1 <html devsite> 2 <head> 3 <title>Android 2.1 Compatibility Definition</title> 4 <link rel="stylesheet" type="text/css" href="cdd.css"/> 5 </head> 6 <body> 7 <p>Copyright © 2010, Google Inc. All rights reserved.<br/> 8 <a href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> 9 </p> 10 11 <h2>1. Introduction</h2> 12 <p>This document enumerates the requirements that must be met in order for 13 mobile phones to be compatible with Android 2.1.</p> 14 <p>The use of "must", "must not", "required", "shall", "shall not", "should", 15 "should not", "recommended", "may" and "optional" is per the IETF standard 16 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 17 <p>As used in this document, a "device implementer" or "implementer" is a 18 person or organization developing a hardware/software solution running Android 19 2.1. A "device implementation" or "implementation" is the hardware/software 20 solution so developed.</p> 21 <p>To be considered compatible with Android 2.1, device implementations:</p> 22 <ul> 23 <li>MUST meet the requirements presented in this Compatibility Definition, 24 including any documents incorporated via reference.</li> 25 <li>MUST pass the most recent version of the Android Compatibility Test Suite 26 (CTS) available at the time of the device implementation's software is 27 completed. (The CTS is available as part of the Android Open Source Project [<a 28 href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the 29 components outlined in this document.</li> 30 </ul> 31 <p>Where this definition or the CTS is silent, ambiguous, or incomplete, it is 32 the responsibility of the device implementer to ensure compatibility with 33 existing implementations. For this reason, the Android Open Source Project [<a 34 href="#resources03">Resources, 3</a>] is both the reference and preferred 35 implementation of Android. Device implementers are strongly encouraged to base 36 their implementations on the "upstream" source code available from the Android 37 Open Source Project. While some components can hypothetically be replaced with 38 alternate implementations this practice is strongly discouraged, as passing 39 the CTS tests will become substantially more difficult. It is the 40 implementer's responsibility to ensure full behavioral compatibility with the 41 standard Android implementation, including and beyond the Compatibility Test 42 Suite. Finally, note that certain component substitutions and modifications 43 are explicitly forbidden by this document.</p> 44 45 <a name="resources"/><h2>2. Resources</h2> 46 <ol> 47 <a name="resources01"/><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li> 48 <a name="resources02"/><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li> 49 <a name="resources03"/><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 50 <a name="resources04"/><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li> 51 <a name="resources05"/><li>Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li> 52 <a name="resources06"/><li>android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li> 53 <a name="resources07"/><li>Android 2.1 allowed version strings: <a href="http://source.android.com/compatibility/2.1/versions.xhtml">http://source.android.com/compatibility/2.1/versions.xhtml</a></li> 54 <a name="resources08"/><li>android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li> 55 <a name="resources09"/><li>HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li> 56 <a name="resources10"/><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 57 <a name="resources11"/><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li> 58 <a name="resources12"/><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li> 59 <a name="resources13"/><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li> 60 <a name="resources14"/><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design.html#statusbarstructure">http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure</a></li> 61 <a name="resources15"/><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li> 62 <a name="resources16"/><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li> 63 <a name="resources17"/><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li> 64 <a name="resources18"/><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li> 65 <a name="resources19"/><li>Reference tool documentation (for adb, aapt, ddms): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li> 66 <a name="resources20"/><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li> 67 <a name="resources21"/><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li> 68 <a name="resources22"/><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li> 69 <a name="resources23"/><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li> 70 <a name="resources24"/><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li> 71 <a name="resources25"/><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li> 72 <a name="resources26"/><li>android.hardware.Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li> 73 <a name="resources27"/><li>Sensor coordinate space: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li> 74 <a name="resources28"/><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li> 75 <a name="resources29"/><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li> 76 </ol> 77 <p>Many of these resources are derived directly or indirectly from the Android 78 2.1 SDK, and will be functionally identical to the information in that SDK's 79 documentation. In any cases where this Compatibility Definition or the 80 Compatibility Test Suite disagrees with the SDK documentation, the SDK 81 documentation is considered authoritative. Any technical details provided in 82 the references included above are considered by inclusion to be part of this 83 Compatibility Definition.