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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 2.1 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 2.1 Compatibility Definition</h1>
11<p>Copyright &copy; 2010, Google Inc. All rights reserved.<br/>
12<a href="mailto:compatibility@android.com">compatibility@android.com</a>
13</p>
14
15<h2>1. Introduction</h2>
16<p>This document enumerates the requirements that must be met in order for
17mobile phones to be compatible with Android 2.1.</p>
18<p>The use of "must", "must not", "required", "shall", "shall not", "should",
19"should not", "recommended", "may" and "optional" is per the IETF standard
20defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p>
21<p>As used in this document, a "device implementer" or "implementer" is a
22person or organization developing a hardware/software solution running Android
232.1. A "device implementation" or "implementation" is the hardware/software
24solution so developed.</p>
25<p>To be considered compatible with Android 2.1, device implementations:</p>
26<ul>
27<li>MUST meet the requirements presented in this Compatibility Definition,
28including any documents incorporated via reference.</li>
29<li>MUST pass the most recent version of the Android Compatibility Test Suite
30(CTS) available at the time of the device implementation's software is
31completed. (The CTS is available as part of the Android Open Source Project [<a
32href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the
33components outlined in this document.</li>
34</ul>
35<p>Where this definition or the CTS is silent, ambiguous, or incomplete, it is
36the responsibility of the device implementer to ensure compatibility with
37existing implementations. For this reason, the Android Open Source Project [<a
38href="#resources03">Resources, 3</a>] is both the reference and preferred
39implementation of Android. Device implementers are strongly encouraged to base
40their implementations on the "upstream" source code available from the Android
41Open Source Project. While some components can hypothetically be replaced with
42alternate implementations this practice is strongly discouraged, as passing
43the CTS tests will become substantially more difficult. It is the
44implementer's responsibility to ensure full behavioral compatibility with the
45standard Android implementation, including and beyond the Compatibility Test
46Suite. Finally, note that certain component substitutions and modifications
47are explicitly forbidden by this document.</p>
48
49<a name="resources"/><h2>2. Resources</h2>
50<ol>
51<a name="resources01"/><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li>
52<a name="resources02"/><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li>
53<a name="resources03"/><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li>
54<a name="resources04"/><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li>
55<a name="resources05"/><li>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>
56<a name="resources06"/><li>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>
57<a name="resources07"/><li>Android 2.1 allowed version strings: <a href="http://source.android.com/compatibility/2.1/versions.xhtml">http://source.android.com/compatibility/2.1/versions.xhtml</a></li>
58<a name="resources08"/><li>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>
59<a name="resources09"/><li>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>
60<a name="resources10"/><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li>
61<a name="resources11"/><li>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>
62<a name="resources12"/><li>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>
63<a name="resources13"/><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li>
64<a name="resources14"/><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design.html#statusbarstructure">http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure</a></li>
65<a name="resources15"/><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li>
66<a name="resources16"/><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li>
67<a name="resources17"/><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li>
68<a name="resources18"/><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li>
69<a name="resources19"/><li>Reference tool documentation (for adb, aapt, ddms): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li>
70<a name="resources20"/><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li>
71<a name="resources21"/><li>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>
72<a name="resources22"/><li>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>
73<a name="resources23"/><li>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>
74<a name="resources24"/><li>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>
75<a name="resources25"/><li>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>
76<a name="resources26"/><li>android.hardware.Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li>
77<a name="resources27"/><li>Sensor coordinate space: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li>
78<a name="resources28"/><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li>
79<a name="resources29"/><li>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>
80</ol>
81<p>Many of these resources are derived directly or indirectly from the Android
822.1 SDK, and will be functionally identical to the information in that SDK's
83documentation. In any cases where this Compatibility Definition or the
84Compatibility Test Suite disagrees with the SDK documentation, the SDK
85documentation is considered authoritative. Any technical details provided in
86the references included above are considered by inclusion to be part of this
87Compatibility Definition.</p>
88
89<h2>3. Software</h2>
90<p>The Android platform includes a set of managed APIs, a set of native APIs,
91and a body of so-called "soft" APIs such as the Intent system and
92web-application APIs. This section details the hard and soft APIs that are
93integral to compatibility, as well as certain other relevant technical and
94user interface behaviors. Device implementations MUST comply with all the
95requirements in this section.</p>
96
97<h3>3.1. Managed API Compatibility</h3>
98<p>The managed (Dalvik-based) execution environment is the primary vehicle for
99Android applications. The Android application programming interface (API) is
100the set of Android platform interfaces exposed to applications running in the
101managed VM environment. Device implementations MUST provide complete
102implementations, including all documented behaviors, of any documented API
103exposed by the Android 2.1 SDK [<a href="#resources04">Resources, 4</a>].</p>
104<p>Device implementations MUST NOT omit any managed APIs, alter API interfaces
105or signatures, deviate from the documented behavior, or include no-ops, except
106where specifically allowed by this Compatibility Definition.</p>
107
108<h3>3.2. Soft API Compatibility</h3>
109<p>In addition to the managed APIs from Section 3.1, Android also includes a
110significant runtime-only "soft" API, in the form of such things such as
111Intents, permissions, and similar aspects of Android applications that cannot
112be enforced at application compile time. This section details the "soft" APIs
113and system behaviors required for compatibility with Android 2.1. Device
114implementations MUST meet all the requirements presented in this section.</p>
115<h4>3.2.1. Permissions</h4>
116<p>Device implementers MUST support and enforce all permission constants as
117documented by the Permission reference page [<a
118href="#resources05">Resources, 5</a>]. Note that Section 10 lists addtional
119requirements related to the Android security model.</p>
120<h4>3.2.2. Build Parameters</h4>
121<p>The Android APIs include a number of constants on the <code>android.os.Build</code>
122class [<a href="#resources06">Resources, 6</a>] that are intended to describe
123the current device. To provide consistent, meaningful values across device
124implementations, the table below includes additional restrictions on the
125formats of these values to which device implementations MUST conform.</p>
126<table>
127<tbody>
128<tr>
129<td><b>Parameter</b></td>
130<td><b>Comments</b></td>
131</tr>
132<tr>
133<td>android.os.Build.VERSION.RELEASE</td>
134<td>The version of the currently-executing Android system, in human-readable
135format. This field MUST have one of the string values defined in [<a
136href="#resources07">Resources, 7</a>].</td>
137</tr>
138<tr>
139<td>android.os.Build.VERSION.SDK</td>
140<td>The version of the currently-executing Android system, in a format
141accessible to third-party application code. For Android 2.1, this field MUST have
142the integer value 7.</td>
143</tr>
144<tr>
145<td>android.os.Build.VERSION.INCREMENTAL</td>
146<td>A value chosen by the device implementer designating the specific build of
147the currently-executing Android system, in human-readable format. This value
148MUST NOT be re-used for different builds shipped to end users. A typical use
149of this field is to indicate which build number or source-control change
150identifier was used to generate the build. There are no requirements on the
151specific format of this field, except that it MUST NOT be null or the empty
152string ("").</td>
153</tr>
154<tr>
155<td>android.os.Build.BOARD</td>
156<td>A value chosen by the device implementer identifying the specific internal
157hardware used by the device, in human-readable format. A possible use of this
158field is to indicate the specific revision of the board powering the device.
