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				4	<head>
				5	<title>Android 2.2 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 2.2 Compatibility Definition</h1>
				11	<!--<span style="color: red; font-weight: bold;"><h2>DRAFT</h2></span>-->
				12	<p>Copyright © 2010, Google Inc. All rights reserved.<br/>
				13	<a href="mailto:compatibility@android.com">compatibility@android.com</a>
				14	</p>
				15
				16	<h2> Table of Contents</h2>
				17	<div style="margin-left: 2em;">
				18	<a href="#section-1">1. Introduction</a><br/>
				19	<a href="#section-2">2. Resources</a><br/>
				20	<a href="#section-3">3. Software</a><br/>
				21	<div style="margin-left: 2em;">
				22	<a href="#section-3.1">3.1. Managed API Compatibility</a><br/>
				23	<a href="#section-3.2">3.2. Soft API Compatibility</a><br/>
				24	<div style="margin-left: 2em;">
				25	<a href="#section-3.2.1">3.2.1. Permissions</a><br/>
				26	<a href="#section-3.2.2">3.2.2. Build Parameters</a><br/>
				27	<a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/>
				28	<div style="margin-left: 2em;">
				29	<a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/>
				30	<a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/>
				31	<a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/>
				32	<a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/>
				33	</div>
				34	</div>
				35	<a href="#section-3.3">3.3. Native API Compatibility</a><br/>
				36	<a href="#section-3.4">3.4. Web Compatibility</a><br/>
				37	<div style="margin-left: 2em;">
				38	<a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/>
				39	<a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/>
				40	</div>
				41	<a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/>
				42	<a href="#section-3.6">3.6. API Namespaces</a><br/>
				43	<a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/>
				44	<a href="#section-3.8">3.8. User Interface Compatibility</a><br/>
				45	<div style="margin-left: 2em;">
				46	<a href="#section-3.8.1">3.8.1. Widgets</a><br/>
				47	<a href="#section-3.8.2">3.8.2. Notifications</a><br/>
				48	<a href="#section-3.8.3">3.8.3. Search</a><br/>
				49	<a href="#section-3.8.4">3.8.4. Toasts</a><br/>
				50	<a href="#section-3.8.5">3.8.5. Live Wallpapers</a><br/>
				51	</div>
				52	</div>
				53	<a href="#section-4">4. Reference Software Compatibility</a><br/>
				54	<a href="#section-5">5. Application Packaging Compatibility</a><br/>
				55	<a href="#section-6">6. Multimedia Compatibility</a><br/>
				56	<div style="margin-left: 2em;">
				57	<a href="#section-6.1">6.1. Media Codecs</a><br/>
				58	<a href="#section-6.2">6.2. Audio Recording</a><br/>
				59	<a href="#section-6.3">6.3. Audio Latency</a><br/>
				60	</div>
				61	<a href="#section-7">7. Developer Tool Compatibility</a><br/>
				62	<a href="#section-8">8. Hardware Compatibility</a><br/>
				63	<div style="margin-left: 2em;">
				64	<a href="#section-8.1">8.1. Display</a><br/>
				65	<div style="margin-left: 2em;">
				66	<a href="#section-8.1.2">8.1.2. Non-Standard Display Configurations</a><br/>
				67	<a href="#section-8.1.3">8.1.3. Display Metrics</a><br/>
				68	<a href="#section-8.1.4">8.1.4. Declared Screen Support</a><br/>
				69	</div>
				70	<a href="#section-8.2">8.2. Keyboard</a><br/>
				71	<a href="#section-8.3">8.3. Non-touch Navigation</a><br/>
				72	<a href="#section-8.4">8.4. Screen Orientation</a><br/>
				73	<a href="#section-8.5">8.5. Touchscreen input</a><br/>
				74	<a href="#section-8.6">8.6. USB</a><br/>
				75	<a href="#section-8.7">8.7. Navigation keys</a><br/>
				76	<a href="#section-8.8">8.8. Wireless Data Networking</a><br/>
				77	<a href="#section-8.9">8.9. Camera</a><br/>
				78	<a href="#section-8.10">8.10. Accelerometer</a><br/>
				79	<a href="#section-8.11">8.11. Compass</a><br/>
				80	<a href="#section-8.12">8.12. GPS</a><br/>
				81	<a href="#section-8.13">8.13. Telephony</a><br/>
				82	<a href="#section-8.14">8.14. Memory and Storage</a><br/>
				83	<a href="#section-8.15">8.15. Application Shared Storage</a><br/>
				84	<a href="#section-8.16">8.16. Bluetooth</a><br/>
				85	</div>
				86	<a href="#section-9">9. Performance Compatibility</a><br/>
				87	<a href="#section-10">10. Security Model Compatibility</a><br/>
				88	<div style="margin-left: 2em;">
				89	<a href="#section-10.1">10.1. Permissions</a><br/>
				90	<a href="#section-10.2">10.2. UID and Process Isolation</a><br/>
				91	<a href="#section-10.3">10.3. Filesystem Permissions</a><br/>
				92	<a href="#section-10.4">10.4. Alternate Execution Environments</a><br/>
				93	</div>
				94	<a href="#section-11">11. Compatibility Test Suite</a><br/>
				95	<a href="#section-12">12. Updatable Software</a><br/>
				96	<a href="#section-13">13. Contact Us</a><br/>
				97	<a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/>
				98	</div>
				99
				100	<div style="page-break-before: always;"></div>
				101
				102	<a name="section-1"></a><h2>1. Introduction</h2>
				103	<p>This document enumerates the requirements that must be met in order for
				104	mobile phones to be compatible with Android 2.2.</p>
				105	<p>The use of "must", "must not", "required", "shall", "shall not", "should",
				106	"should not", "recommended", "may" and "optional" is per the IETF standard
				107	defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p>
				108	<p>As used in this document, a "device implementer" or "implementer" is a
				109	person or organization developing a hardware/software solution running Android
				110	2.2. A "device implementation" or "implementation" is the hardware/software
				111	solution so developed.</p>
				112	<p>To be considered compatible with Android 2.2, device implementations:</p>
				113	<ul>
				114	<li>MUST meet the requirements presented in this Compatibility Definition,
				115	including any documents incorporated via reference.</li>
				116	<li>MUST pass the most recent version of the Android Compatibility Test Suite
				117	(CTS) available at the time of the device implementation's software is
				118	completed. (The CTS is available as part of the Android Open Source Project [<a
				119	href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the
				120	components outlined in this document.</li>
				121	</ul>
				122	<p>Where this definition or the CTS is silent, ambiguous, or incomplete, it is
				123	the responsibility of the device implementer to ensure compatibility with
				124	existing implementations. For this reason, the Android Open Source Project [<a
				125	href="#resources03">Resources, 3</a>] is both the reference and preferred
				126	implementation of Android. Device implementers are strongly encouraged to base
				127	their implementations on the "upstream" source code available from the Android
				128	Open Source Project. While some components can hypothetically be replaced with
				129	alternate implementations this practice is strongly discouraged, as passing
				130	the CTS tests will become substantially more difficult. It is the
				131	implementer's responsibility to ensure full behavioral compatibility with the
				132	standard Android implementation, including and beyond the Compatibility Test
				133	Suite. Finally, note that certain component substitutions and modifications
				134	are explicitly forbidden by this document.</p>
				135
				136	<a name="section-2"></a><h2>2. Resources</h2>
				137	<ol>
				138	<a name="resources01"></a><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li>
				139	<a name="resources02"></a><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li>
				140	<a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li>
				141	<a name="resources04"></a><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li>
				142	<a name="resources05"></a><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>
				143	<a name="resources06"></a><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>
				144	<a name="resources07"></a><li>Android 2.2 allowed version strings: <a href="http://source.android.com/compatibility/2.2/versions.html">http://source.android.com/compatibility/2.2/versions.html</a></li>
				145	<a name="resources08"></a><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>
				146	<a name="resources09"></a><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>
				147	<a name="resources10"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li>
				148	<a name="resources11"></a><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>
				149	<a name="resources12"></a><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>
				150	<a name="resources13"></a><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>
				151	<a name="resources14"></a><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>
				152	<a name="resources15"></a><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>
				153	<a name="resources16"></a><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li>
				154	<a name="resources17"></a><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>
				155	<a name="resources18"></a><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li>
				156	<a name="resources19"></a><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>
				157	<a name="resources20"></a><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>
				158	<a name="resources21"></a><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>
				159	<a name="resources22"></a><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>
				160	<a name="resources23"></a><li>Android 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>
				161	<a name="resources24"></a><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>
				162	<a name="resources25"></a><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>
				163	<a name="resources26"></a><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>
				164	<a name="resources27"></a><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>
				165	<a name="resources28"></a><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>
				166	<a name="resources29"></a><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>
				167	<a name="resources30"></a><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>
				168	</ol>
				169	<p>Many of these resources are derived directly or indirectly from the Android
				170	2.2 SDK, and will be functionally identical to the information in that SDK's
				171	documentation. In any cases where this Compatibility Definition or the
				172	Compatibility Test Suite disagrees with the SDK documentation, the SDK
				173	documentation is considered authoritative. Any technical details provided in
				174	the references included above are considered by inclusion to be part of this
				175	Compatibility Definition.</p>
				176
				177	<a name="section-3"></a><h2>3. Software</h2>