</p> 84 85 <h2>3. Software</h2> 86 <p>The Android platform includes a set of managed APIs, a set of native APIs, 87 and a body of so-called "soft" APIs such as the Intent system and 88 web-application APIs. This section details the hard and soft APIs that are 89 integral to compatibility, as well as certain other relevant technical and 90 user interface behaviors. Device implementations MUST comply with all the 91 requirements in this section.</p> 92 93 <h3>3.1. Managed API Compatibility</h3> 94 <p>The managed (Dalvik-based) execution environment is the primary vehicle for 95 Android applications. The Android application programming interface (API) is 96 the set of Android platform interfaces exposed to applications running in the 97 managed VM environment. Device implementations MUST provide complete 98 implementations, including all documented behaviors, of any documented API 99 exposed by the Android 2.1 SDK [<a href="#resources04">Resources, 4</a>].</p> 100 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 101 or signatures, deviate from the documented behavior, or include no-ops, except 102 where specifically allowed by this Compatibility Definition.</p> 103 104 <h3>3.2. Soft API Compatibility</h3> 105 <p>In addition to the managed APIs from Section 3.1, Android also includes a 106 significant runtime-only "soft" API, in the form of such things such as 107 Intents, permissions, and similar aspects of Android applications that cannot 108 be enforced at application compile time. This section details the "soft" APIs 109 and system behaviors required for compatibility with Android 2.1. Device 110 implementations MUST meet all the requirements presented in this section.</p> 111 <h4>3.2.1. Permissions</h4> 112 <p>Device implementers MUST support and enforce all permission constants as 113 documented by the Permission reference page [<a 114 href="#resources05">Resources, 5</a>]. Note that Section 10 lists addtional 115 requirements related to the Android security model.</p> 116 <h4>3.2.2. Build Parameters</h4> 117 <p>The Android APIs include a number of constants on the <code>android.os.Build</code> 118 class [<a href="#resources06">Resources, 6</a>] that are intended to describe 119 the current device. To provide consistent, meaningful values across device 120 implementations, the table below includes additional restrictions on the 121 formats of these values to which device implementations MUST conform.</p> 122 <table> 123 <tbody> 124 <tr> 125 <td><b>Parameter</b></td> 126 <td><b>Comments</b></td> 127 </tr> 128 <tr> 129 <td>android.os.Build.VERSION.RELEASE</td> 130 <td>The version of the currently-executing Android system, in human-readable 131 format. This field MUST have one of the string values defined in [<a 132 href="#resources07">Resources, 7</a>].</td> 133 </tr> 134 <tr> 135 <td>android.os.Build.VERSION.SDK</td> 136 <td>The version of the currently-executing Android system, in a format 137 accessible to third-party application code. For Android 2.1, this field MUST have 138 the integer value 7.</td> 139 </tr> 140 <tr> 141 <td>android.os.Build.VERSION.INCREMENTAL</td> 142 <td>A value chosen by the device implementer designating the specific build of 143 the currently-executing Android system, in human-readable format. This value 144 MUST NOT be re-used for different builds shipped to end users. A typical use 145 of this field is to indicate which build number or source-control change 146 identifier was used to generate the build. There are no requirements on the 147 specific format of this field, except that it MUST NOT be null or the empty 148 string ("").</td> 149 </tr> 150 <tr> 151 <td>android.os.Build.BOARD</td> 152 <td>A value chosen by the device implementer identifying the specific internal 153 hardware used by the device, in human-readable format. A possible use of this 154 field is to indicate the specific revision of the board powering the device. 155 There are no requirements on the specific format of this field, except that it 156 MUST NOT be null or the empty string ("").</td> 157 </tr> 158 <tr> 159 <td>android.os.Build.BRAND</td> 160 <td>A value chosen by the device implementer identifying the name of the 161 company, organization, individual, etc. who produced the device, in 162 human-readable format. A possible use of this field is to indicate the OEM 163 and/or carrier who sold the device. There are no requirements on the specific 164 format of this field, except that it MUST NOT be null or the empty string 165 ("").</td> 166 </tr> 167 <tr> 168 <td>android.os.Build.DEVICE</td> 169 <td>A value chosen by the device implementer identifying the specific 170 configuration or revision of the body (sometimes called "industrial design") 171 of the device. There are no requirements on the specific format of this field, 172 except that it MUST NOT be null or the empty string ("").</td> 173 </tr> 174 <tr> 175 <td>android.os.Build.FINGERPRINT</td> 176 <td>A string that uniquely identifies this build. It SHOULD be reasonably 177 human-readable. It MUST follow this template: 178 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE)/$(BOARD):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 179 For example: 180 <br/><code>acme/mydevice/generic/generic:2.1-update1/ERC77/3359:userdebug/test-keys</code><br/> 181 The fingerprint MUST NOT include spaces. If other fields included in the 182 template above have spaces, they SHOULD be replaced with the ASCII underscore 183 ("_") character in the fingerprint.