159There are no requirements on the specific format of this field, except that it
160MUST NOT be null or the empty string ("").</td>
161</tr>
162<tr>
163<td>android.os.Build.BRAND</td>
164<td>A value chosen by the device implementer identifying the name of the
165company, organization, individual, etc. who produced the device, in
166human-readable format. A possible use of this field is to indicate the OEM
167and/or carrier who sold the device. There are no requirements on the specific
168format of this field, except that it MUST NOT be null or the empty string
169("").</td>
170</tr>
171<tr>
172<td>android.os.Build.DEVICE</td>
173<td>A value chosen by the device implementer identifying the specific
174configuration or revision of the body (sometimes called "industrial design")
175of the device. There are no requirements on the specific format of this field,
176except that it MUST NOT be null or the empty string ("").</td>
177</tr>
178<tr>
179<td>android.os.Build.FINGERPRINT</td>
180<td>A string that uniquely identifies this build. It SHOULD be reasonably
181human-readable. It MUST follow this template:
182<br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE)/$(BOARD):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/>
183For example:
184<br/><code>acme/mydevice/generic/generic:2.1-update1/ERC77/3359:userdebug/test-keys</code><br/>
185The fingerprint MUST NOT include spaces. If other fields included in the
186template above have spaces, they SHOULD be replaced with the ASCII underscore
187("_") character in the fingerprint.</td>
188</tr>
189<tr>
190<td>android.os.Build.HOST</td>
191<td>A string that uniquely identifies the host the build was built on, in
192human readable format. There are no requirements on the specific format of
193this field, except that it MUST NOT be null or the empty string ("").</td>
194</tr>
195<tr>
196<td>android.os.Build.ID</td>
197<td>An identifier chosen by the device implementer to refer to a specific
198release, in human readable format. This field can be the same as
199android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
200meaningful for end users to distinguish between software builds. There are no
201requirements on the specific format of this field, except that it MUST NOT be
202null or the empty string ("").</td>
203</tr>
204<tr>
205<td>android.os.Build.MODEL</td>
206<td>A value chosen by the device implementer containing the name of the device
207as known to the end user. This SHOULD be the same name under which the device
208is marketed and sold to end users. There are no requirements on the specific
209format of this field, except that it MUST NOT be null or the empty string
210("").</td>
211</tr>
212<tr>
213<td>android.os.Build.PRODUCT</td>
214<td>A value chosen by the device implementer containing the development name
215or code name of the device. MUST be human-readable, but is not necessarily
216intended for view by end users. There are no requirements on the specific
217format of this field, except that it MUST NOT be null or the empty string
218("").</td>
219</tr>
220<tr>
221<td>android.os.Build.TAGS</td>
222<td>A comma-separated list of tags chosen by the device implementer that
223further distinguish the build. For example, "unsigned,debug". This field MUST
224NOT be null or the empty string (""), but a single tag (such as "release") is
225fine.</td>
226</tr>
227<tr>
228<td>android.os.Build.TIME</td>
229<td>A value representing the timestamp of when the build occurred.</td>
230</tr>
231<tr>
232<td>android.os.Build.TYPE</td>
233<td>A value chosen by the device implementer specifying the runtime
234configuration of the build. This field SHOULD have one of the values
235corresponding to the three typical Android runtime configurations: "user",
236"userdebug", or "eng".</td>
237</tr>
238<tr>
239<td>android.os.Build.USER</td>
240<td>A name or user ID of the user (or automated user) that generated the
241build. There are no requirements on the specific format of this field, except
242that it MUST NOT be null or the empty string ("").</td>
243</tr>
244</tbody>
245</table>
246<h4>3.2.3. Intent Compatibility</h4>
247<p>Android uses Intents to achieve loosely-coupled integration between
248applications. This section describes requirements related to the Intent
249patterns that MUST be honored by device implementations. By "honored", it is
250meant that the device implementer MUST provide an Android Activity or Service
251that specifies a matching Intent filter and binds to and implements correct
252behavior for each specified Intent pattern.</p>
253<h4>3.2.3.1. Core Application Intents</h4>
254<p>The Android upstream project defines a number of core applications, such as
255a phone dialer, calendar, contacts book, music player, and so on. Device
256implementers MAY replace these applications with alternative versions.</p>
257<p>However, any such alternative versions MUST honor the same Intent patterns
258provided by the upstream project. For example, if a device contains an
259alternative music player, it must still honor the Intent pattern issued by
260third-party applications to pick a song.</p>
261<p>The following applications are considered core Android system
262applications:</p>
263<ul>
264<li>Desk Clock</li>
265<li>Browser</li>
266<li>Calendar</li>
267<li>Calculator</li>
268<li>Camera</li>
269<li>Contacts</li>
270<li>Email</li>
271<li>Gallery</li>
272<li>GlobalSearch</li>
273<li>Launcher</li>
274<li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted
275if the device does not support Live Wallpapers, per Section 3.8.5.)</li>
276<li>Messaging (AKA "Mms")</li>
277<li>Music</li>
278<li>Phone</li>
279<li>Settings</li>
280<li>SoundRecorder</li>
281</ul>
282<p>The core Android system applications include various Activity, or Service
283components that are considered "public".
284That is, the attribute "android:exported" may be absent, or may have the value
285"true".</p>
286<p>For every Activity or Service defined
287in one of the core Android system apps that is not marked as non-public via an
288android:exported attribute with the value "false", device implementations MUST
289include a compontent of the same type implementing the same Intent filter
290patterns as the core Android system app.</p>
291<p>In other words, a device implementation MAY replace core Android system
292apps; however, if it does, the device implementation MUST support all Intent
293patterns defined by each core Android system app being replaced.</p>
294<h4>3.2.3.2. Intent Overrides</h4>
295<p>As Android is an extensible platform, device implementers MUST allow each
296Intent pattern defined in core system apps to be overridden by third-party
297applications. The upstream Android open source project allows this by default;
298device implementers MUST NOT attach special privileges to system applications'
299use of these Intent patterns, or prevent third-party applications from binding
300to and assuming control of these patterns. This prohibition specifically
301includes but is not limited to disabling the "Chooser" user interface which
302allows the user to select between multiple applications which all handle the
303same Intent pattern.</p>
304<div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div>
305<h4>3.2.3.3. Intent Namespaces</h4>
306<p>Device implementers MUST NOT include any Android component that honors any
307new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other
308key string in the android.* namespace. Device implementers MUST NOT include
309any Android components that honor any new Intent or Broadcast Intent patterns
310using an ACTION, CATEGORY, or other key string in a package space belonging to
311another organization. Device implementers MUST NOT alter or extend any of the
312Intent patterns used by the core apps listed in Section 3.2.3.1.</p>
313<p>This prohibition is analogous to that specified for Java language classes
314in Section 3.6.</p>
315<h4>3.2.3.4. Broadcast Intents</h4>
316<p>Third-party applications rely on the platform to broadcast certain Intents
317to notify them of changes in the hardware or software environment.
