sensor coordinate system as detailed
2114in the Android APIs (see [<a href="#resources41">Resources, 41</a>])</li>
2115<li>MUST be capable of measuring from freefall up to twice gravity (2g) or
2116more on any three-dimensional vector</li>
2117<li>MUST have 8-bits of accuracy or more</li>
2118<li>MUST have a standard deviation no greater than 0.05 m/s^2</li>
2119</ul>
2120<a name="section-7.3.2"></a><h4 id="section-7.3.2">7.3.2. Magnetometer</h4>
2121<p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.)
2122If a device does include a 3-axis magnetometer, it:</p>
2123<ul>
2124<li>MUST be able to deliver events at 10 Hz or greater</li>
2125<li>MUST comply with the Android sensor coordinate system as detailed
2126in the Android APIs (see [<a href="#resources41">Resources, 41</a>]).</li>
2127<li>MUST be capable of sampling a range of field strengths adequate to cover the
2128geomagnetic field</li>
2129<li>MUST have 8-bits of accuracy or more</li>
2130<li>MUST have a standard deviation no greater than 0.5 &micro;T</li>
2131</ul>
2132<a name="section-7.3.3"></a><h4 id="section-7.3.3">7.3.3. GPS</h4>
2133<p>Device implementations SHOULD include a GPS receiver. If a device
2134implementation does include a GPS receiver, it SHOULD include
2135some form of "assisted GPS" technique to minimize GPS lock-on time.</p>
2136<a name="section-7.3.4"></a><h4 id="section-7.3.4">7.3.4. Gyroscope</h4>
2137<p>Device implementations SHOULD include a gyroscope (i.e. angular change
2138sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis
2139accelerometer is also included. If a device implementation includes a
2140gyroscope, it:</p>
2141<ul>
2142<li>MUST be temperature compensated.</li>
2143<li>MUST be capable of measuring orientation changes up to 5.5*Pi
2144radians/second (that is, approximately 1,000 degrees per second).</li>
2145<li>SHOULD be able to deliver events at 200 Hz or greater. Note that while the
2146gyroscope frequency above is stated as "SHOULD" for Android 4.4, the Compatibility Definition
2147for a future version is planned to change these to "MUST". That is, these standards are
2148optional in Android but <b>will be required</b> in future versions. Existing and
2149new devices that run Android are <b>very strongly encouraged to meet these requirements</b>
2150so they will be able to upgrade to the future platform releases.
2151</li>
2152<li>MUST have 12-bits of accuracy or more</li>
2153<li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s).
2154The variance is allowed to vary with the sampling rate, but must be constrained by this value.
2155In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no
2156greater than 1e-7 rad^2/s^2.</li>
2157<li>MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.</li>
2158</ul>
2159<a name="section-7.3.5"></a><h4 id="section-7.3.5">7.3.5. Barometer</h4>
2160<p>Device implementations MAY include a barometer (i.e. ambient air pressure
2161sensor.) If a device implementation includes a barometer, it:</p>
2162<ul>
2163<li>MUST be able to deliver events at 5 Hz or greater</li>
2164<li>MUST have adequate precision to enable estimating altitude</li>
2165<li>MUST be temperature compensated</li>
2166</ul>
2167<a name="section-7.3.6"></a><h4 id="section-7.3.6">7.3.6. Thermometer</h4>
2168<p>Device implementations MAY include an ambient thermometer (i.e. temperature
2169sensor). If present, it MUST be defined as <code>SENSOR_TYPE_AMBIENT_TEMPERATURE</code>
2170and it MUST measure the ambient (room) temperature in degrees Celsius.</p>
2171
2172<p>Device implementations MAY but SHOULD NOT include a CPU temperature sensor.
2173If present, it MUST be defined as <code>SENSOR_TYPE_TEMPERATURE</code>, it MUST
2174measure the temperature of the device CPU, and it MUST NOT measure any other
2175temperature. Note the <code>SENSOR_TYPE_TEMPERATURE</code> sensor type was
2176deprecated in Android 4.0.</p>
2177<a name="section-7.3.7"></a><h4 id="section-7.3.7">7.3.7. Photometer</h4>
2178<p>Device implementations MAY include a photometer (i.e. ambient light
2179sensor.)</p>
2180<a name="section-7.3.8"></a><h4 id="section-7.3.8">7.3.8. Proximity Sensor</h4>
2181<p>Device implementations MAY include a proximity sensor. If a device
2182implementation does include a proximity sensor, it MUST measure the proximity
2183of an object in the same direction as the screen. That is, the proximity
2184sensor MUST be oriented to detect objects close to the screen, as the
2185primary intent of this sensor type is to detect a phone in use by the
2186user. If a device implementation includes a proximity sensor with any other
2187orientation, it MUST NOT be accessible through this API. If a device
2188implementation has a proximity sensor, it MUST be have 1-bit of accuracy or
2189more.</p>
2190
2191<a name="section-7.4"></a><h3 id="section-7.4">7.4. Data Connectivity</h3>
2192<a name="section-7.4.1"></a><h4 id="section-7.4.1">7.4.1. Telephony</h4>
2193<p>"Telephony" as used by the Android APIs and this document refers
2194specifically to hardware related to placing voice calls and sending SMS
2195messages via a GSM or CDMA network. While these voice calls may or may not be
2196packet-switched, they are for the purposes of Android considered
2197independent of any data connectivity that may be implemented using the same
2198network. In other words, the Android "telephony" functionality and APIs refer
2199specifically to voice calls and SMS; for instance, device implementations that
2200cannot place calls or send/receive SMS messages MUST NOT report the
2201"android.hardware.telephony" feature or any sub-features, regardless of
2202whether they use a cellular network for data connectivity.</p>
2203<p>Android MAY be used on devices that do not include telephony hardware.
2204That is, Android is compatible with devices that are not phones.
2205However, if a device implementation does include GSM or CDMA telephony, it
2206MUST implement full support for the API for that technology. Device
2207implementations that do not include telephony hardware MUST implement the full
2208APIs as no-ops.</p>
2209<a name="section-7.4.2"></a><h4 id="section-7.4.2">7.4.2. IEEE 802.11 (Wi-Fi)</h4>
2210<p>Android device implementations SHOULD include support for one or more
2211forms of 802.11 (b/g/a/n, etc.) If a device implementation does include
2212support for 802.11, it MUST implement the corresponding Android API.</p>
2213<p>Device implementations MUST implement the multicast API as described in
2214the SDK documentation [<a href="#resources62">Resources, 62</a>]. Device
2215implementations that do include Wi-Fi support MUST support multicast DNS (mDNS).