</td> 184 </tr> 185 <tr> 186 <td>android.os.Build.HOST</td> 187 <td>A string that uniquely identifies the host the build was built on, in 188 human readable format. There are no requirements on the specific format of 189 this field, except that it MUST NOT be null or the empty string ("").</td> 190 </tr> 191 <tr> 192 <td>android.os.Build.ID</td> 193 <td>An identifier chosen by the device implementer to refer to a specific 194 release, in human readable format. This field can be the same as 195 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 196 meaningful for end users to distinguish between software builds. There are no 197 requirements on the specific format of this field, except that it MUST NOT be 198 null or the empty string ("").</td> 199 </tr> 200 <tr> 201 <td>android.os.Build.MODEL</td> 202 <td>A value chosen by the device implementer containing the name of the device 203 as known to the end user. This SHOULD be the same name under which the device 204 is marketed and sold to end users. There are no requirements on the specific 205 format of this field, except that it MUST NOT be null or the empty string 206 ("").</td> 207 </tr> 208 <tr> 209 <td>android.os.Build.PRODUCT</td> 210 <td>A value chosen by the device implementer containing the development name 211 or code name of the device. MUST be human-readable, but is not necessarily 212 intended for view by end users. There are no requirements on the specific 213 format of this field, except that it MUST NOT be null or the empty string 214 ("").</td> 215 </tr> 216 <tr> 217 <td>android.os.Build.TAGS</td> 218 <td>A comma-separated list of tags chosen by the device implementer that 219 further distinguish the build. For example, "unsigned,debug". This field MUST 220 NOT be null or the empty string (""), but a single tag (such as "release") is 221 fine.</td> 222 </tr> 223 <tr> 224 <td>android.os.Build.TIME</td> 225 <td>A value representing the timestamp of when the build occurred.</td> 226 </tr> 227 <tr> 228 <td>android.os.Build.TYPE</td> 229 <td>A value chosen by the device implementer specifying the runtime 230 configuration of the build. This field SHOULD have one of the values 231 corresponding to the three typical Android runtime configurations: "user", 232 "userdebug", or "eng".</td> 233 </tr> 234 <tr> 235 <td>android.os.Build.USER</td> 236 <td>A name or user ID of the user (or automated user) that generated the 237 build. There are no requirements on the specific format of this field, except 238 that it MUST NOT be null or the empty string ("").</td> 239 </tr> 240 </tbody> 241 </table> 242 <h4>3.2.3. Intent Compatibility</h4> 243 <p>Android uses Intents to achieve loosely-coupled integration between 244 applications. This section describes requirements related to the Intent 245 patterns that MUST be honored by device implementations. By "honored", it is 246 meant that the device implementer MUST provide an Android Activity or Service 247 that specifies a matching Intent filter and binds to and implements correct 248 behavior for each specified Intent pattern.</p> 249 <h4>3.2.3.1. Core Application Intents</h4> 250 <p>The Android upstream project defines a number of core applications, such as 251 a phone dialer, calendar, contacts book, music player, and so on. Device 252 implementers MAY replace these applications with alternative versions.</p> 253 <p>However, any such alternative versions MUST honor the same Intent patterns 254 provided by the upstream project. For example, if a device contains an 255 alternative music player, it must still honor the Intent pattern issued by 256 third-party applications to pick a song.</p> 257 <p>The following applications are considered core Android system 258 applications:</p> 259 <ul> 260 <li>Desk Clock</li> 261 <li>Browser</li> 262 <li>Calendar</li> 263 <li>Calculator</li> 264 <li>Camera</li> 265 <li>Contacts</li> 266 <li>Email</li> 267 <li>Gallery</li> 268 <li>GlobalSearch</li> 269 <li>Launcher</li> 270 <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 271 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> 272 <li>Messaging (AKA "Mms")</li> 273 <li>Music</li> 274 <li>Phone</li> 275 <li>Settings</li> 276 <li>SoundRecorder</li> 277 </ul> 278 <p>The core Android system applications include various Activity, or Service 279 components that are considered "public". 280 That is, the attribute "android:exported" may be absent, or may have the value 281 "true".</p> 282 <p>For every Activity or Service defined 283 in one of the core Android system apps that is not marked as non-public via an 284 android:exported attribute with the value "false", device implementations MUST 285 include a compontent of the same type implementing the same Intent filter 286 patterns as the core Android system app.</p> 287 <p>In other words, a device implementation MAY replace core Android system 288 apps; however, if it does, the device implementation MUST support all Intent 289 patterns defined by each core Android system app being replaced.</p> 290 <h4>3.2.3.2. Intent Overrides</h4> 291 <p>As Android is an extensible platform, device implementers MUST allow each 292 Intent pattern defined in core system apps to be overridden by third-party 293 applications. The upstream Android open source project allows this by default; 294 device implementers MUST NOT attach special privileges to system applications' 295 use of these Intent patterns, or prevent third-party applications from binding 296 to and assuming control of these patterns. This prohibition specifically 297 includes but is not limited to disabling the "Chooser" user interface which 298 allows the user to select between multiple applications which all handle the 299 same Intent pattern.