				178	<p>The Android platform includes a set of managed APIs, a set of native APIs,
				179	and a body of so-called "soft" APIs such as the Intent system and
				180	web-application APIs. This section details the hard and soft APIs that are
				181	integral to compatibility, as well as certain other relevant technical and
				182	user interface behaviors. Device implementations MUST comply with all the
				183	requirements in this section.</p>
				184
				185	<a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3>
				186	<p>The managed (Dalvik-based) execution environment is the primary vehicle for
				187	Android applications. The Android application programming interface (API) is
				188	the set of Android platform interfaces exposed to applications running in the
				189	managed VM environment. Device implementations MUST provide complete
				190	implementations, including all documented behaviors, of any documented API
				191	exposed by the Android 2.2 SDK [<a href="#resources04">Resources, 4</a>].</p>
				192	<p>Device implementations MUST NOT omit any managed APIs, alter API interfaces
				193	or signatures, deviate from the documented behavior, or include no-ops, except
				194	where specifically allowed by this Compatibility Definition.</p>
				195
				196	<a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3>
				197	<p>In addition to the managed APIs from Section 3.1, Android also includes a
				198	significant runtime-only "soft" API, in the form of such things such as
				199	Intents, permissions, and similar aspects of Android applications that cannot
				200	be enforced at application compile time. This section details the "soft" APIs
				201	and system behaviors required for compatibility with Android 2.2. Device
				202	implementations MUST meet all the requirements presented in this section.</p>
				203	<a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4>
				204	<p>Device implementers MUST support and enforce all permission constants as
				205	documented by the Permission reference page [<a
				206	href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional
				207	requirements related to the Android security model.</p>
				208	<a name="section-3.2.2"></a><h4>3.2.2. Build Parameters</h4>
				209	<p>The Android APIs include a number of constants on the <code>android.os.Build</code>
				210	class [<a href="#resources06">Resources, 6</a>] that are intended to describe
				211	the current device. To provide consistent, meaningful values across device
				212	implementations, the table below includes additional restrictions on the
				213	formats of these values to which device implementations MUST conform.</p>
				214	<table>
				215	<tbody>
				216	<tr>
				217	<td><b>Parameter</b></td>
				218	<td><b>Comments</b></td>
				219	</tr>
				220	<tr>
				221	<td>android.os.Build.VERSION.RELEASE</td>
				222	<td>The version of the currently-executing Android system, in human-readable
				223	format. This field MUST have one of the string values defined in [<a
				224	href="#resources07">Resources, 7</a>].</td>
				225	</tr>
				226	<tr>
				227	<td>android.os.Build.VERSION.SDK</td>
				228	<td>The version of the currently-executing Android system, in a format
				229	accessible to third-party application code. For Android 2.2, this field MUST have
				230	the integer value 8.</td>
				231	</tr>
				232	<tr>
				233	<td>android.os.Build.VERSION.INCREMENTAL</td>
				234	<td>A value chosen by the device implementer designating the specific build of
				235	the currently-executing Android system, in human-readable format. This value
				236	MUST NOT be re-used for different builds made available to end users. A typical use
				237	of this field is to indicate which build number or source-control change
				238	identifier was used to generate the build. There are no requirements on the
				239	specific format of this field, except that it MUST NOT be null or the empty
				240	string ("").</td>
				241	</tr>
				242	<tr>
				243	<td>android.os.Build.BOARD</td>
				244	<td>A value chosen by the device implementer identifying the specific internal
				245	hardware used by the device, in human-readable format. A possible use of this
				246	field is to indicate the specific revision of the board powering the device.
				247	There are no requirements on the specific format of this field, except that it
				248	MUST NOT be null or the empty string ("").</td>
				249	</tr>
				250	<tr>
				251	<td>android.os.Build.BRAND</td>
				252	<td>A value chosen by the device implementer identifying the name of the
				253	company, organization, individual, etc. who produced the device, in
				254	human-readable format. A possible use of this field is to indicate the OEM
				255	and/or carrier who sold the device. There are no requirements on the specific
				256	format of this field, except that it MUST NOT be null or the empty string
				257	("").</td>
				258	</tr>
				259	<tr>
				260	<td>android.os.Build.DEVICE</td>
				261	<td>A value chosen by the device implementer identifying the specific
				262	configuration or revision of the body (sometimes called "industrial design")
				263	of the device. There are no requirements on the specific format of this field,
				264	except that it MUST NOT be null or the empty string ("").</td>
				265	</tr>
				266	<tr>
				267	<td>android.os.Build.FINGERPRINT</td>
				268	<td>A string that uniquely identifies this build. It SHOULD be reasonably
				269	human-readable. It MUST follow this template:
				270	<br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE)/$(BOARD):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/>
				271	For example:
				272	<br/><code>acme/mydevice/generic/generic:2.2/ERC77/3359:userdebug/test-keys</code><br/>
				273	The fingerprint MUST NOT include whitespace characters. If other fields included in the
				274	template above have whitespace characters, they MUST be replaced in the build
				275	fingerprint with another character, such as the underscore ("_") character.</td>
				276	</tr>
				277	<tr>
				278	<td>android.os.Build.HOST</td>
				279	<td>A string that uniquely identifies the host the build was built on, in
				280	human readable format. There are no requirements on the specific format of
				281	this field, except that it MUST NOT be null or the empty string ("").</td>
				282	</tr>
				283	<tr>
				284	<td>android.os.Build.ID</td>
				285	<td>An identifier chosen by the device implementer to refer to a specific
				286	release, in human readable format. This field can be the same as
				287	android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
				288	meaningful for end users to distinguish between software builds. There are no
				289	requirements on the specific format of this field, except that it MUST NOT be
				290	null or the empty string ("").</td>
				291	</tr>
				292	<tr>
				293	<td>android.os.Build.MODEL</td>
				294	<td>A value chosen by the device implementer containing the name of the device
				295	as known to the end user. This SHOULD be the same name under which the device
				296	is marketed and sold to end users. There are no requirements on the specific
				297	format of this field, except that it MUST NOT be null or the empty string
				298	("").</td>
				299	</tr>
				300	<tr>
				301	<td>android.os.Build.PRODUCT</td>
				302	<td>A value chosen by the device implementer containing the development name
				303	or code name of the device. MUST be human-readable, but is not necessarily
				304	intended for view by end users. There are no requirements on the specific
				305	format of this field, except that it MUST NOT be null or the empty string
				306	("").</td>
				307	</tr>
				308	<tr>
				309	<td>android.os.Build.TAGS</td>
				310	<td>A comma-separated list of tags chosen by the device implementer that
				311	further distinguish the build. For example, "unsigned,debug". This field MUST
				312	NOT be null or the empty string (""), but a single tag (such as "release") is
				313	fine.</td>
				314	</tr>
				315	<tr>
				316	<td>android.os.Build.TIME</td>
				317	<td>A value representing the timestamp of when the build occurred.</td>
				318	</tr>
				319	<tr>
				320	<td>android.os.Build.TYPE</td>
				321	<td>A value chosen by the device implementer specifying the runtime
				322	configuration of the build. This field SHOULD have one of the values
				323	corresponding to the three typical Android runtime configurations: "user",
				324	"userdebug", or "eng".</td>
				325	</tr>
				326	<tr>
				327	<td>android.os.Build.USER</td>
				328	<td>A name or user ID of the user (or automated user) that generated the
				329	build. There are no requirements on the specific format of this field, except
				330	that it MUST NOT be null or the empty string ("").</td>
				331	</tr>
				332	</tbody>
				333	</table>
				334	<a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4>
				335	<p>Android uses Intents to achieve loosely-coupled integration between
				336	applications. This section describes requirements related to the Intent
				337	patterns that MUST be honored by device implementations. By "honored", it is
				338	meant that the device implementer MUST provide an Android Activity or Service
				339	that specifies a matching Intent filter and binds to and implements correct
				340	behavior for each specified Intent pattern.</p>
				341	<a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4>
				342	<p>The Android upstream project defines a number of core applications, such as
				343	a phone dialer, calendar, contacts book, music player, and so on. Device
				344	implementers MAY replace these applications with alternative versions.</p>
				345	<p>However, any such alternative versions MUST honor the same Intent patterns
				346	provided by the upstream project. For example, if a device contains an
				347	alternative music player, it must still honor the Intent pattern issued by
				348	third-party applications to pick a song.</p>
				349	<p>The following applications are considered core Android system
				350	applications:</p>
				351	<ul>
				352	<li>Desk Clock</li>
				353	<li>Browser</li>
				354	<li>Calendar</li>
				355	<li>Calculator</li>
				356	<li>Camera</li>
				357	<li>Contacts</li>
				358	<li>Email</li>
				359	<li>Gallery</li>
				360	<li>GlobalSearch</li>
				361	<li>Launcher</li>
				362	<li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted
				363	if the device does not support Live Wallpapers, per Section 3.8.5.)</li>
				364	<li>Messaging (AKA "Mms")</li>
				365	<li>Music</li>
				366	<li>Phone</li>
				367	<li>Settings</li>
				368	<li>SoundRecorder</li>
				369	</ul>
				370	<p>The core Android system applications include various Activity, or Service
				371	components that are considered "public".
