1<?xml version="1.0" encoding="UTF-8"?> 2<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4<head> 5<title>Android 2.3 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 2.3 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-3.2.3">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. Application Packaging Compatibility</a><br/> 54 <a href="#section-5">5. Multimedia Compatibility</a><br/> 55 <div style="margin-left: 2em;"> 56 <a href="#section-5.1">5.1. Media Codecs</a><br/> 57 <a href="#section-5.1.1">5.1.1. Media Decoders</a><br/> 58 <a href="#section-5.1.2">5.1.2. Media Encoders</a><br/> 59 <a href="#section-5.2">5.2. Audio Recording</a><br/> 60 <a href="#section-5.3">5.3. Audio Latency</a><br/> 61 </div> 62 <a href="#section-6">6. Developer Tool Compatibility</a><br/> 63 <a href="#section-7">7. Hardware Compatibility</a><br/> 64 <div style="margin-left: 2em;"> 65 <a href="#section-7.1">7.1. Display and Graphics</a><br/> 66 <div style="margin-left: 2em;"> 67 <a href="#section-7.1.1">7.1.1. Screen Configurations</a><br/> 68 <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/> 69 <a href="#section-7.1.3">7.1.3. Declared Screen Support</a><br/> 70 <a href="#section-7.1.4">7.1.4. Screen Orientation</a><br/> 71 <a href="#section-7.1.5">7.1.5. 3D Graphics Accleration</a><br/> 72 </div> 73 <a href="#section-7.2">7.2. Input Devices</a><br/> 74 <div style="margin-left: 2em;"> 75 <a href="#section-7.2.1">7.2.1. Keyboard</a><br/> 76 <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/> 77 <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/> 78 <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/> 79 </div> 80 <a href="#section-7.3">7.3. Sensors</a><br/> 81 <div style="margin-left: 2em;"> 82 <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/> 83 <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/> 84 <a href="#section-7.3.3">7.3.3. GPS</a><br/> 85 <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/> 86 <a href="#section-7.3.5">7.3.5. Barometer</a><br/> 87 <a href="#section-7.3.6">7.3.6. Thermometer</a><br/> 88 <a href="#section-7.3.7">7.3.7. Photometer</a><br/> 89 <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/> 90 </div> 91 <a href="#section-7.4">7.4. Data Connectivity</a><br/> 92 <div style="margin-left: 2em;"> 93 <a href="#section-7.4.1">7.4.1. Telephony</a><br/> 94 <a href="#section-7.4.2">7.4.2. IEEE 802.11 (WiFi)</a><br/> 95 <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/> 96 <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/> 97 <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/> 98 </div> 99 <a href="#section-7.5">7.5. Cameras</a><br/> 100 <div style="margin-left: 2em;"> 101 <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/> 102 <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/> 103 <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/> 104 <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/> 105 </div> 106 <a href="#section-7.6">7.6. Memory and Storage</a><br/> 107 <div style="margin-left: 2em;"> 108 <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/> 109 <a href="#section-7.6.2">7.6.2. Application Shared Storage</a><br/> 110 </div> 111 <a href="#section-7.7">7.7. USB</a><br/> 112 </div> 113 <a href="#section-8">8. Performance Compatibility</a><br/> 114 <a href="#section-9">9. Security Model Compatibility</a><br/> 115 <div style="margin-left: 2em;"> 116 <a href="#section-9.1">9.1. Permissions</a><br/> 117 <a href="#section-9.2">9.2. UID and Process Isolation</a><br/> 118 <a href="#section-9.3">9.3. Filesystem Permissions</a><br/> 119 <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/> 120 </div> 121 <a href="#section-10">10. Software Compatibility Testing</a><br/> 122 <div style="margin-left: 2em;"> 123 <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/> 124 <a href="#section-10.2">10.2. CTS Verifier</a><br/> 125 <a href="#section-10.3">10.3. Reference Applications</a><br/> 126 </div> 127 <a href="#section-11">11. Updatable Software</a><br/> 128 <a href="#section-12">12. Contact Us</a><br/> 129 <a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/> 130</div> 131 132<div style="page-break-before: always;"></div> 133 134<a name="section-1"></a><h2>1. Introduction</h2> 135<p>This document enumerates the requirements that must be met in order for 136mobile phones to be compatible with Android 2.3.</p> 137<p>The use of "must", "must not", "required", "shall", "shall not", "should", 138"should not", "recommended", "may" and "optional" is per the IETF standard 139defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 140<p>As used in this document, a "device implementer" or "implementer" is a 141person or organization developing a hardware/software solution running Android 1422.3. A "device implementation" or "implementation" is the hardware/software 143solution so developed.</p> 144<p>To be considered compatible with Android 2.3, device implementations 145MUST meet the requirements presented in this Compatibility Definition, 146including any documents incorporated via reference.</p> 147<p>Where this definition or the software tests described in <a 148href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is 149the responsibility of the device implementer to ensure compatibility with 150existing implementations. For this reason, the Android Open Source Project [<a 151href="#resources03">Resources, 3</a>] is both the reference and preferred 152implementation of Android. Device implementers are strongly encouraged to base 153their implementations to the greatest extent possible on the "upstream" source 154code available from the Android Open Source Project. While some components can 155hypothetically be replaced with alternate implementations this practice is 156strongly discouraged, as passing the software tests will become substantially 157more difficult. It is the implementer's responsibility to ensure full 158behavioral compatibility with the standard Android implementation, including 159and beyond the Compatibility Test Suite. Finally, note that certain component 160substitutions and modifications are explicitly forbidden by this document.</p> 161<p>Please note that this Compatibility Definition is issued to correspond with 162the 2.3.3 update to Android, which is API level 10. This Definition obsoletes 163and replaces the Compatibility Definition for Android 2.3 versions prior to 1642.3.3. (That is, versions 2.3.1 and 2.3.2 are obsolete.) Future 165Android-compatible devices running Android 2.3 MUST ship with version 2.3.3 or 166later.</p> 167<a name="section-2"></a><h2>2. Resources</h2> 168<ol> 169<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> 170<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> 171<a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 172<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> 173<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> 174<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> 175<a name="resources07"></a><li>Android 2.3 allowed version strings: <a href="http://source.android.com/compatibility/2.3/versions.html">http://source.android.com/compatibility/2.3/versions.html</a></li> 176<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> 177<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> 178<a name="resources10"></a><li>HTML5 offline capabilities: <a href="http://dev.w3.org/html5/spec/Overview.html#offline">http://dev.w3.org/html5/spec/Overview.html#offline</a></li> 179<a name="resources11"></a><li>HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></li> 180<a name="resources12"></a><li>HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></li> 181<a name="resources13"></a><li>HTML5/W3C webdatabase API: <a href="http://www.w3.org/TR/webdatabase/">http://www.w3.org/TR/webdatabase/</a></li> 182<a name="resources14"></a><li>HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></li> 183<a name="resources15"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 184<a name="resources16"></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> 185<a name="resources17"></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> 186<a name="resources18"></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> 187<a name="resources19"></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> 188<a name="resources20"></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> 189<a name="resources21"></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> 190<a name="resources22"></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> 191<a name="resources23"></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> 192<a name="resources24"></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> 193<a name="resources25"></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> 194<a name="resources26"></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> 195<a name="resources27"></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> 196<a name="resources28"></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> 197<a name="resources29"></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> 198<a name="resources30"></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> 199<a name="resources31"></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> 200<a name="resources32"></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> 201<a name="resources33"></a><li>NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></li> 202<a name="resources34"></a><li>MIFARE MF1S503X: <a href="http://www.nxp.com/documents/data_sheet/MF1S503x.pdf">http://www.nxp.com/documents/data_sheet/MF1S503x.pdf</a></li> 203<a name="resources35"></a><li>MIFARE MF1S703X: <a href="http://www.nxp.com/documents/data_sheet/MF1S703x.pdf">http://www.nxp.com/documents/data_sheet/MF1S703x.pdf</a></li> 204<a name="resources36"></a><li>MIFARE MF0ICU1: <a href="http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf">http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf</a></li> 205<a name="resources37"></a><li>MIFARE MF0ICU2: <a href="http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf">http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf</a></li> 206<a name="resources38"></a><li>MIFARE AN130511: <a href="http://www.nxp.com/documents/application_note/AN130511.pdf">http://www.nxp.com/documents/application_note/AN130511.pdf</a></li> 207<a name="resources39"></a><li>MIFARE AN130411: <a href="http://www.nxp.com/documents/application_note/AN130411.pdf">http://www.nxp.com/documents/application_note/AN130411.pdf</a></li> 208<a name="resources40"></a><li>Camera orientation API: <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)</a></li> 209<a name="resources41"></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> 210<a name="resources42"></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> 211<a name="resources43"></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> 212</ol> 213<p>Many of these resources are derived directly or indirectly from the Android 2142.3 SDK, and will be functionally identical to the information in that SDK's 215documentation. In any cases where this Compatibility Definition or the 216Compatibility Test Suite disagrees with the SDK documentation, the SDK 217documentation is considered authoritative. Any technical details provided in 218the references included above are considered by inclusion to be part of this 219Compatibility Definition.</p> 220 221<a name="section-3"></a><h2>3. Software</h2> 222<p>The Android platform includes a set of managed APIs, a set of native APIs, 223and a body of so-called "soft" APIs such as the Intent system and 224web-application APIs. This section details the hard and soft APIs that are 225integral to compatibility, as well as certain other relevant technical and 226user interface behaviors. Device implementations MUST comply with all the 227requirements in this section.</p> 228 229<a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3> 230<p>The managed (Dalvik-based) execution environment is the primary vehicle for 231Android applications. The Android application programming interface (API) is 232the set of Android platform interfaces exposed to applications running in the 233managed VM environment. Device implementations MUST provide complete 234implementations, including all documented behaviors, of any documented API 235exposed by the Android 2.3 SDK [<a href="#resources04">Resources, 4</a>].</p> 236<p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 237or signatures, deviate from the documented behavior, or include no-ops, except 238where specifically allowed by this Compatibility Definition.</p> 239<p>This Compatibility Definition permits some types of hardware for which 240Android includes APIs to be omitted by device implementations. In such cases, 241the APIs MUST still be present and behave in a reasonable way. See Section 7 242for specific requirements for this scenario.