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 2.2 Compatibility Definition</title> 6 <link rel="stylesheet" type="text/css" href="cdd.css"/> 7 </head> 8 <body> 9 <h1>Android 2.2 Compatibility Definition</h1> 10 <!--<span style="color: red; font-weight: bold;"><h2>DRAFT</h2></span>--> 11 <p>Copyright © 2010, Google Inc. All rights reserved.<br/> 12 <a href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> 13 </p> 14 15 <h2> Table of Contents</h2> 16 <div style="margin-left: 2em;"> 17 <a href="#section-1">1. Introduction</a><br/> 18 <a href="#section-2">2. Resources</a><br/> 19 <a href="#section-3">3. Software</a><br/> 20 <div style="margin-left: 2em;"> 21 <a href="#section-3.1">3.1. Managed API Compatibility</a><br/> 22 <a href="#section-3.2">3.2. Soft API Compatibility</a><br/> 23 <div style="margin-left: 2em;"> 24 <a href="#section-3.2.1">3.2.1. Permissions</a><br/> 25 <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/> 26 <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/> 27 <div style="margin-left: 2em;"> 28 <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/> 29 <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/> 30 <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/> 31 <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/> 32 </div> 33 </div> 34 <a href="#section-3.3">3.3. Native API Compatibility</a><br/> 35 <a href="#section-3.4">3.4. Web Compatibility</a><br/> 36 <div style="margin-left: 2em;"> 37 <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/> 38 <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/> 39 </div> 40 <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/> 41 <a href="#section-3.6">3.6. API Namespaces</a><br/> 42 <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/> 43 <a href="#section-3.8">3.8. User Interface Compatibility</a><br/> 44 <div style="margin-left: 2em;"> 45 <a href="#section-3.8.1">3.8.1. Widgets</a><br/> 46 <a href="#section-3.8.2">3.8.2. Notifications</a><br/> 47 <a href="#section-3.8.3">3.8.3. Search</a><br/> 48 <a href="#section-3.8.4">3.8.4. Toasts</a><br/> 49 <a href="#section-3.8.5">3.8.5. Live Wallpapers</a><br/> 50 </div> 51 </div> 52 <a href="#section-4">4. Reference Software Compatibility</a><br/> 53 <a href="#section-5">5. Application Packaging Compatibility</a><br/> 54 <a href="#section-6">6. Multimedia Compatibility</a><br/> 55 <div style="margin-left: 2em;"> 56 <a href="#section-6.1">6.1. Media Codecs</a><br/> 57 <a href="#section-6.2">6.2. Audio Recording</a><br/> 58 <a href="#section-6.3">6.3. Audio Latency</a><br/> 59 </div> 60 <a href="#section-7">7. Developer Tool Compatibility</a><br/> 61 <a href="#section-8">8. Hardware Compatibility</a><br/> 62 <div style="margin-left: 2em;"> 63 <a href="#section-8.1">8.1. Display</a><br/> 64 <div style="margin-left: 2em;"> 65 <a href="#section-8.1.2">8.1.2. Non-Standard Display Configurations</a><br/> 66 <a href="#section-8.1.3">8.1.3. Display Metrics</a><br/> 67 <a href="#section-8.1.4">8.1.4. Declared Screen Support</a><br/> 68 </div> 69 <a href="#section-8.2">8.2. Keyboard</a><br/> 70 <a href="#section-8.3">8.3. Non-touch Navigation</a><br/> 71 <a href="#section-8.4">8.4. Screen Orientation</a><br/> 72 <a href="#section-8.5">8.5. Touchscreen input</a><br/> 73 <a href="#section-8.6">8.6. USB</a><br/> 74 <a href="#section-8.7">8.7. Navigation keys</a><br/> 75 <a href="#section-8.8">8.8. Wireless Data Networking</a><br/> 76 <a href="#section-8.9">8.9. Camera</a><br/> 77 <a href="#section-8.10">8.10. Accelerometer</a><br/> 78 <a href="#section-8.11">8.11. Compass</a><br/> 79 <a href="#section-8.12">8.12. GPS</a><br/> 80 <a href="#section-8.13">8.13. Telephony</a><br/> 81 <a href="#section-8.14">8.14. Memory and Storage</a><br/> 82 <a href="#section-8.15">8.15. Application Shared Storage</a><br/> 83 <a href="#section-8.16">8.16. Bluetooth</a><br/> 84 </div> 85 <a href="#section-9">9. Performance Compatibility</a><br/> 86 <a href="#section-10">10. Security Model Compatibility</a><br/> 87 <div style="margin-left: 2em;"> 88 <a href="#section-10.1">10.1. Permissions</a><br/> 89 <a href="#section-10.2">10.2. UID and Process Isolation</a><br/> 90 <a href="#section-10.3">10.3. Filesystem Permissions</a><br/> 91 <a href="#section-10.4">10.4. Alternate Execution Environments</a><br/> 92 </div> 93 <a href="#section-11">11. Compatibility Test Suite</a><br/> 94 <a href="#section-12">12. Updatable Software</a><br/> 95 <a href="#section-13">13. Contact Us</a><br/> 96 <a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/> 97 </div> 98 99 <div style="page-break-before: always;"></div> 100 101 <a name="section-1"></a><h2>1. Introduction</h2> 102 <p>This document enumerates the requirements that must be met in order for 103 mobile phones to be compatible with Android 2.2.</p> 104 <p>The use of "must", "must not", "required", "shall", "shall not", "should", 105 "should not", "recommended", "may" and "optional" is per the IETF standard 106 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 107 <p>As used in this document, a "device implementer" or "implementer" is a 108 person or organization developing a hardware/software solution running Android 109 2.2. A "device implementation" or "implementation" is the hardware/software 110 solution so developed.</p> 111 <p>To be considered compatible with Android 2.2, device implementations:</p> 112 <ul> 113 <li>MUST meet the requirements presented in this Compatibility Definition, 114 including any documents incorporated via reference.</li> 115 <li>MUST pass the most recent version of the Android Compatibility Test Suite 116 (CTS) available at the time of the device implementation's software is 117 completed. (The CTS is available as part of the Android Open Source Project [<a 118 href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the 119 components outlined in this document.</li> 120 </ul> 121 <p>Where this definition or the CTS is silent, ambiguous, or incomplete, it is 122 the responsibility of the device implementer to ensure compatibility with 123 existing implementations. For this reason, the Android Open Source Project [<a 124 href="#resources03">Resources, 3</a>] is both the reference and preferred 125 implementation of Android. Device implementers are strongly encouraged to base 126 their implementations on the "upstream" source code available from the Android 127 Open Source Project. While some components can hypothetically be replaced with 128 alternate implementations this practice is strongly discouraged, as passing 129 the CTS tests will become substantially more difficult. It is the 130 implementer's responsibility to ensure full behavioral compatibility with the 131 standard Android implementation, including and beyond the Compatibility Test 132 Suite. Finally, note that certain component substitutions and modifications 133 are explicitly forbidden by this document.</p> 134 135 <a name="section-2"></a><h2>2. Resources</h2> 136 <ol> 137 <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> 138 <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> 139 <a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 140 <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> 141 <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> 142 <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> 143 <a name="resources07"></a><li>Android 2.2 allowed version strings: <a href="http://source.android.com/compatibility/2.2/versions.html">http://source.android.com/compatibility/2.2/versions.html</a></li> 144 <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> 145 <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> 146 <a name="resources10"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 147 <a name="resources11"></a><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li> 148 <a name="resources12"></a><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li> 149 <a name="resources13"></a><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li> 150 <a name="resources14"></a><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design.html#statusbarstructure">http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure</a></li> 151 <a name="resources15"></a><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li> 152 <a name="resources16"></a><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li> 153 <a name="resources17"></a><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li> 154 <a name="resources18"></a><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li> 155 <a name="resources19"></a><li>Reference tool documentation (for adb, aapt, ddms): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li> 156 <a name="resources20"></a><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li> 157 <a name="resources21"></a><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li> 158 <a name="resources22"></a><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li> 159 <a name="resources23"></a><li>Android Hardware Features List: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">http://developer.android.com/reference/android/content/pm/PackageManager.html</a></li> 160 <a name="resources24"></a><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li> 161 <a name="resources25"></a><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li> 162 <a name="resources26"></a><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li> 163 <a name="resources27"></a><li>android.hardware.Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li> 164 <a name="resources28"></a><li>Sensor coordinate space: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li> 165 <a name="resources29"></a><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li> 166 <a name="resources30"></a><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li> 167 </ol> 168 <p>Many of these resources are derived directly or indirectly from the Android 169 2.2 SDK, and will be functionally identical to the information in that SDK's 170 documentation. In any cases where this Compatibility Definition or the 171 Compatibility Test Suite disagrees with the SDK documentation, the SDK 172 documentation is considered authoritative. Any technical details provided in 173 the references included above are considered by inclusion to be part of this 174 Compatibility Definition.