				372	That is, the attribute "android:exported" may be absent, or may have the value
				373	"true".</p>
				374	<p>For every Activity or Service defined
				375	in one of the core Android system apps that is not marked as non-public via an
				376	android:exported attribute with the value "false", device implementations MUST
				377	include a compontent of the same type implementing the same Intent filter
				378	patterns as the core Android system app.</p>
				379	<p>In other words, a device implementation MAY replace core Android system
				380	apps; however, if it does, the device implementation MUST support all Intent
				381	patterns defined by each core Android system app being replaced.</p>
				382	<a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4>
				383	<p>As Android is an extensible platform, device implementers MUST allow each
				384	Intent pattern referenced in Section 3.2.3.1 to be overridden by third-party
				385	applications. The upstream Android open source project allows this by default;
				386	device implementers MUST NOT attach special privileges to system applications'
				387	use of these Intent patterns, or prevent third-party applications from binding
				388	to and assuming control of these patterns. This prohibition specifically
				389	includes but is not limited to disabling the "Chooser" user interface which
				390	allows the user to select between multiple applications which all handle the
				391	same Intent pattern.</p>
				392	<a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4>
				393	<p>Device implementers MUST NOT include any Android component that honors any
				394	new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other
				395	key string in the android.* namespace. Device implementers MUST NOT include
				396	any Android components that honor any new Intent or Broadcast Intent patterns
				397	using an ACTION, CATEGORY, or other key string in a package space belonging to
				398	another organization. Device implementers MUST NOT alter or extend any of the
				399	Intent patterns used by the core apps listed in Section 3.2.3.1.</p>
				400	<p>This prohibition is analogous to that specified for Java language classes
				401	in Section 3.6.</p>
				402	<a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4>
				403	<p>Third-party applications rely on the platform to broadcast certain Intents
				404	to notify them of changes in the hardware or software environment.
				405	Android-compatible devices MUST broadcast the public broadcast Intents in
				406	response to appropriate system events. Broadcast Intents are described in the
				407	SDK documentation.</p>
				408
				409	<a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3>
				410	<p>Managed code running in Dalvik can call into native code provided in the
				411	application .apk file as an ELF .so file compiled for the appropriate device
				412	hardware architecture. Device implementations MUST include support for code
				413	running in the managed environment to call into native code, using the
				414	standard Java Native Interface (JNI) semantics. The following APIs MUST be
				415	available to native code:</p>
				416	<ul>
				417	<li>libc (C library)</li>
				418	<li>libm (math library)</li>
				419	<li>JNI interface</li>
				420	<li>libz (Zlib compression)</li>
				421	<li>liblog (Android logging)</li>
				422	<li>Minimal support for C++</li>
				423	<li>Support for OpenGL, as described below</li>
				424	</ul>
				425	<p>Device implementations MUST support OpenGL ES 1.0. Devices that lack
				426	hardware acceleration MUST implement OpenGL ES 1.0 using a software renderer.
				427	Device implementations SHOULD implement as much of OpenGL ES 1.1 as the device
				428	hardware supports. Device implementations SHOULD provide an implementation
				429	for OpenGL ES 2.0, if the hardware is capable of reasonable performance on
				430	those APIs.</p>
				431	<p>These libraries MUST be source-compatible (i.e. header compatible) and
				432	binary-compatible (for a given processor architecture) with the versions
				433	provided in Bionic by the Android Open Source project. Since the Bionic
				434	implementations are not fully compatible with other implementations such as
				435	the GNU C library, device implementers SHOULD use the Android implementation.
				436	If device implementers use a different implementation of these libraries, they
				437	MUST ensure header, binary, and behavioral compatibility.</p>
				438	<p>Device implementations MUST accurately report the native Application Binary
				439	Interface (ABI) supported by the device, via the
				440	<code>android.os.Build.CPU_ABI</code> API. The ABI MUST be one of the entries
				441	documented in the latest version of the Android NDK, in the file
				442	<code>docs/CPU-ARCH-ABIS.txt</code>. Note that additional releases of the
				443	Android NDK may introduce support for additional ABIs.</p>
				444	<p>Native code compatibility is challenging. For this reason, it should be
				445	repeated that device implementers are VERY strongly encouraged to use the
				446	upstream implementations of the libraries listed above to help ensure
				447	compatibility.</p>
				448
				449	<a name="section-3.4"></a><h3>3.4. Web Compatibility</h3>
				450	<p>Many developers and applications rely on the behavior of the
				451	<code>android.webkit.WebView</code> class [<a
				452	href="#resources08">Resources, 8</a>]
				453	for their user interfaces, so the WebView implementation must be
				454	compatible across Android implementations. Similarly, a full web experience is
				455	central to the Android user experience. Device implementations MUST include a
				456	version of <code>android.webkit.WebView</code> consistent with the upstream
				457	Android software, and MUST include a modern HTML5-capable browser, as
				458	described below.</p>
				459	<a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4>
				460	<p>The Android Open Source implementation uses the WebKit rendering engine to
				461	implement the <code>android.webkit.WebView</code>. Because it is not feasible
				462	to develop a comprehensive test suite for a web rendering system, device
				463	implementers MUST use the specific upstream build of WebKit in the WebView
				464	implementation. Specifically:</p>
				465	<ul>
				466	<li>Device implementations' <code>android.webkit.WebView</code>
				467	implementations MUST be based on the 533.1 WebKit build from the upstream
				468	Android Open Source tree for Android 2.2. This build includes a specific set
				469	of functionality and security fixes for the WebView. Device implementers MAY
				470	include customizations to the WebKit implementation; however, any such
				471	customizations MUST NOT alter the behavior of the WebView, including rendering
				472	behavior.</li>
				473	<li>The user agent string reported by the WebView MUST be in this format:<br/>
				474	<code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1</code>
				475	<ul>
				476	<li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li>
				477	<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>
				478	<li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li>
				479	<li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li>
				480	</ul></li>
				481	</ul>
				482	<p>The WebView configuration MUST include support for the HTML5 database,
				483	application cache, and geolocation APIs [<a href="#resources09">Resources,
				484	9</a>]. The WebView MUST include support for the HTML5
				485	<code><video></code> tag. HTML5 APIs, like all JavaScript APIs, MUST be
				486	disabled by default in a WebView, unless the developer explicitly enables them
				487	via the usual Android APIs.</p>
				488	<a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4>
				489	<p>Device implementations MUST include a standalone Browser application for
				490	general user web browsing. The standalone Browser MAY be based on an
				491	browser technology other than WebKit. However, even if an alternate Browser
				492	application is shipped, the <code>android.webkit.WebView</code> component
				493	provided to third-party applications MUST be based on WebKit, as described in
				494	Section 3.4.1.</p>
				495	<p>Implementations MAY ship a custom user agent string in the standalone
				496	Browser application.</p>
				497	<p>The standalone Browser application (whether based on the upstream
				498	WebKit Browser application or a third-party replacement) SHOULD include support
				499	for as much of HTML5 [<a href="#resources09">Resources, 9</a>] as possible.
				500	Minimally, device implementations MUST support HTML5 geolocation, application
				501	cache, and database APIs and the <video> tag in standalone the Browser
				502	application.</p>
				503
				504	<a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3>
				505	<p>The behaviors of each of the API types (managed, soft, native, and web)
				506	must be consistent with the preferred implementation of the upstream Android
				507	open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas
				508	of compatibility are:</p>
				509	<ul>
				510	<li>Devices MUST NOT change the behavior or meaning of a standard Intent</li>
				511	<li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.)</li>
				512	<li>Devices MUST NOT change the semantics of a particular permission</li>
				513	</ul>
				514	<p>The above list is not comprehensive, and the onus is on device implementers
				515	to ensure behavioral compatibility. For this reason, device implementers
				516	SHOULD use the source code available via the Android Open Source Project where
				517	possible, rather than re-implement significant parts of the system.</p>
				518	<p>The Compatibility Test Suite (CTS) tests significant portions of the
				519	platform for behavioral compatibility, but not all. It is the responsibility
				520	of the implementer to ensure behavioral compatibility with the Android Open
				521	Source Project.</p>
				522
				523	<a name="section-3.6"></a><h3>3.6. API Namespaces</h3>
				524	<p>Android follows the package and class namespace conventions defined by the
				525	Java programming language. To ensure compatibility with third-party
				526	applications, device implementers MUST NOT make any prohibited modifications
				527	(see below) to these package namespaces:</p>
				528	<ul>
				529	<li>java.*</li>
				530	<li>javax.*</li>
				531	<li>sun.*</li>
				532	<li>android.*</li>
				533	<li>com.android.*</li>
				534	</ul>
				535	<p>Prohibited modifications include:</p>
				536	<ul>
				537	<li>Device implementations MUST NOT modify the publicly exposed APIs on the
				538	Android platform by changing any method or class signatures, or by removing
				539	classes or class fields.</li>
				540	<li>Device implementers MAY modify the underlying implementation of the APIs,
				541	but such modifications MUST NOT impact the stated behavior and Java-language
				542	signature of any publicly exposed APIs.</li>
				543	<li>Device implementers MUST NOT add any publicly exposed elements (such as
				544	classes or interfaces, or fields or methods to existing classes or interfaces)
				545	to the APIs above.</li>
				546	</ul>
				547	<p>A "publicly exposed element" is any construct which is not decorated with
				548	the "@hide" marker in the upstream Android source code. In other words, device
				549	implementers MUST NOT expose new APIs or alter existing APIs in the namespaces
				550	noted above. Device implementers MAY make internal-only modifications, but
				551	those modifications MUST NOT be advertised or otherwise exposed to
				552	developers.</p>
				553	<p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
				554	namespace owned by or referring to another organization. For instance, device
				555	implementers MUST NOT add APIs to the com.google.* or similar namespace; only
				556	Google may do so. Similarly, Google MUST NOT add APIs to other companies'
				557	namespaces.</p>
				558	<p>If a device implementer proposes to improve one of the package namespaces
				559	above (such as by adding useful new functionality to an existing API, or
				560	adding a new API), the implementer SHOULD visit source.android.com and begin
				561	the process for contributing changes and code, according to the information on
				562	that site.</p>
				563	<p>Note that the restrictions above correspond to standard conventions for
				564	naming APIs in the Java programming language; this section simply aims to
				565	reinforce those conventions and make them binding through inclusion in this
				566	compatibility definition.</p>
				567
				568	<a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3>
				569	<p>Device implementations MUST support the full Dalvik Executable (DEX)
				570	bytecode specification and Dalvik Virtual Machine semantics [<a
				571	href="#resources10">Resources, 10</a>].</p>
				572	<p>Device implementations with screens classified as medium- or low-density
				573	MUST configure Dalvik to allocate at least 16MB of memory to each application.
				574	Device implementations with screens classified as high-density MUST configure
				575	Dalvik to allocate at least 24MB of memory to each application. Note that
				576	device implementations MAY allocate more memory than these figures.</p>
				577
				578	<a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3>
				579	<p>The Android platform includes some developer APIs that allow developers to
				580	hook into the system user interface. Device implementations MUST incorporate
				581	these standard UI APIs into custom user interfaces they develop, as explained
				582	below.</p>
				583	<a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4>
				584	<p>Android defines a component type and corresponding API and lifecycle that
				585	allows applications to expose an "AppWidget" to the end user [<a
				586	href="#resources11">Resources, 11</a>].