</p> 300 <div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div> 301 <h4>3.2.3.3. Intent Namespaces</h4> 302 <p>Device implementers MUST NOT include any Android component that honors any 303 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 304 key string in the android.* namespace. Device implementers MUST NOT include 305 any Android components that honor any new Intent or Broadcast Intent patterns 306 using an ACTION, CATEGORY, or other key string in a package space belonging to 307 another organization. Device implementers MUST NOT alter or extend any of the 308 Intent patterns used by the core apps listed in Section 3.2.3.1.</p> 309 <p>This prohibition is analogous to that specified for Java language classes 310 in Section 3.6.</p> 311 <h4>3.2.3.4. Broadcast Intents</h4> 312 <p>Third-party applications rely on the platform to broadcast certain Intents 313 to notify them of changes in the hardware or software environment. 314 Android-compatible devices MUST broadcast the public broadcast Intents in 315 response to appropriate system events. Broadcast Intents are described in the 316 SDK documentation.</p> 317 318 <h3>3.3. Native API Compatibility</h3> 319 <p>Managed code running in Dalvik can call into native code provided in the 320 application .apk file as an ELF .so file compiled for the appropriate device 321 hardware architecture. Device implementations MUST include support for code 322 running in the managed environment to call into native code, using the 323 standard Java Native Interface (JNI) semantics. The following APIs MUST be 324 available to native code:</p> 325 <ul> 326 <li>libc (C library)</li> 327 <li>libm (math library)</li> 328 <li>JNI interface</li> 329 <li>libz (Zlib compression)</li> 330 <li>liblog (Android logging)</li> 331 <li>Minimal support for C++</li> 332 <li>Support for OpenGL, as described below</li> 333 </ul> 334 <p>Device implementations MUST support OpenGL ES 1.0. Devices that lack 335 hardware acceleration MUST implement OpenGL ES 1.0 using a software renderer. 336 Device implementations SHOULD implement as much of OpenGL ES 1.1 as the device 337 hardware supports. Device implementations SHOULD provide an implementation 338 for OpenGL ES 2.0, if the hardware is capable of reasonable performance on 339 those APIs.</p> 340 <p>These libraries MUST be source-compatible (i.e. header compatible) and 341 binary-compatible (for a given processor architecture) with the versions 342 provided in Bionic by the Android Open Source project. Since the Bionic 343 implementations are not fully compatible with other implementations such as 344 the GNU C library, device implementers SHOULD use the Android implementation. 345 If device implementers use a different implementation of these libraries, they 346 MUST ensure header, binary, and behavioral compatibility.</p> 347 <p>Device implementations MUST accurately report the native Application Binary 348 Interface (ABI) supported by the device, via the 349 <code>android.os.Build.CPU_ABI</code> API. The ABI MUST be one of the entries 350 documented in the latest version of the Android NDK, in the file 351 <code>docs/CPU-ARCH-ABIS.txt</code>. Note that additional releases of the 352 Android NDK may introduce support for additional ABIs.</p> 353 <p>Native code compatibility is challenging. For this reason, it should be 354 repeated that device implementers are VERY strongly encouraged to use the 355 upstream implementations of the libraries listed above, to help ensure 356 compatibility.</p> 357 358 <h3>3.4. Web API Compatibility</h3> 359 <p>Many developers and applications rely on the behavior of the 360 <code>android.webkit.WebView</code> class [<a 361 href="#resources08">Resources, 8</a>] 362 for their user interfaces, so the WebView implementation must be 363 compatible across Android implementations. The Android Open Source 364 implementation uses the WebKit rendering engine to implement the 365 WebView.</p> 366 <p>Because it is not feasible to develop a comprehensive test suite for a web 367 browser, device implementers MUST use the specific upstream build of WebKit in 368 the WebView implementation. Specifically:</p> 369 <ul> 370 <li>WebView MUST use the 530.17 WebKit build from the upstream Android Open 371 Source tree for Android 2.1. This build includes a specific set of functionality 372 and security fixes for the WebView.</li> 373 <li>The user agent string reported by the WebView MUST be in this format:<br/> 374 <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Mobile Safari/530.17</code> 375 <ul> 376 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 377 <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> 378 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 379 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 380 </ul></li> 381 </ul> 382 <p>Implementations MAY ship a custom user agent string in the standalone 383 Browser application. What's more, the standalone Browser MAY be based on an 384 alternate browser technology (such as Firefox, Opera, etc.) However, even if an 385 alternate Browser application is shipped, the WebView component provided to 386 third-party applications MUST be based on WebKit, as above.</p> 387 <p>The WebView configuration MUST include support for the HTML5 database, 388 application cache, and geolocation APIs [<a href="#resources09">Resources, 389 9</a>]. The WebView MUST include support for 390 the HTML5 <code><video></code> tag in 391 some form. The standalone Browser application (whether based on the upstream 392 WebKit Browser application or a third-party replacement) MUST include support 393 for the same HTML5 features just listed for WebView.