</p> 175 176 <a name="section-3"></a><h2>3. Software</h2> 177 <p>The Android platform includes a set of managed APIs, a set of native APIs, 178 and a body of so-called "soft" APIs such as the Intent system and 179 web-application APIs. This section details the hard and soft APIs that are 180 integral to compatibility, as well as certain other relevant technical and 181 user interface behaviors. Device implementations MUST comply with all the 182 requirements in this section.</p> 183 184 <a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3> 185 <p>The managed (Dalvik-based) execution environment is the primary vehicle for 186 Android applications. The Android application programming interface (API) is 187 the set of Android platform interfaces exposed to applications running in the 188 managed VM environment. Device implementations MUST provide complete 189 implementations, including all documented behaviors, of any documented API 190 exposed by the Android 2.2 SDK [<a href="#resources04">Resources, 4</a>].</p> 191 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 192 or signatures, deviate from the documented behavior, or include no-ops, except 193 where specifically allowed by this Compatibility Definition.</p> 194 195 <a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3> 196 <p>In addition to the managed APIs from Section 3.1, Android also includes a 197 significant runtime-only "soft" API, in the form of such things such as 198 Intents, permissions, and similar aspects of Android applications that cannot 199 be enforced at application compile time. This section details the "soft" APIs 200 and system behaviors required for compatibility with Android 2.2. Device 201 implementations MUST meet all the requirements presented in this section.</p> 202 <a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4> 203 <p>Device implementers MUST support and enforce all permission constants as 204 documented by the Permission reference page [<a 205 href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional 206 requirements related to the Android security model.</p> 207 <a name="section-3.2.2"></a><h4>3.2.2. Build Parameters</h4> 208 <p>The Android APIs include a number of constants on the <code>android.os.Build</code> 209 class [<a href="#resources06">Resources, 6</a>] that are intended to describe 210 the current device. To provide consistent, meaningful values across device 211 implementations, the table below includes additional restrictions on the 212 formats of these values to which device implementations MUST conform.</p> 213 <table> 214 <tbody> 215 <tr> 216 <td><b>Parameter</b></td> 217 <td><b>Comments</b></td> 218 </tr> 219 <tr> 220 <td>android.os.Build.VERSION.RELEASE</td> 221 <td>The version of the currently-executing Android system, in human-readable 222 format. This field MUST have one of the string values defined in [<a 223 href="#resources07">Resources, 7</a>].</td> 224 </tr> 225 <tr> 226 <td>android.os.Build.VERSION.SDK</td> 227 <td>The version of the currently-executing Android system, in a format 228 accessible to third-party application code. For Android 2.2, this field MUST have 229 the integer value 8.</td> 230 </tr> 231 <tr> 232 <td>android.os.Build.VERSION.INCREMENTAL</td> 233 <td>A value chosen by the device implementer designating the specific build of 234 the currently-executing Android system, in human-readable format. This value 235 MUST NOT be re-used for different builds made available to end users. A typical use 236 of this field is to indicate which build number or source-control change 237 identifier was used to generate the build. There are no requirements on the 238 specific format of this field, except that it MUST NOT be null or the empty 239 string ("").</td> 240 </tr> 241 <tr> 242 <td>android.os.Build.BOARD</td> 243 <td>A value chosen by the device implementer identifying the specific internal 244 hardware used by the device, in human-readable format. A possible use of this 245 field is to indicate the specific revision of the board powering the device. 246 There are no requirements on the specific format of this field, except that it 247 MUST NOT be null or the empty string ("").</td> 248 </tr> 249 <tr> 250 <td>android.os.Build.BRAND</td> 251 <td>A value chosen by the device implementer identifying the name of the 252 company, organization, individual, etc. who produced the device, in 253 human-readable format. A possible use of this field is to indicate the OEM 254 and/or carrier who sold the device. There are no requirements on the specific 255 format of this field, except that it MUST NOT be null or the empty string 256 ("").</td> 257 </tr> 258 <tr> 259 <td>android.os.Build.DEVICE</td> 260 <td>A value chosen by the device implementer identifying the specific 261 configuration or revision of the body (sometimes called "industrial design") 262 of the device. There are no requirements on the specific format of this field, 263 except that it MUST NOT be null or the empty string ("").</td> 264 </tr> 265 <tr> 266 <td>android.os.Build.FINGERPRINT</td> 267 <td>A string that uniquely identifies this build. It SHOULD be reasonably 268 human-readable. It MUST follow this template: 269 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE)/$(BOARD):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 270 For example: 271 <br/><code>acme/mydevice/generic/generic:2.2/ERC77/3359:userdebug/test-keys</code><br/> 272 The fingerprint MUST NOT include whitespace characters. If other fields included in the 273 template above have whitespace characters, they MUST be replaced in the build 274 fingerprint with another character, such as the underscore ("_") character.</td> 275 </tr> 276 <tr> 277 <td>android.os.Build.HOST</td> 278 <td>A string that uniquely identifies the host the build was built on, in 279 human readable format. There are no requirements on the specific format of 280 this field, except that it MUST NOT be null or the empty string ("").</td> 281 </tr> 282 <tr> 283 <td>android.os.Build.ID</td> 284 <td>An identifier chosen by the device implementer to refer to a specific 285 release, in human readable format. This field can be the same as 286 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 287 meaningful for end users to distinguish between software builds. There are no 288 requirements on the specific format of this field, except that it MUST NOT be 289 null or the empty string ("").</td> 290 </tr> 291 <tr> 292 <td>android.os.Build.MODEL</td> 293 <td>A value chosen by the device implementer containing the name of the device 294 as known to the end user. This SHOULD be the same name under which the device 295 is marketed and sold to end users. There are no requirements on the specific 296 format of this field, except that it MUST NOT be null or the empty string 297 ("").</td> 298 </tr> 299 <tr> 300 <td>android.os.Build.PRODUCT</td> 301 <td>A value chosen by the device implementer containing the development name 302 or code name of the device. MUST be human-readable, but is not necessarily 303 intended for view by end users. There are no requirements on the specific 304 format of this field, except that it MUST NOT be null or the empty string 305 ("").</td> 306 </tr> 307 <tr> 308 <td>android.os.Build.TAGS</td> 309 <td>A comma-separated list of tags chosen by the device implementer that 310 further distinguish the build. For example, "unsigned,debug". This field MUST 311 NOT be null or the empty string (""), but a single tag (such as "release") is 312 fine.</td> 313 </tr> 314 <tr> 315 <td>android.os.Build.TIME</td> 316 <td>A value representing the timestamp of when the build occurred.</td> 317 </tr> 318 <tr> 319 <td>android.os.Build.TYPE</td> 320 <td>A value chosen by the device implementer specifying the runtime 321 configuration of the build. This field SHOULD have one of the values 322 corresponding to the three typical Android runtime configurations: "user", 323 "userdebug", or "eng".</td> 324 </tr> 325 <tr> 326 <td>android.os.Build.USER</td> 327 <td>A name or user ID of the user (or automated user) that generated the 328 build. There are no requirements on the specific format of this field, except 329 that it MUST NOT be null or the empty string ("").</td> 330 </tr> 331 </tbody> 332 </table> 333 <a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4> 334 <p>Android uses Intents to achieve loosely-coupled integration between 335 applications. This section describes requirements related to the Intent 336 patterns that MUST be honored by device implementations. By "honored", it is 337 meant that the device implementer MUST provide an Android Activity or Service 338 that specifies a matching Intent filter and binds to and implements correct 339 behavior for each specified Intent pattern.</p> 340 <a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4> 341 <p>The Android upstream project defines a number of core applications, such as 342 a phone dialer, calendar, contacts book, music player, and so on. Device 343 implementers MAY replace these applications with alternative versions.</p> 344 <p>However, any such alternative versions MUST honor the same Intent patterns 345 provided by the upstream project. For example, if a device contains an 346 alternative music player, it must still honor the Intent pattern issued by 347 third-party applications to pick a song.</p> 348 <p>The following applications are considered core Android system 349 applications:</p> 350 <ul> 351 <li>Desk Clock</li> 352 <li>Browser</li> 353 <li>Calendar</li> 354 <li>Calculator</li> 355 <li>Camera</li> 356 <li>Contacts</li> 357 <li>Email</li> 358 <li>Gallery</li> 359 <li>GlobalSearch</li> 360 <li>Launcher</li> 361 <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 362 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> 363 <li>Messaging (AKA "Mms")</li> 364 <li>Music</li> 365 <li>Phone</li> 366 <li>Settings</li> 367 <li>SoundRecorder</li> 368 </ul> 369 <p>The core Android system applications include various Activity, or Service 370 components that are considered "public". 371 That is, the attribute "android:exported" may be absent, or may have the value 372 "true".