</p> 243 244<a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3> 245<p>In addition to the managed APIs from Section 3.1, Android also includes a 246significant runtime-only "soft" API, in the form of such things such as 247Intents, permissions, and similar aspects of Android applications that cannot 248be enforced at application compile time. This section details the "soft" APIs 249and system behaviors required for compatibility with Android 2.3. Device 250implementations MUST meet all the requirements presented in this section.</p> 251<a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4> 252<p>Device implementers MUST support and enforce all permission constants as 253documented by the Permission reference page [<a 254href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional 255requirements related to the Android security model.</p> 256<a name="section-3.2.3"></a><h4>3.2.2. Build Parameters</h4> 257<p>The Android APIs include a number of constants on the <code>android.os.Build</code> 258class [<a href="#resources06">Resources, 6</a>] that are intended to describe 259the current device. To provide consistent, meaningful values across device 260implementations, the table below includes additional restrictions on the 261formats of these values to which device implementations MUST conform.</p> 262<table> 263<tbody> 264<tr> 265<td><b>Parameter</b></td> 266<td><b>Comments</b></td> 267</tr> 268<tr> 269<td>android.os.Build.VERSION.RELEASE</td> 270<td>The version of the currently-executing Android system, in human-readable 271format. This field MUST have one of the string values defined in [<a 272href="#resources07">Resources, 7</a>].</td> 273</tr> 274<tr> 275<td>android.os.Build.VERSION.SDK</td> 276<td>The version of the currently-executing Android system, in a format 277accessible to third-party application code. For Android 2.3, this field MUST have 278the integer value 9.</td> 279</tr> 280<tr> 281<td>android.os.Build.VERSION.INCREMENTAL</td> 282<td>A value chosen by the device implementer designating the specific build of 283the currently-executing Android system, in human-readable format. This value 284MUST NOT be re-used for different builds made available to end users. A typical use 285of this field is to indicate which build number or source-control change 286identifier was used to generate the build. There are no requirements on the 287specific format of this field, except that it MUST NOT be null or the empty 288string ("").</td> 289</tr> 290<tr> 291<td>android.os.Build.BOARD</td> 292<td>A value chosen by the device implementer identifying the specific internal 293hardware used by the device, in human-readable format. A possible use of this 294field is to indicate the specific revision of the board powering the device. 295The value of this field MUST be encodable as 7-bit ASCII and match the regular expression 296<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 297</tr> 298<tr> 299<td>android.os.Build.BRAND</td> 300<td>A value chosen by the device implementer identifying the name of the 301company, organization, individual, etc. who produced the device, in 302human-readable format. A possible use of this field is to indicate the OEM 303and/or carrier who sold the device. The value of this field MUST be 304encodable as 7-bit ASCII and match the regular expression 305<code>"^[a-zA-Z0-9.,_-]+$"</code>. 306</td> 307</tr> 308<tr> 309<td>android.os.Build.DEVICE</td> 310<td>A value chosen by the device implementer identifying the specific 311configuration or revision of the body (sometimes called "industrial design") 312of the device. The value of this field MUST be encodable as 7-bit ASCII and 313match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 314</tr> 315<tr> 316<td>android.os.Build.FINGERPRINT</td> 317<td>A string that uniquely identifies this build. It SHOULD be reasonably 318human-readable. It MUST follow this template: 319<br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 320For example: 321<br/><code>acme/mydevice/generic/generic:2.3/ERC77/3359:userdebug/test-keys</code><br/> 322The fingerprint MUST NOT include whitespace characters. If other fields included in the 323template above have whitespace characters, they MUST be replaced in the build 324fingerprint with another character, such as the underscore ("_") character. 325The value of this field MUST be encodable as 7-bit ASCII.</td> 326</tr> 327<tr> 328<td>android.os.Build.HOST</td> 329<td>A string that uniquely identifies the host the build was built on, in 330human readable format. There are no requirements on the specific format of 331this field, except that it MUST NOT be null or the empty string ("").</td> 332</tr> 333<tr> 334<td>android.os.Build.ID</td> 335<td>An identifier chosen by the device implementer to refer to a specific 336release, in human readable format. This field can be the same as 337android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 338meaningful for end users to distinguish between software builds. The value of 339this field MUST be encodable as 7-bit ASCII and match the regular expression 340<code>"^[a-zA-Z0-9.,_-]+$"</code>. 341</td> 342</tr> 343<tr> 344<td>android.os.Build.MODEL</td> 345<td>A value chosen by the device implementer containing the name of the device 346as known to the end user. This SHOULD be the same name under which the device 347is marketed and sold to end users. There are no requirements on the specific 348format of this field, except that it MUST NOT be null or the empty string 349("").</td> 350</tr> 351<tr> 352<td>android.os.Build.PRODUCT</td> 353<td>A value chosen by the device implementer containing the development name 354or code name of the device. MUST be human-readable, but is not necessarily 355intended for view by end users. The value of this field MUST be 356encodable as 7-bit ASCII and match the regular expression 357<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 358</tr> 359<tr> 360<td>android.os.Build.TAGS</td> 361<td>A comma-separated list of tags chosen by the device implementer that 362further distinguish the build. For example, "unsigned,debug". The value of 363this field MUST be encodable as 7-bit ASCII and match the regular expression 364<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 365</tr> 366<tr> 367<td>android.os.Build.TIME</td> 368<td>A value representing the timestamp of when the build occurred.</td> 369</tr> 370<tr> 371<td>android.os.Build.TYPE</td> 372<td>A value chosen by the device implementer specifying the runtime 373configuration of the build. This field SHOULD have one of the values 374corresponding to the three typical Android runtime configurations: "user", 375"userdebug", or "eng". The value of this field MUST be 376encodable as 7-bit ASCII and match the regular expression 377<code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 378</tr> 379<tr> 380<td>android.os.Build.USER</td> 381<td>A name or user ID of the user (or automated user) that generated the 382build. There are no requirements on the specific format of this field, except 383that it MUST NOT be null or the empty string ("").</td> 384</tr> 385</tbody> 386</table> 387<a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4> 388<p>Android uses Intents to achieve loosely-coupled integration between 389applications. This section describes requirements related to the Intent 390patterns that MUST be honored by device implementations. By "honored", it is 391meant that the device implementer MUST provide an Android Activity or Service 392that specifies a matching Intent filter and binds to and implements correct 393behavior for each specified Intent pattern.</p> 394<a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4> 395<p>The Android upstream project defines a number of core applications, such as 396a phone dialer, calendar, contacts book, music player, and so on. Device 397implementers MAY replace these applications with alternative versions.</p> 398<p>However, any such alternative versions MUST honor the same Intent patterns 399provided by the upstream project. For example, if a device contains an 400alternative music player, it must still honor the Intent pattern issued by 401third-party applications to pick a song.</p> 402<p>The following applications are considered core Android system 403applications:</p> 404<ul> 405<li>Desk Clock</li> 406<li>Browser</li> 407<li>Calendar</li> 408<li>Calculator</li> 409<!-- <li>Camera</li> --> 410<li>Contacts</li> 411<li>Email</li> 412<li>Gallery</li> 413<li>GlobalSearch</li> 414<li>Launcher</li> 415<!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 416if the device does not support Live Wallpapers, per Section 3.8.5.)</li> --> 417<!-- <li>Messaging (AKA "Mms")</li> --> 418<li>Music</li> 419<!-- <li>Phone</li> --> 420<li>Settings</li> 421<!-- <li>SoundRecorder</li> --> 422</ul> 423<p>The core Android system applications include various Activity, or Service 424components that are considered "public". That is, the attribute 425"android:exported" may be absent, or may have the value "true".</p> 426<p>For every Activity or Service defined 427in one of the core Android system apps that is not marked as non-public via an 428android:exported attribute with the value "false", device implementations MUST 429include a compontent of the same type implementing the same Intent filter 430patterns as the core Android system app.</p> 431<p>In other words, a device implementation MAY replace core Android system 432apps; however, if it does, the device implementation MUST support all Intent 433patterns defined by each core Android system app being replaced.</p> 434<a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4> 435<p>As Android is an extensible platform, device implementers MUST allow each 436Intent pattern referenced in Section 3.2.3.1 to be overridden by third-party 437applications. The upstream Android open source project allows this by default; 438device implementers MUST NOT attach special privileges to system applications' 439use of these Intent patterns, or prevent third-party applications from binding 440to and assuming control of these patterns. This prohibition specifically 441includes but is not limited to disabling the "Chooser" user interface which 442allows the user to select between multiple applications which all handle the 443same Intent pattern.</p> 444<a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4> 445<p>Device implementers MUST NOT include any Android component that honors any 446new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 447key string in the android.* namespace. Device implementers MUST NOT include 448any Android components that honor any new Intent or Broadcast Intent patterns 449using an ACTION, CATEGORY, or other key string in a package space belonging to 450another organization. Device implementers MUST NOT alter or extend any of the 451Intent patterns used by the core apps listed in Section 3.2.3.1.</p> 452<p>This prohibition is analogous to that specified for Java language classes 453in Section 3.6.</p> 454<a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4> 455<p>Third-party applications rely on the platform to broadcast certain Intents 456to notify them of changes in the hardware or software environment. 457Android-compatible devices MUST broadcast the public broadcast Intents in 458response to appropriate system events. Broadcast Intents are described in the 459SDK documentation.</p> 460 461<a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3> 462<p>Managed code running in Dalvik can call into native code provided in the 463application .apk file as an ELF .so file compiled for the appropriate device 464hardware architecture. As native code is highly dependent on the underlying 465processor technology, Android defines a number of Application Binary 466Interfaces (ABIs) in the Android NDK, in the file 467<code>docs/CPU-ARCH-ABIS.txt</code>. If a device implementation is compatible 468with one or more defined ABIs, it SHOULD implement compatibility with the 469Android NDK, as below.</p> 470<p>If a device implementation includes support for an Android ABI, it:</p> 471<ul> 472<li>MUST include support for code running in the managed environment to call 473into native code, using the standard Java Native Interface (JNI) 474semantics.</li> 475<li>MUST be source-compatible (i.e. header compatible) and binary-compatible 476(for the ABI) with each required library in the list below</li> 477<li>MUST accurately report the native Application Binary Interface (ABI) 478supported by the device, via the <code>android.os.Build.CPU_ABI</code> 479API</li> 480<li>MUST report only those ABIs documented in the latest version of the 481Android NDK, in the file <code>docs/CPU-ARCH-ABIS.txt</code></li> 482<li>SHOULD be built using the source code and header files available in the 483upstream Android open-source project</li> 484</ul> 485<p>The following native code APIs MUST be available to apps that include 486native code:</p> 487<ul> 488<li>libc (C library)</li> 489<li>libm (math library)</li> 490<li>Minimal support for C++</li> 491<li>JNI interface</li> 492<li>liblog (Android logging)</li> 493<li>libz (Zlib compression)</li> 494<li>libdl (dynamic linker)</li> 495<li>libGLESv1_CM.so (OpenGL ES 1.0)</li> 496<li>libGLESv2.so (OpenGL ES 2.0)</li> 497<li>libEGL.so (native OpenGL surface management)</li> 498<li>libjnigraphics.so</li> 499<li>libOpenSLES.so (Open Sound Library audio support)</li> 500<li>libandroid.so (native Android activity support)</li> 501<li>Support for OpenGL, as described below</li> 502</ul> 503<p>Note that future releases of the Android NDK may introduce support for 504additional ABIs. If a device implementation is not compatible with an existing 505predefined ABI, it MUST NOT report support for any ABI at all.