</p> 394 395 <h3>3.5. API Behavioral Compatibility</h3> 396 <p>The behaviors of each of the API types (managed, soft, native, and web) 397 must be consistent with the preferred implementation of the upstream Android 398 open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 399 of compatibility are:</p> 400 <ul> 401 <li>Devices MUST NOT change the behavior or meaning of a standard Intent</li> 402 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.)</li> 403 <li>Devices MUST NOT change the semantics of a particular permission</li> 404 </ul> 405 <p>The above list is not comprehensive, and the onus is on device implementers 406 to ensure behavioral compatibility. For this reason, device implementers 407 SHOULD use the source code available via the Android Open Source Project where 408 possible, rather than re-implement significant parts of the system.</p> 409 <p>The Compatibility Test Suite (CTS) tests significant portions of the 410 platform for behavioral compatibility, but not all. It is the responsibility 411 of the implementer to ensure behavioral compatibility with the Android Open 412 Source Project.</p> 413 414 <h3>3.6. API Namespaces</h3> 415 <p>Android follows the package and class namespace conventions defined by the 416 Java programming language. To ensure compatibility with third-party 417 applications, device implementers MUST NOT make any prohibited modifications 418 (see below) to these package namespaces:</p> 419 <ul> 420 <li>java.*</li> 421 <li>javax.*</li> 422 <li>sun.*</li> 423 <li>android.*</li> 424 <li>com.android.*</li> 425 </ul> 426 <p>Prohibited modifications include:</p> 427 <ul> 428 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 429 Android platform by changing any method or class signatures, or by removing 430 classes or class fields.</li> 431 <li>Device implementers MAY modify the underlying implementation of the APIs, 432 but such modifications MUST NOT impact the stated behavior and Java-language 433 signature of any publicly exposed APIs.</li> 434 <li>Device implementers MUST NOT add any publicly exposed elements (such as 435 classes or interfaces, or fields or methods to existing classes or interfaces) 436 to the APIs above.</li> 437 </ul> 438 <p>A "publicly exposed element" is any construct which is not decorated with 439 the "@hide" marker in the upstream Android source code. In other words, device 440 implementers MUST NOT expose new APIs or alter existing APIs in the namespaces 441 noted above. Device implementers MAY make internal-only modifications, but 442 those modifications MUST NOT be advertised or otherwise exposed to 443 developers.</p> 444 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 445 namespace owned by or referring to another organization. For instance, device 446 implementers MUST NOT add APIs to the com.google.* or similar namespace; only 447 Google may do so. Similarly, Google MUST NOT add APIs to other companies' 448 namespaces.</p> 449 <p>If a device implementer proposes to improve one of the package namespaces 450 above (such as by adding useful new functionality to an existing API, or 451 adding a new API), the implementer SHOULD visit source.android.com and begin 452 the process for contributing changes and code, according to the information on 453 that site.</p> 454 <p>Note that the restrictions above correspond to standard conventions for 455 naming APIs in the Java programming language; this section simply aims to 456 reinforce those conventions and make them binding through inclusion in this 457 compatibility definition.</p> 458 459 <h3>3.7. Virtual Machine Compatibility</h3> 460 <p>Device implementations MUST support the full Dalvik Executable (DEX) 461 bytecode specification and Dalvik Virtual Machine semantics [<a 462 href="#resources10">Resources, 10</a>].</p> 463 <p>Device implementations MUST configure Dalvik to allocate at least 16MB of 464 memory to each application on devices with screens classified as medium- or 465 low-density. Device implementations MUST configure Dalvik to allocate at least 466 24MB of memory to each application on devices with screens classified as 467 high-density. Note that device implementations MAY allocate more memory than 468 these figures, but are not required to.</p> 469 470 <h3>3.8. User Interface Compatibility</h3> 471 <p>The Android platform includes some developer APIs that allow developers to 472 hook into the system user interface. Device implementations MUST incorporate 473 these standard UI APIs into custom user interfaces they develop, as explained 474 below.</p> 475 <h4>3.8.1. Widgets</h4> 476 <p>Android defines a component type and corresponding API and lifecycle that 477 allows applications to expose an "AppWidget" to the end user [<a 478 href="#resources11">Resources, 11</a>]. 479 The Android Open Source reference release includes a Launcher application that 480 includes user interface elements allowing the user to add, view, and remove 481 AppWidgets from the home screen.</p> 482 <p>Device implementers MAY substitute an alternative to the reference Launcher 483 (i.e. home screen). Alternative Launchers SHOULD include built-in support for 484 AppWidgets, and expose user interface elements to add, configure, view, and remove 485 AppWidgets directly within the Launcher. Alternative Launchers MAY omit these 486 user interface elements; however, if they are omitted, the device implementer 487 MUST provide a separate application accessible from the Launcher that allows 488 users to add, configure, view, and remove AppWidgets.