318Android-compatible devices MUST broadcast the public broadcast Intents in
319response to appropriate system events. Broadcast Intents are described in the
320SDK documentation.</p>
321
322<h3>3.3. Native API Compatibility</h3>
323<p>Managed code running in Dalvik can call into native code provided in the
324application .apk file as an ELF .so file compiled for the appropriate device
325hardware architecture. Device implementations MUST include support for code
326running in the managed environment to call into native code, using the
327standard Java Native Interface (JNI) semantics. The following APIs MUST be
328available to native code:</p>
329<ul>
330<li>libc (C library)</li>
331<li>libm (math library)</li>
332<li>JNI interface</li>
333<li>libz (Zlib compression)</li>
334<li>liblog (Android logging)</li>
335<li>Minimal support for C++</li>
336<li>Support for OpenGL, as described below</li>
337</ul>
338<p>Device implementations MUST support OpenGL ES 1.0. Devices that lack
339hardware acceleration MUST implement OpenGL ES 1.0 using a software renderer.
340Device implementations SHOULD implement as much of OpenGL ES 1.1 as the device
341hardware supports. Device implementations SHOULD provide an implementation
342for OpenGL ES 2.0, if the hardware is capable of reasonable performance on
343those APIs.</p>
344<p>These libraries MUST be source-compatible (i.e. header compatible) and
345binary-compatible (for a given processor architecture) with the versions
346provided in Bionic by the Android Open Source project. Since the Bionic
347implementations are not fully compatible with other implementations such as
348the GNU C library, device implementers SHOULD use the Android implementation.
349If device implementers use a different implementation of these libraries, they
350MUST ensure header, binary, and behavioral compatibility.</p>
351<p>Device implementations MUST accurately report the native Application Binary
352Interface (ABI) supported by the device, via the
353<code>android.os.Build.CPU_ABI</code> API. The ABI MUST be one of the entries
354documented in the latest version of the Android NDK, in the file
355<code>docs/CPU-ARCH-ABIS.txt</code>. Note that additional releases of the
356Android NDK may introduce support for additional ABIs.</p>
357<p>Native code compatibility is challenging. For this reason, it should be
358repeated that device implementers are VERY strongly encouraged to use the
359upstream implementations of the libraries listed above, to help ensure
360compatibility.</p>
361
362<h3>3.4. Web API Compatibility</h3>
363<p>Many developers and applications rely on the behavior of the
364<code>android.webkit.WebView</code> class [<a
365href="#resources08">Resources, 8</a>]
366for their user interfaces, so the WebView implementation must be
367compatible across Android implementations. The Android Open Source
368implementation uses the WebKit rendering engine to implement the
369WebView.</p>
370<p>Because it is not feasible to develop a comprehensive test suite for a web
371browser, device implementers MUST use the specific upstream build of WebKit in
372the WebView implementation. Specifically:</p>
373<ul>
374<li>WebView MUST use the 530.17 WebKit build from the upstream Android Open
375Source tree for Android 2.1. This build includes a specific set of functionality
376and security fixes for the WebView.</li>
377<li>The user agent string reported by the WebView MUST be in this format:<br/>
378 <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Mobile Safari/530.17</code>
379 <ul>
380 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li>
381 <li>The value of the $(LOCALE) string SHOULD follow the ISO conventions for country code and language, and SHOULD refer to the current configured locale of the device</li>
382 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li>
383 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li>
384 </ul></li>
385</ul>
386<p>Implementations MAY ship a custom user agent string in the standalone
387Browser application. What's more, the standalone Browser MAY be based on an
388alternate browser technology (such as Firefox, Opera, etc.) However, even if an
389alternate Browser application is shipped, the WebView component provided to
390third-party applications MUST be based on WebKit, as above.</p>
391<p>The WebView configuration MUST include support for the HTML5 database,
392application cache, and geolocation APIs [<a href="#resources09">Resources,
3939</a>]. The WebView MUST include support for
394the HTML5 <code>&lt;video&gt;</code> tag in
395some form. The standalone Browser application (whether based on the upstream
396WebKit Browser application or a third-party replacement) MUST include support
397for the same HTML5 features just listed for WebView.</p>
398
399<h3>3.5. API Behavioral Compatibility</h3>
400<p>The behaviors of each of the API types (managed, soft, native, and web)
401must be consistent with the preferred implementation of the upstream Android
402open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas
403of compatibility are:</p>
404<ul>
405<li>Devices MUST NOT change the behavior or meaning of a standard Intent</li>
406<li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.)</li>
407<li>Devices MUST NOT change the semantics of a particular permission</li>
408</ul>
409<p>The above list is not comprehensive, and the onus is on device implementers
410to ensure behavioral compatibility. For this reason, device implementers
411SHOULD use the source code available via the Android Open Source Project where
412possible, rather than re-implement significant parts of the system.</p>
413<p>The Compatibility Test Suite (CTS) tests significant portions of the
414platform for behavioral compatibility, but not all. It is the responsibility
415of the implementer to ensure behavioral compatibility with the Android Open
416Source Project.</p>
417
418<h3>3.6. API Namespaces</h3>
419<p>Android follows the package and class namespace conventions defined by the
420Java programming language. To ensure compatibility with third-party
421applications, device implementers MUST NOT make any prohibited modifications
422(see below) to these package namespaces:</p>
423<ul>
424<li>java.*</li>
425<li>javax.*</li>
426<li>sun.*</li>
427<li>android.*</li>
428<li>com.android.*</li>
429</ul>
430<p>Prohibited modifications include:</p>
431<ul>
432<li>Device implementations MUST NOT modify the publicly exposed APIs on the
433Android platform by changing any method or class signatures, or by removing
434classes or class fields.</li>
435<li>Device implementers MAY modify the underlying implementation of the APIs,
436but such modifications MUST NOT impact the stated behavior and Java-language
437signature of any publicly exposed APIs.</li>
438<li>Device implementers MUST NOT add any publicly exposed elements (such as
439classes or interfaces, or fields or methods to existing classes or interfaces)
440to the APIs above.</li>
441</ul>
442<p>A "publicly exposed element" is any construct which is not decorated with
443the "@hide" marker in the upstream Android source code. In other words, device
444implementers MUST NOT expose new APIs or alter existing APIs in the namespaces
445noted above. Device implementers MAY make internal-only modifications, but
446those modifications MUST NOT be advertised or otherwise exposed to
447developers.</p>
448<p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
449namespace owned by or referring to another organization. For instance, device
450implementers MUST NOT add APIs to the com.google.* or similar namespace; only
451Google may do so. Similarly, Google MUST NOT add APIs to other companies'
452namespaces.</p>
453<p>If a device implementer proposes to improve one of the package namespaces
454above (such as by adding useful new functionality to an existing API, or
455adding a new API), the implementer SHOULD visit source.android.com and begin
456the process for contributing changes and code, according to the information on
457that site.</p>
458<p>Note that the restrictions above correspond to standard conventions for
459naming APIs in the Java programming language; this section simply aims to