2216Device implementations MUST NOT filter mDNS packets (224.0.0.251) at any time
2217of operation including when the screen is not in an active state.</p>
2218
2219<a name="section-7.4.2.1"></a>
2220<h4 id="section-7.4.2.1">7.4.2.1. Wi-Fi Direct</h4>
2221<p>Device implementations SHOULD include support for Wi-Fi direct (Wi-Fi peer-to-peer).
2222If a device implementation does include support for Wi-Fi direct, it MUST implement the corresponding
2223Android API as described in the SDK documentation [<a href="#resources68">Resources, 68</a>].
2224If a device implementation includes support for Wi-Fi direct, then it:</p>
2225<ul>
2226 <li>MUST support regular Wi-Fi operation</li>
2227 <li>SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation</li>
2228</ul>
2229
2230<a name="section-7.4.2.2"></a><h4 id="section-7.4.2.2">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</h4>
2231<p>Device implementations SHOULD include support for Wi-Fi Tunneled Direct Link
2232Setup (TDLS) as described in the Android SDK Documentation
2233[<a href="#resources85">Resources, 85</a>]. If a device implementation does
2234include support for TDLS and TDLS is enabled by the WiFiManager API, the device:
2235</p>
2236<ul>
2237 <li>SHOULD use TDLS only when it is possible AND beneficial.</li>
2238 <li>SHOULD have some heuristic and NOT use TDLS when its performance might be
2239 worse than going through the Wi-Fi access point.</li>
2240</ul>
2241
2242<a name="section-7.4.3"></a><h4 id="section-7.4.3">7.4.3. Bluetooth</h4>
2243<p>Device implementations SHOULD include a Bluetooth transceiver. Device
2244implementations that do include a Bluetooth transceiver MUST enable the
2245RFCOMM-based Bluetooth API as described in the SDK documentation and declare
2246hardware feature android.hardware.bluetooth [<a href="#resources42">Resources, 42</a>].
2247Device implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as
2248appropriate for the device.</p>
2249
2250<p>Device implementations that do include support for Bluetooth GATT (generic attribute profile)
2251to enable communication with Bluetooth Smart or Smart Ready devices MUST enable the
2252GATT-based Bluetooth API as described in the SDK documentation and declare hardware feature
2253android.hardware.bluetooth_le [<a href="#resources42">Resources, 42</a>].</p>
2254
2255<a name="section-7.4.4"></a><h4 id="section-7.4.4">7.4.4. Near-Field Communications</h4>
2256<p>Device implementations SHOULD include a transceiver and related hardware
2257for Near-Field Communications (NFC). If a device implementation does include
2258NFC hardware, then it:</p>
2259<ul>
2260 <li>MUST report the android.hardware.nfc feature from the
2261 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.
2262 [<a href="#resources37">Resources, 37</a>]</li>
2263 <li>MUST be capable of reading and writing NDEF messages via the following NFC
2264 standards:
2265 <ul>
2266 <li>MUST be capable of acting as an NFC Forum reader/writer
2267 (as defined by the NFC Forum technical specification
2268 NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:
2269 <ul>
2270 <li>NfcA (ISO14443-3A)</li>
2271 <li>NfcB (ISO14443-3B) </li>
2272 <li>NfcF (JIS 6319-4)</li>
2273 <li>IsoDep (ISO 14443-4)</li>
2274 <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li>
2275 </ul>
2276 </li>
2277 </ul>
2278 </li>
2279 <li>SHOULD be capable of reading and writing NDEF messages via the following
2280 NFC standards. Note that while the NFC standards below are stated as
2281 "SHOULD", the Compatibility Definition for a future version is planned to
2282 change these to "MUST". That is, these standards are optional in this
2283 version but <b>will be required</b> in future versions. Existing and new
2284 devices that run this version of Android are <b>very strongly encouraged
2285 to meet these requirements now</b> so they will be able to upgrade to the
2286 future platform releases.
2287 <ul>
2288 <li>NfcV (ISO 15693)</li>
2289 </ul>
2290 </li>
2291 <li>MUST be capable of transmitting and receiving data via the following
2292 peer-to-peer standards and protocols:
2293 <ul>
2294 <li>ISO 18092</li>
2295 <li>LLCP 1.0 (defined by the NFC Forum)</li>
2296 <li>SDP 1.0 (defined by the NFC Forum)</li>
2297 <li>NDEF Push Protocol [<a href="#resources43">Resources, 43</a>]</li>
2298 <li>SNEP 1.0 (defined by the NFC Forum)</li>
2299 </ul>
2300 </li>
2301 <li>MUST include support for Android Beam [<a href="#resources65">Resources, 65</a>]:
2302 <ul>
2303 <li>MUST implement the SNEP default server. Valid NDEF messages received
2304 by the default SNEP server MUST be dispatched to applications using
2305 the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam
2306 in settings MUST NOT disable dispatch of incoming NDEF message.</li>
2307 <li>Device implementations MUST honor the android.settings.NFCSHARING_SETTINGS intent
2308 to show NFC sharing settings [<a href="#resources67">Resources, 67</a>].</li>
2309 <li>MUST implement the NPP server. Messages received by the NPP server MUST
2310 be processed the same way as the SNEP default server.</li>
2311 <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to
2312 the default SNEP server when Android Beam is enabled. If no default
2313 SNEP server is found then the client MUST attempt to send to an NPP
2314 server.</li>
2315 <li>MUST allow foreground activities to set the outbound P2P NDEF message
2316 using android.nfc.NfcAdapter.setNdefPushMessage, and
2317 android.nfc.NfcAdapter.setNdefPushMessageCallback, and
2318 android.nfc.NfcAdapter.enableForegroundNdefPush.</li>
2319 <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam',
2320 before sending outbound P2P NDEF messages.</li>
2321 <li>SHOULD enable Android Beam by default</li>
2322 <li>MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile.