</p> 506<p>Native code compatibility is challenging. For this reason, it should be 507repeated that device implementers are VERY strongly encouraged to use the 508upstream implementations of the libraries listed above to help ensure 509compatibility.</p> 510 511<a name="section-3.4"></a><h3>3.4. Web Compatibility</h3> 512<p>Many developers and applications rely on the behavior of the 513<code>android.webkit.WebView</code> class [<a 514href="#resources08">Resources, 8</a>] 515for their user interfaces, so the WebView implementation must be 516compatible across Android implementations. Similarly, a complete, modern web 517broswer is central to the Android user experience. Device implementations MUST 518include a version of <code>android.webkit.WebView</code> consistent with the 519upstream Android software, and MUST include a modern HTML5-capable browser, as 520described below.</p> 521<a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4> 522<p>The Android Open Source implementation uses the WebKit rendering engine to 523implement the <code>android.webkit.WebView</code>. Because it is not feasible 524to develop a comprehensive test suite for a web rendering system, device 525implementers MUST use the specific upstream build of WebKit in the WebView 526implementation. Specifically:</p> 527<ul> 528<li>Device implementations' <code>android.webkit.WebView</code> 529implementations MUST be based on the 533.1 WebKit build from the upstream 530Android Open Source tree for Android 2.3. This build includes a specific set 531of functionality and security fixes for the WebView. Device implementers MAY 532include customizations to the WebKit implementation; however, any such 533customizations MUST NOT alter the behavior of the WebView, including rendering 534behavior.</li> 535<li>The user agent string reported by the WebView MUST be in this format:<br/> 536 <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> 537 <ul> 538 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 539 <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> 540 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 541 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 542 </ul></li> 543</ul> 544<p>The WebView component SHOULD include support for as much of HTML5 [<a 545href="#resources09">Resources, 9</a>] as possible. 546Minimally, device implementations MUST support each of these APIs associated 547with HTML5 in the WebView:</p> 548<ul> 549<li>application cache/offline operation [<a href="#resources10">Resources, 10</a>]</li> 550<li>the <video> tag [<a href="#resources11">Resources, 11</a>]</li> 551<li>geolocation [<a href="#resources12">Resources, 12</a>]</li> 552</ul> 553<p>Additionally, device implementations MUST support the HTML5/W3C webstorage 554API [<a href="#resources13">Resources, 13</a>], and SHOULD support the 555HTML5/W3C IndexedDB API [<a href="#resources14">Resources, 14</a>]. <i>Note 556that as the web development standards bodies are transitioning to favor 557IndexedDB over webstorage, IndexedDB is expected to become a required 558component in a future version of Android.</i></p> 559<p>HTML5 APIs, like all JavaScript APIs, MUST be disabled by default in a 560WebView, unless the developer explicitly enables them via the usual Android 561APIs.</p> 562 563<a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4> 564<p>Device implementations MUST include a standalone Browser application for 565general user web browsing. The standalone Browser MAY be based on a 566browser technology other than WebKit. However, even if an alternate Browser 567application is used, the <code>android.webkit.WebView</code> component 568provided to third-party applications MUST be based on WebKit, as described in 569Section 3.4.1.</p> 570<p>Implementations MAY ship a custom user agent string in the standalone 571Browser application.</p> 572<p>The standalone Browser application (whether based on the upstream 573WebKit Browser application or a third-party replacement) SHOULD include support 574for as much of HTML5 [<a href="#resources09">Resources, 9</a>] as possible. 575Minimally, device implementations MUST support each of these APIs associated 576with HTML5:</p> 577<ul> 578<li>application cache/offline operation [<a href="#resources10">Resources, 10</a>]</li> 579<li>the <video> tag [<a href="#resources11">Resources, 11</a>]</li> 580<li>geolocation [<a href="#resources12">Resources, 12</a>]</li> 581</ul> 582<p>Additionally, device implementations MUST support the HTML5/W3C webstorage 583API [<a href="#resources13">Resources, 13</a>], and SHOULD support the 584HTML5/W3C IndexedDB API [<a href="#resources14">Resources, 14</a>]. <i>Note 585that as the web development standards bodies are transitioning to favor 586IndexedDB over webstorage, IndexedDB is expected to become a required 587component in a future version of Android.</i></p> 588 589<a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3> 590<p>The behaviors of each of the API types (managed, soft, native, and web) 591must be consistent with the preferred implementation of the upstream Android 592open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 593of compatibility are:</p> 594<ul> 595<li>Devices MUST NOT change the behavior or semantics of a standard Intent</li> 596<li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a 597 particular type of system component (such as Service, Activity, 598 ContentProvider, etc.)</li> 599<li>Devices MUST NOT change the semantics of a standard permission</li> 600</ul> 601<p>The above list is not comprehensive. The Compatibility Test Suite (CTS) 602tests significant portions of the platform for behavioral compatibility, but 603not all. It is the responsibility of the implementer to ensure behavioral 604compatibility with the Android Open Source Project. For this reason, device 605implementers SHOULD use the source code available via the Android Open Source 606Project where possible, rather than re-implement significant parts of the 607system.</p> 608 609 610<a name="section-3.6"></a><h3>3.6. API Namespaces</h3> 611<p>Android follows the package and class namespace conventions defined by the 612Java programming language. To ensure compatibility with third-party 613applications, device implementers MUST NOT make any prohibited modifications 614(see below) to these package namespaces:</p> 615<ul> 616<li>java.*</li> 617<li>javax.*</li> 618<li>sun.*</li> 619<li>android.*</li> 620<li>com.android.*</li> 621</ul> 622<p>Prohibited modifications include:</p> 623<ul> 624<li>Device implementations MUST NOT modify the publicly exposed APIs on the 625Android platform by changing any method or class signatures, or by removing 626classes or class fields.</li> 627<li>Device implementers MAY modify the underlying implementation of the APIs, 628but such modifications MUST NOT impact the stated behavior and Java-language 629signature of any publicly exposed APIs.</li> 630<li>Device implementers MUST NOT add any publicly exposed elements (such as 631classes or interfaces, or fields or methods to existing classes or interfaces) 632to the APIs above.</li> 633</ul> 634<p>A "publicly exposed element" is any construct which is not decorated with 635the "@hide" marker as used in the upstream Android source code. In other 636words, device implementers MUST NOT expose new APIs or alter existing APIs in 637the namespaces noted above. Device implementers MAY make internal-only 638modifications, but those modifications MUST NOT be advertised or otherwise 639exposed to developers.</p> 640<p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 641namespace owned by or referring to another organization. For instance, device 642implementers MUST NOT add APIs to the com.google.* or similar namespace; only 643Google may do so. Similarly, Google MUST NOT add APIs to other companies' 644namespaces. Additionally, if a device implementation includes custom APIs 645outside the standard Android namespace, those APIs MUST be packaged in an 646Android shared library so that only apps that explicitly use them (via the 647<code><uses-library></code> mechanism) are affected by the increased 648memory usage of such APIs.</p> 649<p>If a device implementer proposes to improve one of the package namespaces 650above (such as by adding useful new functionality to an existing API, or 651adding a new API), the implementer SHOULD visit source.android.com and begin 652the process for contributing changes and code, according to the information on 653that site.</p> 654<p>Note that the restrictions above correspond to standard conventions for 655naming APIs in the Java programming language; this section simply aims to 656reinforce those conventions and make them binding through inclusion in this 657compatibility definition.</p> 658 659<a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3> 660<p>Device implementations MUST support the full Dalvik Executable (DEX) 661bytecode specification and Dalvik Virtual Machine semantics [<a 662href="#resources15">Resources, 15</a>].</p> 663<p>Device implementations with screens classified as medium- or low-density 664MUST configure Dalvik to allocate at least 16MB of memory to each application. 665Device implementations with screens classified as high-density or 666extra-high-density MUST configure Dalvik to allocate at least 24MB of memory 667to each application. Note that device implementations MAY allocate more memory 668than these figures.</p> 669 670<a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3> 671<p>The Android platform includes some developer APIs that allow developers to 672hook into the system user interface. Device implementations MUST incorporate 673these standard UI APIs into custom user interfaces they develop, as explained 674below.</p> 675<a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4> 676<p>Android defines a component type and corresponding API and lifecycle that 677allows applications to expose an "AppWidget" to the end user [<a 678href="#resources16">Resources, 16</a>]. 679The Android Open Source reference release includes a Launcher application that 680includes user interface elements allowing the user to add, view, and remove 681AppWidgets from the home screen.</p> 682<p>Device implementers MAY substitute an alternative to the reference Launcher 683(i.e. home screen). Alternative Launchers SHOULD include built-in support for 684AppWidgets, and expose user interface elements to add, configure, view, and remove 685AppWidgets directly within the Launcher. Alternative Launchers MAY omit these 686user interface elements; however, if they are omitted, the device implementer 687MUST provide a separate application accessible from the Launcher that allows 688users to add, configure, view, and remove AppWidgets.</p> 689<a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4> 690<p>Android includes APIs that allow developers to notify users of notable 691events [<a href="#resources17">Resources, 17</a>]. Device implementers MUST provide support for each 692class of notification so defined; specifically: sounds, vibration, light and 693status bar.</p> 694<p>Additionally, the implementation MUST correctly render all resources 695(icons, sound files, etc.) provided for in the APIs [<a 696href="#resources18">Resources, 18</a>], or in the 697Status Bar icon style guide [<a href="#resources19">Resources, 19</a>]. Device implementers MAY provide 698an alternative user experience for notifications than that provided by the 699reference Android Open Source implementation; however, such alternative 700notification systems MUST support existing notification resources, as 701above.</p> 702<a name="section-3.8.3"></a><h4>3.8.3. Search</h4> 703<p>Android includes APIs [<a href="#resources20">Resources, 20</a>] that allow developers to incorporate 704search into their applications, and expose their application's data into the 705global system search. Generally speaking, this functionality consists of a 706single, system-wide user interface that allows users to enter queries, 707displays suggestions as users type, and displays results. The Android APIs 708allow developers to reuse this interface to provide search within their own 709apps, and allow developers to supply results to the common global search user 710interface.</p> 711<p>Device implementations MUST include a single, shared, system-wide search 712user interface capable of real-time suggestions in response to user input. 