460reinforce those conventions and make them binding through inclusion in this
461compatibility definition.</p>
462
463<h3>3.7. Virtual Machine Compatibility</h3>
464<p>Device implementations MUST support the full Dalvik Executable (DEX)
465bytecode specification and Dalvik Virtual Machine semantics [<a
466href="#resources10">Resources, 10</a>].</p>
467<p>Device implementations MUST configure Dalvik to allocate at least 16MB of
468memory to each application on devices with screens classified as medium- or
469low-density. Device implementations MUST configure Dalvik to allocate at least
47024MB of memory to each application on devices with screens classified as
471high-density. Note that device implementations MAY allocate more memory than
472these figures, but are not required to.</p>
473
474<h3>3.8. User Interface Compatibility</h3>
475<p>The Android platform includes some developer APIs that allow developers to
476hook into the system user interface. Device implementations MUST incorporate
477these standard UI APIs into custom user interfaces they develop, as explained
478below.</p>
479<h4>3.8.1. Widgets</h4>
480<p>Android defines a component type and corresponding API and lifecycle that
481allows applications to expose an "AppWidget" to the end user [<a
482href="#resources11">Resources, 11</a>].
483The Android Open Source reference release includes a Launcher application that
484includes user interface elements allowing the user to add, view, and remove
485AppWidgets from the home screen.</p>
486<p>Device implementers MAY substitute an alternative to the reference Launcher
487(i.e. home screen). Alternative Launchers SHOULD include built-in support for
488AppWidgets, and expose user interface elements to add, configure, view, and remove
489AppWidgets directly within the Launcher. Alternative Launchers MAY omit these
490user interface elements; however, if they are omitted, the device implementer
491MUST provide a separate application accessible from the Launcher that allows
492users to add, configure, view, and remove AppWidgets.</p>
493<h4>3.8.2. Notifications</h4>
494<p>Android includes APIs that allow developers to notify users of notable
495events [<a href="#resources12">Resources, 12</a>]. Device implementers MUST provide support for each
496class of notification so defined; specifically: sounds, vibration, light and
497status bar.</p>
498<p>Additionally, the implementation MUST correctly render all resources
499(icons, sound files, etc.) provided for in the APIs [<a
500href="#resources13">Resources, 13</a>], or in the
501Status Bar icon style guide [<a href="#resources14">Resources, 14</a>]. Device implementers MAY provide
502an alternative user experience for notifications than that provided by the
503reference Android Open Source implementation; however, such alternative
504notification systems MUST support existing notification resources, as
505above.</p>
506<h4>3.8.3. Search</h4>
507<p>Android includes APIs [<a href="#resources15">Resources, 15</a>] that allow developers to incorporate
508search into their applications, and expose their application's data into the
509global system search. Generally speaking, this functionality consists of a
510single, system-wide user interface that allows users to enter queries,
511displays suggestions as users type, and displays results. The Android APIs
512allow developers to reuse this interface to provide search within their own
513apps, and allow developers to supply results to the common global search user
514interface.</p>
515<p>Device implementations MUST include a single, shared, system-wide search
516user interface capable of real-time suggestions in response to user input.
517Device implementations MUST implement the APIs that allow developers to reuse
518this user interface to provide search within their own applications. Device
519implementations MUST implement the APIs that allow third-party applications to
520add suggestions to the search box when it is run in global search mode. If no
521third-party applications are installed that make use of this functionality,
522the default behavior SHOULD be to display web search engine results and
523suggestions.</p>
524<p>Device implementations MAY ship alternate search user interfaces, but
525SHOULD include a hard or soft dedicated search button, that can be used at any
526time within any app to invoke the search framework, with the behavior provided
527for in the API documentation.</p>
528<h4>3.8.4. Toasts</h4>
529<p>Applications can use the "Toast" API (defined in [<a
530href="#resources16">Resources, 16</a>]) to
531display short non-modal strings to the end user, that disappear after a brief
532period of time. Device implementations MUST display Toasts from applications
533to end users in some high-visibility manner.</p>
534<h4>3.8.5. Live Wallpapers</h4>
535<p>Android defines a component type and corresponding API and lifecycle that
536allows applications to expose one or more "Live Wallpapers" to the end user
537[<a href="#resources17">Resources, 17</a>]. Live Wallpapers are animations,
538patterns, or similar images with limited input capabilities that display as a
539wallpaper, behind other applications.</p>
540<p>Hardware is considered capable of reliably running live wallpapers if it
541can run all live wallpapers, with no limitations on functionality, at a
542reasonable framerate with no adverse affects on other applications. If
543limitations in the hardware cause wallpapers and/or applications to crash,
544malfunction, consume excessive CPU or battery power, or run at unacceptably
545low frame rates, the hardware is considered incapable of running live
546wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0
547context to render their content. Live wallpaper will not run reliably on
548hardware that does not support multiple OpenGL contexts because the live
549wallpaper use of an OpenGL context may conflict with other applications that
550also use an OpenGL context. </p>
551<p>Device implemenations capable of running live wallpapers reliably as
552described above SHOULD implement live wallpapers. Device implementations
553determined to not run live wallpapers reliably as described above MUST NOT
554implement live wallpapers.</p>
555
556<h2>4. Reference Software Compatibility</h2>
557<p>Device implementers MUST test implementation compatibility using the
558following open-source applications:</p>
559<ul>
560<li>Calculator (included in SDK)</li>
561<li>Lunar Lander (included in SDK)</li>
562<li>The "Apps for Android" applications [<a href="#resources18">Resources, 18</a>].</li>
563</ul>
564<p>Each app above MUST launch and behave correctly on the implementation, for
565the implementation to be considered compatible.</p>
566<p>Additionally, device implementations MUST test each menu item (including all
567sub-menus) of each of these smoke-test applications:</p>
568<ul>
569<li>ApiDemos (included in SDK)</li>
570<li>ManualSmokeTests (included in CTS)</li>
571</ul>
572<p>Each test case in the applications above MUST run correctly on the device
573implementation.</p>
574
575<h2>5. Application Packaging Compatibility</h2>
576<p>Device implementations MUST install and run Android ".apk" files as
577generated by the "aapt" tool included in the official Android SDK [<a
578href="#resources19">Resources, 19</a>].</p>
579<p>Devices implementations MUST NOT extend either the .apk [<a
580href="#resources20">Resources, 20</a>], Android Manifest [<a
581href="#resources21">Resources, 21</a>],
582or Dalvik bytecode [<a href="#resources10">Resources, 10</a>] formats in such
583a way that would prevent those files from
584installing and running correctly on other compatible devices. Device
585implementers SHOULD use the reference upstream implementation of Dalvik, and
586the reference implementation's package management system.</p>
587
588<h2>6. Multimedia Compatibility</h2>
589<p>Device implemenations MUST support the following multimedia codecs. All of
590these codecs are provided as software implementations in the preferred Android
591implementation from the Android Open Source Project.</p>
592<p>Please note that neither Google nor the Open Handset Alliance make any
593representation that these codecs are unencumbered by third-party patents.