2323 Device implementations must support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris,
2324 by implementing the "Connection Handover version 1.2" [<a href="#resources60">Resources, 60</a>]
2325 and "Bluetooth Secure Simple Pairing Using NFC version 1.0" [<a href="#resources61">Resources, 61</a>]
2326 specs from the NFC Forum. Such an implementation MUST implement the
2327 handover LLCP service with service name "urn:nfc:sn:handover" for
2328 exchanging the handover request/select records over NFC, and it MUST use
2329 the Bluetooth Object Push Profile for the actual Bluetooth data
2330 transfer. For legacy reasons (to remain compatible with Android 4.1
2331 devices), the implementation SHOULD still accept SNEP GET requests for
2332 exchanging the handover request/select records over NFC. However an
2333 implementation itself SHOULD NOT send SNEP GET requests for performing
2334 connection handover.</li>
2335 </ul>
2336 </li>
2337 <li>MUST poll for all supported technologies while in NFC discovery mode.</li>
2338 <li>SHOULD be in NFC discovery mode while the device is awake with the screen active
2339 and the lock-screen unlocked.</li>
2340</ul>
2341
2342<p>(Note that publicly available links are not available for the JIS, ISO, and
2343NFC Forum specifications cited above.)</p>
2344<p>Android 4.4 introduces support for NFC Host Card Emulation (HCE) mode. If a
2345device implementation does include an NFC controller capable of HCE and
2346Application ID (AID) routing, then it:</p>
2347<ul>
2348 <li>MUST report the <code>android.hardware.nfc.hce</code> feature constant
2349 </li>
2350 <li>MUST support NFC HCE APIs as defined in the Android SDK
2351 [<a href="#resources90">Resources, 90</a>]</li>
2352</ul>
2353<p>Additionally, device implementations MAY include reader/writer support for
2354the following MIFARE technologies.</p>
2355<ul>
2356 <li>MIFARE Classic (NXP MF1S503x [<a href="#resources44">Resources, 44</a>],
2357 MF1S703x [<a href="#resources45">Resources, 45</a>])</li>
2358 <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources46">Resources, 46</a>],
2359 MF0ICU2 [<a href="#resources47">Resources, 47</a>])</li>
2360 <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources48">Resources, 48</a>],
2361 AN130411 [<a href="#resources49">Resources, 49</a>])</li>
2362</ul>
2363<p>Note that Android includes APIs for these MIFARE types. If a
2364device implementation supports MIFARE in the reader/writer role, it:</p>
2365<ul>
2366 <li>MUST implement the corresponding Android APIs as documented by the
2367 Android SDK</li>
2368 <li>MUST report the feature com.nxp.mifare from the
2369 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method.
2370 [<a href="#resources37">Resources, 37</a>] Note that this is not a standard
2371 Android feature, and as such does not appear as a constant on the
2372 <code>PackageManager</code> class.</li>
2373 <li>MUST NOT implement the corresponding Android APIs nor report the
2374 com.nxp.mifare feature unless it also implements general NFC support as
2375 described in this section</li>
2376</ul>
2377<p>If a device implementation does not include NFC hardware, it MUST NOT
2378declare the android.hardware.nfc feature from the
2379<code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a
2380href="#resources37">Resources, 37</a>], and MUST implement the Android NFC
2381API as a no-op.</p>
2382<p>As the classes <code>android.nfc.NdefMessage</code> and
2383<code>android.nfc.NdefRecord</code> represent a protocol-independent data
2384representation format, device implementations MUST implement these APIs even
2385if they do not include support for NFC or declare the android.hardware.nfc
2386feature.</p>
2387<a name="section-7.4.5"></a><h4 id="section-7.4.5">7.4.5. Minimum Network Capability</h4>
2388<p>Device implementations MUST include support for one or more forms of data
2389networking. Specifically, device implementations MUST include support for at
2390least one data standard capable of 200Kbit/sec or greater. Examples of
2391technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g,
2392Ethernet, etc.</p>
2393<p>Device implementations where a physical networking standard (such as
2394Ethernet) is the primary data connection SHOULD also include support for at
2395least one common wireless data standard, such as 802.11 (Wi-Fi).</p>
2396<p>Devices MAY implement more than one form of data connectivity.</p>
2397
2398<a name="section-7.4.6"></a><h4 id="section-7.4.6">7.4.6. Sync Settings</h4>
2399<p>Device implementations MUST have the master auto-sync setting on by default
2400so that the method <code>getMasterSyncAutomatically()</code> returns
2401&quot;true&quot; [<a href="#resources88">Resources, 88</a>].</p>
2402
2403<a name="section-7.5"></a><h3 id="section-7.5">7.5. Cameras</h3>
2404<p>Device implementations SHOULD include a rear-facing camera, and MAY include
2405a front-facing camera. A rear-facing camera is a camera located on the side of
2406the device opposite the display; that is, it images scenes on the far side of
2407the device, like a traditional camera. A front-facing camera is a camera
2408located on the same side of the device as the display; that is, a camera
2409typically used to image the user, such as for video conferencing and similar
2410applications.</p>
2411<a name="section-7.5.1"></a><h4 id="section-7.5.1">7.5.1. Rear-Facing Camera</h4>
2412<p>Device implementations SHOULD include a rear-facing camera. If a device
2413implementation includes a rear-facing camera, it:</p>
2414<ul>
2415<li>MUST have a resolution of at least 2 megapixels</li>
2416<li>SHOULD have either hardware auto-focus, or software auto-focus implemented
2417in the camera driver (transparent to application software)</li>
2418<li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li>
2419<li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST
2420NOT be lit while an android.hardware.Camera.PreviewCallback instance has been
2421registered on a Camera preview surface, unless the application has explicitly
2422enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or
2423<code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code>
2424object. Note that this constraint does not apply to the device's built-in
2425system camera application, but only to third-party applications using
2426<code>Camera.PreviewCallback</code>.</li>
2427</ul>
2428<a name="section-7.5.2"></a><h4 id="section-7.5.2">7.5.2. Front-Facing Camera</h4>
2429<p>Device implementations MAY include a front-facing camera. If a device
2430implementation includes a front-facing camera, it:</p>
2431<ul>
2432<li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li>
2433<li>MUST NOT use a front-facing camera as the default for the Camera API.
2434That is, the camera API in Android has specific support for front-facing
2435cameras, and device implementations MUST NOT configure the API to to treat a
2436front-facing camera as the default rear-facing camera, even if it is the only
2437camera on the device.</li>
2438<li>MAY include features (such as auto-focus, flash, etc.)