713Device implementations MUST implement the APIs that allow developers to reuse 714this user interface to provide search within their own applications. Device 715implementations MUST implement the APIs that allow third-party applications to 716add suggestions to the search box when it is run in global search mode. If no 717third-party applications are installed that make use of this functionality, 718the default behavior SHOULD be to display web search engine results and 719suggestions.</p> 720<p>Device implementations MAY ship alternate search user interfaces, but 721SHOULD include a hard or soft dedicated search button, that can be used at any 722time within any app to invoke the search framework, with the behavior provided 723for in the API documentation.</p> 724<a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4> 725<p>Applications can use the "Toast" API (defined in [<a 726href="#resources21">Resources, 21</a>]) to 727display short non-modal strings to the end user, that disappear after a brief 728period of time. Device implementations MUST display Toasts from applications 729to end users in some high-visibility manner.</p> 730<a name="section-3.8.5"></a><h4>3.8.5. Live Wallpapers</h4> 731<p>Android defines a component type and corresponding API and lifecycle that 732allows applications to expose one or more "Live Wallpapers" to the end user 733[<a href="#resources22">Resources, 22</a>]. Live Wallpapers are animations, 734patterns, or similar images with limited input capabilities that display as a 735wallpaper, behind other applications.</p> 736<p>Hardware is considered capable of reliably running live wallpapers if it 737can run all live wallpapers, with no limitations on functionality, at a 738reasonable framerate with no adverse affects on other applications. If 739limitations in the hardware cause wallpapers and/or applications to crash, 740malfunction, consume excessive CPU or battery power, or run at unacceptably 741low frame rates, the hardware is considered incapable of running live 742wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 743context to render their content. Live wallpaper will not run reliably on 744hardware that does not support multiple OpenGL contexts because the live 745wallpaper use of an OpenGL context may conflict with other applications that 746also use an OpenGL context.</p> 747<p>Device implementations capable of running live wallpapers reliably as 748described above SHOULD implement live wallpapers. Device implementations 749determined to not run live wallpapers reliably as described above MUST NOT 750implement live wallpapers.</p> 751 752<a name="section-4"></a><h2>4. Application Packaging Compatibility</h2> 753<p>Device implementations MUST install and run Android ".apk" files as 754generated by the "aapt" tool included in the official Android SDK [<a 755href="#resources23">Resources, 23</a>].</p> 756<p>Devices implementations MUST NOT extend either the .apk [<a 757href="#resources24">Resources, 24</a>], Android Manifest [<a 758href="#resources25">Resources, 25</a>], 759or Dalvik bytecode [<a href="#resources15">Resources, 15</a>] formats in such 760a way that would prevent those files from 761installing and running correctly on other compatible devices. Device 762implementers SHOULD use the reference upstream implementation of Dalvik, and 763the reference implementation's package management system.</p> 764 765<a name="section-5"></a><h2>5. Multimedia Compatibility</h2> 766<p>Device implementations MUST fully implement all multimedia APIs. Device 767implementations MUST include support for all multimedia codecs described 768below, and SHOULD meet the sound processing guidelines described below. Device 769implementations MUST include at least one form of audio output, such as 770speakers, headphone jack, external speaker connection, etc.</p> 771<a name="section-5.1"></a><h3>5.1. Media Codecs</h3> 772<p>Device implementations MUST support the multimedia codecs as detailed in 773the following sections. All of these codecs are provided as software 774implementations in the preferred Android implementation from the Android 775Open-Source Project.</p> 776<p>Please note that neither Google nor the Open Handset Alliance make any 777representation that these codecs are unencumbered by third-party patents. 778Those intending to use this source code in hardware or software products are 779advised that implementations of this code, including in open source software 780or shareware, may require patent licenses from the relevant patent 781holders.</p> 782<p>The tables below do not list specific bitrate requirements for 783most video codecs. The reason for this is that in practice, current device 784hardware does not necessarily support bitrates that map exactly to the 785required bitrates specified by the relevant standards. Instead, device 786implementations SHOULD support the highest bitrate practical on the hardware, 787up to the limits defined by the specifications.</p> 788<a name="section-5.1.1"></a><h3>5.1.1. Media Decoders</h3> 789<p>Device implementations MUST include an implementation of an decoder for 790each codec and format described in the table below. Note that decoders for 791each of these media types are provided by the upstream Android Open-Source 792Project.</p> 793<table><tbody> 794<tr> 795<td rowspan="11"><b>Audio</b></td> 796</tr> 797<tr> 798<td><b>Name</b></td> 799<td><b>Details</b></td> 800<td><b>File/Container Format</b></td> 801</tr> 802<tr> 803<td>AAC LC/LTP</td> 804<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> 805<td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td> 806</tr> 807<tr> 808<td>HE-AACv1 (AAC+)</td> 809</tr> 810<tr> 811<td>HE-AACv2 (enhanced AAC+)</td> 812</tr> 813<tr> 814<td>AMR-NB</td> 815<td>4.75 to 12.2 kbps sampled @ 8kHz</td> 816<td>3GPP (.3gp)</td> 817</tr> 818<tr> 819<td>AMR-WB</td> 820<td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 821<td>3GPP (.3gp)</td> 822</tr> 823<tr> 824<td>MP3</td> 825<td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td> 826<td>MP3 (.mp3)</td> 827</tr> 828<tr> 829<td>MIDI</td> 830<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> 831<td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td> 832</tr> 833<tr> 834<td>Ogg Vorbis</td> 835<td> </td> 836<td>Ogg (.ogg)</td> 837</tr> 838<tr> 839<td>PCM</td> 840<td>8- and 16-bit linear PCM (rates up to limit of hardware)</td> 841<td>WAVE (.wav)</td> 842</tr> 843<tr> 844<td rowspan="5"><b>Image</b></td> 845</tr> 846<tr> 847<td>JPEG</td> 848<td>base+progressive</td> 849<td> </td> 850</tr> 851<tr> 852<td>GIF</td> 853<td> </td> 854<td> </td> 855</tr> 856<tr> 857<td>PNG</td> 858<td> </td> 859<td> </td> 860</tr> 861<tr> 862<td>BMP</td> 863<td> </td> 864<td> </td> 865</tr> 866<tr> 867<td rowspan="4"><b>Video</b></td> 868</tr> 869<tr> 870<td>H.263</td> 871<td> </td> 872<td>3GPP (.3gp) files</td> 873</tr> 874<tr> 875<td>H.264</td> 876<td> </td> 877<td>3GPP (.3gp) and MPEG-4 (.mp4) files</td> 878</tr> 879<tr> 880<td>MPEG4 Simple Profile</td> 881<td> </td> 882<td>3GPP (.3gp) file</td> 883</tr> 884</tbody> 885</table> 886 887<a name="section-5.1.2"></a><h3>5.1.2. Media Encoders</h3> 888<p>Device implementations SHOULD include encoders for as many of the media 889formats listed in Section 5.1.1. as possible. However, some encoders do not 890make sense for devices that lack certain optional hardware; for instance, 891an encoder for the H.263 video does not make sense, if the device lacks any 892cameras. Device implementations MUST therefore implement media encoders 893according to the conditions described in the table below.</p> 894<p>See Section 7 for details on the conditions under which hardware may be 895omitted by device implementations.</p> 896<table><tbody> 897<tr> 898<td rowspan="5"><b>Audio</b></td> 899</tr> 900<tr> 901<td><b>Name</b></td> 902<td><b>Details</b></td> 903<td><b>File/Container Format</b></td> 904<td><b>Conditions</b></td> 905</tr> 906<tr> 907<td>AMR-NB</td> 908<td>4.75 to 12.2 kbps sampled @ 8kHz</td> 909<td>3GPP (.3gp)</td> 910<td rowspan="3">Device implementations that include microphone hardware and define 911<code>android.hardware.microphone</code> MUST include encoders for these audio 912formats.</td> 913</tr> 914<tr> 915<td>AMR-WB</td> 916<td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 917<td>3GPP (.3gp)</td> 918</tr> 919<tr> 920<td>AAC LC/LTP</td> 921<td rowspan="1">Mono/Stereo content in any combination of standard bit rates up to 160 kbps and sampling rates between 8 to 48kHz</td> 922<td rowspan="1">3GPP (.3gp) and MPEG-4 (.mp4, .m4a).</td> 923</tr> 924<tr> 925<td rowspan="2"><b>Image</b></td> 926<td>JPEG</td> 927<td>base+progressive</td> 928<td> </td> 929<td rowspan="2">All device implementations MUST include encoders for these 930image formats, as Android 2.3 includes APIs that applications can use to 931programmatically generate files of these types.</td> 932</tr> 933<tr> 934<td>PNG</td> 935<td> </td> 936<td> </td> 937</tr> 938<tr> 939<td><b>Video</b></td> 940<td>H.263</td> 941<td> </td> 942<td>3GPP (.3gp) files</td> 943<td>Device implementations that include camera hardware and define 944either <code>android.hardware.camera</code> or 945<code>android.hardware.camera.front</code> MUST include encoders for these 946video formats.</td> 947</tr> 948</tbody> 949</table> 950<p>In addition to the encoders listed above, device implementations SHOULD include an H.264 951encoder. Note that the Compatibility Definition for a future version is planned 952to change this requirement to "MUST". That is, H.264 encoding is optional in Android 9532.3 but <b>will be required</b> by a future version. Existing and new devices 954that run Android 2.3 are <b>very strongly encouraged to meet 955this requirement in Android 2.3</b>, or they will not be able to attain 956Android compatibility when upgraded to the future version.</p> 957 958<a name="section-5.2"></a><h3>5.2. Audio Recording</h3> 959<p>When an application has used the <code>android.media.AudioRecord</code> API to 960start recording an audio stream, device implementations SHOULD sample and 961record audio with each of these behaviors:</p> 962<ul> 963<li>Noise reduction processing, if present, SHOULD be disabled.</li> 964<li>Automatic gain control, if present, SHOULD be disabled.</li> 965<li>The device SHOULD exhibit approximately flat amplitude versus frequency 966 characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz</li> 967<li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level 968 (SPL) source at 1000 Hz yields RMS of 5000 for 16-bit samples.</li> 969<li>PCM amplitude levels SHOULD linearly track input SPL changes over at least 970 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li> 971<li>Total harmonic distortion SHOULD be less than 1% from 100 Hz to 4000 Hz at 972 90 dB SPL input level.</li> 973</ul> 974<p><b>Note:</b> while the requirements outlined above are stated as "SHOULD" 975for Android 2.3, the Compatibility Definition for a future version is planned 976to change these to "MUST". That is, these requirements are optional in Android 9772.3 but <b>will be required</b> by a future version. Existing and new devices 978that run Android 2.3 are <b>very strongly encouraged to meet 979these requirements in Android 2.3</b>, or they will not be able to attain 980Android compatibility when upgraded to the future version.</p> 981 982<a name="section-5.3"></a><h3>5.3. Audio Latency</h3> 983<p>Audio latency is broadly defined as the interval between when an 984application requests an audio playback or record operation, and when the 985device implementation actually begins the operation. Many classes of 986applications rely on short latencies, to achieve real-time effects such sound 987effects or VOIP communication. Device implementations that include microphone 988hardware and declare <code>android.hardware.microphone</code> SHOULD meet all 989audio latency requirements outlined in this section. See Section 7 for 990details on the conditions under which microphone hardware may be omitted by 991device implementations.</p> 992<p>For the purposes of this section:</p> 993<ul> 994<li>"cold output latency" is defined to be the interval between when an 995 application requests audio playback and when sound begins playing, when 996 the audio system has been idle and powered down prior to the request</li> 997<li>"warm output latency" is defined to be the interval between when an 998 application requests audio playback and when sound begins playing, when 999 the audio system has been recently used but is currently idle (that is, 1000 silent)</li> 1001<li>"continuous output latency" is defined to be the interval between when an 1002 application issues a sample to be played and when the speaker physically 1003 plays the corresponding sound, while the device is currently playing back 1004 audio</li> 1005<li>"cold input latency" is defined to be the interval between when an 1006 application requests audio recording and when the first sample is 1007 delivered to the application via its callback, when the audio system and 1008 microphone has been idle and powered down prior to the request</li> 1009<li>"continuous input latency" is defined to be when an ambient sound occurs 1010 and when the sample corresponding to that sound is delivered to a 1011 recording application via its callback, while the device is in recording 1012 mode</li> 1013</ul> 1014<p>Using the above definitions, device implementations SHOULD exhibit each of 1015these properties:</p> 1016<ul> 1017<li>cold output latency of 100 milliseconds or less</li> 1018<li>warm output latency of 10 milliseconds or less</li> 1019<li>continuous output latency of 45 milliseconds or less</li> 1020<li>cold input latency of 100 milliseconds or less</li> 1021<li>continuous input latency of 50 milliseconds or less</li> 1022</ul> 1023<p><b>Note:</b> while the requirements outlined above are stated as "SHOULD" 1024for Android 2.3, the Compatibility Definition for a future version is planned 1025to change these to "MUST". That is, these requirements are optional in Android 10262.3 but <b>will be required</b> by a future version. Existing and new devices 1027that run Android 2.3 are <b>very strongly encouraged to meet 1028these requirements in Android 2.3</b>, or they will not be able to attain 1029Android compatibility when upgraded to the future version.