594Those intending to use this source code in hardware or software products are
595advised that implementations of this code, including in open source software
596or shareware, may require patent licenses from the relevant patent
597holders.</p>
598<table><tbody>
599<tr>
600<td rowspan="11"><b>Audio</b></td>
601</tr>
602<tr>
603<td><b>Name</b></td>
604<td><b>Encoder</b></td>
605<td><b>Decoder</b></td>
606<td><b>Details</b></td>
607<td><b>File/Container Format</b></td>
608</tr>
609<tr>
610<td>AAC LC/LTP</td>
611<td>&nbsp;</td>
612<td>X</td>
613<td rowspan="3">Mono/Stereo content in any combination of standard bit rates up to 160 kbps and sampling rates between 8 to 48kHz</td>
614<td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td>
615</tr>
616<tr>
617<td>HE-AACv1 (AAC+)</td>
618<td>&nbsp;</td>
619<td>X</td>
620</tr>
621<tr>
622<td>HE-AACv2 (enhanced AAC+)</td>
623<td>&nbsp;</td>
624<td>X</td>
625</tr>
626<tr>
627<td>AMR-NB</td>
628<td>X</td>
629<td>X</td>
630<td>4.75 to 12.2 kbps sampled @ 8kHz</td>
631<td>3GPP (.3gp)</td>
632</tr>
633<tr>
634<td>AMR-WB</td>
635<td>&nbsp;</td>
636<td>X</td>
637<td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>
638<td>3GPP (.3gp)</td>
639</tr>
640<tr>
641<td>MP3</td>
642<td>&nbsp;</td>
643<td>X</td>
644<td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td>
645<td>MP3 (.mp3)</td>
646</tr>
647<tr>
648<td>MIDI</td>
649<td>&nbsp;</td>
650<td>X</td>
651<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>
652<td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td>
653</tr>
654<tr>
655<td>Ogg Vorbis</td>
656<td>&nbsp;</td>
657<td>X</td>
658<td>&nbsp;</td>
659<td>Ogg (.ogg)</td>
660</tr>
661<tr>
662<td>PCM</td>
663<td>&nbsp;</td>
664<td>X</td>
665<td>8- and 16-bit linear PCM (rates up to limit of hardware)</td>
666<td>WAVE (.wav)</td>
667</tr>
668<tr>
669<td rowspan="5"><b>Image</b></td>
670</tr>
671<tr>
672<td>JPEG</td>
673<td>X</td>
674<td>X</td>
675<td>base+progressive</td>
676<td>&nbsp;</td>
677</tr>
678<tr>
679<td>GIF</td>
680<td>&nbsp;</td>
681<td>X</td>
682<td>&nbsp;</td>
683<td>&nbsp;</td>
684</tr>
685<tr>
686<td>PNG</td>
687<td>X</td>
688<td>X</td>
689<td>&nbsp;</td>
690<td>&nbsp;</td>
691</tr>
692<tr>
693<td>BMP</td>
694<td>&nbsp;</td>
695<td>X</td>
696<td>&nbsp;</td>
697<td>&nbsp;</td>
698</tr>
699<tr>
700<td rowspan="4"><b>Video</b></td>
701</tr>
702<tr>
703<td>H.263</td>
704<td>X</td>
705<td>X</td>
706<td>&nbsp;</td>
707<td>3GPP (.3gp) files</td>
708</tr>
709<tr>
710<td>H.264</td>
711<td>&nbsp;</td>
712<td>X</td>
713<td>&nbsp;</td>
714<td>3GPP (.3gp) and MPEG-4 (.mp4) files</td>
715</tr>
716<tr>
717<td>MPEG4 Simple Profile</td>
718<td>&nbsp;</td>
719<td>X</td>
720<td>&nbsp;</td>
721<td>3GPP (.3gp) file</td>
722</tr>
723</tbody>
724</table>
725<p>Note that the table above does not list specific bitrate requirements for
726most video codecs. The reason for this is that in practice, current device
727hardware does not necessarily support bitrates that map exactly to the
728required bitrates specified by the relevant standards. Instead, device
729implementations SHOULD support the highest bitrate practical on the hardware,
730up to the limits defined by the specifications.</p>
731
732<h2>7. Developer Tool Compatibility</h2>
733<p>Device implemenations MUST support the Android Developer Tools provided in
734the Android SDK. Specifically, Android-compatible devices MUST be compatible
735with:</p>
736<ul>
737<li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources19">Resources, 19</a>]<br/>
738Device implementations MUST support all <code>adb</code> functions as
739documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD
740be inactive by default, but there MUST be a user-accessible mechanism to turn
741on the Android Debug Bridge.</li>
742<li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources19">Resources, 19</a>]<br/>
743Device implementations MUST support all <code>ddms</code> features as documented in the
744Android SDK. As <code>ddms</code> uses <code>adb</code>, support for
745<code>ddms</code> SHOULD be inactive by default,
746but MUST be supported whenever the user has activated the Android Debug
747Bridge, as above.</li>
748<li><b>Monkey</b> [<a href="#resources22">Resources, 22</a>]<br/>
749Device implementations MUST include the Monkey framework, and make it
750available for applications to use.</li>
751</ul>
752
753<h2>8. Hardware Compatibility</h2>
754<p>Android is intended to support device implementers creating innovative form
755factors and configurations. At the same time Android developers expect
756certain hardware, sensors and APIs across all Android device. This section
757lists the hardware features that all Android 2.1 compatible devices must
758support.</p>
759<p>If a device includes a particular hardware component that has a
760corresponding API for third-party developers, the device implementation MUST
761implement that API as defined in the Android SDK documentation. If an API in
762the SDK interacts with a hardware component that is stated to be optional and the device
763implementation does not possess that component:</p>
764<ul>
765<li>class definitions for the component's APIs MUST be present</li>
766<li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li>
767<li>API methods MUST return null values where permitted by the SDK documentation</li>
768<li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li>
769</ul>
770<p>A typical example of a scenario where these requirements apply is the
771telephony API: even on non-phone devices, these APIs must be implemented as
772reasonable no-ops.</p>
773<p>Device implementations MUST accurate report accurate hardware configuration
774information via the <code>getSystemAvailableFeatures()</code> and
775<code>hasSystemFeature(String)</code> methods on the
776<code>android.content.pm.PackageManager</code> class.</p>
777
778<h3>8.1. Display</h3>
779<p>Android 2.1 includes facilities that perform certain automatic scaling and
780transformation operations under some circumstances, to ensure that third-party
781applications run reasonably well on a variety of hardware configurations [<a
782href="#resources23">Resources, 23</a>]. Devices MUST properly implement these
783behaviors, as detailed in this section.</p>
784<p>For Android 2.1, this are the most common display configurations:</p>
785<table><tbody>
786<tr>
787<td>Screen Type</td>
788<td>Width (Pixels)</td>
789<td>Height (Pixels)</td>
790<td>Diagonal Length Range (inches)</td>
791<td>Screen Size Group</td>
792<td>Screen Density Group</td>
793</tr>
794<tr>
795<td>QVGA</td>
796<td>240</td>
797<td>320</td>
798<td>2.6 - 3.0</td>
799<td>Small</td>
800<td>Low</td>
801</tr>
802<tr>
803<td>WQVGA</td>
804<td>240</td>
805<td>400</td>
806<td>3.2 - 3.5</td>
807<td>Normal</td>
808<td>Low</td>
809</tr>
810<tr>