</p> 373 <p>For every Activity or Service defined 374 in one of the core Android system apps that is not marked as non-public via an 375 android:exported attribute with the value "false", device implementations MUST 376 include a compontent of the same type implementing the same Intent filter 377 patterns as the core Android system app.</p> 378 <p>In other words, a device implementation MAY replace core Android system 379 apps; however, if it does, the device implementation MUST support all Intent 380 patterns defined by each core Android system app being replaced.</p> 381 <a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4> 382 <p>As Android is an extensible platform, device implementers MUST allow each 383 Intent pattern referenced in Section 3.2.3.1 to be overridden by third-party 384 applications. The upstream Android open source project allows this by default; 385 device implementers MUST NOT attach special privileges to system applications' 386 use of these Intent patterns, or prevent third-party applications from binding 387 to and assuming control of these patterns. This prohibition specifically 388 includes but is not limited to disabling the "Chooser" user interface which 389 allows the user to select between multiple applications which all handle the 390 same Intent pattern.</p> 391 <a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4> 392 <p>Device implementers MUST NOT include any Android component that honors any 393 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 394 key string in the android.* namespace. Device implementers MUST NOT include 395 any Android components that honor any new Intent or Broadcast Intent patterns 396 using an ACTION, CATEGORY, or other key string in a package space belonging to 397 another organization. Device implementers MUST NOT alter or extend any of the 398 Intent patterns used by the core apps listed in Section 3.2.3.1.</p> 399 <p>This prohibition is analogous to that specified for Java language classes 400 in Section 3.6.</p> 401 <a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4> 402 <p>Third-party applications rely on the platform to broadcast certain Intents 403 to notify them of changes in the hardware or software environment. 404 Android-compatible devices MUST broadcast the public broadcast Intents in 405 response to appropriate system events. Broadcast Intents are described in the 406 SDK documentation.</p> 407 408 <a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3> 409 <p>Managed code running in Dalvik can call into native code provided in the 410 application .apk file as an ELF .so file compiled for the appropriate device 411 hardware architecture. Device implementations MUST include support for code 412 running in the managed environment to call into native code, using the 413 standard Java Native Interface (JNI) semantics. The following APIs MUST be 414 available to native code:</p> 415 <ul> 416 <li>libc (C library)</li> 417 <li>libm (math library)</li> 418 <li>JNI interface</li> 419 <li>libz (Zlib compression)</li> 420 <li>liblog (Android logging)</li> 421 <li>Minimal support for C++</li> 422 <li>Support for OpenGL, as described below</li> 423 </ul> 424 <p>Device implementations MUST support OpenGL ES 1.0. Devices that lack 425 hardware acceleration MUST implement OpenGL ES 1.0 using a software renderer. 426 Device implementations SHOULD implement as much of OpenGL ES 1.1 as the device 427 hardware supports. Device implementations SHOULD provide an implementation 428 for OpenGL ES 2.0, if the hardware is capable of reasonable performance on 429 those APIs.</p> 430 <p>These libraries MUST be source-compatible (i.e. header compatible) and 431 binary-compatible (for a given processor architecture) with the versions 432 provided in Bionic by the Android Open Source project. Since the Bionic 433 implementations are not fully compatible with other implementations such as 434 the GNU C library, device implementers SHOULD use the Android implementation. 435 If device implementers use a different implementation of these libraries, they 436 MUST ensure header, binary, and behavioral compatibility.</p> 437 <p>Device implementations MUST accurately report the native Application Binary 438 Interface (ABI) supported by the device, via the 439 <code>android.os.Build.CPU_ABI</code> API. The ABI MUST be one of the entries 440 documented in the latest version of the Android NDK, in the file 441 <code>docs/CPU-ARCH-ABIS.txt</code>. Note that additional releases of the 442 Android NDK may introduce support for additional ABIs.</p> 443 <p>Native code compatibility is challenging. For this reason, it should be 444 repeated that device implementers are VERY strongly encouraged to use the 445 upstream implementations of the libraries listed above to help ensure 446 compatibility.</p> 447 448 <a name="section-3.4"></a><h3>3.4. Web Compatibility</h3> 449 <p>Many developers and applications rely on the behavior of the 450 <code>android.webkit.WebView</code> class [<a 451 href="#resources08">Resources, 8</a>] 452 for their user interfaces, so the WebView implementation must be 453 compatible across Android implementations. Similarly, a full web experience is 454 central to the Android user experience. Device implementations MUST include a 455 version of <code>android.webkit.WebView</code> consistent with the upstream 456 Android software, and MUST include a modern HTML5-capable browser, as 457 described below.</p> 458 <a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4> 459 <p>The Android Open Source implementation uses the WebKit rendering engine to 460 implement the <code>android.webkit.WebView</code>. Because it is not feasible 461 to develop a comprehensive test suite for a web rendering system, device 462 implementers MUST use the specific upstream build of WebKit in the WebView 463 implementation. Specifically:</p> 464 <ul> 465 <li>Device implementations' <code>android.webkit.WebView</code> 466 implementations MUST be based on the 533.1 WebKit build from the upstream 467 Android Open Source tree for Android 2.2. This build includes a specific set 468 of functionality and security fixes for the WebView. Device implementers MAY 469 include customizations to the WebKit implementation; however, any such 470 customizations MUST NOT alter the behavior of the WebView, including rendering 471 behavior.</li> 472 <li>The user agent string reported by the WebView MUST be in this format:<br/> 473 <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> 474 <ul> 475 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 476 <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> 477 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 478 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 479 </ul></li> 480 </ul> 481 <p>The WebView configuration MUST include support for the HTML5 database, 482 application cache, and geolocation APIs [<a href="#resources09">Resources, 483 9</a>]. The WebView MUST include support for the HTML5 484 <code><video></code> tag. HTML5 APIs, like all JavaScript APIs, MUST be 485 disabled by default in a WebView, unless the developer explicitly enables them 486 via the usual Android APIs.</p> 487 <a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4> 488 <p>Device implementations MUST include a standalone Browser application for 489 general user web browsing. The standalone Browser MAY be based on an 490 browser technology other than WebKit. However, even if an alternate Browser 491 application is shipped, the <code>android.webkit.WebView</code> component 492 provided to third-party applications MUST be based on WebKit, as described in 493 Section 3.4.1.</p> 494 <p>Implementations MAY ship a custom user agent string in the standalone 495 Browser application.</p> 496 <p>The standalone Browser application (whether based on the upstream 497 WebKit Browser application or a third-party replacement) SHOULD include support 498 for as much of HTML5 [<a href="#resources09">Resources, 9</a>] as possible. 499 Minimally, device implementations MUST support HTML5 geolocation, application 500 cache, and database APIs and the <video> tag in standalone the Browser 501 application.</p> 502 503 <a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3> 504 <p>The behaviors of each of the API types (managed, soft, native, and web) 505 must be consistent with the preferred implementation of the upstream Android 506 open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 507 of compatibility are:</p> 508 <ul> 509 <li>Devices MUST NOT change the behavior or meaning of a standard Intent</li> 510 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.)</li> 511 <li>Devices MUST NOT change the semantics of a particular permission</li> 512 </ul> 513 <p>The above list is not comprehensive, and the onus is on device implementers 514 to ensure behavioral compatibility. For this reason, device implementers 515 SHOULD use the source code available via the Android Open Source Project where 516 possible, rather than re-implement significant parts of the system.</p> 517 <p>The Compatibility Test Suite (CTS) tests significant portions of the 518 platform for behavioral compatibility, but not all. It is the responsibility 519 of the implementer to ensure behavioral compatibility with the Android Open 520 Source Project.</p> 521 522 <a name="section-3.6"></a><h3>3.6. API Namespaces</h3> 523 <p>Android follows the package and class namespace conventions defined by the 524 Java programming language. To ensure compatibility with third-party 525 applications, device implementers MUST NOT make any prohibited modifications 526 (see below) to these package namespaces:</p> 527 <ul> 528 <li>java.*</li> 529 <li>javax.*</li> 530 <li>sun.*</li> 531 <li>android.*</li> 532 <li>com.android.*</li> 533 </ul> 534 <p>Prohibited modifications include:</p> 535 <ul> 536 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 537 Android platform by changing any method or class signatures, or by removing 538 classes or class fields.</li> 539 <li>Device implementers MAY modify the underlying implementation of the APIs, 540 but such modifications MUST NOT impact the stated behavior and Java-language 541 signature of any publicly exposed APIs.