2439available to rear-facing cameras as described in Section 7.5.1.</li>
2440<li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a
2441CameraPreview, as follows:</li>
2442<ul>
2443<li>If the device implementation is capable of being rotated by user (such as
2444automatically via an accelerometer or manually via user input), the camera
2445preview MUST be mirrored horizontally relative to the device's current
2446orientation.</li>
2447<li>If the current application has explicitly requested that the Camera
2448display be rotated via a call to the
2449<code>android.hardware.Camera.setDisplayOrientation()</code> [<a
2450href="#resources50">Resources, 50</a>] method, the camera preview MUST be
2451mirrored horizontally relative to the orientation specified by the
2452application.</li>
2453<li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li>
2454</ul>
2455<li>MUST mirror the image displayed by the postview in the same manner as
2456the camera preview image stream. (If the device implementation does not
2457support postview, this requirement obviously does not apply.)</li>
2458<li>MUST NOT mirror the final captured still image or video streams returned
2459to application callbacks or committed to media storage</li>
2460</ul>
2461<a name="section-7.5.3"></a><h4 id="section-7.5.3">7.5.3. Camera API Behavior</h4>
2462<p>Device implementations MUST implement the following behaviors for the
2463camera-related APIs, for both front- and rear-facing cameras:</p>
2464<ol>
2465<li>If an application has never called
2466<code>android.hardware.Camera.Parameters.setPreviewFormat(int)</code>, then the
2467device MUST use <code>android.hardware.PixelFormat.YCbCr_420_SP</code> for
2468preview data provided to application callbacks.</li>
2469<li>If an application registers an <code>android.hardware.Camera.PreviewCallback
2470</code> instance and the system calls the <code>onPreviewFrame()</code> method
2471when the preview format is YCbCr_420_SP, the data in the <code>byte[]</code>
2472passed into <code>onPreviewFrame()</code> must further be in the NV21 encoding
2473format. That is, NV21 MUST be the default.</li>
2474<li>Device implementations MUST support the YV12 format (as denoted by the
2475<code>android.graphics.ImageFormat.YV12</code> constant) for camera previews
2476for both front- and rear-facing cameras. (The hardware video encoder and camera
2477may use any native pixel format, but the device implementation MUST support conversion
2478to YV12.)</li>
2479</ol>
2480<p>Device implementations MUST implement the full Camera API included in the
2481Android SDK documentation [<a href="#resources51">Resources, 51</a>]),
2482regardless of whether the device includes hardware autofocus or other
2483capabilities. For instance, cameras that lack autofocus MUST still call any
2484registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though
2485this has no relevance to a non-autofocus camera.) Note that this does apply
2486to front-facing cameras; for instance, even though most front-facing cameras
2487do not support autofocus, the API callbacks must still be "faked" as
2488described.</p>
2489<p>Device implementations MUST recognize and honor each parameter name defined
2490as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the
2491underlying hardware supports the feature. If the device hardware does not
2492support a feature, the API must behave as documented. Conversely, Device
2493implementations MUST NOT honor or recognize string constants passed
2494to the <code>android.hardware.Camera.setParameters()</code> method other than
2495those documented as constants on the
2496<code>android.hardware.Camera.Parameters</code>. That is,
2497device implementations MUST support all standard Camera parameters if the
2498hardware allows, and MUST NOT support custom Camera parameter types.
2499For instance, device implementations that support image capture using high dynamic range (HDR)
2500imaging techniques MUST support camera parameter <code>Camera.SCENE_MODE_HDR</code>
2501[<a href="#resources78">Resources, 78</a>]).</p>
2502<p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_PICTURE</code>
2503intent whenever a new picture is taken by the camera and the entry of the picture
2504has been added to the media store.</p>
2505<p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_VIDEO</code>
2506intent whenever a new video is recorded by the camera and the entry of the picture
2507has been added to the media store.</p>
2508<a name="section-7.5.4"></a><h4 id="section-7.5.4">7.5.4. Camera Orientation</h4>
2509<p>Both front- and rear-facing cameras, if present, MUST be oriented so that
2510the long dimension of the camera aligns with the screen's long dimension. That
2511is, when the device is held in the landscape orientation, cameras MUST
2512capture images in the landscape orientation. This applies regardless of the
2513device's natural orientation; that is, it applies to landscape-primary devices
2514as well as portrait-primary devices.</p>
2515
2516<a name="section-7.6"></a><h3 id="section-7.6">7.6. Memory and Storage</h3>
2517<a name="section-7.6.1"></a><h4 id="section-7.6.1">7.6.1. Minimum Memory and Storage</h4>
2518<p>Device implementations MUST have at least 340MB of memory available to the
2519kernel and userspace. The 340MB MUST be in addition to any memory dedicated to
2520hardware components such as radio, video, and so on that is not under the
2521kernel's control.</p>
2522<p>Device implementations with less than 512MB of memory available to the kernel
2523and userspace MUST return the value &quot;true&quot; for
2524<code>ActivityManager.isLowRamDevice()</code>.</p>
2525<p>Device implementations MUST have at least 1GB of non-volatile storage available
2526for application private data. That is, the <code>/data</code> partition MUST be at
2527least 1GB. Device implementations that run Android are <b>very strongly encouraged to
2528have at least 2GB of non-volatile storage for application private data</b> so they will be
2529able to upgrade to the future platform releases.</p>
2530
2531<p>The Android APIs include a Download Manager that applications may use to
2532download data files [<a href="#resources56">Resources, 56</a>]. The device
2533implementation of the Download Manager MUST be capable of downloading individual
2534files of at least 100MB in size to the default "cache" location.</p>
2535<a name="section-7.6.2"></a><h4 id="section-7.6.2">7.6.2. Shared External Storage</h4>
2536<p>Device implementations MUST offer shared storage for applications. The
2537shared storage provided MUST be at least 1GB in size.</p>
2538<p>Device implementations MUST be configured with shared storage mounted by
2539default, "out of the box". If the shared storage is not mounted on the Linux
2540path <code>/sdcard</code>, then the device MUST include a Linux symbolic link
2541from <code>/sdcard</code> to the actual mount point.</p>
2542<p>Device implementations MUST enforce as documented the
2543<code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this
2544shared storage. Shared storage MUST otherwise be writable by any application
2545that obtains that permission.</p>
2546<p>Device implementations MAY have hardware for user-accessible removable
2547storage, such as a Secure Digital card. Alternatively, device implementations
2548MAY allocate internal (non-removable) storage as shared storage for apps. The
2549upstream Android Open Source Project includes an implementation that uses
2550internal device storage for shared external storage APIs; device implementations
2551SHOULD use this configuration and software implementation.</p>
2552<p>Regardless of the form of shared storage used, device implementations MUST
2553provide some mechanism to access the contents of shared storage from a host
2554computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device
2555implementations MAY use USB mass storage, but SHOULD use Media Transfer
2556Protocol. If the device implementation supports Media Transfer Protocol:</p>
2557<ul>
2558<li>The device implementation SHOULD be compatible with the reference Android
2559MTP host, Android File Transfer [<a href="#resources57">Resources, 57</a>].</li>
2560<li>The device implementation SHOULD report a USB device class of <code>0x00</code>.</li>
2561<li>The device implementation SHOULD report a USB interface name of 'MTP'.</li>
2562</ul>
2563<p>If the device implementation lacks USB ports, it MUST provide a host
2564computer with access to the contents of shared storage by some other means,
2565such as a network file system.</p>
2566<p>It is illustrative to consider two common examples. If a device
2567implementation includes an SD card slot to satisfy the shared storage
2568requirement, a FAT-formatted SD card 1GB in size or larger MUST be included
2569with the device as sold to users, and MUST be mounted by default.