</p> 489 <h4>3.8.2. Notifications</h4> 490 <p>Android includes APIs that allow developers to notify users of notable 491 events [<a href="#resources12">Resources, 12</a>]. Device implementers MUST provide support for each 492 class of notification so defined; specifically: sounds, vibration, light and 493 status bar.</p> 494 <p>Additionally, the implementation MUST correctly render all resources 495 (icons, sound files, etc.) provided for in the APIs [<a 496 href="#resources13">Resources, 13</a>], or in the 497 Status Bar icon style guide [<a href="#resources14">Resources, 14</a>]. Device implementers MAY provide 498 an alternative user experience for notifications than that provided by the 499 reference Android Open Source implementation; however, such alternative 500 notification systems MUST support existing notification resources, as 501 above.</p> 502 <h4>3.8.3. Search</h4> 503 <p>Android includes APIs [<a href="#resources15">Resources, 15</a>] that allow developers to incorporate 504 search into their applications, and expose their application's data into the 505 global system search. Generally speaking, this functionality consists of a 506 single, system-wide user interface that allows users to enter queries, 507 displays suggestions as users type, and displays results. The Android APIs 508 allow developers to reuse this interface to provide search within their own 509 apps, and allow developers to supply results to the common global search user 510 interface.</p> 511 <p>Device implementations MUST include a single, shared, system-wide search 512 user interface capable of real-time suggestions in response to user input. 513 Device implementations MUST implement the APIs that allow developers to reuse 514 this user interface to provide search within their own applications. Device 515 implementations MUST implement the APIs that allow third-party applications to 516 add suggestions to the search box when it is run in global search mode. If no 517 third-party applications are installed that make use of this functionality, 518 the default behavior SHOULD be to display web search engine results and 519 suggestions.</p> 520 <p>Device implementations MAY ship alternate search user interfaces, but 521 SHOULD include a hard or soft dedicated search button, that can be used at any 522 time within any app to invoke the search framework, with the behavior provided 523 for in the API documentation.</p> 524 <h4>3.8.4. Toasts</h4> 525 <p>Applications can use the "Toast" API (defined in [<a 526 href="#resources16">Resources, 16</a>]) to 527 display short non-modal strings to the end user, that disappear after a brief 528 period of time. Device implementations MUST display Toasts from applications 529 to end users in some high-visibility manner.</p> 530 <h4>3.8.5. Live Wallpapers</h4> 531 <p>Android defines a component type and corresponding API and lifecycle that 532 allows applications to expose one or more "Live Wallpapers" to the end user 533 [<a href="#resources17">Resources, 17</a>]. Live Wallpapers are animations, 534 patterns, or similar images with limited input capabilities that display as a 535 wallpaper, behind other applications.</p> 536 <p>Hardware is considered capable of reliably running live wallpapers if it 537 can run all live wallpapers, with no limitations on functionality, at a 538 reasonable framerate with no adverse affects on other applications. If 539 limitations in the hardware cause wallpapers and/or applications to crash, 540 malfunction, consume excessive CPU or battery power, or run at unacceptably 541 low frame rates, the hardware is considered incapable of running live 542 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 543 context to render their content. Live wallpaper will not run reliably on 544 hardware that does not support multiple OpenGL contexts because the live 545 wallpaper use of an OpenGL context may conflict with other applications that 546 also use an OpenGL context. </p> 547 <p>Device implemenations capable of running live wallpapers reliably as 548 described above SHOULD implement live wallpapers. Device implementations 549 determined to not run live wallpapers reliably as described above MUST NOT 550 implement live wallpapers.</p> 551 552 <h2>4. Reference Software Compatibility</h2> 553 <p>Device implementers MUST test implementation compatibility using the 554 following open-source applications:</p> 555 <ul> 556 <li>Calculator (included in SDK)</li> 557 <li>Lunar Lander (included in SDK)</li> 558 <li>The "Apps for Android" applications [<a href="#resources18">Resources, 18</a>].</li> 559 </ul> 560 <p>Each app above MUST launch and behave correctly on the implementation, for 561 the implementation to be considered compatible.</p> 562 <p>Additionally, device implementations MUST test each menu item (including all 563 sub-menus) of each of these smoke-test applications:</p> 564 <ul> 565 <li>ApiDemos (included in SDK)</li> 566 <li>ManualSmokeTests (included in CTS)</li> 567 </ul> 568 <p>Each test case in the applications above MUST run correctly on the device 569 implementation.</p> 570 571 <h2>5. Application Packaging Compatibility</h2> 572 <p>Device implementations MUST install and run Android ".apk" files as 573 generated by the "aapt" tool included in the official Android SDK [<a 574 href="#resources19">Resources, 19</a>].</p> 575 <p>Devices implementations MUST NOT extend either the .apk [<a 576 href="#resources20">Resources, 20</a>], Android Manifest [<a 577 href="#resources21">Resources, 21</a>], 578 or Dalvik bytecode [<a href="#resources10">Resources, 10</a>] formats in such 579 a way that would prevent those files from 580 installing and running correctly on other compatible devices. Device 581 implementers SHOULD use the reference upstream implementation of Dalvik, and 582 the reference implementation's package management system.