</p> 1030<p>If a device implementation meets the requirements of this section, it MAY 1031report support for low-latency audio, by reporting the feature 1032"android.hardware.audio.low-latency" via the 1033<code>android.content.pm.PackageManager</code> class. [<a 1034href="#resources27">Resources, 27</a>] Conversely, if the device 1035implementation does not meet these requirements it MUST NOT report support for 1036low-latency audio.</p> 1037 1038<a name="section-6"></a><h2>6. Developer Tool Compatibility</h2> 1039<p>Device implementations MUST support the Android Developer Tools provided in 1040the Android SDK. Specifically, Android-compatible devices MUST be compatible 1041with:</p> 1042<ul> 1043<li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources23">Resources, 23</a>]<br/> 1044Device implementations MUST support all <code>adb</code> functions as 1045documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD 1046be inactive by default, but there MUST be a user-accessible mechanism to turn 1047on the Android Debug Bridge.</li> 1048<li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources23">Resources, 23</a>]<br/> 1049Device implementations MUST support all <code>ddms</code> features as documented in the 1050Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 1051<code>ddms</code> SHOULD be inactive by default, 1052but MUST be supported whenever the user has activated the Android Debug 1053Bridge, as above.</li> 1054<li><b>Monkey</b> [<a href="#resources26">Resources, 26</a>]<br/> 1055Device implementations MUST include the Monkey framework, and make it 1056available for applications to use.</li> 1057</ul> 1058<p>Most Linux-based systems and Apple Macintosh systems recognize Android 1059devices using the standard Android SDK tools, without additional support; 1060however Microsoft Windows systems typically require a driver for new Android 1061devices. (For instance, new vendor IDs and sometimes new device IDs require 1062custom USB drivers for Windows systems.) If a device implementation is 1063unrecognized by the <code>adb</code> tool as provided in the standard Android 1064SDK, device implementers MUST provide Windows drivers allowing developers to 1065connect to the device using the <code>adb</code> protocol. These drivers MUST 1066be provided for Windows XP, Windows Vista, and Windows 7, in both 32-bit and 106764-bit versions.</p> 1068 1069<a name="section-7"></a><h2>7. Hardware Compatibility</h2> 1070<p>Android is intended to enable device implementers to create innovative form 1071factors and configurations. At the same time Android developers write 1072innovative applications that rely on the various hardware and features 1073available through the Android APIs. The requirements in this section strike a 1074balance between innovations available to device implementers, and the needs of 1075developers to ensure their apps are only available to devices where they will 1076run properly.</p> 1077<p>If a device includes a particular hardware component that has a 1078corresponding API for third-party developers, the device implementation MUST 1079implement that API as described in the Android SDK documentation. If an API in 1080the SDK interacts with a hardware component that is stated to be optional and the device 1081implementation does not possess that component:</p> 1082<ul> 1083<li>complete class definitions (as documented by the SDK) for the component's APIs MUST still be present</li> 1084<li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li> 1085<li>API methods MUST return null values where permitted by the SDK documentation</li> 1086<li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li> 1087<li>API methods MUST NOT throw exceptions not documented by the SDK documentation</li> 1088</ul> 1089<p>A typical example of a scenario where these requirements apply is the 1090telephony API: even on non-phone devices, these APIs must be implemented as 1091reasonable no-ops.</p> 1092<p>Device implementations MUST accurately report accurate hardware configuration 1093information via the <code>getSystemAvailableFeatures()</code> and 1094<code>hasSystemFeature(String)</code> methods on the 1095<code>android.content.pm.PackageManager</code> class. [<a 1096href="#resources27">Resources, 27</a>]</p> 1097 1098<a name="section-7.1"></a><h3>7.1. Display and Graphics</h3> 1099<p>Android 2.3 includes facilities that automatically adjust application 1100assets and UI layouts appropriately for the device, to ensure that third-party 1101applications run well on a variety of hardware configurations [<a 1102href="#resources28">Resources, 28</a>]. Devices MUST properly implement these 1103APIs and behaviors, as detailed in this section.</p> 1104<a name="section-7.1.1"></a><h4>7.1.1. Screen Configurations</h4> 1105<p>Device implementations MAY use screens of any pixel dimensions, provided 1106that they meet the following requirements:</p> 1107<ul> 1108<li>screens MUST be at least 2.5 inches in physical diagonal size</li> 1109<li>density MUST be at least 100 dpi</li> 1110<li>the aspect ratio MUST be between 1.333 (4:3) and 1.779 (16:9)</li> 1111<li>the display technology used consists of square pixels</li> 1112</ul> 1113<p>Device implementations with a screen meeting the requirements above are 1114considered compatible, and no additional action is necessary. The Android 1115framework implementation automatically computes display characteristics such 1116as screen size bucket and density bucket. In the majority of cases, the 1117framework decisions are the correct ones. If the default framework 1118computations are used, no additional action is necessary. Device implementers 1119wishing to change the defaults, or use a screen that does not meet the 1120requirements above MUST contact the Android Compatibility Team for guidance, 1121as provided for in Section 12.</p> 1122<p>The units used by the requirements above are defined as follows:</p> 1123<ul> 1124<li>"Physical diagonal size" is the distance in inches between two opposing 1125corners of the illuminated portion of the display.</li> 1126<li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a 1127linear horizontal or vertical span of 1". Where dpi values are listed, both 1128horizontal and vertical dpi must fall within the range.</li> 1129<li>"Aspect ratio" is the ratio of the longer dimension of the screen to the 1130shorter dimension. For example, a display of 480x854 pixels would be 854 / 480 1131= 1.779, or roughly "16:9".</li> 1132</ul> 1133<p>Device implementations MUST use only displays with a single static 1134configuration. That is, device implementations MUST NOT enable multiple 1135screen configurations. For instance, since a typical television supports 1136multiple resolutions such as 1080p, 720p, and so on, this configuration is not 1137compatible with Android 2.3. (However, support for such configurations is 1138under investigation and planned for a future version of Android.)</p> 1139<a name="section-7.1.2"></a><h4>7.1.2. Display Metrics</h4> 1140<p>Device implementations MUST report correct values for all display metrics 1141defined in <code>android.util.DisplayMetrics</code> [<a 1142href="#resources29">Resources, 29</a>].</p> 1143<a name="section-7.1.3"></a><h4>7.1.3. Declared Screen Support</h4> 1144<p>Applications optionally indicate which screen sizes they support via the 1145<code><supports-screens></code> attribute in the AndroidManifest.xml 1146file. Device implementations MUST correctly honor applications' stated support 1147for small, medium, and large screens, as described in the Android 1148SDK documentation.</p> 1149<a name="section-7.1.4"></a><h4>7.1.4. Screen Orientation</h4> 1150<p>Compatible devices MUST support dynamic orientation by applications to 1151either portrait or landscape screen orientation. That is, the device must 1152respect the application's request for a specific screen orientation. Device 1153implementations MAY select either portrait or landscape orientation as the 1154default. Devices that cannot be physically rotated MAY meet this requirement 1155by "letterboxing" applications that request portrait mode, using only a 1156portion of the available display.</p> 1157<p>Devices MUST report the correct value for the device's current orientation, 1158whenever queried via the android.content.res.Configuration.orientation, 1159android.view.Display.getOrientation(), or other APIs.</p> 1160<a name="section-7.1.5"></a><h4>7.1.5. 3D Graphics Acceleration</h4> 1161<p>Device implementations MUST support OpenGL ES 1.0, as required by the 1162Android 2.3 APIs. For devices that lack 3D acceleration hardware, a software 1163implementation of OpenGL ES 1.0 is provided by the upstream Android 1164Open-Source Project. Device implementations SHOULD support OpenGL ES 2.0.</p> 1165<p>Implementations MAY omit Open GL ES 2.0 support; however if support is 1166ommitted, device implementations MUST NOT report as supporting OpenGL ES 2.0. 1167Specifically, if a device implementations lacks OpenGL ES 2.0 support:</p> 1168<ul> 1169<li>the managed APIs (such as via the <code>GLES10.getString()</code> method) 1170MUST NOT report support for OpenGL ES 2.0</li> 1171<li>the native C/C++ OpenGL APIs (that is, those available to apps via 1172libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST NOT report support for 1173OpenGL ES 2.0.</li> 1174</ul> 1175<p>Conversely, if a device implementation <i>does</i> support OpenGL ES 2.0, 1176it MUST accurately report that support via the routes just listed.</p> 1177<p>Note that Android 2.3 includes support for applications to optionally 1178specify that they require specific OpenGL texture compression formats. These 1179formats are typically vendor-specific. Device implementations are not required 1180by Android 2.3 to implement any specific texture compression format. However, 1181they SHOULD accurately report any texture compression formats that they do 1182support, via the <code>getString()</code> method in the OpenGL API.</p> 1183 1184<a name="section-7.2"></a><h3>7.2. Input Devices</h3> 1185<p>Android 2.3 supports a number of modalities for user input. Device 1186implementations MUST support user input devices as provided for in this 1187section.</p> 1188<a name="section-7.2.1"></a><h4>7.2.1. Keyboard</h4> 1189<p>Device implementations:</p> 1190<ul> 1191<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> 1192<li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li> 1193<li>MAY include additional soft keyboard implementations</li> 1194<li>MAY include a hardware keyboard</li> 1195<li>MUST NOT include a hardware keyboard that does not match one of the 1196formats specified in <code>android.content.res.Configuration.keyboard</code> 1197[<a href="#resources30">Resources, 30</a>] (that is, QWERTY, or 12-key)</li> 1198</ul> 1199<a name="section-7.2.2"></a><h4>7.2.2. Non-touch Navigation</h4> 1200<p>Device implementations:</p> 1201<ul> 1202<li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad, or wheel)</li> 1203<li>MUST report the correct value for 1204<code>android.content.res.Configuration.navigation</code> [<a href="#resources30">Resources, 30</a>]</li> 1205<li>MUST provide a reasonable alternative user interface mechanism for the 1206selection and editing of text, compatible with Input Management Engines. The 1207upstream Android Open-Source code includes a selection mechanism suitable for 1208use with devices that lack non-touch navigation inputs.</li> 1209</ul> 1210<a name="section-7.2.3"></a><h4>7.2.3. Navigation keys</h4> 1211<p>The Home, Menu and Back functions are essential to the Android navigation 1212paradigm. Device implementations MUST make these functions available to the 1213user at all times, regardless of application state. These functions SHOULD be 1214implemented via dedicated buttons. They MAY be implemented using software, 1215gestures, touch panel, etc., but if so they MUST be always accessible and not 1216obscure or interfere with the available application display area.