2570Alternatively, if a device implementation uses internal fixed storage to
2571satisfy this requirement, that storage MUST be 1GB in size or larger
2572and mounted on <code>/sdcard</code> (or <code>/sdcard</code>
2573MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p>
2574<p>Device implementations that include multiple shared storage paths (such as
2575both an SD card slot and shared internal storage) MUST NOT allow Android
2576applications to write to the secondary external storage, except for their
2577package-specific directories on the secondary external storage, but SHOULD
2578expose content from both storage paths transparently through Android's media
2579scanner service and android.provider.MediaStore.</p>
2580
2581<a name="section-7.7"></a><h3 id="section-7.7">7.7. USB</h3>
2582<p>Device implementations SHOULD include a USB client port, and SHOULD include
2583a USB host port.</p>
2584<p>If a device implementation includes a USB client port:</p>
2585<ul>
2586<li>the port MUST be connectable to a USB host with a standard USB-A port</li>
2587<li>the port SHOULD use the micro USB form factor on the device side. Existing and
2588new devices that run Android are <b>very strongly encouraged to meet these requirements
2589in Android</b> so they will be able to upgrade to the future platform releases</li>
2590<li>the port SHOULD be centered in the middle of an edge. Device implementations SHOULD either
2591locate the port on the bottom of the device (according to natural orientation) or enable software
2592screen rotation for all apps (including home screen), so that the display draws correctly when the device
2593is oriented with the port at bottom. Existing and new devices that run Androidare <b>very strongly
2594encouraged to meet these requirements in Android</b> so they will be able to upgrade to future platform releases.</li>
2595<li>if the device has other ports (such as a non-USB charging port) it SHOULD be on the same edge as the
2596micro-USB port</li>
2597<li>it MUST allow a host connected to the device to access the contents of the
2598shared storage volume using either USB mass storage or Media Transfer
2599Protocol</li>
2600<li>it MUST implement the Android Open Accessory API and specification as documented
2601in the Android SDK documentation, and MUST declare support for the hardware
2602feature <code>android.hardware.usb.accessory</code> [<a href="#resources52">Resources,
260352</a>]</li>
2604<li>it MUST implement the USB audio class as documented in the Android SDK documentation [<a href="#resources66">Resources, 66</a>]</li>
2605<li>it SHOULD implement support for USB battery charging specification [<a href="#resources64">Resources, 64</a>]
2606Existing and new devices that run Android are <b>very strongly encouraged to
2607meet these requirements</b>
2608so they will be able to upgrade to the future platform releases</li>
2609<li>The value of iSerialNumber in USB standard device descriptor MUST be equal to the value of android.os.Build.SERIAL.</li>
2610</ul>
2611<p>If a device implementation includes a USB host port:</p>
2612<ul>
2613<li>it MAY use a non-standard port form factor, but if so MUST ship with a
2614cable or cables adapting the port to standard USB-A</li>
2615<li>it MUST implement the Android USB host API as documented in the Android
2616SDK, and MUST declare support for the hardware feature
2617<code>android.hardware.usb.host</code> [<a href="#resources53">Resources, 53</a>]</li>
2618</ul>
2619<p>Device implementations MUST implement the Android Debug Bridge. If a device
2620implementation omits a USB client port, it MUST implement the Android Debug
2621Bridge via local-area network (such as Ethernet or 802.11)</p>
2622
2623<a name="section-8"></a><h2 id="section-8">8. Performance Compatibility</h2>
2624<p>Device implementations MUST meet the key performance metrics of an Android-
2625compatible device defined in the table below:</p>
2626<table><tbody><tr>
2627<td><b>Metric</b></td>
2628<td><b>Performance Threshold</b></td>
2629<td><b>Comments</b></td>
2630</tr>
2631<tr>
2632<td>Application Launch Time</td>
2633<td>The following applications should launch within the specified time.<ul>
2634<li>Browser: less than 1300ms</li>
2635<li>Contacts: less than 700ms</li>
2636<li>Settings: less than 700ms</li>
2637</ul></td>
2638<td>The launch time is measured as the total time to
2639complete loading the default activity for the application, including the time
2640it takes to start the Linux process, load the Android package into the Dalvik
2641VM, and call onCreate.</td>
2642</tr>
2643<tr>
2644<td>Simultaneous Applications</td>
2645<td>When multiple applications have been launched, re-launching an
2646already-running application after it has been launched must take less than the
2647original launch time.</td>
2648<td>&nbsp;</td>
2649</tr>
2650</tbody>
2651</table>
2652
2653<a name="section-9"></a><h2 id="section-9">9. Security Model Compatibility</h2>
2654<p>Device implementations MUST implement a security model consistent with the
2655Android platform security model as defined in Security and Permissions
2656reference document in the APIs [<a href="#resources54">Resources, 54</a>] in the
2657Android developer documentation. Device implementations MUST support
2658installation of self-signed applications without requiring any additional
2659permissions/certificates from any third parties/authorities. Specifically,
2660compatible devices MUST support the security mechanisms described in the
2661follow sub-sections.</p>
2662<a name="section-9.1"></a><h3 id="section-9.1">9.1. Permissions</h3>
2663<p>Device implementations MUST support the Android permissions model as
2664defined in the Android developer documentation [<a
2665href="#resources54">Resources, 54</a>]. Specifically,
2666implementations MUST enforce each permission defined as described in the SDK
2667documentation; no permissions may be omitted, altered, or ignored.