</li> 542 <li>Device implementers MUST NOT add any publicly exposed elements (such as 543 classes or interfaces, or fields or methods to existing classes or interfaces) 544 to the APIs above.</li> 545 </ul> 546 <p>A "publicly exposed element" is any construct which is not decorated with 547 the "@hide" marker in the upstream Android source code. In other words, device 548 implementers MUST NOT expose new APIs or alter existing APIs in the namespaces 549 noted above. Device implementers MAY make internal-only modifications, but 550 those modifications MUST NOT be advertised or otherwise exposed to 551 developers.</p> 552 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 553 namespace owned by or referring to another organization. For instance, device 554 implementers MUST NOT add APIs to the com.google.* or similar namespace; only 555 Google may do so. Similarly, Google MUST NOT add APIs to other companies' 556 namespaces.</p> 557 <p>If a device implementer proposes to improve one of the package namespaces 558 above (such as by adding useful new functionality to an existing API, or 559 adding a new API), the implementer SHOULD visit source.android.com and begin 560 the process for contributing changes and code, according to the information on 561 that site.</p> 562 <p>Note that the restrictions above correspond to standard conventions for 563 naming APIs in the Java programming language; this section simply aims to 564 reinforce those conventions and make them binding through inclusion in this 565 compatibility definition.</p> 566 567 <a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3> 568 <p>Device implementations MUST support the full Dalvik Executable (DEX) 569 bytecode specification and Dalvik Virtual Machine semantics [<a 570 href="#resources10">Resources, 10</a>].</p> 571 <p>Device implementations with screens classified as medium- or low-density 572 MUST configure Dalvik to allocate at least 16MB of memory to each application. 573 Device implementations with screens classified as high-density MUST configure 574 Dalvik to allocate at least 24MB of memory to each application. Note that 575 device implementations MAY allocate more memory than these figures.</p> 576 577 <a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3> 578 <p>The Android platform includes some developer APIs that allow developers to 579 hook into the system user interface. Device implementations MUST incorporate 580 these standard UI APIs into custom user interfaces they develop, as explained 581 below.</p> 582 <a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4> 583 <p>Android defines a component type and corresponding API and lifecycle that 584 allows applications to expose an "AppWidget" to the end user [<a 585 href="#resources11">Resources, 11</a>]. 586 The Android Open Source reference release includes a Launcher application that 587 includes user interface elements allowing the user to add, view, and remove 588 AppWidgets from the home screen.</p> 589 <p>Device implementers MAY substitute an alternative to the reference Launcher 590 (i.e. home screen). Alternative Launchers SHOULD include built-in support for 591 AppWidgets, and expose user interface elements to add, configure, view, and remove 592 AppWidgets directly within the Launcher. Alternative Launchers MAY omit these 593 user interface elements; however, if they are omitted, the device implementer 594 MUST provide a separate application accessible from the Launcher that allows 595 users to add, configure, view, and remove AppWidgets.</p> 596 <a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4> 597 <p>Android includes APIs that allow developers to notify users of notable 598 events [<a href="#resources12">Resources, 12</a>]. Device implementers MUST provide support for each 599 class of notification so defined; specifically: sounds, vibration, light and 600 status bar.</p> 601 <p>Additionally, the implementation MUST correctly render all resources 602 (icons, sound files, etc.) provided for in the APIs [<a 603 href="#resources13">Resources, 13</a>], or in the 604 Status Bar icon style guide [<a href="#resources14">Resources, 14</a>]. Device implementers MAY provide 605 an alternative user experience for notifications than that provided by the 606 reference Android Open Source implementation; however, such alternative 607 notification systems MUST support existing notification resources, as 608 above.</p> 609 <a name="section-3.8.3"></a><h4>3.8.3. Search</h4> 610 <p>Android includes APIs [<a href="#resources15">Resources, 15</a>] that allow developers to incorporate 611 search into their applications, and expose their application's data into the 612 global system search. Generally speaking, this functionality consists of a 613 single, system-wide user interface that allows users to enter queries, 614 displays suggestions as users type, and displays results. The Android APIs 615 allow developers to reuse this interface to provide search within their own 616 apps, and allow developers to supply results to the common global search user 617 interface.</p> 618 <p>Device implementations MUST include a single, shared, system-wide search 619 user interface capable of real-time suggestions in response to user input. 620 Device implementations MUST implement the APIs that allow developers to reuse 621 this user interface to provide search within their own applications. Device 622 implementations MUST implement the APIs that allow third-party applications to 623 add suggestions to the search box when it is run in global search mode. If no 624 third-party applications are installed that make use of this functionality, 625 the default behavior SHOULD be to display web search engine results and 626 suggestions.</p> 627 <p>Device implementations MAY ship alternate search user interfaces, but 628 SHOULD include a hard or soft dedicated search button, that can be used at any 629 time within any app to invoke the search framework, with the behavior provided 630 for in the API documentation.</p> 631 <a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4> 632 <p>Applications can use the "Toast" API (defined in [<a 633 href="#resources16">Resources, 16</a>]) to 634 display short non-modal strings to the end user, that disappear after a brief 635 period of time. Device implementations MUST display Toasts from applications 636 to end users in some high-visibility manner.</p> 637 <a name="section-3.8.5"></a><h4>3.8.5. Live Wallpapers</h4> 638 <p>Android defines a component type and corresponding API and lifecycle that 639 allows applications to expose one or more "Live Wallpapers" to the end user 640 [<a href="#resources17">Resources, 17</a>]. Live Wallpapers are animations, 641 patterns, or similar images with limited input capabilities that display as a 642 wallpaper, behind other applications.</p> 643 <p>Hardware is considered capable of reliably running live wallpapers if it 644 can run all live wallpapers, with no limitations on functionality, at a 645 reasonable framerate with no adverse affects on other applications. If 646 limitations in the hardware cause wallpapers and/or applications to crash, 647 malfunction, consume excessive CPU or battery power, or run at unacceptably 648 low frame rates, the hardware is considered incapable of running live 649 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 650 context to render their content. Live wallpaper will not run reliably on 651 hardware that does not support multiple OpenGL contexts because the live 652 wallpaper use of an OpenGL context may conflict with other applications that 653 also use an OpenGL context. </p> 654 <p>Device implementations capable of running live wallpapers reliably as 655 described above SHOULD implement live wallpapers. Device implementations 656 determined to not run live wallpapers reliably as described above MUST NOT 657 implement live wallpapers.</p> 658 659 <a name="section-4"></a><h2>4. Reference Software Compatibility</h2> 660 <p>Device implementers MUST test implementation compatibility using the 661 following open-source applications:</p> 662 <ul> 663 <li>Calculator (included in SDK)</li> 664 <li>Lunar Lander (included in SDK)</li> 665 <li>The "Apps for Android" applications [<a href="#resources18">Resources, 18</a>].</li> 666 <li>Replica Island (available in Android Market; only required for device 667 implementations that support with OpenGL ES 2.0)</li> 668 </ul> 669 <p>Each app above MUST launch and behave correctly on the implementation, for 670 the implementation to be considered compatible.</p> 671 <p>Additionally, device implementations MUST test each menu item (including all 672 sub-menus) of each of these smoke-test applications:</p> 673 <ul> 674 <li>ApiDemos (included in SDK)</li> 675 <li>ManualSmokeTests (included in CTS)</li> 676 </ul> 677 <p>Each test case in the applications above MUST run correctly on the device 678 implementation.</p> 679 680 <a name="section-5"></a><h2>5. Application Packaging Compatibility</h2> 681 <p>Device implementations MUST install and run Android ".apk" files as 682 generated by the "aapt" tool included in the official Android SDK [<a 683 href="#resources19">Resources, 19</a>].</p> 684 <p>Devices implementations MUST NOT extend either the .apk [<a 685 href="#resources20">Resources, 20</a>], Android Manifest [<a 686 href="#resources21">Resources, 21</a>], 687 or Dalvik bytecode [<a href="#resources10">Resources, 10</a>] formats in such 688 a way that would prevent those files from 689 installing and running correctly on other compatible devices. Device 690 implementers SHOULD use the reference upstream implementation of Dalvik, and 691 the reference implementation's package management system.</p> 692 693 <a name="section-6"></a><h2>6. Multimedia Compatibility</h2> 694 <p>Device implementations MUST fully implement all multimedia APIs. Device 695 implementations MUST include support for all multimedia codecs described 696 below, and SHOULD meet the sound processing guidelines described below.</p> 697 <a name="section-6.1"></a><h3>6.1. Media Codecs</h3> 698 <p>Device implementations MUST support the following multimedia codecs. All of 699 these codecs are provided as software implementations in the preferred Android 700 implementation from the Android Open Source Project.