				587	The Android Open Source reference release includes a Launcher application that
				588	includes user interface elements allowing the user to add, view, and remove
				589	AppWidgets from the home screen.</p>
				590	<p>Device implementers MAY substitute an alternative to the reference Launcher
				591	(i.e. home screen). Alternative Launchers SHOULD include built-in support for
				592	AppWidgets, and expose user interface elements to add, configure, view, and remove
				593	AppWidgets directly within the Launcher. Alternative Launchers MAY omit these
				594	user interface elements; however, if they are omitted, the device implementer
				595	MUST provide a separate application accessible from the Launcher that allows
				596	users to add, configure, view, and remove AppWidgets.</p>
				597	<a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4>
				598	<p>Android includes APIs that allow developers to notify users of notable
				599	events [<a href="#resources12">Resources, 12</a>]. Device implementers MUST provide support for each
				600	class of notification so defined; specifically: sounds, vibration, light and
				601	status bar.</p>
				602	<p>Additionally, the implementation MUST correctly render all resources
				603	(icons, sound files, etc.) provided for in the APIs [<a
				604	href="#resources13">Resources, 13</a>], or in the
				605	Status Bar icon style guide [<a href="#resources14">Resources, 14</a>]. Device implementers MAY provide
				606	an alternative user experience for notifications than that provided by the
				607	reference Android Open Source implementation; however, such alternative
				608	notification systems MUST support existing notification resources, as
				609	above.</p>
				610	<a name="section-3.8.3"></a><h4>3.8.3. Search</h4>
				611	<p>Android includes APIs [<a href="#resources15">Resources, 15</a>] that allow developers to incorporate
				612	search into their applications, and expose their application's data into the
				613	global system search. Generally speaking, this functionality consists of a
				614	single, system-wide user interface that allows users to enter queries,
				615	displays suggestions as users type, and displays results. The Android APIs
				616	allow developers to reuse this interface to provide search within their own
				617	apps, and allow developers to supply results to the common global search user
				618	interface.</p>
				619	<p>Device implementations MUST include a single, shared, system-wide search
				620	user interface capable of real-time suggestions in response to user input.
				621	Device implementations MUST implement the APIs that allow developers to reuse
				622	this user interface to provide search within their own applications. Device
				623	implementations MUST implement the APIs that allow third-party applications to
				624	add suggestions to the search box when it is run in global search mode. If no
				625	third-party applications are installed that make use of this functionality,
				626	the default behavior SHOULD be to display web search engine results and
				627	suggestions.</p>
				628	<p>Device implementations MAY ship alternate search user interfaces, but
				629	SHOULD include a hard or soft dedicated search button, that can be used at any
				630	time within any app to invoke the search framework, with the behavior provided
				631	for in the API documentation.</p>
				632	<a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4>
				633	<p>Applications can use the "Toast" API (defined in [<a
				634	href="#resources16">Resources, 16</a>]) to
				635	display short non-modal strings to the end user, that disappear after a brief
				636	period of time. Device implementations MUST display Toasts from applications
				637	to end users in some high-visibility manner.</p>
				638	<a name="section-3.8.5"></a><h4>3.8.5. Live Wallpapers</h4>
				639	<p>Android defines a component type and corresponding API and lifecycle that
				640	allows applications to expose one or more "Live Wallpapers" to the end user
				641	[<a href="#resources17">Resources, 17</a>]. Live Wallpapers are animations,
				642	patterns, or similar images with limited input capabilities that display as a
				643	wallpaper, behind other applications.</p>
				644	<p>Hardware is considered capable of reliably running live wallpapers if it
				645	can run all live wallpapers, with no limitations on functionality, at a
				646	reasonable framerate with no adverse affects on other applications. If
				647	limitations in the hardware cause wallpapers and/or applications to crash,
				648	malfunction, consume excessive CPU or battery power, or run at unacceptably
				649	low frame rates, the hardware is considered incapable of running live
				650	wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0
				651	context to render their content. Live wallpaper will not run reliably on
				652	hardware that does not support multiple OpenGL contexts because the live
				653	wallpaper use of an OpenGL context may conflict with other applications that
				654	also use an OpenGL context. </p>
				655	<p>Device implementations capable of running live wallpapers reliably as
				656	described above SHOULD implement live wallpapers. Device implementations
				657	determined to not run live wallpapers reliably as described above MUST NOT
				658	implement live wallpapers.</p>
				659
				660	<a name="section-4"></a><h2>4. Reference Software Compatibility</h2>
				661	<p>Device implementers MUST test implementation compatibility using the
				662	following open-source applications:</p>
				663	<ul>
				664	<li>Calculator (included in SDK)</li>
				665	<li>Lunar Lander (included in SDK)</li>
				666	<li>The "Apps for Android" applications [<a href="#resources18">Resources, 18</a>].</li>
				667	<li>Replica Island (available in Android Market; only required for device
				668	implementations that support with OpenGL ES 2.0)</li>
				669	</ul>
				670	<p>Each app above MUST launch and behave correctly on the implementation, for
				671	the implementation to be considered compatible.</p>
				672	<p>Additionally, device implementations MUST test each menu item (including all
				673	sub-menus) of each of these smoke-test applications:</p>
				674	<ul>
				675	<li>ApiDemos (included in SDK)</li>
				676	<li>ManualSmokeTests (included in CTS)</li>
				677	</ul>
				678	<p>Each test case in the applications above MUST run correctly on the device
				679	implementation.</p>
				680
				681	<a name="section-5"></a><h2>5. Application Packaging Compatibility</h2>
				682	<p>Device implementations MUST install and run Android ".apk" files as
				683	generated by the "aapt" tool included in the official Android SDK [<a
				684	href="#resources19">Resources, 19</a>].</p>
				685	<p>Devices implementations MUST NOT extend either the .apk [<a
				686	href="#resources20">Resources, 20</a>], Android Manifest [<a
				687	href="#resources21">Resources, 21</a>],
				688	or Dalvik bytecode [<a href="#resources10">Resources, 10</a>] formats in such
				689	a way that would prevent those files from
				690	installing and running correctly on other compatible devices. Device
				691	implementers SHOULD use the reference upstream implementation of Dalvik, and
				692	the reference implementation's package management system.</p>
				693
				694	<a name="section-6"></a><h2>6. Multimedia Compatibility</h2>
				695	<p>Device implementations MUST fully implement all multimedia APIs. Device
				696	implementations MUST include support for all multimedia codecs described
				697	below, and SHOULD meet the sound processing guidelines described below.</p>
				698	<a name="section-6.1"></a><h3>6.1. Media Codecs</h3>
				699	<p>Device implementations MUST support the following multimedia codecs. All of
				700	these codecs are provided as software implementations in the preferred Android
				701	implementation from the Android Open Source Project.</p>
				702	<p>Please note that neither Google nor the Open Handset Alliance make any
				703	representation that these codecs are unencumbered by third-party patents.