811<td>FWQVGA</td>
812<td>240</td>
813<td>432</td>
814<td>3.5 - 3.8</td>
815<td>Normal</td>
816<td>Low</td>
817</tr>
818<tr>
819<td>HVGA</td>
820<td>320</td>
821<td>480</td>
822<td>3.0 - 3.5</td>
823<td>Normal</td>
824<td>Medium</td>
825</tr>
826<tr>
827<td>WVGA</td>
828<td>480</td>
829<td>800</td>
830<td>3.3 - 4.0</td>
831<td>Normal</td>
832<td>High</td>
833</tr>
834<tr>
835<td>FWVGA</td>
836<td>480</td>
837<td>854</td>
838<td>3.5 - 4.0</td>
839<td>Normal</td>
840<td>High</td>
841</tr>
842<tr>
843<td>WVGA </td>
844<td>480 </td>
845<td>800 </td>
846<td>4.8 - 5.5 </td>
847<td>Large </td>
848<td>Medium</td>
849</tr>
850<tr>
851<td>FWVGA</td>
852<td>480</td>
853<td>854</td>
854<td>5.0 - 5.8</td>
855<td>Large</td>
856<td>Medium</td>
857</tr>
858</tbody></table>
859
860<p>Device implementations corresponding to one of the standard configurations
861above MUST be configured to report the indicated screen size to applications
862via the <code>android.content.res.Configuration</code> [<a href="#resources24">Resources,
86324</a>] class.</p>
864<p>Some .apk packages have manifests that do not identify them as supporting a
865specific density range. When running such applications, the following
866constraints apply:</p>
867<ul>
868<li>Device implementations MUST interpret resources in a .apk that lack a
869density qualifier as defaulting to "medium" (known as "mdpi" in the SDK
870documentation.)</li>
871<li>When operating on a "low" density screen, device implementations MUST
872scale down medium/mdpi assets by a factor of 0.75.</li>
873<li>When operating on a "high" density screen, device implementations MUST
874scale up medium/mdpi assets by a factor of 1.5.</li>
875<li>Device implementations MUST NOT scale assets within a density range, and
876MUST scale assets by exactly these factors between density ranges.</li>
877</ul>
878
879<h4>8.1.2. Non-Standard Display Configurations</h4>
880<p>Display configurations that do not match one of the standard configurations
881listed in Section 8.1.1 require additional consideration and work to be
882compatible. Device implementers MUST contact Android Compatibility Team as
883provided for in Section 12 to obtain classifications for screen-size bucket,
884density, and scaling factor. When provided with this information, device
885implementations MUST implement them as specified.</p>
886<p>Note that some display configurations (such as very large or very small
887screens, and some aspect ratios) are fundamentally incompatible with Android
8882.1; therefore device implementers are encouraged to contact Android
889Compatibility Team as early as possible in the development process.</p>
890<h4>8.1.3. Display Metrics</h4>
891<p>Device implementations MUST report correct valuesfor all display metrics
892defined in <code>android.util.DisplayMetrics</code> [<a
893href="#resources25">Resources, 25</a>].</p>
894
895<h3>8.2. Keyboard</h3>
896<p>Device implementations:</p>
897<ul>
898<li>MUST include support for the Input Management Framework (which allows third party developers to create Input Management Engines -- i.e. soft keyboard) as detailed at developer.android.com</li>
899<li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li>
900<li>MAY include additional soft keyboard implementations</li>
901<li>MAY include a hardware keyboard</li>
902<li>MUST NOT include a hardware keyboard that does not match one of the
903formats specified in <code>android.content.res.Configuration.keyboard</code>
904[<a href="#resources24">Resources, 24</a>] (that is, QWERTY, or 12-key)</li>
905</ul>
906<h3>8.3. Non-touch Navigation</h3>
907<p>Device implementations:</p>
908<ul>
909<li>MAY omit a non-touch navigation options (that is, may omit a trackball, d-pad, or wheel)</li>
910<li>MUST report the correct value for
911<code>android.content.res.Configuration.navigation</code> [<a href="#resources24">Resources, 24</a>]</li>
912</ul>
913<h3>8.4. Screen Orientation</h3>
914<p>Compatible devices MUST support dynamic orientation by applications to
915either portrait or landscape screen orientation. That is, the device must
916respect the application's request for a specific screen orientation. Device
917implementations MAY select either portrait or landscape orientation as the
918default.</p>
919<p>Devices MUST report the correct value for the device's current orientation,
920whenever queried via the android.content.res.Configuration.orientation,
921android.view.Display.getOrientation(), or other APIs.</p>
922
923<h3>8.5. Touchscreen input</h3>
924<p>Device implementations:</p>
925<ul>
926<li>MUST have a touchscreen</li>
927<li>MAY have either capacative or resistive touchscreen</li>
928<li>MUST report the value of <code>android.content.res.Configuration</code>
929[<a href="#resources24">Resources, 24</a>]
930reflecting corresponding to the type of the specific touchscreen on the
931device</li>
932</ul>
933
934<h3>8.6. USB</h3>
935<p>Device implementations:</p>
936<ul>
937<li>MUST implement a USB client, connectable to a USB host with a standard
938USB-A port</li>
939<li>MUST implement the Android Debug Bridge over USB (as described in Section
9407)</li>
941<li>MUST implement the USB mass storage specification, to allow a host
942connected to the device to access the contents of the /sdcard volume </li>
943<li>SHOULD use the micro USB form factor on the device side</li>
944<li>MAY include a non-standard port on the device side, but if so MUST ship
945with a cable capable of connecting the custom pinout to standard USB-A
946port</li>
947</ul>
948
949<h3>8.7. Navigation keys</h3>
950<p>The Home, Menu and Back functions are essential to the Android navigation
951paradigm. Device implementations MUST make these functions available to the
952user at all times, regardless of application state. These functions SHOULD be
953implemented via dedicated buttons. They MAY be implemented using software,
954gestures, touch panel, etc., but if so they MUST be always accessible and not
955obscure or interfere with the available application display area.</p>
956<p>Device implementers SHOULD also provide a dedicated search key. Device
957implementers MAY also provide send and end keys for phone calls.</p>
958
959<h3>8.8. Wireless Data Networking</h3>
960<p>Device implementations MUST include support for wireless high-speed data
961networking. Specifically, device implementations MUST include support for at
962least one wireless data standard capable of 200Kbit/sec or greater. Examples of
963technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, etc.</p>
964<p>If a device implementation includes a particular modality for which the
965Android SDK includes an API (that is, WiFi, GSM, or CDMA), the implementation
966MUST support the API.</p>
967<p>Devices MAY implement more than one form of wireless data connectivity.