</p> 701 <p>Please note that neither Google nor the Open Handset Alliance make any 702 representation that these codecs are unencumbered by third-party patents. 703 Those intending to use this source code in hardware or software products are 704 advised that implementations of this code, including in open source software 705 or shareware, may require patent licenses from the relevant patent 706 holders.</p> 707 <table><tbody> 708 <tr> 709 <td rowspan="11"><b>Audio</b></td> 710 </tr> 711 <tr> 712 <td><b>Name</b></td> 713 <td><b>Encoder</b></td> 714 <td><b>Decoder</b></td> 715 <td><b>Details</b></td> 716 <td><b>File/Container Format</b></td> 717 </tr> 718 <tr> 719 <td>AAC LC/LTP</td> 720 <td> </td> 721 <td>X</td> 722 <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> 723 <td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td> 724 </tr> 725 <tr> 726 <td>HE-AACv1 (AAC+)</td> 727 <td> </td> 728 <td>X</td> 729 </tr> 730 <tr> 731 <td>HE-AACv2 (enhanced AAC+)</td> 732 <td> </td> 733 <td>X</td> 734 </tr> 735 <tr> 736 <td>AMR-NB</td> 737 <td>X</td> 738 <td>X</td> 739 <td>4.75 to 12.2 kbps sampled @ 8kHz</td> 740 <td>3GPP (.3gp)</td> 741 </tr> 742 <tr> 743 <td>AMR-WB</td> 744 <td> </td> 745 <td>X</td> 746 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 747 <td>3GPP (.3gp)</td> 748 </tr> 749 <tr> 750 <td>MP3</td> 751 <td> </td> 752 <td>X</td> 753 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td> 754 <td>MP3 (.mp3)</td> 755 </tr> 756 <tr> 757 <td>MIDI</td> 758 <td> </td> 759 <td>X</td> 760 <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> 761 <td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td> 762 </tr> 763 <tr> 764 <td>Ogg Vorbis</td> 765 <td> </td> 766 <td>X</td> 767 <td> </td> 768 <td>Ogg (.ogg)</td> 769 </tr> 770 <tr> 771 <td>PCM</td> 772 <td> </td> 773 <td>X</td> 774 <td>8- and 16-bit linear PCM (rates up to limit of hardware)</td> 775 <td>WAVE (.wav)</td> 776 </tr> 777 <tr> 778 <td rowspan="5"><b>Image</b></td> 779 </tr> 780 <tr> 781 <td>JPEG</td> 782 <td>X</td> 783 <td>X</td> 784 <td>base+progressive</td> 785 <td> </td> 786 </tr> 787 <tr> 788 <td>GIF</td> 789 <td> </td> 790 <td>X</td> 791 <td> </td> 792 <td> </td> 793 </tr> 794 <tr> 795 <td>PNG</td> 796 <td>X</td> 797 <td>X</td> 798 <td> </td> 799 <td> </td> 800 </tr> 801 <tr> 802 <td>BMP</td> 803 <td> </td> 804 <td>X</td> 805 <td> </td> 806 <td> </td> 807 </tr> 808 <tr> 809 <td rowspan="4"><b>Video</b></td> 810 </tr> 811 <tr> 812 <td>H.263</td> 813 <td>X</td> 814 <td>X</td> 815 <td> </td> 816 <td>3GPP (.3gp) files</td> 817 </tr> 818 <tr> 819 <td>H.264</td> 820 <td> </td> 821 <td>X</td> 822 <td> </td> 823 <td>3GPP (.3gp) and MPEG-4 (.mp4) files</td> 824 </tr> 825 <tr> 826 <td>MPEG4 Simple Profile</td> 827 <td> </td> 828 <td>X</td> 829 <td> </td> 830 <td>3GPP (.3gp) file</td> 831 </tr> 832 </tbody> 833 </table> 834 <p>Note that the table above does not list specific bitrate requirements for 835 most video codecs. The reason for this is that in practice, current device 836 hardware does not necessarily support bitrates that map exactly to the 837 required bitrates specified by the relevant standards. Instead, device 838 implementations SHOULD support the highest bitrate practical on the hardware, 839 up to the limits defined by the specifications.</p> 840 841 <a name="section-6.2"></a><h3>6.2. Audio Recording</h3> 842 <p>When an application has used the <code>android.media.AudioRecord</code> API to 843 start recording an audio stream, device implementations SHOULD sample and 844 record audio with each of these behaviors:</p> 845 <ul> 846 <li>Noise reduction processing, if present, SHOULD be disabled.</li> 847 <li>Automatic gain control, if present, SHOULD be disabled.</li> 848 <li>The device SHOULD exhibit approximately flat amplitude versus frequency 849 characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz</li> 850 <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level 851 (SPL) source at 1000 Hz yields RMS of 5000 for 16-bit samples.</li> 852 <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least 853 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li> 854 <li>Total harmonic distortion SHOULD be less than 1% from 100 Hz to 4000 Hz at 855 90 dB SPL input level.</li> 856 </ul> 857 <p><b>Note:</b> while the requirements outlined above are stated as "SHOULD" 858 for Android 2.2, the Compatibility Definition for a future version is planned 859 to change these to "MUST". That is, these requirements are optional in Android 860 2.2 but <b>will be required</b> by a future version. Existing and new devices 861 that run Android 2.2 Android are <b>very strongly encouraged to meet 862 these requirements in Android 2.2</b>, or they will not be able to attain 863 Android compatibility when upgraded to the future version.</p> 864 865 <a name="section-6.3"></a><h3>6.3. Audio Latency</h3> 866 <p>Audio latency is broadly defined as the interval between when an 867 application requests an audio playback or record operation, and when the 868 device implementation actually begins the operation. Many classes of 869 applications rely on short latencies, to achieve real-time effects such sound 870 effects or VOIP communication. Device implementations SHOULD meet all audio 871 latency requirements outlined in this section.</p> 872 <p>For the purposes of this section:</p> 873 <ul> 874 <li>"cold output latency" is defined to be the interval between when an 875 application requests audio playback and when sound begins playing, when 876 the audio system has been idle and powered down prior to the request</li> 877 <li>"warm output latency" is defined to be the interval between when an 878 application requests audio playback and when sound begins playing, when 879 the audio system has been recently used but is currently idle (that is, 880 silent)</li> 881 <li>"continuous output latency" is defined to be the interval between when an 882 application issues a sample to be played and when the speaker physically 883 plays the corresponding sound, while the device is currently playing back 884 audio</li> 885 <li>"cold input latency" is defined to be the interval between when an 886 application requests audio recording and when the first sample is 887 delivered to the application via its callback, when the audio system and 888 microphone has been idle and powered down prior to the request</li> 889 <li>"continuous input latency" is defined to be when an ambient sound occurs 890 and when the sample corresponding to that sound is delivered to a 891 recording application via its callback, while the device is in recording 892 mode</li> 893 </ul> 894 <p>Using the above definitions, device implementations SHOULD exhibit each of 895 these properties:</p> 896 <ul> 897 <li>cold output latency of 100 milliseconds or less</li> 898 <li>warm output latency of 10 milliseconds or less</li> 899 <li>continuous output latency of 45 milliseconds or less</li> 900 <li>cold input latency of 100 milliseconds or less</li> 901 <li>continuous input latency of 50 milliseconds or less</li> 902 </ul> 903 <p><b>Note:</b> while the requirements outlined above are stated as "SHOULD" 904 for Android 2.2, the Compatibility Definition for a future version is planned 905 to change these to "MUST". That is, these requirements are optional in Android 906 2.2 but <b>will be required</b> by a future version. Existing and new devices 907 that run Android 2.2 Android are <b>very strongly encouraged to meet 908 these requirements in Android 2.2</b>, or they will not be able to attain 909 Android compatibility when upgraded to the future version.</p> 910 911 <a name="section-7"></a><h2>7. Developer Tool Compatibility</h2> 912 <p>Device implementations MUST support the Android Developer Tools provided in 913 the Android SDK. Specifically, Android-compatible devices MUST be compatible 914 with:</p> 915 <ul> 916 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources19">Resources, 19</a>]<br/> 917 Device implementations MUST support all <code>adb</code> functions as 918 documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD 919 be inactive by default, but there MUST be a user-accessible mechanism to turn 920 on the Android Debug Bridge.</li> 921 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources19">Resources, 19</a>]<br/> 922 Device implementations MUST support all <code>ddms</code> features as documented in the 923 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 924 <code>ddms</code> SHOULD be inactive by default, 925 but MUST be supported whenever the user has activated the Android Debug 926 Bridge, as above.</li> 927 <li><b>Monkey</b> [<a href="#resources22">Resources, 22</a>]<br/> 928 Device implementations MUST include the Monkey framework, and make it 929 available for applications to use.</li> 930 </ul> 931 932 <a name="section-8"></a><h2>8. Hardware Compatibility</h2> 933 <p>Android is intended to support device implementers creating innovative form 934 factors and configurations. At the same time Android developers expect 935 certain hardware, sensors and APIs across all Android device. This section 936 lists the hardware features that all Android 2.2 compatible devices must 937 support.</p> 938 <p>If a device includes a particular hardware component that has a 939 corresponding API for third-party developers, the device implementation MUST 940 implement that API as defined in the Android SDK documentation. If an API in 941 the SDK interacts with a hardware component that is stated to be optional and the device 942 implementation does not possess that component:</p> 943 <ul> 944 <li>class definitions for the component's APIs MUST be present</li> 945 <li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li> 946 <li>API methods MUST return null values where permitted by the SDK documentation</li> 947 <li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li> 948 </ul> 949 <p>A typical example of a scenario where these requirements apply is the 950 telephony API: even on non-phone devices, these APIs must be implemented as 951 reasonable no-ops.