				704	Those intending to use this source code in hardware or software products are
				705	advised that implementations of this code, including in open source software
				706	or shareware, may require patent licenses from the relevant patent
				707	holders.</p>
				708	<table><tbody>
				709	<tr>
				710	<td rowspan="11"><b>Audio</b></td>
				711	</tr>
				712	<tr>
				713	<td><b>Name</b></td>
				714	<td><b>Encoder</b></td>
				715	<td><b>Decoder</b></td>
				716	<td><b>Details</b></td>
				717	<td><b>File/Container Format</b></td>
				718	</tr>
				719	<tr>
				720	<td>AAC LC/LTP</td>
				721	<td> </td>
				722	<td>X</td>
				723	<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>
				724	<td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td>
				725	</tr>
				726	<tr>
				727	<td>HE-AACv1 (AAC+)</td>
				728	<td> </td>
				729	<td>X</td>
				730	</tr>
				731	<tr>
				732	<td>HE-AACv2 (enhanced AAC+)</td>
				733	<td> </td>
				734	<td>X</td>
				735	</tr>
				736	<tr>
				737	<td>AMR-NB</td>
				738	<td>X</td>
				739	<td>X</td>
				740	<td>4.75 to 12.2 kbps sampled @ 8kHz</td>
				741	<td>3GPP (.3gp)</td>
				742	</tr>
				743	<tr>
				744	<td>AMR-WB</td>
				745	<td> </td>
				746	<td>X</td>
				747	<td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td>
				748	<td>3GPP (.3gp)</td>
				749	</tr>
				750	<tr>
				751	<td>MP3</td>
				752	<td> </td>
				753	<td>X</td>
				754	<td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td>
				755	<td>MP3 (.mp3)</td>
				756	</tr>
				757	<tr>
				758	<td>MIDI</td>
				759	<td> </td>
				760	<td>X</td>
				761	<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>
				762	<td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td>
				763	</tr>
				764	<tr>
				765	<td>Ogg Vorbis</td>
				766	<td> </td>
				767	<td>X</td>
				768	<td> </td>
				769	<td>Ogg (.ogg)</td>
				770	</tr>
				771	<tr>
				772	<td>PCM</td>
				773	<td> </td>
				774	<td>X</td>
				775	<td>8- and 16-bit linear PCM (rates up to limit of hardware)</td>
				776	<td>WAVE (.wav)</td>
				777	</tr>
				778	<tr>
				779	<td rowspan="5"><b>Image</b></td>
				780	</tr>
				781	<tr>
				782	<td>JPEG</td>
				783	<td>X</td>
				784	<td>X</td>
				785	<td>base+progressive</td>
				786	<td> </td>
				787	</tr>
				788	<tr>
				789	<td>GIF</td>
				790	<td> </td>
				791	<td>X</td>
				792	<td> </td>
				793	<td> </td>
				794	</tr>
				795	<tr>
				796	<td>PNG</td>
				797	<td>X</td>
				798	<td>X</td>
				799	<td> </td>
				800	<td> </td>
				801	</tr>
				802	<tr>
				803	<td>BMP</td>
				804	<td> </td>
				805	<td>X</td>
				806	<td> </td>
				807	<td> </td>
				808	</tr>
				809	<tr>
				810	<td rowspan="4"><b>Video</b></td>
				811	</tr>
				812	<tr>
				813	<td>H.263</td>
				814	<td>X</td>
				815	<td>X</td>
				816	<td> </td>
				817	<td>3GPP (.3gp) files</td>
				818	</tr>
				819	<tr>
				820	<td>H.264</td>
				821	<td> </td>
				822	<td>X</td>
				823	<td> </td>
				824	<td>3GPP (.3gp) and MPEG-4 (.mp4) files</td>
				825	</tr>
				826	<tr>
				827	<td>MPEG4 Simple Profile</td>
				828	<td> </td>
				829	<td>X</td>
				830	<td> </td>
				831	<td>3GPP (.3gp) file</td>
				832	</tr>
				833	</tbody>
				834	</table>
				835	<p>Note that the table above does not list specific bitrate requirements for
				836	most video codecs. The reason for this is that in practice, current device
				837	hardware does not necessarily support bitrates that map exactly to the
				838	required bitrates specified by the relevant standards. Instead, device
				839	implementations SHOULD support the highest bitrate practical on the hardware,
				840	up to the limits defined by the specifications.</p>
				841
				842	<a name="section-6.2"></a><h3>6.2. Audio Recording</h3>
				843	<p>When an application has used the <code>android.media.AudioRecord</code> API to
				844	start recording an audio stream, device implementations SHOULD sample and
				845	record audio with each of these behaviors:</p>
				846	<ul>
				847	<li>Noise reduction processing, if present, SHOULD be disabled.</li>
				848	<li>Automatic gain control, if present, SHOULD be disabled.</li>
				849	<li>The device SHOULD exhibit approximately flat amplitude versus frequency
				850	characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz</li>
				851	<li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level
				852	(SPL) source at 1000 Hz yields RMS of 5000 for 16-bit samples.</li>
				853	<li>PCM amplitude levels SHOULD linearly track input SPL changes over at least
				854	a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li>
				855	<li>Total harmonic distortion SHOULD be less than 1% from 100 Hz to 4000 Hz at
				856	90 dB SPL input level.</li>
				857	</ul>
				858	<p><b>Note:</b> while the requirements outlined above are stated as "SHOULD"
				859	for Android 2.2, the Compatibility Definition for a future version is planned
				860	to change these to "MUST". That is, these requirements are optional in Android
				861	2.2 but <b>will be required</b> by a future version. Existing and new devices
				862	that run Android 2.2 Android are <b>very strongly encouraged to meet
				863	these requirements in Android 2.2</b>, or they will not be able to attain
				864	Android compatibility when upgraded to the future version.</p>
				865
				866	<a name="section-6.3"></a><h3>6.3. Audio Latency</h3>
				867	<p>Audio latency is broadly defined as the interval between when an
				868	application requests an audio playback or record operation, and when the
				869	device implementation actually begins the operation. Many classes of
				870	applications rely on short latencies, to achieve real-time effects such sound
				871	effects or VOIP communication. Device implementations SHOULD meet all audio
				872	latency requirements outlined in this section.</p>
				873	<p>For the purposes of this section:</p>
				874	<ul>
				875	<li>"cold output latency" is defined to be the interval between when an
				876	application requests audio playback and when sound begins playing, when
				877	the audio system has been idle and powered down prior to the request</li>
				878	<li>"warm output latency" is defined to be the interval between when an
				879	application requests audio playback and when sound begins playing, when
				880	the audio system has been recently used but is currently idle (that is,
				881	silent)</li>
				882	<li>"continuous output latency" is defined to be the interval between when an
				883	application issues a sample to be played and when the speaker physically
				884	plays the corresponding sound, while the device is currently playing back
				885	audio</li>
				886	<li>"cold input latency" is defined to be the interval between when an
				887	application requests audio recording and when the first sample is
				888	delivered to the application via its callback, when the audio system and
				889	microphone has been idle and powered down prior to the request</li>
				890	<li>"continuous input latency" is defined to be when an ambient sound occurs
				891	and when the sample corresponding to that sound is delivered to a
				892	recording application via its callback, while the device is in recording
				893	mode</li>
				894	</ul>
				895	<p>Using the above definitions, device implementations SHOULD exhibit each of
				896	these properties:</p>
				897	<ul>
				898	<li>cold output latency of 100 milliseconds or less</li>
				899	<li>warm output latency of 10 milliseconds or less</li>
				900	<li>continuous output latency of 45 milliseconds or less</li>
				901	<li>cold input latency of 100 milliseconds or less</li>
				902	<li>continuous input latency of 50 milliseconds or less</li>
				903	</ul>
				904	<p><b>Note:</b> while the requirements outlined above are stated as "SHOULD"
				905	for Android 2.2, the Compatibility Definition for a future version is planned
				906	to change these to "MUST". That is, these requirements are optional in Android
				907	2.2 but <b>will be required</b> by a future version. Existing and new devices
				908	that run Android 2.2 Android are <b>very strongly encouraged to meet
				909	these requirements in Android 2.2</b>, or they will not be able to attain
				910	Android compatibility when upgraded to the future version.</p>
				911
				912	<a name="section-7"></a><h2>7. Developer Tool Compatibility</h2>
				913	<p>Device implementations MUST support the Android Developer Tools provided in
				914	the Android SDK. Specifically, Android-compatible devices MUST be compatible
				915	with:</p>
				916	<ul>
				917	<li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources19">Resources, 19</a>]<br/>
				918	Device implementations MUST support all <code>adb</code> functions as
				919	documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD
				920	be inactive by default, but there MUST be a user-accessible mechanism to turn
				921	on the Android Debug Bridge.</li>
				922	<li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources19">Resources, 19</a>]<br/>
				923	Device implementations MUST support all <code>ddms</code> features as documented in the
				924	Android SDK. As <code>ddms</code> uses <code>adb</code>, support for
				925	<code>ddms</code> SHOULD be inactive by default,
				926	but MUST be supported whenever the user has activated the Android Debug
				927	Bridge, as above.</li>
				928	<li><b>Monkey</b> [<a href="#resources22">Resources, 22</a>]<br/>
				929	Device implementations MUST include the Monkey framework, and make it
				930	available for applications to use.</li>
				931	</ul>
				932
				933	<a name="section-8"></a><h2>8. Hardware Compatibility</h2>
				934	<p>Android is intended to support device implementers creating innovative form
				935	factors and configurations. At the same time Android developers expect
				936	certain hardware, sensors and APIs across all Android device. This section
				937	lists the hardware features that all Android 2.2 compatible devices must
				938	support.</p>
				939	<p>If a device includes a particular hardware component that has a
				940	corresponding API for third-party developers, the device implementation MUST
				941	implement that API as defined in the Android SDK documentation. If an API in
				942	the SDK interacts with a hardware component that is stated to be optional and the device
				943	implementation does not possess that component:</p>
				944	<ul>
				945	<li>class definitions for the component's APIs MUST be present</li>