</p> 1217<p>Device implementers SHOULD also provide a dedicated search key. Device 1218implementers MAY also provide send and end keys for phone calls.</p> 1219<a name="section-7.2.4"></a><h4>7.2.4. Touchscreen input</h4> 1220<p>Device implementations:</p> 1221<ul> 1222<li>MUST have a touchscreen</li> 1223<li>MAY have either capacitive or resistive touchscreen</li> 1224<li>MUST report the value of <code>android.content.res.Configuration</code> 1225[<a href="#resources30">Resources, 30</a>] 1226reflecting corresponding to the type of the specific touchscreen on the 1227device</li> 1228<li>SHOULD support fully independently tracked pointers, if the touchscreen supports multiple pointers</li> 1229</ul> 1230 1231<a name="section-7.3"></a><h3>7.3. Sensors</h3> 1232<p>Android 2.3 includes APIs for accessing a variety of sensor types. Devices 1233implementations generally MAY omit these sensors, as provided for in the 1234following subsections. If a device includes a particular sensor type that has a 1235corresponding API for third-party developers, the device implementation MUST 1236implement that API as described in the Android SDK documentation. For example, 1237device implementations:</p> 1238<ul> 1239<li>MUST accurately report the presence or absence of sensors per the 1240<code>android.content.pm.PackageManager</code> class. [<a 1241href="#resources27">Resources, 27</a>]</li> 1242<li>MUST return an accurate list of supported sensors via the 1243<code>SensorManager.getSensorList()</code> and similar methods</li> 1244<li>MUST behave reasonably for all other sensor APIs (for example, by 1245returning true or false as appropriate when applications attempt to register 1246listeners, not calling sensor listeners when the corresponding sensors are not 1247present; etc.)</li> 1248</ul> 1249<p>The list above is not comprehensive; the documented behavior of the Android 1250SDK is to be considered authoritative.</p> 1251<p>Some sensor types are synthetic, meaning they can be derived from data 1252provided by one or more other sensors. (Examples include the orientation 1253sensor, and the linear acceleration sensor.) Device implementations SHOULD 1254implement these sensor types, when they include the prerequisite physical 1255sensors.</p> 1256<p>The Android 2.3 APIs introduce a notion of a "streaming" sensor, which is 1257one that returns data continuously, rather than only when the data changes. 1258Device implementations MUST continuously provide periodic data samples for any 1259API indicated by the Android 2.3 SDK documentation to be a streaming 1260sensor.</p> 1261<a name="section-7.3.1"></a><h4>7.3.1. Accelerometer</h4> 1262<p>Device implementations SHOULD include a 3-axis accelerometer. If a device 1263implementation does include a 3-axis accelerometer, it:</p> 1264<ul> 1265<li>MUST be able to deliver events at 50 Hz or greater</li> 1266<li>MUST comply with the Android sensor coordinate system as detailed 1267in the Android APIs (see [<a href="#resources31">Resources, 31</a>])</li> 1268<li>MUST be capable of measuring from freefall up to twice gravity (2g) or 1269more on any three-dimensional vector</li> 1270<li>MUST have 8-bits of accuracy or more</li> 1271<li>MUST have a standard deviation no greater than 0.05 m/s^2</li> 1272</ul> 1273<a name="section-7.3.2"></a><h4>7.3.2. Magnetometer</h4> 1274<p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.) 1275If a device does include a 3-axis magnetometer, it:</p> 1276<ul> 1277<li>MUST be able to deliver events at 10 Hz or greater</li> 1278<li>MUST comply with the Android sensor coordinate system as detailed 1279in the Android APIs (see [<a href="#resources31">Resources, 31</a>]).</li> 1280<li>MUST be capable of sampling a range of field strengths adequate to cover the geomagnetic field</li> 1281<li>MUST have 8-bits of accuracy or more</li> 1282<li>MUST have a standard deviation no greater than 0.5 µT</li> 1283</ul> 1284<a name="section-7.3.3"></a><h4>7.3.3. GPS</h4> 1285<p>Device implementations SHOULD include a GPS receiver. If a device 1286implementation does include a GPS receiver, it SHOULD include 1287some form of "assisted GPS" technique to minimize GPS lock-on time.</p> 1288<a name="section-7.3.4"></a><h4>7.3.4. Gyroscope</h4> 1289<p>Device implementations SHOULD include a gyroscope (i.e. angular change 1290sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis 1291accelerometer is also included. If a device implementation includes a 1292gyroscope, it:</p> 1293<ul> 1294<li>MUST be capable of measuring orientation changes up to 5.5*Pi 1295radians/second (that is, approximately 1,000 degrees per second)</li> 1296<li>MUST be able to deliver events at 100 Hz or greater</li> 1297<li>MUST have 8-bits of accuracy or more</li> 1298</ul> 1299<a name="section-7.3.5"></a><h4>7.3.5. Barometer</h4> 1300<p>Device implementations MAY include a barometer (i.e. ambient air pressure 1301sensor.) If a device implementation includes a barometer, it:</p> 1302<ul> 1303<li>MUST be able to deliver events at 5 Hz or greater</li> 1304<li>MUST have adequate precision to enable estimating altitude</li> 1305</ul> 1306<a name="section-7.3.6"></a><h4>7.3.7. Thermometer</h4> 1307<p>Device implementations MAY but SHOULD NOT include a thermometer (i.e. 1308temperature sensor.) If a device implementation does include a thermometer, it 1309MUST measure the temperature of the device CPU. It MUST NOT measure any other 1310temperature. (Note that this sensor type is deprecated in the Android 2.3 1311APIs.)</p> 1312<a name="section-7.3.7"></a><h4>7.3.7. Photometer</h4> 1313<p>Device implementations MAY include a photometer (i.e. ambient light 1314sensor.)</p> 1315<a name="section-7.3.8"></a><h4>7.3.8. Proximity Sensor</h4> 1316<p>Device implementations MAY include a proximity sensor. If a device 1317implementation does include a proximity sensor, it MUST measure the proximity 1318of an object in the same direction as the screen. That is, the proximity 1319sensor MUST be oriented to detect objects close to the screen, as the 1320primary intent of this sensor type is to detect a phone in use by the 1321user. If a device implementation includes a proximity sensor with any other 1322orientation, it MUST NOT be accessible through this API. If a device 1323implementation has a proximity sensor, it MUST be have 1-bit of accuracy or 1324more.</p> 1325 1326<a name="section-7.4"></a><h3>7.4. Data Connectivity</h3> 1327<p>Network connectivity and access to the Internet are vital features of 1328Android. Meanwhile, device-to-device interaction adds significant value to 1329Android devices and applications. Device implementations MUST meet the 1330data connectivity requirements in this section.</p> 1331<a name="section-7.4.1"></a><h4>7.4.1. Telephony</h4> 1332<p>"Telephony" as used by the Android 2.3 APIs and this document refers 1333specifically to hardware related to placing voice calls and sending SMS 1334messages via a GSM or CDMA network. While these voice calls may or may not be 1335packet-switched, they are for the purposes of Android 2.3 considered 1336independent of any data connectivity that may be implemented using the same 1337network. In other words, the Android "telephony" functionality and APIs refer 1338specifically to voice calls and SMS; for instance, device implementations that 1339cannot place calls or send/receive SMS messages MUST NOT report the 1340"android.hardware.telephony" feature or any sub-features, regardless of 1341whether they use a cellular network for data connectivity.</p> 1342<p>Android 2.3 MAY be used on devices that do not include telephony hardware. 1343That is, Android 2.3 is compatible with devices that are not phones. 1344However, if a device implementation does include GSM or CDMA telephony, it 1345MUST implement full support for the API for that technology. Device 1346implementations that do not include telephony hardware MUST implement the full 1347APIs as no-ops.</p> 1348<a name="section-7.4.2"></a><h4>7.4.2. IEEE 802.11 (WiFi)</h4> 1349<p>Android 2.3 device implementations SHOULD include support for one or more 1350forms of 802.11 (b/g/a/n, etc.) If a device implementation does include 1351support for 802.11, it MUST implement the corresponding Android API.</p> 1352<a name="section-7.4.3"></a><h4>7.4.3. Bluetooth</h4> 1353<p>Device implementations SHOULD include a Bluetooth transceiver. Device 1354implementations that do include a Bluetooth transceiver MUST enable the 1355RFCOMM-based Bluetooth API as described in the SDK documentation [<a 1356href="#resources32">Resources, 32</a>]. Device implementations SHOULD 1357implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as 1358appropriate for the device.</p> 1359<p>The Compatibility Test Suite includes cases that cover basic operation of 1360the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 1361protocol between devices, it cannot be fully tested by unit tests running on a 1362single device. Consequently, device implementations MUST also pass the 1363human-driven Bluetooth test procedure described in Appendix A.</p> 1364<a name="section-7.4.4"></a><h4>7.4.4. Near-Field Communications</h4> 1365<p>Device implementations SHOULD include a transceiver and related hardware 1366for Near-Field Communications (NFC). If a device implementation does include 1367NFC hardware, then it:</p> 1368<ul> 1369<li>MUST report the android.hardware.nfc feature from the 1370<code>android.content.pm.PackageManager.hasSystemFeature()</code> method. [<a href="#resources27">Resources, 27</a>]</li> 1371<li>MUST be capable of reading and writing NDEF messages via the following NFC 1372standards:<ul> 1373<li>MUST be capable of acting as an NFC Forum reader/writer 1374(as defined by the NFC Forum technical specification 1375NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards:<ul> 1376 <li>NfcA (ISO14443-3A)</li> 1377 <li>NfcB (ISO14443-3B) </li> 1378 <li>NfcF (JIS 6319-4)</li> 1379 <li>NfcV (ISO 15693)</li> 1380 <li>IsoDep (ISO 14443-4)</li> 1381 <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li> 1382</ul></li> 1383<li>MUST be capable of transmitting and receiving data via the following 1384peer-to-peer standards and protocols:<ul> 1385 <li>ISO 18092</li> 1386 <li>LLCP 1.0 (defined by the NFC Forum)</li> 1387 <li>SDP 1.0 (defined by the NFC Forum)</li> 1388 <li>NDEF Push Protocol [<a href="#resources33">Resources, 33</a>]</li> 1389</ul></li> 1390<li>MUST scan for all supported technologies while in NFC discovery mode.</li> 1391<li>SHOULD be in NFC discovery mode while the device is awake with the screen active.</li> 1392</ul> 1393<p>(Note that publicly available links are not available for the JIS, ISO, and 1394NFC Forum specifications cited above.)</p> 1395<p>Additionally, device implementations SHOULD support the following 1396widely-deployed MIFARE technologies.</p> 1397<ul> 1398 <li>MIFARE Classic (NXP MF1S503x [<a href="#resources34">Resources, 34</a>], MF1S703x [<a href="#resources35">Resources, 35</a>])</li> 1399 <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources36">Resources, 36</a>], MF0ICU2 [<a href="#resources37">Resources, 37</a>])</li> 1400 <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources38">Resources, 38</a>], AN130411 [<a href="#resources39">Resources, 39</a>])</li> 1401</ul> 1402<p>Note that Android 2.3.3 includes APIs for these MIFARE types. If a 1403device implementation supports MIFARE, it:</p> 1404<ul> 1405 <li>MUST implement the corresponding Android APIs as documented by the 1406 Android SDK</li> 1407 <li>MUST report the feature com.nxp.mifare from the 1408 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method. 1409 [<a href="#resources27">Resources, 27</a>] Note that this is not a standard 1410 Android feature, and as such does not appear as a constant on the 1411 <code>PackageManager</code> class.</li> 1412 <li>MUST NOT implement the corresponding Android APIs nor report the 1413 com.nxp.mifare feature unless it also implements general NFC support as 1414 described in this section</li> 1415</ul> 1416<p>If a device implementation does not include NFC hardware, it MUST NOT 1417declare the android.hardware.nfc feature from the 1418<code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a 1419href="#resources27">Resources, 27</a>], and MUST implement the Android 2.3 NFC 1420API as a no-op.</p> 1421<p>As the classes <code>android.nfc.NdefMessage</code> and 1422<code>android.nfc.NdefRecord</code> represent a protocol-independent data 1423representation format, device implementations MUST implement these APIs even 1424if they do not include support for NFC or declare the android.hardware.nfc 1425feature.</p> 1426<a name="section-7.4.5"></a><h4>7.4.5. Minimum Network Capability</h4> 1427<p>Device implementations MUST include support for one or more forms of data 1428networking. Specifically, device implementations MUST include support for at 1429least one data standard capable of 200Kbit/sec or greater. Examples of 1430technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, 1431Ethernet, etc.