968Devices MAY implement wired data connectivity (such as Ethernet), but MUST
969nonetheless include at least one form of wireless connectivity, as above.</p>
970<h3>8.9. Camera</h3>
971<p>Device implementations MUST include a camera. The included camera:</p>
972<ul>
973<li>MUST have a resolution of at least 2 megapixels</li>
974<li>SHOULD have either hardware auto-focus, or software auto-focus implemented
975in the camera driver (transparent to application software)</li>
976<li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li>
977<li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST
978NOT be lit while an android.hardware.Camera.PreviewCallback instance has been
979registered on a Camera preview surface, unless the application has explicitly
980enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or
981<code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code>
982object. Note that this constraint does not apply to the device's built-in
983system camera application, but only to third-party applications using
984<code>Camera.PreviewCallback</code>.</li>
985</ul>
986<p>Device implementations MUST implement the following behaviors for the
987camera-related APIs:</p>
988<ol>
989<li>If an application has never called
990android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST
991use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to
992application callbacks.</li>
993<li>If an application registers an android.hardware.Camera.PreviewCallback
994instance and the system calls the onPreviewFrame() method when the preview
995format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame()
996must further be in the NV21 encoding format. (This is the format used natively
997by the 7k hardware family.) That is, NV21 MUST be the default.</li>
998</ol>
999<p>Device implementations MUST implement the full Camera API included in the
1000Android 2.1 SDK documentation [<a href="#resources26">Resources, 26</a>]),
1001regardless of whether the device includes hardware autofocus or other
1002capabilities. For instance, cameras that lack autofocus MUST still call any
1003registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though
1004this has no relevance to a non-autofocus camera.)</p>
1005<p>Device implementations MUST recognize and honor each parameter name defined
1006as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the
1007underlying hardware supports the feature. If the device hardware does not
1008support a feature, the API must behave as documented. Conversely, Device
1009implementations MUST NOT honor or recognize string constants passed
1010to the <code>android.hardware.Camera.setParameters()</code> method other than
1011those documented as constants on the
1012<code>android.hardware.Camera.Parameters</code>, unless the constants are
1013prefixed with a string indicating the name of the device implementer. That is,
1014device implementations MUST support all standard Camera parameters if the
1015hardware allows, and MUST NOT support custom Camera parameter types unless
1016the parameter names are clearly indicated via a string prefix to be non-standard.</p>
1017
1018<h3>8.10. Accelerometer</h3>
1019<p>Device implementations MUST include a 3-axis accelerometer and MUST be able
1020to deliver events at 50 Hz or greater. The coordinate system used by the
1021accelerometer MUST comply with the Android sensor coordinate system as detailed
1022in the Android APIs (see [<a href="#resources27">Resources, 27</a>]).</p>
1023
1024<h3>8.11. Compass</h3>
1025<p>Device implementations MUST include a 3-axis compass and MUST be able to
1026deliver events 10 Hz or greater. The coordinate system used by the compass
1027MUST comply with the Android sensor coordinate system as defined in the Android
1028API (see [<a href="#resources27">Resources, 27</a>]).</p>
1029
1030<h3>8.12. GPS</h3>
1031<p>Device implementations MUST include a GPS, and SHOULD include some form of
1032"assisted GPS" technique to minimize GPS lock-on time.</p>
1033
1034<h3>8.13. Telephony</h3>
1035<p>Android 2.1 MAY be used on devices that do not include telephony hardware.
1036That is, Android 2.1 is compatible with devices that are not phones.
1037However, if a device implementation does include GSM or CDMA telephony, it
1038MUST implement the full support for the API for that technology. Device
1039implementations that do not include telephony hardware MUST implement the full
1040APIs as no-ops.</p>
1041<p>See also Section 8.8, Wireless Data Networking.</p>
1042
1043<h3>8.14. Memory and Storage</h3>
1044<p>Device implementations MUST have at least 92MB of memory available to the
1045kernel and userspace. The 92MB MUST be in addition to any memory dedicated to
1046hardware components such as radio, memory, and so on that is not under the
1047kernel's control.</p>
1048<p>Device implementations MUST have at least 150MB of non-volatile storage
1049available for user data. That is, the <code>/data</code> partition must be at
1050least 150MB.</p>
1051<div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div>
1052
1053<h3>8.15. Application Shared Storage</h3>
1054<p>Device implementations MUST offer shared storage for applications. The
1055shared storage provided MUST be at least 2GB in size.</p>
1056<p>Device implementations MUST be configured with shared storage mounted by
1057default, "out of the box". If the shared storage is not mounted on the Linux
1058path <code>/sdcard</code>, then the device MUST include a Linux symbolic link
1059from <code>/sdcard</code> to the actual mount point.</p>
1060<p>Device implementations MUST enforce as documented the
1061<code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this
1062shared storage. Shared storage MUST otherwise be writable by any application
1063that obtains that permission.</p>
1064<p>Device implementations MAY have hardware for user-accessible removable
1065storage, such as a Secure Digital card. Alternatively, device implementations
1066MAY allocate internal (non-removable) storage as shared storage for apps.</p>
1067<p>Regardless of the form of shared storage used, the shared storage MUST
1068implement USB mass storage, as described in Section 8.6. As shipped out of the
1069box, the shared storage MUST be mounted with the FAT filesystem.</p>
1070<p>It is illustrative to consider two common examples. If a device
1071implementation includes an SD card slot to satisfy the shared storage
1072requirement, a FAT-formatted SD card 2GB in size or larger MUST be included
1073with the device as sold to users, and MUST be mounted by default.