</p> 952 <p>Device implementations MUST accurately report accurate hardware configuration 953 information via the <code>getSystemAvailableFeatures()</code> and 954 <code>hasSystemFeature(String)</code> methods on the 955 <code>android.content.pm.PackageManager</code> class. [<a 956 href="#resources23">Resources, 23</a>]</p> 957 958 <a name="section-8.1"></a><h3>8.1. Display</h3> 959 <p>Android 2.2 includes facilities that perform certain automatic scaling and 960 transformation operations under some circumstances, to ensure that third-party 961 applications run reasonably well on a variety of hardware configurations [<a 962 href="#resources24">Resources, 24</a>]. Devices MUST properly implement these 963 behaviors, as detailed in this section.</p> 964 <p>For Android 2.2, these are the most common display configurations:</p> 965 <table><tbody> 966 <tr> 967 <td>Screen Type</td> 968 <td>Width (Pixels)</td> 969 <td>Height (Pixels)</td> 970 <td>Diagonal Length Range (inches)</td> 971 <td>Screen Size Group</td> 972 <td>Screen Density Group</td> 973 </tr> 974 <tr> 975 <td>QVGA</td> 976 <td>240</td> 977 <td>320</td> 978 <td>2.6 - 3.0</td> 979 <td>Small</td> 980 <td>Low</td> 981 </tr> 982 <tr> 983 <td>WQVGA</td> 984 <td>240</td> 985 <td>400</td> 986 <td>3.2 - 3.5</td> 987 <td>Normal</td> 988 <td>Low</td> 989 </tr> 990 <tr> 991 <td>FWQVGA</td> 992 <td>240</td> 993 <td>432</td> 994 <td>3.5 - 3.8</td> 995 <td>Normal</td> 996 <td>Low</td> 997 </tr> 998 <tr> 999 <td>HVGA</td> 1000 <td>320</td> 1001 <td>480</td> 1002 <td>3.0 - 3.5</td> 1003 <td>Normal</td> 1004 <td>Medium</td> 1005 </tr> 1006 <tr> 1007 <td>WVGA</td> 1008 <td>480</td> 1009 <td>800</td> 1010 <td>3.3 - 4.0</td> 1011 <td>Normal</td> 1012 <td>High</td> 1013 </tr> 1014 <tr> 1015 <td>FWVGA</td> 1016 <td>480</td> 1017 <td>854</td> 1018 <td>3.5 - 4.0</td> 1019 <td>Normal</td> 1020 <td>High</td> 1021 </tr> 1022 <tr> 1023 <td>WVGA </td> 1024 <td>480 </td> 1025 <td>800 </td> 1026 <td>4.8 - 5.5 </td> 1027 <td>Large </td> 1028 <td>Medium</td> 1029 </tr> 1030 <tr> 1031 <td>FWVGA</td> 1032 <td>480</td> 1033 <td>854</td> 1034 <td>5.0 - 5.8</td> 1035 <td>Large</td> 1036 <td>Medium</td> 1037 </tr> 1038 1039 </tbody></table> 1040 1041 <p>Device implementations corresponding to one of the standard configurations 1042 above MUST be configured to report the indicated screen size to applications 1043 via the <code>android.content.res.Configuration</code> [<a href="#resources25">Resources, 1044 24</a>] class.</p> 1045 <p>Some .apk packages have manifests that do not identify them as supporting a 1046 specific density range. When running such applications, the following 1047 constraints apply:</p> 1048 <ul> 1049 <li>Device implementations MUST interpret resources in a .apk that lack a 1050 density qualifier as defaulting to "medium" (known as "mdpi" in the SDK 1051 documentation.)</li> 1052 <li>When operating on a "low" density screen, device implementations MUST 1053 scale down medium/mdpi assets by a factor of 0.75.</li> 1054 <li>When operating on a "high" density screen, device implementations MUST 1055 scale up medium/mdpi assets by a factor of 1.5.</li> 1056 <li>Device implementations MUST NOT scale assets within a density range, and 1057 MUST scale assets by exactly these factors between density ranges.</li> 1058 </ul> 1059 1060 <a name="section-8.1.2"></a><h4>8.1.2. Non-Standard Display Configurations</h4> 1061 <p>Display configurations that do not match one of the standard configurations 1062 listed in Section 8.1.1 require additional consideration and work to be 1063 compatible. Device implementers MUST contact Android Compatibility Team as 1064 described in Section 13 to obtain classifications for screen-size bucket, 1065 density, and scaling factor. When provided with this information, device 1066 implementations MUST implement them as specified.</p> 1067 <p>Note that some display configurations (such as very large or very small 1068 screens, and some aspect ratios) are fundamentally incompatible with Android 1069 2.2; therefore device implementers are encouraged to contact Android 1070 Compatibility Team as early as possible in the development process.</p> 1071 1072 <a name="section-8.1.3"></a><h4>8.1.3. Display Metrics</h4> 1073 <p>Device implementations MUST report correct valuesfor all display metrics 1074 defined in <code>android.util.DisplayMetrics</code> [<a 1075 href="#resources26">Resources, 26</a>].</p> 1076 1077 <a name="section-8.1.4"></a><h4>8.1.4. Declared Screen Support</h4> 1078 <p>Applications may indicate which screen sizes they support via the 1079 <code><supports-screens></code> attribute in the AndroidManifest.xml 1080 file. Device implementations MUST correctly honor applications' stated support 1081 for small, medium, and large screens, as described in the Android 1082 SDK documentation.</p> 1083 1084 <a name="section-8.2"></a><h3>8.2. Keyboard</h3> 1085 <p>Device implementations:</p> 1086 <ul> 1087 <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> 1088 <li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li> 1089 <li>MAY include additional soft keyboard implementations</li> 1090 <li>MAY include a hardware keyboard</li> 1091 <li>MUST NOT include a hardware keyboard that does not match one of the 1092 formats specified in <code>android.content.res.Configuration.keyboard</code> 1093 [<a href="#resources25">Resources, 25</a>] (that is, QWERTY, or 12-key)</li> 1094 </ul> 1095 <a name="section-8.3"></a><h3>8.3. Non-touch Navigation</h3> 1096 <p>Device implementations:</p> 1097 <ul> 1098 <li>MAY omit a non-touch navigation options (that is, may omit a trackball, d-pad, or wheel)</li> 1099 <li>MUST report the correct value for 1100 <code>android.content.res.Configuration.navigation</code> [<a href="#resources25">Resources, 25</a>]</li> 1101 </ul> 1102 <a name="section-8.4"></a><h3>8.4. Screen Orientation</h3> 1103 <p>Compatible devices MUST support dynamic orientation by applications to 1104 either portrait or landscape screen orientation. That is, the device must 1105 respect the application's request for a specific screen orientation. Device 1106 implementations MAY select either portrait or landscape orientation as the 1107 default.</p> 1108 <p>Devices MUST report the correct value for the device's current orientation, 1109 whenever queried via the android.content.res.Configuration.orientation, 1110 android.view.Display.getOrientation(), or other APIs.</p> 1111 1112 <a name="section-8.5"></a><h3>8.5. Touchscreen input</h3> 1113 <p>Device implementations:</p> 1114 <ul> 1115 <li>MUST have a touchscreen</li> 1116 <li>MAY have either capacative or resistive touchscreen</li> 1117 <li>MUST report the value of <code>android.content.res.Configuration</code> 1118 [<a href="#resources25">Resources, 25</a>] 1119 reflecting corresponding to the type of the specific touchscreen on the 1120 device</li> 1121 <li>SHOULD support fully independently tracked pointers, if the touchscreen supports multiple pointers</li> 1122 </ul> 1123 1124 <a name="section-8.6"></a><h3>8.6. USB</h3> 1125 <p>Device implementations:</p> 1126 <ul> 1127 <li>MUST implement a USB client, connectable to a USB host with a standard 1128 USB-A port</li> 1129 <li>MUST implement the Android Debug Bridge over USB (as described in Section 1130 7)</li> 1131 <li>MUST implement the USB mass storage specification, to allow a host 1132 connected to the device to access the contents of the /sdcard volume </li> 1133 <li>SHOULD use the micro USB form factor on the device side</li> 1134 <li>MAY include a non-standard port on the device side, but if so MUST ship 1135 with a cable capable of connecting the custom pinout to standard USB-A 1136 port</li> 1137 <li>SHOULD implement support for the USB Mass Storage specification (so that 1138 either removable or fixed storage on the device can be accessed from a host 1139 PC)</li> 1140 </ul> 1141 1142 <a name="section-8.7"></a><h3>8.7. Navigation keys</h3> 1143 <p>The Home, Menu and Back functions are essential to the Android navigation 1144 paradigm. Device implementations MUST make these functions available to the 1145 user at all times, regardless of application state. These functions SHOULD be 1146 implemented via dedicated buttons. They MAY be implemented using software, 1147 gestures, touch panel, etc., but if so they MUST be always accessible and not 1148 obscure or interfere with the available application display area.</p> 1149 <p>Device implementers SHOULD also provide a dedicated search key. Device 1150 implementers MAY also provide send and end keys for phone calls.</p> 1151 1152 <a name="section-8.8"></a><h3>8.8. Wireless Data Networking</h3> 1153 <p>Device implementations MUST include support for wireless high-speed data 1154 networking. Specifically, device implementations MUST include support for at 1155 least one wireless data standard capable of 200Kbit/sec or greater. Examples of 1156 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, etc.</p> 1157 <p>If a device implementation includes a particular modality for which the 1158 Android SDK includes an API (that is, WiFi, GSM, or CDMA), the implementation 1159 MUST support the API.</p> 1160 <p>Devices MAY implement more than one form of wireless data connectivity. 1161 Devices MAY implement wired data connectivity (such as Ethernet), but MUST 1162 nonetheless include at least one form of wireless connectivity, as above.</p> 1163 1164 <a name="section-8.9"></a><h3>8.9. Camera</h3> 1165 <p>Device implementations MUST include a rear-facing camera. The included 1166 rear-facing camera:</p> 1167 <ul> 1168 <li>MUST have a resolution of at least 2 megapixels</li> 1169 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented 1170 in the camera driver (transparent to application software)</li> 1171 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 1172 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 1173 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 1174 registered on a Camera preview surface, unless the application has explicitly 1175 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 1176 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 1177 object. Note that this constraint does not apply to the device's built-in 1178 system camera application, but only to third-party applications using 1179 <code>Camera.PreviewCallback</code>.