</p> 1432<p>Device implementations where a physical networking standard (such as 1433Ethernet) is the primary data connection SHOULD also include support for at 1434least one common wireless data standard, such as 802.11 (WiFi).</p> 1435<p>Devices MAY implement more than one form of data connectivity.</p> 1436 1437 1438<a name="section-7.5"></a><h3>7.5. Cameras</h3> 1439<p>Device implementations SHOULD include a rear-facing camera, and MAY include 1440a front-facing camera. A rear-facing camera is a camera located on the side of 1441the device opposite the display; that is, it images scenes on the far side of 1442the device, like a traditional camera. A front-facing camera is a camera 1443located on the same side of the device as the display; that is, a camera 1444typically used to image the user, such as for video conferencing and similar 1445applications.</p> 1446<a name="section-7.5.1"></a><h4>7.5.1. Rear-Facing Camera</h4> 1447<p>Device implementations SHOULD include a rear-facing camera. If a device 1448implementation includes a rear-facing camera, it:</p> 1449<ul> 1450<li>MUST have a resolution of at least 2 megapixels</li> 1451<li>SHOULD have either hardware auto-focus, or software auto-focus implemented 1452in the camera driver (transparent to application software)</li> 1453<li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 1454<li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 1455NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 1456registered on a Camera preview surface, unless the application has explicitly 1457enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 1458<code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 1459object. Note that this constraint does not apply to the device's built-in 1460system camera application, but only to third-party applications using 1461<code>Camera.PreviewCallback</code>.</li> 1462</ul> 1463<a name="section-7.5.2"></a><h4>7.5.2. Front-Facing Camera</h4> 1464<p>Device implementations MAY include a front-facing camera. If a device 1465implementation includes a front-facing camera, it:</p> 1466<ul> 1467<li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li> 1468<li>MUST NOT use a front-facing camera as the default for the Camera API. 1469That is, the camera API in Android 2.3 has specific support for front-facing 1470cameras, and device implementations MUST NOT configure the API to to treat a 1471front-facing camera as the default rear-facing camera, even if it is the only 1472camera on the device.</li> 1473<li>MAY include features (such as auto-focus, flash, etc.) 1474available to rear-facing cameras as described in Section 7.5.1.</li> 1475<li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a 1476CameraPreview, as follows:</li> 1477<ul> 1478<li>If the device implementation is capable of being rotated by user (such as 1479automatically via an accelerometer or manually via user input), the camera 1480preview MUST be mirrored horizontally relative to the device's current 1481orientation.</li> 1482<li>If the current application has explicitly requested that the Camera 1483display be rotated via a call to the 1484<code>android.hardware.Camera.setDisplayOrientation()</code> [<a 1485href="#resources40">Resources, 40</a>] method, the camera preview MUST be 1486mirrored horizontally relative to the orientation specified by the 1487application.</li> 1488<li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li> 1489</ul> 1490<li>MUST mirror the image data returned to any "postview" camera callback 1491handlers, in the same manner as the camera preview image stream. (If the device 1492implementation does not support postview callbacks, this requirement obviously 1493does not apply.)</li> 1494<li>MUST NOT mirror the final captured still image or video streams returned 1495to application callbacks or committed to media storage</li> 1496</ul> 1497<a name="section-7.5.3"></a><h4>7.5.3. Camera API Behavior</h4> 1498<p>Device implementations MUST implement the following behaviors for the 1499camera-related APIs, for both front- and rear-facing cameras:</p> 1500<ol> 1501<li>If an application has never called 1502android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST 1503use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to 1504application callbacks.</li> 1505<li>If an application registers an android.hardware.Camera.PreviewCallback 1506instance and the system calls the onPreviewFrame() method when the preview 1507format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() 1508must further be in the NV21 encoding format. That is, NV21 MUST be the default.</li> 1509<li>Device implementations SHOULD support the YV12 format (as denoted by the 1510<code>android.graphics.ImageFormat.YV12</code> constant) for camera previews 1511for both front- and rear-facing cameras. Note that the Compatibility 1512Definition for a future version is planned to change this requirement to 1513"MUST". That is, YV12 support is optional in Android 2.3 but <b>will be 1514required</b> by a future version. Existing and new devices that run Android 15152.3 are <b>very strongly encouraged to meet this requirement in Android 15162.3</b>, or they will not be able to attain Android compatibility when 1517upgraded to the future version.</li> 1518</ol> 1519<p>Device implementations MUST implement the full Camera API included in the 1520Android 2.3 SDK documentation [<a href="#resources41">Resources, 41</a>]), 1521regardless of whether the device includes hardware autofocus or other 1522capabilities. For instance, cameras that lack autofocus MUST still call any 1523registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 1524this has no relevance to a non-autofocus camera.) Note that this does apply 1525to front-facing cameras; for instance, even though most front-facing cameras 1526do not support autofocus, the API callbacks must still be "faked" as 1527described.</p> 1528<p>Device implementations MUST recognize and honor each parameter name defined 1529as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 1530underlying hardware supports the feature. If the device hardware does not 1531support a feature, the API must behave as documented. Conversely, Device 1532implementations MUST NOT honor or recognize string constants passed 1533to the <code>android.hardware.Camera.setParameters()</code> method other than 1534those documented as constants on the 1535<code>android.hardware.Camera.Parameters</code>. That is, 1536device implementations MUST support all standard Camera parameters if the 1537hardware allows, and MUST NOT support custom Camera parameter types.</p> 1538<a name="section-7.5.4"></a><h4>7.5.4. Camera Orientation</h4> 1539<p>Both front- and rear-facing cameras, if present, MUST be oriented so that 1540the long dimension of the camera aligns with the screen's long dimention. That 1541is, when the device is held in the landscape orientation, a cameras MUST 1542capture images in the landscape orientation. This applies regardless of the 1543device's natural orientation; that is, it applies to landscape-primary devices 1544as well as portrait-primary devices.</p> 1545 1546 1547<a name="section-7.6"></a><h3>7.6. Memory and Storage</h3> 1548<p>The fundamental function of Android 2.3 is to run applications. Device 1549implementations MUST the requirements of this section, to ensure adequate 1550storage and memory for applications to run properly.</p> 1551<a name="section-7.6.1"></a><h4>7.6.1. Minimum Memory and Storage</h4> 1552<p>Device implementations MUST have at least 128MB of memory available to the 1553kernel and userspace. The 128MB MUST be in addition to any memory dedicated to 1554hardware components such as radio, memory, and so on that is not under the 1555kernel's control.</p> 1556<p>Device implementations MUST have at least 150MB of non-volatile storage 1557available for user data. That is, the <code>/data</code> partition MUST be at 1558least 150MB.</p> 1559<p>Beyond the requirements above, device implementations SHOULD have at least 15601GB of non-volatile storage available for user data. Note that this higher 1561requirement is planned to become a hard minimum in a future version of 1562Android. Device implementations are strongly encouraged to meet these 1563requirements now, or else they may not be eligible for compatibility for a 1564future version of Android.</p> 1565<p>The Android APIs include a Download Manager that applications may use to 1566download data files. The Download Manager implementation MUST be capable of 1567downloading individual files 55MB in size, or larger. The Download Manager 1568implementation SHOULD be capable of downloading files 100MB in size, or 1569larger.</p> 1570<a name="section-7.6.2"></a><h4>7.6.2. Application Shared Storage</h4> 1571<p>Device implementations MUST offer shared storage for applications. The 1572shared storage provided MUST be at least 1GB in size.</p> 1573<p>Device implementations MUST be configured with shared storage mounted by 1574default, "out of the box". If the shared storage is not mounted on the Linux 1575path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 1576from <code>/sdcard</code> to the actual mount point.</p> 1577<p>Device implementations MUST enforce as documented the 1578<code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 1579shared storage. Shared storage MUST otherwise be writable by any application 1580that obtains that permission.</p> 1581<p>Device implementations MAY have hardware for user-accessible removable 1582storage, such as a Secure Digital card. Alternatively, device implementations 1583MAY allocate internal (non-removable) storage as shared storage for apps.</p> 1584<p>Regardless of the form of shared storage used, device implementations MUST 1585provide some mechanism to access the contents of shared storage from a host 1586computer, such as USB mass storage or Media Transfer Protocol.</p> 1587<p>It is illustrative to consider two common examples. If a device 1588implementation includes an SD card slot to satisfy the shared storage 1589requirement, a FAT-formatted SD card 1GB in size or larger MUST be included 1590with the device as sold to users, and MUST be mounted by default. 1591Alternatively, if a device implementation uses internal fixed storage to 1592satisfy this requirement, that storage MUST be 1GB in size or larger 1593and mounted on <code>/sdcard</code> (or <code>/sdcard</code> 1594MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p> 1595<p>Device implementations that include multiple shared storage paths (such as 1596both an SD card slot and shared internal storage) SHOULD modify the core 1597applications such as the media scanner and ContentProvider to transparently 1598support files placed in both locations.</p> 1599 1600<a name="section-7.7"></a><h3>7.7. USB</h3> 1601<p>Device implementations:</p> 1602<ul> 1603<li>MUST implement a USB client, connectable to a USB host with a standard 1604USB-A port</li> 1605<li>MUST implement the Android Debug Bridge over USB (as described in Section 16067)</li> 1607<li>MUST implement the USB mass storage specification, to allow a host 1608connected to the device to access the contents of the /sdcard volume </li> 1609<li>SHOULD use the micro USB form factor on the device side</li> 1610<li>MAY include a non-standard port on the device side, but if so MUST ship 1611with a cable capable of connecting the custom pinout to standard USB-A 1612port</li> 1613</ul> 1614 1615 1616<a name="section-8"></a><h2>8. Performance Compatibility</h2> 1617<p>Compatible implementations must ensure not only that applications simply 1618run correctly on the device, but that they do so with reasonable performance 1619and overall good user experience. Device implementations MUST meet the key 1620performance metrics of an Android 2.3 compatible device defined in the table 1621below:</p> 1622<table><tbody><tr> 1623<td><b>Metric</b></td> 1624<td><b>Performance Threshold</b></td> 1625<td><b>Comments</b></td> 1626</tr> 1627<tr> 1628<td>Application Launch Time</td> 1629<td>The following applications should launch within the specified time.<ul> 1630<li>Browser: less than 1300ms</li> 1631<li>MMS/SMS: less than 700ms</li> 1632<li>AlarmClock: less than 650ms</li> 1633</ul></td> 1634<td>The launch time is measured as the total time to 1635complete loading the default activity for the application, including the time 1636it takes to start the Linux process, load the Android package into the Dalvik 1637VM, and call onCreate.</td> 1638</tr> 1639<tr> 1640<td>Simultaneous Applications</td> 1641<td>When multiple applications have been launched, re-launching an 1642already-running application after it has been launched must take less than the 1643original launch time.</td> 1644<td> </td> 1645</tr> 1646</tbody> 1647</table> 1648 1649<a name="section-9"></a><h2>9. Security Model Compatibility</h2> 1650<p>Device implementations MUST implement a security model consistent with the 1651Android platform security model as defined in Security and Permissions 1652reference document in the APIs [<a href="#resources42">Resources, 42</a>] in the 1653Android developer documentation. Device implementations MUST support 1654installation of self-signed applications without requiring any additional 1655permissions/certificates from any third parties/authorities. Specifically, 1656compatible devices MUST support the security mechanisms described in the 1657follow sub-sections.