2668Implementations MAY add additional permissions, provided the new permission ID
2669strings are not in the android.* namespace.</p>
2670<a name="section-9.2"></a><h3 id="section-9.2">9.2. UID and Process Isolation</h3>
2671<p>Device implementations MUST support the Android application sandbox model,
2672in which each application runs as a unique Unix-style UID and in a separate
2673process. Device implementations MUST support running multiple applications as
2674the same Linux user ID, provided that the applications are properly signed and
2675constructed, as defined in the Security and Permissions reference [<a
2676href="#resources54">Resources, 54</a>].</p>
2677<a name="section-9.3"></a><h3 id="section-9.3">9.3. Filesystem Permissions</h3>
2678<p>Device implementations MUST support the Android file access permissions
2679model as defined in the Security and Permissions reference [<a
2680href="#resources54">Resources, 54</a>].</p>
2681<a name="section-9.4"></a><h3 id="section-9.4">9.4. Alternate Execution Environments</h3>
2682<p>Device implementations MAY include runtime environments that execute
2683applications using some other software or technology than the Dalvik virtual
2684machine or native code. However, such alternate execution environments MUST
2685NOT compromise the Android security model or the security of installed Android
2686applications, as described in this section.</p>
2687<p>Alternate runtimes MUST themselves be Android applications, and abide by
2688 the standard Android security model, as described elsewhere in Section 9.</p>
2689<p>Alternate runtimes MUST NOT be granted access to resources protected by
2690 permissions not requested in the runtime's AndroidManifest.xml file via the
2691 <code>&lt;uses-permission&gt;</code> mechanism.</p>
2692<p>Alternate runtimes MUST NOT permit applications to make use of features
2693 protected by Android permissions restricted to system applications.</p>
2694<p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p>
2695<ul>
2696<li>Alternate runtimes SHOULD install apps via the PackageManager into
2697 separate Android sandboxes (that is, Linux user IDs, etc.)</li>
2698<li>Alternate runtimes MAY provide a single Android sandbox shared by all
2699 applications using the alternate runtime</li>
2700<li>Alternate runtimes and installed applications using an alternate runtime
2701 MUST NOT reuse the sandbox of any other app installed on the device, except
2702 through the standard Android mechanisms of shared user ID and signing
2703 certificate</li>
2704<li>Alternate runtimes MUST NOT launch with, grant, or be granted access to
2705 the sandboxes corresponding to other Android applications</li>
2706</ul>
2707<p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other
2708 applications any privileges of the superuser (root), or of any other user ID.</p>
2709<p>The .apk files of alternate runtimes MAY be included in the system image of
2710 a device implementation, but MUST be signed with a key distinct
2711 from the key used to sign other applications included with the device
2712 implementation.</p>
2713<p>When installing applications, alternate runtimes MUST obtain user consent
2714 for the Android permissions used by the application. That is, if an
2715 application needs to make use of a device resource for which there is a
2716 corresponding Android permission (such as Camera, GPS, etc.), the alternate
2717 runtime MUST inform the user that the application will be able to access
2718 that resource. If the runtime environment does not record application
2719 capabilities in this manner, the runtime environment MUST list all
2720 permissions held by the runtime itself when installing any application
2721 using that runtime.</p>
2722
2723<a name="section-9.5"></a><h3 id="section-9.5">9.5. Multi-User Support </h3>
2724<p>Android includes support for multiple users and provides support for full user isolation
2725[<a href="#resources70">Resources, 70</a>].</p>
2726<p>Device implementations MUST meet these requirements related to multi-user support [<a href="#resources71">Resources, 71</a>]:</p>
2727<ul>
2728<li>As the behavior of the telephony APIs on devices with multiple users is currently undefined, device implementations that
2729declare android.hardware.telephony MUST NOT enable multi-user support. </li>
2730<li>Device implementations MUST, for each user, implement a security model consistent with the Android platform security model
2731as defined in Security and Permissions reference document in the APIs [Resources, 54]</li>
2732<li>Android includes support for restricted profiles, a feature that allows device owners to manage additional users and their capabilities
2733on the device. With restricted profiles, device owners can quickly set up separate environments for additional users to work in, with the ability to
2734manage finer-grained restrictions in the apps that are available in those environments. Device implementations that include support for multiple users
2735MUST include support for restricted profiles. The upstream Android Open Source Project includes an implementation that satisfies this requirement.</li>
2736</ul>
2737
2738<p>Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem.
2739However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user.
2740Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the
2741external storage APIs MUST encrypt the contents of the SD card if multi-user is enabled using a key stored only on non-removable media accessible only to the system. As this will make the
2742media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device
2743implementations MAY but SHOULD NOT enable multi-user if they use removable media [<a href="#resources72">Resources, 72</a>] for primary external storage.</p>
2744
2745<a name="section-9.6"></a><h3 id="section-9.6">9.6. Premium SMS Warning</h3>
2746<p>Android includes support for warning users for any outgoing premium SMS message [<a href="#resources73">Resources, 73</a>] . Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user.
2747Device implementations that declare support for <code>android.hardware.telephony</code> MUST warn users before sending a SMS message to numbers identified by regular expressions defined in <code>/data/misc/sms/codes.xml</code> file in the device.
2748The upstream Android Open Source Project provides an implementation that satisfies this requirement.