				946	<li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li>
				947	<li>API methods MUST return null values where permitted by the SDK documentation</li>
				948	<li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li>
				949	</ul>
				950	<p>A typical example of a scenario where these requirements apply is the
				951	telephony API: even on non-phone devices, these APIs must be implemented as
				952	reasonable no-ops.</p>
				953	<p>Device implementations MUST accurately report accurate hardware configuration
				954	information via the <code>getSystemAvailableFeatures()</code> and
				955	<code>hasSystemFeature(String)</code> methods on the
				956	<code>android.content.pm.PackageManager</code> class. [<a
				957	href="#resources23">Resources, 23</a>]</p>
				958
				959	<a name="section-8.1"></a><h3>8.1. Display</h3>
				960	<p>Android 2.2 includes facilities that perform certain automatic scaling and
				961	transformation operations under some circumstances, to ensure that third-party
				962	applications run reasonably well on a variety of hardware configurations [<a
				963	href="#resources24">Resources, 24</a>]. Devices MUST properly implement these
				964	behaviors, as detailed in this section.</p>
				965	<p>For Android 2.2, these are the most common display configurations:</p>
				966	<table><tbody>
				967	<tr>
				968	<td>Screen Type</td>
				969	<td>Width (Pixels)</td>
				970	<td>Height (Pixels)</td>
				971	<td>Diagonal Length Range (inches)</td>
				972	<td>Screen Size Group</td>
				973	<td>Screen Density Group</td>
				974	</tr>
				975	<tr>
				976	<td>QVGA</td>
				977	<td>240</td>
				978	<td>320</td>
				979	<td>2.6 - 3.0</td>
				980	<td>Small</td>
				981	<td>Low</td>
				982	</tr>
				983	<tr>
				984	<td>WQVGA</td>
				985	<td>240</td>
				986	<td>400</td>
				987	<td>3.2 - 3.5</td>
				988	<td>Normal</td>
				989	<td>Low</td>
				990	</tr>
				991	<tr>
				992	<td>FWQVGA</td>
				993	<td>240</td>
				994	<td>432</td>
				995	<td>3.5 - 3.8</td>
				996	<td>Normal</td>
				997	<td>Low</td>
				998	</tr>
				999	<tr>
				1000	<td>HVGA</td>
				1001	<td>320</td>
				1002	<td>480</td>
				1003	<td>3.0 - 3.5</td>
				1004	<td>Normal</td>
				1005	<td>Medium</td>
				1006	</tr>
				1007	<tr>
				1008	<td>WVGA</td>
				1009	<td>480</td>
				1010	<td>800</td>
				1011	<td>3.3 - 4.0</td>
				1012	<td>Normal</td>
				1013	<td>High</td>
				1014	</tr>
				1015	<tr>
				1016	<td>FWVGA</td>
				1017	<td>480</td>
				1018	<td>854</td>
				1019	<td>3.5 - 4.0</td>
				1020	<td>Normal</td>
				1021	<td>High</td>
				1022	</tr>
				1023	<tr>
				1024	<td>WVGA </td>
				1025	<td>480 </td>
				1026	<td>800 </td>
				1027	<td>4.8 - 5.5 </td>
				1028	<td>Large </td>
				1029	<td>Medium</td>
				1030	</tr>
				1031	<tr>
				1032	<td>FWVGA</td>
				1033	<td>480</td>
				1034	<td>854</td>
				1035	<td>5.0 - 5.8</td>
				1036	<td>Large</td>
				1037	<td>Medium</td>
				1038	</tr>
				1039
				1040	</tbody></table>
				1041
				1042	<p>Device implementations corresponding to one of the standard configurations
				1043	above MUST be configured to report the indicated screen size to applications
				1044	via the <code>android.content.res.Configuration</code> [<a href="#resources25">Resources,
				1045	24</a>] class.</p>
				1046	<p>Some .apk packages have manifests that do not identify them as supporting a
				1047	specific density range. When running such applications, the following
				1048	constraints apply:</p>
				1049	<ul>
				1050	<li>Device implementations MUST interpret resources in a .apk that lack a
				1051	density qualifier as defaulting to "medium" (known as "mdpi" in the SDK
				1052	documentation.)</li>
				1053	<li>When operating on a "low" density screen, device implementations MUST
				1054	scale down medium/mdpi assets by a factor of 0.75.</li>
				1055	<li>When operating on a "high" density screen, device implementations MUST
				1056	scale up medium/mdpi assets by a factor of 1.5.</li>
				1057	<li>Device implementations MUST NOT scale assets within a density range, and
				1058	MUST scale assets by exactly these factors between density ranges.</li>
				1059	</ul>
				1060
				1061	<a name="section-8.1.2"></a><h4>8.1.2. Non-Standard Display Configurations</h4>
				1062	<p>Display configurations that do not match one of the standard configurations
				1063	listed in Section 8.1.1 require additional consideration and work to be
				1064	compatible. Device implementers MUST contact Android Compatibility Team as
				1065	described in Section 13 to obtain classifications for screen-size bucket,
				1066	density, and scaling factor. When provided with this information, device
				1067	implementations MUST implement them as specified.</p>
				1068	<p>Note that some display configurations (such as very large or very small
				1069	screens, and some aspect ratios) are fundamentally incompatible with Android
				1070	2.2; therefore device implementers are encouraged to contact Android
				1071	Compatibility Team as early as possible in the development process.</p>
				1072
				1073	<a name="section-8.1.3"></a><h4>8.1.3. Display Metrics</h4>
				1074	<p>Device implementations MUST report correct valuesfor all display metrics
				1075	defined in <code>android.util.DisplayMetrics</code> [<a
				1076	href="#resources26">Resources, 26</a>].</p>
				1077
				1078	<a name="section-8.1.4"></a><h4>8.1.4. Declared Screen Support</h4>
				1079	<p>Applications may indicate which screen sizes they support via the
				1080	<code><supports-screens></code> attribute in the AndroidManifest.xml
				1081	file. Device implementations MUST correctly honor applications' stated support
				1082	for small, medium, and large screens, as described in the Android
				1083	SDK documentation.</p>
				1084
				1085	<a name="section-8.2"></a><h3>8.2. Keyboard</h3>
				1086	<p>Device implementations:</p>
				1087	<ul>
				1088	<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>
				1089	<li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li>
				1090	<li>MAY include additional soft keyboard implementations</li>
				1091	<li>MAY include a hardware keyboard</li>
				1092	<li>MUST NOT include a hardware keyboard that does not match one of the
				1093	formats specified in <code>android.content.res.Configuration.keyboard</code>
				1094	[<a href="#resources25">Resources, 25</a>] (that is, QWERTY, or 12-key)</li>
				1095	</ul>
				1096	<a name="section-8.3"></a><h3>8.3. Non-touch Navigation</h3>
				1097	<p>Device implementations:</p>
				1098	<ul>
				1099	<li>MAY omit a non-touch navigation options (that is, may omit a trackball, d-pad, or wheel)</li>
				1100	<li>MUST report the correct value for
				1101	<code>android.content.res.Configuration.navigation</code> [<a href="#resources25">Resources, 25</a>]</li>
				1102	</ul>
				1103	<a name="section-8.4"></a><h3>8.4. Screen Orientation</h3>
				1104	<p>Compatible devices MUST support dynamic orientation by applications to
				1105	either portrait or landscape screen orientation. That is, the device must
				1106	respect the application's request for a specific screen orientation. Device
				1107	implementations MAY select either portrait or landscape orientation as the
				1108	default.</p>
				1109	<p>Devices MUST report the correct value for the device's current orientation,
				1110	whenever queried via the android.content.res.Configuration.orientation,
				1111	android.view.Display.getOrientation(), or other APIs.</p>
				1112
				1113	<a name="section-8.5"></a><h3>8.5. Touchscreen input</h3>
				1114	<p>Device implementations:</p>
				1115	<ul>
				1116	<li>MUST have a touchscreen</li>
				1117	<li>MAY have either capacative or resistive touchscreen</li>
				1118	<li>MUST report the value of <code>android.content.res.Configuration</code>
				1119	[<a href="#resources25">Resources, 25</a>]
				1120	reflecting corresponding to the type of the specific touchscreen on the
				1121	device</li>
				1122	<li>SHOULD support fully independently tracked pointers, if the touchscreen supports multiple pointers</li>
				1123	</ul>
				1124
				1125	<a name="section-8.6"></a><h3>8.6. USB</h3>
				1126	<p>Device implementations:</p>
				1127	<ul>
				1128	<li>MUST implement a USB client, connectable to a USB host with a standard
				1129	USB-A port</li>
				1130	<li>MUST implement the Android Debug Bridge over USB (as described in Section
				1131	7)</li>
				1132	<li>MUST implement the USB mass storage specification, to allow a host
				1133	connected to the device to access the contents of the /sdcard volume </li>
				1134	<li>SHOULD use the micro USB form factor on the device side</li>
				1135	<li>MAY include a non-standard port on the device side, but if so MUST ship
				1136	with a cable capable of connecting the custom pinout to standard USB-A
				1137	port</li>
				1138	<li>SHOULD implement support for the USB Mass Storage specification (so that
				1139	either removable or fixed storage on the device can be accessed from a host
				1140	PC)</li>
				1141	</ul>
				1142
				1143	<a name="section-8.7"></a><h3>8.7. Navigation keys</h3>
				1144	<p>The Home, Menu and Back functions are essential to the Android navigation
				1145	paradigm. Device implementations MUST make these functions available to the
				1146	user at all times, regardless of application state. These functions SHOULD be
				1147	implemented via dedicated buttons. They MAY be implemented using software,
				1148	gestures, touch panel, etc., but if so they MUST be always accessible and not
				1149	obscure or interfere with the available application display area.</p>
				1150	<p>Device implementers SHOULD also provide a dedicated search key. Device
				1151	implementers MAY also provide send and end keys for phone calls.</p>
				1152
				1153	<a name="section-8.8"></a><h3>8.8. Wireless Data Networking</h3>
				1154	<p>Device implementations MUST include support for wireless high-speed data
				1155	networking. Specifically, device implementations MUST include support for at
				1156	least one wireless data standard capable of 200Kbit/sec or greater. Examples of
				1157	technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, etc.</p>
				1158	<p>If a device implementation includes a particular modality for which the
				1159	Android SDK includes an API (that is, WiFi, GSM, or CDMA), the implementation
				1160	MUST support the API.</p>
				1161	<p>Devices MAY implement more than one form of wireless data connectivity.