1074Alternatively, if a device implementation uses internal fixed storage to
1075satisfy this requirement, that storage MUST be 2GB in size or larger and
1076mounted on <code>/sdcard</code> (or <code>/sdcard</code> MUST be a symbolic
1077link to the physical location if it is mounted elsewhere.)</p>
1078<div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div>
1079
1080<h3>8.16. Bluetooth</h3>
1081<p>Device implementations MUST include a Bluetooth transceiver. Device
1082implementations MUST enable the RFCOMM-based Bluetooth API as described in the
1083SDK documentation [<a href="#resources29">Resources, 29</a>]. Device
1084implementations SHOULD implement relevant Bluetooth profiles, such as A2DP,
1085AVRCP, OBEX, etc. as appropriate for the device.</p>
1086<div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div>
1087
1088<h2>9. Performance Compatibility</h2>
1089<p>One of the goals of the Android Compatibility Program is to enable
1090consistent application experience to consumers. Compatible implementations
1091must ensure not only that applications simply run correctly on the device, but
1092that they do so with reasonable performance and overall good user experience.
1093Device implementations MUST meet the key performance metrics of an Android 2.1
1094compatible device defined in the table below:</p>
1095<table><tbody><tr>
1096<td><b>Metric</b></td>
1097<td><b>Performance Threshold</b></td>
1098<td><b>Comments</b></td>
1099</tr>
1100<tr>
1101<td>Application Launch Time</td>
1102<td>The following applications should launch within the specified time.<ul>
1103<li>Browser: less than 1300ms</li>
1104<li>MMS/SMS: less than 700ms</li>
1105<li>AlarmClock: less than 650ms</li>
1106</ul></td>
1107<td>The launch time is measured as the total time to
1108complete loading the default activity for the application, including the time
1109it takes to start the Linux process, load the Android package into the Dalvik
1110VM, and call onCreate.</td>
1111</tr>
1112<tr>
1113<td>Simultaneous Applications</td>
1114<td>When multiple applications have been launched, re-launching an
1115already-running application after it has been launched must take less than the
1116original launch time.</td>
1117<td>&nbsp;</td>
1118</tr>
1119</tbody>
1120</table>
1121
1122<h2>10. Security Model Compatibility</h2>
1123<p>Device implementations MUST implement a security model consistent with the
1124Android platform security model as defined in Security and Permissions
1125reference document in the APIs [<a href="#resources28">Resources, 28</a>] in the
1126Android developer documentation. Device implementations MUST support
1127installation of self-signed applications without requiring any additional
1128permissions/certificates from any third parties/authorities. Specifically,
1129compatible devices MUST support the security mechanisms described in the
1130follow sub-sections.</p>
1131<h3>10.1. Permissions</h3>
1132<p>Device implementations MUST support the Android permissions model as
1133defined in the Android developer documentation [<a
1134href="#resources28">Resources, 28</a>]. Specifically,
1135implementations MUST enforce each permission defined as described in the SDK
1136documentation; no permissions may be omitted, altered, or ignored.
1137Implementations MAY add additional permissions, provided the new permission ID
1138strings are not in the android.* namespace.</p>
1139<h3>10.2. UID and Process Isolation</h3>
1140<p>Device implementations MUST support the Android application sandbox model,
1141in which each application runs as a unique Unix-style UID and in a separate
1142process. Device implementations MUST support running multiple applications as
1143the same Linux user ID, provided that the applications are properly signed and
1144constructed, as defined in the Security and Permissions reference [<a
1145href="#resources28">Resources, 28</a>].</p>
1146<h3>10.3. Filesystem Permissions</h3>
1147<p>Device implementations MUST support the Android file access permissions
1148model as defined in as defined in the Security and Permissions reference [<a
1149href="#resources28">Resources, 28</a>].</p>
1150
1151<h2>11. Compatibility Test Suite</h2>
1152<p>Device implementations MUST pass the Android Compatibility Test Suite (CTS)
1153[<a href="#resources02">Resources, 2</a>] available from the Android Open Source
1154Project, using the final shipping software on the device. Additionally, device
1155implementers SHOULD use the reference implementation in the Android Open
1156Source tree as much as possible, and MUST ensure compatibility in cases of
1157ambiguity in CTS and for any reimplementations of parts of the reference
1158source code.</p>
1159<p>The CTS is designed to be run on an actual device. Like any software, the
1160CTS may itself contain bugs. The CTS will be versioned independently of this
1161Compatibility Definition, and multiple revisions of the CTS may be released
1162for Android 2.1. Device implementations MUST pass the latest CTS version
1163available at the time the device software is completed.</p>
1164
1165<h2>12. Updatable Software</h2>
1166<p>Device implementations MUST include a mechanism to replace the entirety of
1167the system software. The mechanism need not perform "live" upgrades -- that
1168is, a device restart MAY be required.</p>
1169<p>Any method can be used, provided that it can replace the entirety of the
1170software preinstalled on the device. For instance, any of the following
1171approaches will satisfy this requirement:</p>
1172<ul>
1173<li>Over-the-air (OTA) downloads with offline update via reboot</li>
1174<li>"Tethered" updates over USB from a host PC</li>
1175<li>"Offline" updates via a reboot and update from a file on removable
1176storage</li>
1177</ul>
1178<p>The update mechanism used MUST support updates without wiping user data.
1179Note that the upstream Android software includes an update mechanism that
1180satisfies this requirement.</p>
1181<p>If an error is found in a device implementation after it has been released
1182but within its reasonable product lifetime that is determined in consultation
1183with the Android Compatibility Team to affect the compatibility of thid-party
1184applications, the device implementer MUST correct the error via a software
1185update available that can be applied per the mechanism just described.</p>
1186
1187<h2>13. Contact Us</h2>
1188<p>You can contact the document authors at <a
1189href="mailto:compatibility@android.com">compatibility@android.com</a> for
1190clarifications and to bring up any issues that you think the document does not
1191cover.</p>
1192</body>
1193</html>