</p> 1658<a name="section-9.1"></a><h3>9.1. Permissions</h3> 1659<p>Device implementations MUST support the Android permissions model as 1660defined in the Android developer documentation [<a 1661href="#resources42">Resources, 42</a>]. Specifically, 1662implementations MUST enforce each permission defined as described in the SDK 1663documentation; no permissions may be omitted, altered, or ignored. 1664Implementations MAY add additional permissions, provided the new permission ID 1665strings are not in the android.* namespace.</p> 1666<a name="section-9.2"></a><h3>9.2. UID and Process Isolation</h3> 1667<p>Device implementations MUST support the Android application sandbox model, 1668in which each application runs as a unique Unix-style UID and in a separate 1669process. Device implementations MUST support running multiple applications as 1670the same Linux user ID, provided that the applications are properly signed and 1671constructed, as defined in the Security and Permissions reference [<a 1672href="#resources42">Resources, 42</a>].</p> 1673<a name="section-9.3"></a><h3>9.3. Filesystem Permissions</h3> 1674<p>Device implementations MUST support the Android file access permissions 1675model as defined in as defined in the Security and Permissions reference [<a 1676href="#resources42">Resources, 42</a>].</p> 1677<a name="section-9.4"></a><h3>9.4. Alternate Execution Environments</h3> 1678<p>Device implementations MAY include runtime environments that execute 1679applications using some other software or technology than the Dalvik virtual 1680machine or native code. However, such alternate execution environments MUST 1681NOT compromise the Android security model or the security of installed Android 1682applications, as described in this section.</p> 1683<p>Alternate runtimes MUST themselves be Android applications, and abide by 1684 the standard Android security model, as described elsewhere in Section 9.</p> 1685<p>Alternate runtimes MUST NOT be granted access to resources protected by 1686 permissions not requested in the runtime's AndroidManifest.xml file via the 1687 <code><uses-permission></code> mechanism.</p> 1688<p>Alternate runtimes MUST NOT permit applications to make use of features 1689 protected by Android permissions restricted to system applications.</p> 1690<p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p> 1691<ul> 1692<li>Alternate runtimes SHOULD install apps via the PackageManager into 1693 separate Android sandboxes (that is, Linux user IDs, etc.)</li> 1694<li>Alternate runtimes MAY provide a single Android sandbox shared by all 1695 applications using the alternate runtime.</li> 1696<li>Alternate runtimes and installed applications using an alternate runtime 1697 MUST NOT reuse the sandbox of any other app installed on the device, except 1698 through the standard Android mechanisms of shared user ID and signing 1699 certificate</li> 1700<li>Alternate runtimes MUST NOT launch with, grant, or be granted access to 1701 the sandboxes corresponding to other Android applications.</li> 1702</ul> 1703<p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other 1704 applications any privileges of the superuser (root), or of any other user ID.</p> 1705<p>The .apk files of alternate runtimes MAY be included in the system image of 1706 a device implementation, but MUST be signed with a key distinct 1707 from the key used to sign other applications included with the device 1708 implementation.</p> 1709<p>When installing applications, alternate runtimes MUST obtain user consent 1710 for the Android permissions used by the application. That is, if an 1711 application needs to make use of a device resource for which there is a 1712 corresponding Android permission (such as Camera, GPS, etc.), the alternate 1713 runtime MUST inform the user that the application will be able to access 1714 that resource. If the runtime environment does not record application 1715 capabilities in this manner, the runtime environment MUST list all 1716 permissions held by the runtime itself when installing any application 1717 using that runtime.</p> 1718 1719<a name="section-10"></a><h2>10. Software Compatibility Testing</h2> 1720<p>The Android Open-Source Project includes various testing tools to verify 1721that device implementations are compatible. Device implementations MUST pass 1722all tests described in this section.</p> 1723<p>However, note that no software test package is fully comprehensive. For 1724this reason, device implementers are very strongly encouraged to make the 1725minimum number of changes as possible to the reference and preferred 1726implementation of Android 2.3 available from the Android Open-Source Project. 1727This will minimize the risk of introducing bugs that create incompatibilities 1728requiring rework and potential device updates.</p> 1729<a name="section-10.1"></a><h3>10.1. Compatibility Test Suite</h3> 1730<p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 1731[<a href="#resources02">Resources, 2</a>] available from the Android Open Source 1732Project, using the final shipping software on the device. Additionally, device 1733implementers SHOULD use the reference implementation in the Android Open 1734Source tree as much as possible, and MUST ensure compatibility in cases of 1735ambiguity in CTS and for any reimplementations of parts of the reference 1736source code.</p> 1737<p>The CTS is designed to be run on an actual device. Like any software, the 1738CTS may itself contain bugs. The CTS will be versioned independently of this 1739Compatibility Definition, and multiple revisions of the CTS may be released 1740for Android 2.3. Device implementations MUST pass the latest CTS version 1741available at the time the device software is completed.</p> 1742<p>MUST pass the most recent version of the Android Compatibility Test Suite 1743(CTS) available at the time of the device implementation's software is 1744completed. (The CTS is available as part of the Android Open Source Project [<a 1745href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the 1746components outlined in this document.</p> 1747<a name="section-10.2"></a><h3>10.2. CTS Verifier</h3> 1748<p>Device implementations MUST correctly execute all applicable cases in the 1749CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, 1750and is intended to be run by a human operator to test functionality that 1751cannot be tested by an automated system, such as correct functioning of a 1752camera and sensors.</p> 1753<p>The CTS Verifier has tests for many kinds of hardware, including some 1754hardware that is optional. Device implementations MUST pass all tests for 1755hardware which they possess; for instance, if a device possesses an 1756accelerometer, it MUST correctly execute the Accelerometer test case in the 1757CTS Verifier. Test cases for features noted as optional by this Compatibility 1758Definition Document MAY be skipped or omitted.</p> 1759<p>Every device and every build MUST correctly run the CTS Verifier, as noted 1760above. However, since many builds are very similar, device implementers are 1761not expected to explicitly run the CTS Verifier on builds that differ only in 1762trivial ways. Specifically, device implementations that differ from an 1763implementation that has passed the CTS Verfier only by the set of included 1764locales, branding, etc. MAY omit the CTS Verifier test.</p> 1765<a name="section-10.3"></a><h3>10.3. Reference Applications</h3> 1766<p>Device implementers MUST test implementation compatibility using the 1767following open-source applications:</p> 1768<ul> 1769<li>The "Apps for Android" applications [<a href="#resources43">Resources, 43</a>].</li> 1770<li>Replica Island (available in Android Market; only required for device 1771 implementations that support with OpenGL ES 2.0)</li> 1772</ul> 1773<p>Each app above MUST launch and behave correctly on the implementation, for 1774the implementation to be considered compatible.</p> 1775 1776 1777<a name="section-11"></a><h2>11. Updatable Software</h2> 1778<p>Device implementations MUST include a mechanism to replace the entirety of 1779the system software. The mechanism need not perform "live" upgrades -- that 1780is, a device restart MAY be required.</p> 1781<p>Any method can be used, provided that it can replace the entirety of the 1782software preinstalled on the device. For instance, any of the following 1783approaches will satisfy this requirement:</p> 1784<ul> 1785<li>Over-the-air (OTA) downloads with offline update via reboot</li> 1786<li>"Tethered" updates over USB from a host PC</li> 1787<li>"Offline" updates via a reboot and update from a file on removable 1788storage</li> 1789</ul> 1790<p>The update mechanism used MUST support updates without wiping user data. 1791Note that the upstream Android software includes an update mechanism that 1792satisfies this requirement.</p> 1793<p>If an error is found in a device implementation after it has been released 1794but within its reasonable product lifetime that is determined in consultation 1795with the Android Compatibility Team to affect the compatibility of third-party 1796applications, the device implementer MUST correct the error via a software 1797update available that can be applied per the mechanism just described.</p> 1798 1799<a name="section-12"></a><h2>12. Contact Us</h2> 1800<p>You can contact the document authors at <a 1801href="mailto:compatibility@android.com">compatibility@android.com</a> for 1802clarifications and to bring up any issues that you think the document does not 1803cover.</p> 1804 1805<div style="page-break-before: always;"></div> 1806 1807<a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2> 1808<p>The Compatibility Test Suite includes cases that cover basic operation of 1809the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 1810protocol between devices, it cannot be fully tested by unit tests running on a 1811single device. Consequently, device implementations MUST also pass the 1812human-operated Bluetooth test procedure described below.</p> 1813<p>The test procedure is based on the BluetoothChat sample app included in the 1814Android open-source project tree. The procedure requires two devices:</p> 1815<ul> 1816<li>a candidate device implementation running the software build to be tested</li> 1817<li>a separate device implementation already known to be compatible, and of a 1818 model from the device implementation being tested -- that is, a "known 1819 good" device implementation</li> 1820</ul> 1821<p>The test procedure below refers to these devices as the "candidate" and "known 1822good" devices, respectively.</p> 1823<h3>Setup and Installation</h3> 1824<ol> 1825<li>Build BluetoothChat.apk via 'make samples' from an Android source code tree.</li> 1826<li>Install BluetoothChat.apk on the known-good device.</li> 1827<li>Install BluetoothChat.apk on the candidate device.</li> 1828</ol> 1829<h3>Test Bluetooth Control by Apps</h3> 1830<ol> 1831<li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled.</li> 1832<li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.</li> 1833</ol> 1834<h3>Test Pairing and Communication</h3> 1835<ol> 1836<li>Launch the Bluetooth Chat app on both devices.</li> 1837<li>Make the known-good device discoverable from within BluetoothChat (using the Menu).</li> 1838<li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.</li> 1839<li>Send 10 or more messages from each device, and verify that the other device receives them correctly.</li> 1840<li>Close the BluetoothChat app on both devices by pressing <b>Home</b>.</li> 1841<li>Unpair each device from the other, using the device Settings app.</li> 1842</ol> 1843<h3>Test Pairing and Communication in the Reverse Direction</h3> 1844<ol> 1845<li>Launch the Bluetooth Chat app on both devices.</li> 1846<li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li> 1847<li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li> 1848<li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 1849<li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li> 1850</ol> 1851<h3>Test Re-Launches</h3> 1852<ol> 1853<li>Re-launch the Bluetooth Chat app on both devices.</li> 1854<li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 1855</ol> 1856<p>Note: the above tests have some cases which end a test section by using 1857Home, and some using Back. These tests are not redundant and are not optional: 1858the objective is to verify that the Bluetooth API and stack works correctly 1859both when Activities are explicitly terminated (via the user pressing Back, 1860which calls finish()), and implicitly sent to background (via the user 1861pressing Home.) Each test sequence MUST be performed as described.</p> 1862<div id="footerContent" xmlns:pdf="http://whatever"> 1863<pdf:pagenumber/> 1864</div> 1865</body> 1866</html> 1867