</li> 1180 </ul> 1181 <p>Device implementations MUST implement the following behaviors for the 1182 camera-related APIs:</p> 1183 <ol> 1184 <li>If an application has never called 1185 android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST 1186 use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to 1187 application callbacks.</li> 1188 <li>If an application registers an android.hardware.Camera.PreviewCallback 1189 instance and the system calls the onPreviewFrame() method when the preview 1190 format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() 1191 must further be in the NV21 encoding format. (This is the format used natively 1192 by the 7k hardware family.) That is, NV21 MUST be the default.</li> 1193 </ol> 1194 <p>Device implementations MUST implement the full Camera API included in the 1195 Android 2.2 SDK documentation [<a href="#resources27">Resources, 27</a>]), 1196 regardless of whether the device includes hardware autofocus or other 1197 capabilities. For instance, cameras that lack autofocus MUST still call any 1198 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 1199 this has no relevance to a non-autofocus camera.)</p> 1200 <p>Device implementations MUST recognize and honor each parameter name defined 1201 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 1202 underlying hardware supports the feature. If the device hardware does not 1203 support a feature, the API must behave as documented. Conversely, Device 1204 implementations MUST NOT honor or recognize string constants passed 1205 to the <code>android.hardware.Camera.setParameters()</code> method other than 1206 those documented as constants on the 1207 <code>android.hardware.Camera.Parameters</code>. That is, 1208 device implementations MUST support all standard Camera parameters if the 1209 hardware allows, and MUST NOT support custom Camera parameter types.</p> 1210 <p>Device implementations MAY include a front-facing camera. However, if 1211 a device implementation includes a front-facing camera, the camera API as 1212 implemented on the device MUST NOT use the front-facing camera by default. 1213 That is, the camera API in Android 2.2 is for rear-facing cameras only, and 1214 device implementations MUST NOT reuse or overload the API to act on a 1215 front-facing camera, if one is present. Note that any custom APIs added by 1216 device implementers to support front-facing cameras MUST abide by sections 3.5 1217 and 3.6; for instance, if a custom <code>android.hardware.Camera</code> or 1218 <code>Camera.Parameters</code> subclass is provided to support front-facing 1219 cameras, it MUST NOT be located in an existing namespace, as described by 1220 sections 3.5 and 3.6. Note that the inclusion of a front-facing camera does 1221 not meet the requirement that devices include a rear-facing camera.</p> 1222 1223 <a name="section-8.10"></a><h3>8.10. Accelerometer</h3> 1224 <p>Device implementations MUST include a 3-axis accelerometer and MUST be able 1225 to deliver events at 50 Hz or greater. The coordinate system used by the 1226 accelerometer MUST comply with the Android sensor coordinate system as detailed 1227 in the Android APIs (see [<a href="#resources28">Resources, 28</a>]).</p> 1228 1229 <a name="section-8.11"></a><h3>8.11. Compass</h3> 1230 <p>Device implementations MUST include a 3-axis compass and MUST be able to 1231 deliver events 10 Hz or greater. The coordinate system used by the compass 1232 MUST comply with the Android sensor coordinate system as defined in the Android 1233 API (see [<a href="#resources28">Resources, 28</a>]).</p> 1234 1235 <a name="section-8.12"></a><h3>8.12. GPS</h3> 1236 <p>Device implementations MUST include a GPS receiver, and SHOULD include 1237 some form of "assisted GPS" technique to minimize GPS lock-on time.</p> 1238 1239 <a name="section-8.13"></a><h3>8.13. Telephony</h3> 1240 <p>Android 2.2 MAY be used on devices that do not include telephony hardware. 1241 That is, Android 2.2 is compatible with devices that are not phones. 1242 However, if a device implementation does include GSM or CDMA telephony, it 1243 MUST implement the full support for the API for that technology. Device 1244 implementations that do not include telephony hardware MUST implement the full 1245 APIs as no-ops.</p> 1246 <p>See also Section 8.8, Wireless Data Networking.</p> 1247 1248 <a name="section-8.14"></a><h3>8.14. Memory and Storage</h3> 1249 <p>Device implementations MUST have at least 92MB of memory available to the 1250 kernel and userspace. The 92MB MUST be in addition to any memory dedicated to 1251 hardware components such as radio, memory, and so on that is not under the 1252 kernel's control.</p> 1253 <p>Device implementations MUST have at least 150MB of non-volatile storage 1254 available for user data. That is, the <code>/data</code> partition MUST be at 1255 least 150MB.</p> 1256 <p>Beyond the requirements above, device implementations SHOULD have at least 1257 128MB of memory available to kernel and userspace, in addition to any memory 1258 dedicated to hardware components that is not under the kernel's control. 1259 Device implementations SHOULD have at least 1GB of non-volatile storage 1260 available for user data. Note that these higher requirements are planned to 1261 become hard minimums in a future version of Android. Device implementations are 1262 strongly encouraged to meet these requirements now, or else they may not be 1263 eligible for compatibility for a future version of Android.</p> 1264 1265 <a name="section-8.15"></a><h3>8.15. Application Shared Storage</h3> 1266 <p>Device implementations MUST offer shared storage for applications. The 1267 shared storage provided MUST be at least 2GB in size.</p> 1268 <p>Device implementations MUST be configured with shared storage mounted by 1269 default, "out of the box". If the shared storage is not mounted on the Linux 1270 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 1271 from <code>/sdcard</code> to the actual mount point.</p> 1272 <p>Device implementations MUST enforce as documented the 1273 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 1274 shared storage. Shared storage MUST otherwise be writable by any application 1275 that obtains that permission.</p> 1276 <p>Device implementations MAY have hardware for user-accessible removable 1277 storage, such as a Secure Digital card. Alternatively, device implementations 1278 MAY allocate internal (non-removable) storage as shared storage for apps.</p> 1279 <p>Regardless of the form of shared storage used, the shared storage MUST 1280 implement USB mass storage, as described in Section 8.6. As shipped out of the 1281 box, the shared storage MUST be mounted with the FAT filesystem.</p> 1282 <p>It is illustrative to consider two common examples. If a device 1283 implementation includes an SD card slot to satisfy the shared storage 1284 requirement, a FAT-formatted SD card 2GB in size or larger MUST be included 1285 with the device as sold to users, and MUST be mounted by default. 1286 Alternatively, if a device implementation uses internal fixed storage to 1287 satisfy this requirement, that storage MUST be 2GB in size or larger, 1288 formatted as FAT, and mounted on <code>/sdcard</code> (or <code>/sdcard</code> 1289 MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p> 1290 <p>Device implementations that include multiple shared storage paths (such as 1291 both an SD card slot and shared internal storage) SHOULD modify the core 1292 applications such as the media scanner and ContentProvider to transparently 1293 support files placed in both locations.</p> 1294 1295 <a name="section-8.16"></a><h3>8.16. Bluetooth</h3> 1296 <p>Device implementations MUST include a Bluetooth transceiver. Device 1297 implementations MUST enable the RFCOMM-based Bluetooth API as described in the 1298 SDK documentation [<a href="#resources30">Resources, 30</a>]. Device 1299 implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, 1300 AVRCP, OBEX, etc. as appropriate for the device.</p> 1301 <p>The Compatibility Test Suite includes cases that cover basic operation of 1302 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 1303 protocol between devices, it cannot be fully tested by unit tests running on a 1304 single device. Consequently, device implementations MUST also pass the 1305 human-driven Bluetooth test procedure described in Appendix A.</p> 1306 1307 <a name="section-9"></a><h2>9. Performance Compatibility</h2> 1308 <p>One of the goals of the Android Compatibility Program is to enable 1309 consistent application experience to consumers. Compatible implementations 1310 must ensure not only that applications simply run correctly on the device, but 1311 that they do so with reasonable performance and overall good user experience. 1312 Device implementations MUST meet the key performance metrics of an Android 2.2 1313 compatible device defined in the table below:</p> 1314 <table><tbody><tr> 1315 <td><b>Metric</b></td> 1316 <td><b>Performance Threshold</b></td> 1317 <td><b>Comments</b></td> 1318 </tr> 1319 <tr> 1320 <td>Application Launch Time</td> 1321 <td>The following applications should launch within the specified time.<ul> 1322 <li>Browser: less than 1300ms</li> 1323 <li>MMS/SMS: less than 700ms</li> 1324 <li>AlarmClock: less than 650ms</li> 1325 </ul></td> 1326 <td>The launch time is measured as the total time to 1327 complete loading the default activity for the application, including the time 1328 it takes to start the Linux process, load the Android package into the Dalvik 1329 VM, and call onCreate.</td> 1330 </tr> 1331 <tr> 1332 <td>Simultaneous Applications</td> 1333 <td>When multiple applications have been launched, re-launching an 1334 already-running application after it has been launched must take less than the 1335 original launch time.</td> 1336 <td> </td> 1337 </tr> 1338 </tbody> 1339 </table> 1340 1341 <a name="section-10"></a><h2>10. Security Model Compatibility</h2> 1342 <p>Device implementations MUST implement a security model consistent with the 1343 Android platform security model as defined in Security and Permissions 1344 reference document in the APIs [<a href="#resources29">Resources, 29</a>] in the 1345 Android developer documentation. Device implementations MUST support 1346 installation of self-signed applications without requiring any additional 1347 permissions/certificates from any third parties/authorities. Specifically, 1348 compatible devices MUST support the security mechanisms described in the 1349 follow sub-sections.