</p> 583 584 <h2>6. Multimedia Compatibility</h2> 585 <p>Device implemenations MUST support the following multimedia codecs. All of 586 these codecs are provided as software implementations in the preferred Android 587 implementation from the Android Open Source Project.</p> 588 <p>Please note that neither Google nor the Open Handset Alliance make any 589 representation that these codecs are unencumbered by third-party patents. 590 Those intending to use this source code in hardware or software products are 591 advised that implementations of this code, including in open source software 592 or shareware, may require patent licenses from the relevant patent 593 holders.</p> 594 <table><tbody> 595 <tr> 596 <td rowspan="11"><b>Audio</b></td> 597 </tr> 598 <tr> 599 <td><b>Name</b></td> 600 <td><b>Encoder</b></td> 601 <td><b>Decoder</b></td> 602 <td><b>Details</b></td> 603 <td><b>File/Container Format</b></td> 604 </tr> 605 <tr> 606 <td>AAC LC/LTP</td> 607 <td> </td> 608 <td>X</td> 609 <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> 610 <td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td> 611 </tr> 612 <tr> 613 <td>HE-AACv1 (AAC+)</td> 614 <td> </td> 615 <td>X</td> 616 </tr> 617 <tr> 618 <td>HE-AACv2 (enhanced AAC+)</td> 619 <td> </td> 620 <td>X</td> 621 </tr> 622 <tr> 623 <td>AMR-NB</td> 624 <td>X</td> 625 <td>X</td> 626 <td>4.75 to 12.2 kbps sampled @ 8kHz</td> 627 <td>3GPP (.3gp)</td> 628 </tr> 629 <tr> 630 <td>AMR-WB</td> 631 <td> </td> 632 <td>X</td> 633 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 634 <td>3GPP (.3gp)</td> 635 </tr> 636 <tr> 637 <td>MP3</td> 638 <td> </td> 639 <td>X</td> 640 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td> 641 <td>MP3 (.mp3)</td> 642 </tr> 643 <tr> 644 <td>MIDI</td> 645 <td> </td> 646 <td>X</td> 647 <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> 648 <td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td> 649 </tr> 650 <tr> 651 <td>Ogg Vorbis</td> 652 <td> </td> 653 <td>X</td> 654 <td> </td> 655 <td>Ogg (.ogg)</td> 656 </tr> 657 <tr> 658 <td>PCM</td> 659 <td> </td> 660 <td>X</td> 661 <td>8- and 16-bit linear PCM (rates up to limit of hardware)</td> 662 <td>WAVE (.wav)</td> 663 </tr> 664 <tr> 665 <td rowspan="5"><b>Image</b></td> 666 </tr> 667 <tr> 668 <td>JPEG</td> 669 <td>X</td> 670 <td>X</td> 671 <td>base+progressive</td> 672 <td> </td> 673 </tr> 674 <tr> 675 <td>GIF</td> 676 <td> </td> 677 <td>X</td> 678 <td> </td> 679 <td> </td> 680 </tr> 681 <tr> 682 <td>PNG</td> 683 <td>X</td> 684 <td>X</td> 685 <td> </td> 686 <td> </td> 687 </tr> 688 <tr> 689 <td>BMP</td> 690 <td> </td> 691 <td>X</td> 692 <td> </td> 693 <td> </td> 694 </tr> 695 <tr> 696 <td rowspan="4"><b>Video</b></td> 697 </tr> 698 <tr> 699 <td>H.263</td> 700 <td>X</td> 701 <td>X</td> 702 <td> </td> 703 <td>3GPP (.3gp) files</td> 704 </tr> 705 <tr> 706 <td>H.264</td> 707 <td> </td> 708 <td>X</td> 709 <td> </td> 710 <td>3GPP (.3gp) and MPEG-4 (.mp4) files</td> 711 </tr> 712 <tr> 713 <td>MPEG4 Simple Profile</td> 714 <td> </td> 715 <td>X</td> 716 <td> </td> 717 <td>3GPP (.3gp) file</td> 718 </tr> 719 </tbody> 720 </table> 721 <p>Note that the table above does not list specific bitrate requirements for 722 most video codecs. The reason for this is that in practice, current device 723 hardware does not necessarily support bitrates that map exactly to the 724 required bitrates specified by the relevant standards. Instead, device 725 implementations SHOULD support the highest bitrate practical on the hardware, 726 up to the limits defined by the specifications.</p> 727 728 <h2>7. Developer Tool Compatibility</h2> 729 <p>Device implemenations MUST support the Android Developer Tools provided in 730 the Android SDK. Specifically, Android-compatible devices MUST be compatible 731 with:</p> 732 <ul> 733 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources19">Resources, 19</a>]<br/> 734 Device implementations MUST support all <code>adb</code> functions as 735 documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD 736 be inactive by default, but there MUST be a user-accessible mechanism to turn 737 on the Android Debug Bridge.</li> 738 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources19">Resources, 19</a>]<br/> 739 Device implementations MUST support all <code>ddms</code> features as documented in the 740 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 741 <code>ddms</code> SHOULD be inactive by default, 742 but MUST be supported whenever the user has activated the Android Debug 743 Bridge, as above.</li> 744 <li><b>Monkey</b> [<a href="#resources22">Resources, 22</a>]<br/> 745 Device implementations MUST include the Monkey framework, and make it 746 available for applications to use.</li> 747 </ul> 748 749 <h2>8. Hardware Compatibility</h2> 750 <p>Android is intended to support device implementers creating innovative form 751 factors and configurations. At the same time Android developers expect 752 certain hardware, sensors and APIs across all Android device. This section 753 lists the hardware features that all Android 2.1 compatible devices must 754 support.