2749</p>
2750
2751<a name="section-9.7"></a><h3 id="section-9.7">9.7. Kernel Security Features</h3>
2752<p>The Android Sandbox includes features that can use the Security-Enhanced
2753Linux (SELinux) mandatory access control (MAC) system and other security
2754features in the Linux kernel. SELinux or any other security features, if
2755implemented below the Android framework:</p>
2756<ul>
2757<li>MUST maintain compatibility with existing applications</li>
2758<li>MUST not have a visible user interface, even when violations are detected
2759</li>
2760<li>SHOULD NOT be user or developer configurable</li>
2761</ul>
2762<p>If any API for configuration of policy is exposed to an application that can
2763affect another application (such as a Device Administration API), the API MUST
2764NOT allow configurations that break compatibility.</p>
2765<p>Devices MUST implement SELinux and meet the following requirements, which
2766are satisfied by the reference implementation in the upstream Android Open
2767Source Project.</p>
2768<ul>
2769<li>it MUST support a SELinux policy that allows the SELinux mode to be set on
2770a per-domain basis with:</li>
2771<ul>
2772 <li>domains that are in enforcing mode in the upstream Android Open Source
2773 implementation (such as installd, netd, and vold) MUST be in enforcing mode
2774 </li>
2775 <li>domain(s) for third-party applications SHOULD remain in permissive mode to
2776 ensure continued compatibility</li>
2777</ul>
2778<li>it SHOULD load policy from <code>/sepolicy</code> file on the device</li>
2779<li>it MUST support dynamic updates of the SELinux policy file without requiring
2780a system image update</li>
2781<li>it MUST log any policy violations without breaking applications or affecting
2782system behavior</li>
2783</ul>
2784
2785<p>Device implementations SHOULD retain the default SELinux policy provided in
2786the upstream Android Open Source Project, until they have first audited their
2787additions to the SELinux policy. Device implementations MUST be compatible with
2788the upstream Android Open Source Project.</p>
2789
2790<a name="section-9.8"></a><h3 id="section-9.8">9.8. Privacy</h3>
2791<p>If the device implements functionality in the system that captures the
2792contents displayed on the screen and/or records the audio stream played on the
2793device, it MUST continuously notify the user whenever this functionality is
2794enabled and actively capturing/recording.</p>
2795
2796<a name="section-9.9"></a><h3 id="section-9.9">9.9. Full-Disk Encryption</h3>
2797<p>IF the device has lockscreen, the device MUST support full-disk
2798encryption.</p>
2799
2800<a name="section-10"></a><h2 id="section-10">10. Software Compatibility Testing</h2>
2801<p>Device implementations MUST pass all tests described in this section.</p>
2802<p>However, note that no software test package is fully comprehensive. For
2803this reason, device implementers are very strongly encouraged to make the
2804minimum number of changes as possible to the reference and preferred
2805implementation of Android available from the Android Open Source Project.
2806This will minimize the risk of introducing bugs that create incompatibilities
2807requiring rework and potential device updates.</p>
2808<a name="section-10.1"></a><h3 id="section-10.1">10.1. Compatibility Test Suite</h3>
2809<p>Device implementations MUST pass the Android Compatibility Test Suite (CTS)
2810[<a href="#resources02">Resources, 2</a>] available from the Android Open Source
2811Project, using the final shipping software on the device. Additionally, device
2812implementers SHOULD use the reference implementation in the Android Open
2813Source tree as much as possible, and MUST ensure compatibility in cases of
2814ambiguity in CTS and for any reimplementations of parts of the reference
2815source code.</p>
2816<p>The CTS is designed to be run on an actual device. Like any software, the
2817CTS may itself contain bugs. The CTS will be versioned independently of this
2818Compatibility Definition, and multiple revisions of the CTS may be released
2819for Android 4.4. Device implementations MUST pass the latest CTS version
2820available at the time the device software is completed.</p>
2821<a name="section-10.2"></a><h3 id="section-10.2">10.2. CTS Verifier</h3>
2822<p>Device implementations MUST correctly execute all applicable cases in the
2823CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite,
2824and is intended to be run by a human operator to test functionality that
2825cannot be tested by an automated system, such as correct functioning of a
2826camera and sensors.</p>
2827<p>The CTS Verifier has tests for many kinds of hardware, including some
2828hardware that is optional. Device implementations MUST pass all tests for
2829hardware which they possess; for instance, if a device possesses an
2830accelerometer, it MUST correctly execute the Accelerometer test case in the
2831CTS Verifier. Test cases for features noted as optional by this Compatibility
2832Definition Document MAY be skipped or omitted.</p>
2833<p>Every device and every build MUST correctly run the CTS Verifier, as noted
2834above. However, since many builds are very similar, device implementers are
2835not expected to explicitly run the CTS Verifier on builds that differ only in
2836trivial ways. Specifically, device implementations that differ from an
2837implementation that has passed the CTS Verifier only by the set of included
2838locales, branding, etc. MAY omit the CTS Verifier test.</p>
2839<a name="section-10.3"></a><h3 id="section-10.3">10.3. Reference Applications</h3>
2840<p>Device implementers MUST test implementation compatibility using the
2841following open source applications:</p>
2842<ul>
2843<li>The "Apps for Android" applications [<a href="#resources55">Resources, 55</a>]</li>
2844<li>Replica Island (available in Google Play Store)</li>
2845</ul>
2846<p>Each app above MUST launch and behave correctly on the implementation, for
2847the implementation to be considered compatible.</p>
2848
2849
2850<a name="section-11"></a><h2 id="section-11">11. Updatable Software</h2>
2851<p>Device implementations MUST include a mechanism to replace the entirety of
2852the system software. The mechanism need not perform "live" upgrades - that
2853is, a device restart MAY be required.</p>
2854<p>Any method can be used, provided that it can replace the entirety of the
2855software preinstalled on the device. For instance, any of the following
2856approaches will satisfy this requirement:</p>
2857<ul>
2858<li>Over-the-air (OTA) downloads with offline update via reboot</li>
2859<li>"Tethered" updates over USB from a host PC</li>
2860<li>"Offline" updates via a reboot and update from a file on removable
2861storage</li>
2862</ul>
2863<p>The update mechanism used MUST support updates without wiping user data.