				1162	Devices MAY implement wired data connectivity (such as Ethernet), but MUST
				1163	nonetheless include at least one form of wireless connectivity, as above.</p>
				1164
				1165	<a name="section-8.9"></a><h3>8.9. Camera</h3>
				1166	<p>Device implementations MUST include a rear-facing camera. The included
				1167	rear-facing camera:</p>
				1168	<ul>
				1169	<li>MUST have a resolution of at least 2 megapixels</li>
				1170	<li>SHOULD have either hardware auto-focus, or software auto-focus implemented
				1171	in the camera driver (transparent to application software)</li>
				1172	<li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li>
				1173	<li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST
				1174	NOT be lit while an android.hardware.Camera.PreviewCallback instance has been
				1175	registered on a Camera preview surface, unless the application has explicitly
				1176	enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or
				1177	<code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code>
				1178	object. Note that this constraint does not apply to the device's built-in
				1179	system camera application, but only to third-party applications using
				1180	<code>Camera.PreviewCallback</code>.</li>
				1181	</ul>
				1182	<p>Device implementations MUST implement the following behaviors for the
				1183	camera-related APIs:</p>
				1184	<ol>
				1185	<li>If an application has never called
				1186	android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST
				1187	use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to
				1188	application callbacks.</li>
				1189	<li>If an application registers an android.hardware.Camera.PreviewCallback
				1190	instance and the system calls the onPreviewFrame() method when the preview
				1191	format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame()
				1192	must further be in the NV21 encoding format. (This is the format used natively
				1193	by the 7k hardware family.) That is, NV21 MUST be the default.</li>
				1194	</ol>
				1195	<p>Device implementations MUST implement the full Camera API included in the
				1196	Android 2.2 SDK documentation [<a href="#resources27">Resources, 27</a>]),
				1197	regardless of whether the device includes hardware autofocus or other
				1198	capabilities. For instance, cameras that lack autofocus MUST still call any
				1199	registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though
				1200	this has no relevance to a non-autofocus camera.)</p>
				1201	<p>Device implementations MUST recognize and honor each parameter name defined
				1202	as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the
				1203	underlying hardware supports the feature. If the device hardware does not
				1204	support a feature, the API must behave as documented. Conversely, Device
				1205	implementations MUST NOT honor or recognize string constants passed
				1206	to the <code>android.hardware.Camera.setParameters()</code> method other than
				1207	those documented as constants on the
				1208	<code>android.hardware.Camera.Parameters</code>. That is,
				1209	device implementations MUST support all standard Camera parameters if the
				1210	hardware allows, and MUST NOT support custom Camera parameter types.</p>
				1211	<p>Device implementations MAY include a front-facing camera. However, if
				1212	a device implementation includes a front-facing camera, the camera API as
				1213	implemented on the device MUST NOT use the front-facing camera by default.
				1214	That is, the camera API in Android 2.2 is for rear-facing cameras only, and
				1215	device implementations MUST NOT reuse or overload the API to act on a
				1216	front-facing camera, if one is present. Note that any custom APIs added by
				1217	device implementers to support front-facing cameras MUST abide by sections 3.5
				1218	and 3.6; for instance, if a custom <code>android.hardware.Camera</code> or
				1219	<code>Camera.Parameters</code> subclass is provided to support front-facing
				1220	cameras, it MUST NOT be located in an existing namespace, as described by
				1221	sections 3.5 and 3.6. Note that the inclusion of a front-facing camera does
				1222	not meet the requirement that devices include a rear-facing camera.</p>
				1223
				1224	<a name="section-8.10"></a><h3>8.10. Accelerometer</h3>
				1225	<p>Device implementations MUST include a 3-axis accelerometer and MUST be able
				1226	to deliver events at 50 Hz or greater. The coordinate system used by the
				1227	accelerometer MUST comply with the Android sensor coordinate system as detailed
				1228	in the Android APIs (see [<a href="#resources28">Resources, 28</a>]).</p>
				1229
				1230	<a name="section-8.11"></a><h3>8.11. Compass</h3>
				1231	<p>Device implementations MUST include a 3-axis compass and MUST be able to
				1232	deliver events 10 Hz or greater. The coordinate system used by the compass
				1233	MUST comply with the Android sensor coordinate system as defined in the Android
				1234	API (see [<a href="#resources28">Resources, 28</a>]).</p>
				1235
				1236	<a name="section-8.12"></a><h3>8.12. GPS</h3>
				1237	<p>Device implementations MUST include a GPS receiver, and SHOULD include
				1238	some form of "assisted GPS" technique to minimize GPS lock-on time.</p>
				1239
				1240	<a name="section-8.13"></a><h3>8.13. Telephony</h3>
				1241	<p>Android 2.2 MAY be used on devices that do not include telephony hardware.
				1242	That is, Android 2.2 is compatible with devices that are not phones.
				1243	However, if a device implementation does include GSM or CDMA telephony, it
				1244	MUST implement the full support for the API for that technology. Device
				1245	implementations that do not include telephony hardware MUST implement the full
				1246	APIs as no-ops.</p>
				1247	<p>See also Section 8.8, Wireless Data Networking.</p>
				1248
				1249	<a name="section-8.14"></a><h3>8.14. Memory and Storage</h3>
				1250	<p>Device implementations MUST have at least 92MB of memory available to the
				1251	kernel and userspace. The 92MB MUST be in addition to any memory dedicated to
				1252	hardware components such as radio, memory, and so on that is not under the
				1253	kernel's control.</p>
				1254	<p>Device implementations MUST have at least 150MB of non-volatile storage
				1255	available for user data. That is, the <code>/data</code> partition MUST be at
				1256	least 150MB.</p>
				1257	<p>Beyond the requirements above, device implementations SHOULD have at least
				1258	128MB of memory available to kernel and userspace, in addition to any memory
				1259	dedicated to hardware components that is not under the kernel's control.
				1260	Device implementations SHOULD have at least 1GB of non-volatile storage
				1261	available for user data. Note that these higher requirements are planned to
				1262	become hard minimums in a future version of Android. Device implementations are
				1263	strongly encouraged to meet these requirements now, or else they may not be
				1264	eligible for compatibility for a future version of Android.</p>
				1265
				1266	<a name="section-8.15"></a><h3>8.15. Application Shared Storage</h3>
				1267	<p>Device implementations MUST offer shared storage for applications. The
				1268	shared storage provided MUST be at least 2GB in size.</p>
				1269	<p>Device implementations MUST be configured with shared storage mounted by
				1270	default, "out of the box". If the shared storage is not mounted on the Linux
				1271	path <code>/sdcard</code>, then the device MUST include a Linux symbolic link
				1272	from <code>/sdcard</code> to the actual mount point.</p>
				1273	<p>Device implementations MUST enforce as documented the
				1274	<code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this
				1275	shared storage. Shared storage MUST otherwise be writable by any application
				1276	that obtains that permission.</p>
				1277	<p>Device implementations MAY have hardware for user-accessible removable
				1278	storage, such as a Secure Digital card. Alternatively, device implementations
				1279	MAY allocate internal (non-removable) storage as shared storage for apps.</p>
				1280	<p>Regardless of the form of shared storage used, the shared storage MUST
				1281	implement USB mass storage, as described in Section 8.6. As shipped out of the
				1282	box, the shared storage MUST be mounted with the FAT filesystem.</p>
				1283	<p>It is illustrative to consider two common examples. If a device
				1284	implementation includes an SD card slot to satisfy the shared storage
				1285	requirement, a FAT-formatted SD card 2GB in size or larger MUST be included
				1286	with the device as sold to users, and MUST be mounted by default.
				1287	Alternatively, if a device implementation uses internal fixed storage to
				1288	satisfy this requirement, that storage MUST be 2GB in size or larger,
				1289	formatted as FAT, and mounted on <code>/sdcard</code> (or <code>/sdcard</code>
				1290	MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p>
				1291	<p>Device implementations that include multiple shared storage paths (such as
				1292	both an SD card slot and shared internal storage) SHOULD modify the core
				1293	applications such as the media scanner and ContentProvider to transparently
				1294	support files placed in both locations.</p>
				1295
				1296	<a name="section-8.16"></a><h3>8.16. Bluetooth</h3>
				1297	<p>Device implementations MUST include a Bluetooth transceiver. Device
				1298	implementations MUST enable the RFCOMM-based Bluetooth API as described in the
				1299	SDK documentation [<a href="#resources30">Resources, 30</a>]. Device
				1300	implementations SHOULD implement relevant Bluetooth profiles, such as A2DP,
				1301	AVRCP, OBEX, etc. as appropriate for the device.</p>
				1302	<p>The Compatibility Test Suite includes cases that cover basic operation of
				1303	the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications
				1304	protocol between devices, it cannot be fully tested by unit tests running on a
				1305	single device. Consequently, device implementations MUST also pass the
				1306	human-driven Bluetooth test procedure described in Appendix A.</p>
				1307
				1308	<a name="section-9"></a><h2>9. Performance Compatibility</h2>
				1309	<p>One of the goals of the Android Compatibility Program is to enable
				1310	consistent application experience to consumers. Compatible implementations
				1311	must ensure not only that applications simply run correctly on the device, but
				1312	that they do so with reasonable performance and overall good user experience.
				1313	Device implementations MUST meet the key performance metrics of an Android 2.2
				1314	compatible device defined in the table below:</p>
				1315	<table><tbody><tr>
				1316	<td><b>Metric</b></td>
				1317	<td><b>Performance Threshold</b></td>
				1318	<td><b>Comments</b></td>
				1319	</tr>
				1320	<tr>
				1321	<td>Application Launch Time</td>
				1322	<td>The following applications should launch within the specified time.<ul>
				1323	<li>Browser: less than 1300ms</li>
				1324	<li>MMS/SMS: less than 700ms</li>
				1325	<li>AlarmClock: less than 650ms</li>
				1326	</ul></td>
				1327	<td>The launch time is measured as the total time to
				1328	complete loading the default activity for the application, including the time
				1329	it takes to start the Linux process, load the Android package into the Dalvik
				1330	VM, and call onCreate.</td>
				1331	</tr>
				1332	<tr>
				1333	<td>Simultaneous Applications</td>
				1334	<td>When multiple applications have been launched, re-launching an
				1335	already-running application after it has been launched must take less than the
				1336	original launch time.</td>
				1337	<td> </td>
				1338	</tr>
				1339	</tbody>
				1340	</table>
				1341
				1342	<a name="section-10"></a><h2>10. Security Model Compatibility</h2>
				1343	<p>Device implementations MUST implement a security model consistent with the
				1344	Android platform security model as defined in Security and Permissions
				1345	reference document in the APIs [<a href="#resources29">Resources, 29</a>] in the
				1346	Android developer documentation. Device implementations MUST support
				1347	installation of self-signed applications without requiring any additional
				1348	permissions/certificates from any third parties/authorities. Specifically,
				1349	compatible devices MUST support the security mechanisms described in the
				1350	follow sub-sections.</p>
				1351	<a name="section-10.1"></a><h3>10.1. Permissions</h3>
				1352	<p>Device implementations MUST support the Android permissions model as
				1353	defined in the Android developer documentation [<a
				1354	href="#resources29">Resources, 29</a>]. Specifically,
				1355	implementations MUST enforce each permission defined as described in the SDK
				1356	documentation; no permissions may be omitted, altered, or ignored.