</p> 1350 <a name="section-10.1"></a><h3>10.1. Permissions</h3> 1351 <p>Device implementations MUST support the Android permissions model as 1352 defined in the Android developer documentation [<a 1353 href="#resources29">Resources, 29</a>]. Specifically, 1354 implementations MUST enforce each permission defined as described in the SDK 1355 documentation; no permissions may be omitted, altered, or ignored. 1356 Implementations MAY add additional permissions, provided the new permission ID 1357 strings are not in the android.* namespace.</p> 1358 <a name="section-10.2"></a><h3>10.2. UID and Process Isolation</h3> 1359 <p>Device implementations MUST support the Android application sandbox model, 1360 in which each application runs as a unique Unix-style UID and in a separate 1361 process. Device implementations MUST support running multiple applications as 1362 the same Linux user ID, provided that the applications are properly signed and 1363 constructed, as defined in the Security and Permissions reference [<a 1364 href="#resources29">Resources, 29</a>].</p> 1365 <a name="section-10.3"></a><h3>10.3. Filesystem Permissions</h3> 1366 <p>Device implementations MUST support the Android file access permissions 1367 model as defined in as defined in the Security and Permissions reference [<a 1368 href="#resources29">Resources, 29</a>].</p> 1369 <a name="section-10.4"></a><h3>10.4. Alternate Execution Environments</h3> 1370 <p>Device implementations MAY include runtime environments that execute 1371 applications using some other software or technology than the Dalvik virtual 1372 machine or native code. However, such alternate execution environments MUST 1373 NOT compromise the Android security model or the security of installed Android 1374 applications, as described in this section.</p> 1375 <p>Alternate runtimes MUST themselves be Android applications, and abide by 1376 the standard Android security model, as described elsewhere in Section 10.</p> 1377 <p>Alternate runtimes MUST NOT be granted access to resources protected by 1378 permissions not requested in the runtime's AndroidManifest.xml file via the 1379 <code><uses-permission></code> mechanism.</p> 1380 <p>Alternate runtimes MUST NOT permit applications to make use of features 1381 protected by Android permissions restricted to system applications.</p> 1382 <p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p> 1383 <ul> 1384 <li>Alternate runtimes SHOULD install apps via the PackageManager into 1385 separate Android sandboxes (that is, Linux user IDs, etc.)</li> 1386 <li>Alternate runtimes MAY provide a single Android sandbox shared by all 1387 applications using the alternate runtime.</li> 1388 <li>Alternate runtimes and installed applications using an alternate runtime 1389 MUST NOT reuse the sandbox of any other app installed on the device, except 1390 through the standard Android mechanisms of shared user ID and signing 1391 certificate</li> 1392 <li>Alternate runtimes MUST NOT launch with, grant, or be granted access to 1393 the sandboxes corresponding to other Android applications.</li> 1394 </ul> 1395 <p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other 1396 applications any privileges of the superuser (root), or of any other user ID.</p> 1397 <p>The .apk files of alternate runtimes MAY be included in the system image of 1398 a device implementation, but MUST be signed with a key distinct 1399 from the key used to sign other applications included with the device 1400 implementation.</p> 1401 <p>When installing applications, alternate runtimes MUST obtain user consent 1402 for the Android permissions used by the application. That is, if an 1403 application needs to make use of a device resource for which there is a 1404 corresponding Android permission (such as Camera, GPS, etc.), the alternate 1405 runtime MUST inform the user that the application will be able to access 1406 that resource. If the runtime environment does not record application 1407 capabilities in this manner, the runtime environment MUST list all 1408 permissions held by the runtime itself when installing any application 1409 using that runtime.</p> 1410 1411 <a name="section-11"></a><h2>11. Compatibility Test Suite</h2> 1412 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 1413 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source 1414 Project, using the final shipping software on the device. Additionally, device 1415 implementers SHOULD use the reference implementation in the Android Open 1416 Source tree as much as possible, and MUST ensure compatibility in cases of 1417 ambiguity in CTS and for any reimplementations of parts of the reference 1418 source code.</p> 1419 <p>The CTS is designed to be run on an actual device. Like any software, the 1420 CTS may itself contain bugs. The CTS will be versioned independently of this 1421 Compatibility Definition, and multiple revisions of the CTS may be released 1422 for Android 2.2. Device implementations MUST pass the latest CTS version 1423 available at the time the device software is completed.</p> 1424 1425 <a name="section-12"></a><h2>12. Updatable Software</h2> 1426 <p>Device implementations MUST include a mechanism to replace the entirety of 1427 the system software. The mechanism need not perform "live" upgrades -- that 1428 is, a device restart MAY be required.</p> 1429 <p>Any method can be used, provided that it can replace the entirety of the 1430 software preinstalled on the device. For instance, any of the following 1431 approaches will satisfy this requirement:</p> 1432 <ul> 1433 <li>Over-the-air (OTA) downloads with offline update via reboot</li> 1434 <li>"Tethered" updates over USB from a host PC</li> 1435 <li>"Offline" updates via a reboot and update from a file on removable 1436 storage</li> 1437 </ul> 1438 <p>The update mechanism used MUST support updates without wiping user data. 1439 Note that the upstream Android software includes an update mechanism that 1440 satisfies this requirement.</p> 1441 <p>If an error is found in a device implementation after it has been released 1442 but within its reasonable product lifetime that is determined in consultation 1443 with the Android Compatibility Team to affect the compatibility of thid-party 1444 applications, the device implementer MUST correct the error via a software 1445 update available that can be applied per the mechanism just described.</p> 1446 1447 <a name="section-13"></a><h2>13. Contact Us</h2> 1448 <p>You can contact the document authors at <a 1449 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for 1450 clarifications and to bring up any issues that you think the document does not 1451 cover.</p> 1452 1453 <div style="page-break-before: always;"></div> 1454 1455 <a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2> 1456 <p>The Compatibility Test Suite includes cases that cover basic operation of 1457 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 1458 protocol between devices, it cannot be fully tested by unit tests running on a 1459 single device. Consequently, device implementations MUST also pass the 1460 human-driven Bluetooth test procedure described below.</p> 1461 <p>The test procedure is based on the BluetoothChat sample app included in the 1462 Android open-source project tree. The procedure requires two devices:</p> 1463 <ul> 1464 <li>a candidate device implementation running the software build to be tested</li> 1465 <li>a separate device implementation already known to be compatible, and of a 1466 model from the device implementation being tested -- that is, a "known 1467 good" device implementation</li> 1468 </ul> 1469 <p>The test procedure below refers to these devices as the "candidate" and "known 1470 good" devices, respectively.</p> 1471 <h3>Setup and Installation</h3> 1472 <ol> 1473 <li>Build BluetoothChat.apk via 'make samples' from an Android source code tree.</li> 1474 <li>Install BluetoothChat.apk on the known-good device.</li> 1475 <li>Install BluetoothChat.apk on the candidate device.</li> 1476 </ol> 1477 <h3>Test Bluetooth Control by Apps</h3> 1478 <ol> 1479 <li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled.</li> 1480 <li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.</li> 1481 </ol> 1482 <h3>Test Pairing and Communication</h3> 1483 <ol> 1484 <li>Launch the Bluetooth Chat app on both devices.</li> 1485 <li>Make the known-good device discoverable from within BluetoothChat (using the Menu).</li> 1486 <li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.</li> 1487 <li>Send 10 or more messages from each device, and verify that the other device receives them correctly.</li> 1488 <li>Close the BluetoothChat app on both devices by pressing <b>Home</b>.</li> 1489 <li>Unpair each device from the other, using the device Settings app.</li> 1490 </ol> 1491 <h3>Test Pairing and Communication in the Reverse Direction</h3> 1492 <ol> 1493 <li>Launch the Bluetooth Chat app on both devices.</li> 1494 <li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li> 1495 <li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li> 1496 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 1497 <li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li> 1498 </ol> 1499 <h3>Test Re-Launches</h3> 1500 <ol> 1501 <li>Re-launch the Bluetooth Chat app on both devices.</li> 1502 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 1503 </ol> 1504 <p>Note: the above tests have some cases which end a test section by using 1505 Home, and some using Back. These tests are not redundant and are not optional: 1506 the objective is to verify that the Bluetooth API and stack works correctly 1507 both when Activities are explicitly terminated (via the user pressing Back, 1508 which calls finish()), and implicitly sent to background (via the user 1509 pressing Home.) Each test sequence MUST be performed as described.</p> 1510 <div id="footerContent"> 1511 </div> 1512 </body> 1513 </html> 1514