2864That is, the update mechanism MUST preserve application private data
2865and application shared data. Note that the upstream Android software includes
2866an update mechanism that satisfies this requirement.</p>
2867<p>If an error is found in a device implementation after it has been released
2868but within its reasonable product lifetime that is determined in consultation
2869with the Android Compatibility Team to affect the compatibility of third-party
2870applications, the device implementer MUST correct the error via a software
2871update available that can be applied per the mechanism just described.</p>
2872
2873<a name="section-12"></a><h2 id="section-12">12. Document Changelog</h2>
2874<p>The following table contains a summary of the changes to the Compatibility Definition in this release.</p>
2875<table width="100%" border="1">
2876 <tr>
2877 <th width="25%" scope="col">Section(s)</th>
2878 <th width="75%" scope="col">Summary of change</th>
2879 </tr>
2880 <tr>
2881 <td>3.2.2. Build Parameters</td>
2882 <td>Revised descriptions of BRAND, DEVICE, and PRODUCT. SERIAL is now
2883required.</td>
2884 </tr>
2885 <tr>
2886 <td>3.2.3.5. Default App Settings</td>
2887 <td>New section that adds requirement to comply with new default
2888 application settings</td>
2889 </tr>
2890 <tr>
2891 <td>3.3.1 Application Binary Interfaces</td>
2892 <td>Clarified allowed values for the <code>android.os.Build.CPU_ABI</code>
2893 and <code>android.os.Build.CPU_ABI2</code> parameters.</td>
2894 </tr>
2895 <tr>
2896 <td>3.4.1. WebView Compatibility</td>
2897 <td>Added Chromium as required WebView implementation.</td>
2898 </tr>
2899 <tr>
2900 <td>3.7. Virtual Machine Compatibility</td>
2901 <td>Added requirement for xxhdpi and 400dpi screen densities.</td>
2902 </tr>
2903 <tr>
2904 <td>3.8.6. Themes</td>
2905 <td>Updated to reflect use of translucent system bars.</td>
2906 </tr>
2907 <tr>
2908 <td>3.8.12. Location</td>
2909 <td>New section that adds requirement location settings be centralized.</td>
2910 </tr>
2911 <tr>
2912 <td>3.8.13. Unicode</td>
2913 <td>New section that adds requirement for emoji support.</td>
2914 </tr>
2915 <tr>
2916 <td>3.9. Device Administration</td>
2917 <td>Noted preinstalled administrative applications cannot be the default
2918 Device Owner application.</td>
2919 </tr>
2920 <tr>
2921 <td>5.1. Media Codecs</td>
2922 <td>Added VP9 decoder requirement. Added recommended specification for
2923 hardware VP8 codecs.</td>
2924 </tr>
2925 <tr>
2926 <td>5.3. Video Decoding</td>
2927 <td>Added VP9. Added recommendation for dynamic resolution switching.</td>
2928 </tr>
2929 <tr>
2930 <td>5.4. Audio Recording</td>
2931 <td>Added <code>REMOTE_SUBMIX</code> as new required audio source. Made use
2932 of <code>android.media.audiofx.NoiseSuppressor</code> API a requirement.</td>
2933 </tr>
2934 <tr>
2935 <td>6.2.1 Experimental</td>
2936 <td>New section that introduces the ART runtime and requires Dalvik as the
2937 default runtime.</td>
2938 </tr>
2939 <tr>
2940 <td>7.1.1. Screen Configuration</td>
2941 <td>Replaced 1.85 aspect ratio with 1.86. Added 400dpi screen density.</td>
2942 </tr>
2943 <tr>
2944 <td>7.1.6. Screen Types</td>
2945 <td>Added 640 dpi (4K) resolution configuration.</td>
2946 </tr>
2947 <tr>
2948 <td>7.2.3. Navigation keys</td>
2949 <td>Added Recents function as essential; demoted Menu function in priority.</td>
2950 </tr>
2951 <tr>
2952 <td>7.3.6. Thermometer</td>
2953 <td>Added SENSOR_TYPE_AMBIENT_TEMPERATURE as recommended thermometer.</td>
2954 </tr>
2955 <tr>
2956 <td>7.4.2.2. Wi-Fi Tunneled Direct Link Setup</td>
2957 <td>New section that adds support for Wi-Fi Tunneled Direct Link Setup
2958 (TDLS).</td>
2959 </tr>
2960 <tr>
2961 <td>7.4.4. Near-Field Communications</td>
2962 <td>Added Host Card Emulation (HCE) as a requirement. Replaced SNEP GET with
2963 Logical Link Control Protocol (LLCP) and added the Bluetooth Object Push
2964 Profile as a requirement.</td>
2965 </tr>
2966 <tr>
2967 <td>7.4.6. Sync Settings</td>
2968 <td>New section that adds requirement auto-sync data be enabled by default.</td>
2969 </tr>
2970 <tr>
2971 <td>7.6.1. Minimum Memory and Storage</td>
2972 <td>Added <code>ActivityManager.isLowRamDevice()</code> setting requirement
2973 for devices with less than 512MB of memory. Increased storage requirements
2974 from 512MB and 1GB to 1GB and 2GB, respectively.</td>
2975 </tr>
2976 <tr>
2977 <td>7.6.2. Shared "External" Storage</td>
2978 <td>Editorial fixes such as change of section name, and moved text that fits
2979 in this section from section 9.5. Noted applications may write to their
2980 package-specific directories on secondary external storage.</td>
2981 </tr>
2982 <tr>
2983 <td>7.7. USB</td>
2984 <td>Added requirement all devices report a USB serial number.</td>
2985 </tr>
2986 <tr>
2987 <td>9.5. Multi-User Support</td>
2988 <td>Moved non multi-user specific text to section 7.6.2.</td>
2989 </tr>
2990 <tr>
2991 <td>9.7. Kernel Security Features</td>
2992 <td>Rewritten to note switch of SELinux to enforcing mode and requirement
2993 SELinux output not be rendered in the user interface.</td>
2994 </tr>
2995 <tr>
2996 <td>9.8. Privacy</td>
2997 <td>New section that adds requirement audio and video recording must trigger
2998 continuous notifications to the user.</td>
2999 </tr>
3000 <tr>
3001 <td>9.9. Full-Disk Encryption</td>
3002 <td>New section that adds requirement devices with lockscreen support full-disk encryption.</td>
3003 </tr>
3004 <tr>
3005 <td>12. Document Changelog</td>
3006 <td>New section that summarizes changes in the CDD by section.</td>
3007 </tr>
3008</table>
3009<p>&nbsp;</p>
3010
3011<a name="section-13"></a><h2 id="section-13">13. Contact Us</h2>
3012<p>You can contact the document authors at <a
3013href="mailto:compatibility@android.com">compatibility@android.com</a> for
3014clarifications and to bring up any issues that you think the document does not
3015cover.</p>
3016
3017<div style="page-break-before: always;"></div>
3018
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3020<pdf:pagenumber/>
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