				1357	Implementations MAY add additional permissions, provided the new permission ID
				1358	strings are not in the android.* namespace.</p>
				1359	<a name="section-10.2"></a><h3>10.2. UID and Process Isolation</h3>
				1360	<p>Device implementations MUST support the Android application sandbox model,
				1361	in which each application runs as a unique Unix-style UID and in a separate
				1362	process. Device implementations MUST support running multiple applications as
				1363	the same Linux user ID, provided that the applications are properly signed and
				1364	constructed, as defined in the Security and Permissions reference [<a
				1365	href="#resources29">Resources, 29</a>].</p>
				1366	<a name="section-10.3"></a><h3>10.3. Filesystem Permissions</h3>
				1367	<p>Device implementations MUST support the Android file access permissions
				1368	model as defined in as defined in the Security and Permissions reference [<a
				1369	href="#resources29">Resources, 29</a>].</p>
				1370	<a name="section-10.4"></a><h3>10.4. Alternate Execution Environments</h3>
				1371	<p>Device implementations MAY include runtime environments that execute
				1372	applications using some other software or technology than the Dalvik virtual
				1373	machine or native code. However, such alternate execution environments MUST
				1374	NOT compromise the Android security model or the security of installed Android
				1375	applications, as described in this section.</p>
				1376	<p>Alternate runtimes MUST themselves be Android applications, and abide by
				1377	the standard Android security model, as described elsewhere in Section 10.</p>
				1378	<p>Alternate runtimes MUST NOT be granted access to resources protected by
				1379	permissions not requested in the runtime's AndroidManifest.xml file via the
				1380	<code><uses-permission></code> mechanism.</p>
				1381	<p>Alternate runtimes MUST NOT permit applications to make use of features
				1382	protected by Android permissions restricted to system applications.</p>
				1383	<p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p>
				1384	<ul>
				1385	<li>Alternate runtimes SHOULD install apps via the PackageManager into
				1386	separate Android sandboxes (that is, Linux user IDs, etc.)</li>
				1387	<li>Alternate runtimes MAY provide a single Android sandbox shared by all
				1388	applications using the alternate runtime.</li>
				1389	<li>Alternate runtimes and installed applications using an alternate runtime
				1390	MUST NOT reuse the sandbox of any other app installed on the device, except
				1391	through the standard Android mechanisms of shared user ID and signing
				1392	certificate</li>
				1393	<li>Alternate runtimes MUST NOT launch with, grant, or be granted access to
				1394	the sandboxes corresponding to other Android applications.</li>
				1395	</ul>
				1396	<p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other
				1397	applications any privileges of the superuser (root), or of any other user ID.</p>
				1398	<p>The .apk files of alternate runtimes MAY be included in the system image of
				1399	a device implementation, but MUST be signed with a key distinct
				1400	from the key used to sign other applications included with the device
				1401	implementation.</p>
				1402	<p>When installing applications, alternate runtimes MUST obtain user consent
				1403	for the Android permissions used by the application. That is, if an
				1404	application needs to make use of a device resource for which there is a
				1405	corresponding Android permission (such as Camera, GPS, etc.), the alternate
				1406	runtime MUST inform the user that the application will be able to access
				1407	that resource. If the runtime environment does not record application
				1408	capabilities in this manner, the runtime environment MUST list all
				1409	permissions held by the runtime itself when installing any application
				1410	using that runtime.</p>
				1411
				1412	<a name="section-11"></a><h2>11. Compatibility Test Suite</h2>
				1413	<p>Device implementations MUST pass the Android Compatibility Test Suite (CTS)
				1414	[<a href="#resources02">Resources, 2</a>] available from the Android Open Source
				1415	Project, using the final shipping software on the device. Additionally, device
				1416	implementers SHOULD use the reference implementation in the Android Open
				1417	Source tree as much as possible, and MUST ensure compatibility in cases of
				1418	ambiguity in CTS and for any reimplementations of parts of the reference
				1419	source code.</p>
				1420	<p>The CTS is designed to be run on an actual device. Like any software, the
				1421	CTS may itself contain bugs. The CTS will be versioned independently of this
				1422	Compatibility Definition, and multiple revisions of the CTS may be released
				1423	for Android 2.2. Device implementations MUST pass the latest CTS version
				1424	available at the time the device software is completed.</p>
				1425
				1426	<a name="section-12"></a><h2>12. Updatable Software</h2>
				1427	<p>Device implementations MUST include a mechanism to replace the entirety of
				1428	the system software. The mechanism need not perform "live" upgrades -- that
				1429	is, a device restart MAY be required.</p>
				1430	<p>Any method can be used, provided that it can replace the entirety of the
				1431	software preinstalled on the device. For instance, any of the following
				1432	approaches will satisfy this requirement:</p>
				1433	<ul>
				1434	<li>Over-the-air (OTA) downloads with offline update via reboot</li>
				1435	<li>"Tethered" updates over USB from a host PC</li>
				1436	<li>"Offline" updates via a reboot and update from a file on removable
				1437	storage</li>
				1438	</ul>
				1439	<p>The update mechanism used MUST support updates without wiping user data.
				1440	Note that the upstream Android software includes an update mechanism that
				1441	satisfies this requirement.</p>
				1442	<p>If an error is found in a device implementation after it has been released
				1443	but within its reasonable product lifetime that is determined in consultation
				1444	with the Android Compatibility Team to affect the compatibility of thid-party
				1445	applications, the device implementer MUST correct the error via a software
				1446	update available that can be applied per the mechanism just described.</p>
				1447
				1448	<a name="section-13"></a><h2>13. Contact Us</h2>
				1449	<p>You can contact the document authors at <a
				1450	href="mailto:compatibility@android.com">compatibility@android.com</a> for
				1451	clarifications and to bring up any issues that you think the document does not
				1452	cover.</p>
				1453
				1454	<div style="page-break-before: always;"></div>
				1455
				1456	<a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2>
				1457	<p>The Compatibility Test Suite includes cases that cover basic operation of
				1458	the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications
				1459	protocol between devices, it cannot be fully tested by unit tests running on a
				1460	single device. Consequently, device implementations MUST also pass the
				1461	human-driven Bluetooth test procedure described below.</p>
				1462	<p>The test procedure is based on the BluetoothChat sample app included in the
				1463	Android open-source project tree. The procedure requires two devices:</p>
				1464	<ul>
				1465	<li>a candidate device implementation running the software build to be tested</li>
				1466	<li>a separate device implementation already known to be compatible, and of a
				1467	model from the device implementation being tested -- that is, a "known
				1468	good" device implementation</li>
				1469	</ul>
				1470	<p>The test procedure below refers to these devices as the "candidate" and "known
				1471	good" devices, respectively.</p>
				1472	<h3>Setup and Installation</h3>
				1473	<ol>
				1474	<li>Build BluetoothChat.apk via 'make samples' from an Android source code tree.</li>
				1475	<li>Install BluetoothChat.apk on the known-good device.</li>
				1476	<li>Install BluetoothChat.apk on the candidate device.</li>
				1477	</ol>
				1478	<h3>Test Bluetooth Control by Apps</h3>
				1479	<ol>
				1480	<li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled.</li>
				1481	<li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.</li>
				1482	</ol>
				1483	<h3>Test Pairing and Communication</h3>
				1484	<ol>
				1485	<li>Launch the Bluetooth Chat app on both devices.</li>
				1486	<li>Make the known-good device discoverable from within BluetoothChat (using the Menu).</li>
				1487	<li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.</li>
				1488	<li>Send 10 or more messages from each device, and verify that the other device receives them correctly.</li>
				1489	<li>Close the BluetoothChat app on both devices by pressing <b>Home</b>.</li>
				1490	<li>Unpair each device from the other, using the device Settings app.</li>
				1491	</ol>
				1492	<h3>Test Pairing and Communication in the Reverse Direction</h3>
				1493	<ol>
				1494	<li>Launch the Bluetooth Chat app on both devices.</li>
				1495	<li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li>
				1496	<li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li>
				1497	<li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li>
				1498	<li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li>
				1499	</ol>
				1500	<h3>Test Re-Launches</h3>
				1501	<ol>
				1502	<li>Re-launch the Bluetooth Chat app on both devices.</li>
				1503	<li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li>
				1504	</ol>
				1505	<p>Note: the above tests have some cases which end a test section by using
				1506	Home, and some using Back. These tests are not redundant and are not optional:
				1507	the objective is to verify that the Bluetooth API and stack works correctly
				1508	both when Activities are explicitly terminated (via the user pressing Back,
				1509	which calls finish()), and implicitly sent to background (via the user
				1510	pressing Home.) Each test sequence MUST be performed as described.</p>
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