</p> 755 <p>If a device includes a particular hardware component that has a 756 corresponding API for third-party developers, the device implementation MUST 757 implement that API as defined in the Android SDK documentation. If an API in 758 the SDK interacts with a hardware component that is stated to be optional and the device 759 implementation does not possess that component:</p> 760 <ul> 761 <li>class definitions for the component's APIs MUST be present</li> 762 <li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li> 763 <li>API methods MUST return null values where permitted by the SDK documentation</li> 764 <li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li> 765 </ul> 766 <p>A typical example of a scenario where these requirements apply is the 767 telephony API: even on non-phone devices, these APIs must be implemented as 768 reasonable no-ops.</p> 769 <p>Device implementations MUST accurate report accurate hardware configuration 770 information via the <code>getSystemAvailableFeatures()</code> and 771 <code>hasSystemFeature(String)</code> methods on the 772 <code>android.content.pm.PackageManager</code> class.</p> 773 774 <h3>8.1. Display</h3> 775 <p>Android 2.1 includes facilities that perform certain automatic scaling and 776 transformation operations under some circumstances, to ensure that third-party 777 applications run reasonably well on a variety of hardware configurations [<a 778 href="#resources23">Resources, 23</a>]. Devices MUST properly implement these 779 behaviors, as detailed in this section.</p> 780 <p>For Android 2.1, this are the most common display configurations:</p> 781 <table><tbody> 782 <tr> 783 <td>Screen Type</td> 784 <td>Width (Pixels)</td> 785 <td>Height (Pixels)</td> 786 <td>Diagonal Length Range (inches)</td> 787 <td>Screen Size Group</td> 788 <td>Screen Density Group</td> 789 </tr> 790 <tr> 791 <td>QVGA</td> 792 <td>240</td> 793 <td>320</td> 794 <td>2.6 - 3.0</td> 795 <td>Small</td> 796 <td>Low</td> 797 </tr> 798 <tr> 799 <td>WQVGA</td> 800 <td>240</td> 801 <td>400</td> 802 <td>3.2 - 3.5</td> 803 <td>Normal</td> 804 <td>Low</td> 805 </tr> 806 <tr> 807 <td>FWQVGA</td> 808 <td>240</td> 809 <td>432</td> 810 <td>3.5 - 3.8</td> 811 <td>Normal</td> 812 <td>Low</td> 813 </tr> 814 <tr> 815 <td>HVGA</td> 816 <td>320</td> 817 <td>480</td> 818 <td>3.0 - 3.5</td> 819 <td>Normal</td> 820 <td>Medium</td> 821 </tr> 822 <tr> 823 <td>WVGA</td> 824 <td>480</td> 825 <td>800</td> 826 <td>3.3 - 4.0</td> 827 <td>Normal</td> 828 <td>High</td> 829 </tr> 830 <tr> 831 <td>FWVGA</td> 832 <td>480</td> 833 <td>854</td> 834 <td>3.5 - 4.0</td> 835 <td>Normal</td> 836 <td>High</td> 837 </tr> 838 <tr> 839 <td>WVGA </td> 840 <td>480 </td> 841 <td>800 </td> 842 <td>4.8 - 5.5 </td> 843 <td>Large </td> 844 <td>Medium</td> 845 </tr> 846 <tr> 847 <td>FWVGA</td> 848 <td>480</td> 849 <td>854</td> 850 <td>5.0 - 5.8</td> 851 <td>Large</td> 852 <td>Medium</td> 853 </tr> 854 </tbody></table> 855 856 <p>Device implementations corresponding to one of the standard configurations 857 above MUST be configured to report the indicated screen size to applications 858 via the <code>android.content.res.Configuration</code> [<a href="#resources24">Resources, 859 24</a>] class.</p> 860 <p>Some .apk packages have manifests that do not identify them as supporting a 861 specific density range. When running such applications, the following 862 constraints apply:</p> 863 <ul> 864 <li>Device implementations MUST interpret resources in a .apk that lack a 865 density qualifier as defaulting to "medium" (known as "mdpi" in the SDK 866 documentation.)</li> 867 <li>When operating on a "low" density screen, device implementations MUST 868 scale down medium/mdpi assets by a factor of 0.75.</li> 869 <li>When operating on a "high" density screen, device implementations MUST 870 scale up medium/mdpi assets by a factor of 1.5.</li> 871 <li>Device implementations MUST NOT scale assets within a density range, and 872 MUST scale assets by exactly these factors between density ranges.</li> 873 </ul> 874 875 <h4>8.1.2. Non-Standard Display Configurations</h4> 876 <p>Display configurations that do not match one of the standard configurations 877 listed in Section 8.1.1 require additional consideration and work to be 878 compatible. Device implementers MUST contact Android Compatibility Team as 879 provided for in Section 12 to obtain classifications for screen-size bucket, 880 density, and scaling factor. When provided with this information, device 881 implementations MUST implement them as specified.</p> 882 <p>Note that some display configurations (such as very large or very small 883 screens, and some aspect ratios) are fundamentally incompatible with Android 884 2.1; therefore device implementers are encouraged to contact Android 885 Compatibility Team as early as possible in the development process.</p> 886 <h4>8.1.3. Display Metrics</h4> 887 <p>Device implementations MUST report correct valuesfor all display metrics 888 defined in <code>android.util.DisplayMetrics</code> [<a 889 href="#resources25">Resources, 25</a>].</p> 890 891 <h3>8.2. Keyboard</h3> 892 <p>Device implementations:</p> 893 <ul> 894 <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> 895 <li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li> 896 <li>MAY include additional soft keyboard implementations</li> 897 <li>MAY include a hardware keyboard</li> 898 <li>MUST NOT include a hardware keyboard that does not match one of the 899 formats specified in <code>android.content.res.Configuration.keyboard</code> 900 [<a href="#resources24">Resources, 24</a>] (that is, QWERTY, or 12-key)</li> 901 </ul> 902 <h3>8.3. Non-touch Navigation</h3> 903 <p>Device implementations:</p> 904 <ul> 905 <li>MAY omit a non-touch navigation options (that is, may omit a trackball, d-pad, or wheel)</li> 906 <li>MUST report the correct value for 907 <code>android.content.res.Configuration.navigation</code> [<a href="#resources24">Resources, 24</a>]</li> 908 </ul> 909 <h3>8.4. Screen Orientation</h3> 910 <p>Compatible devices MUST support dynamic orientation by applications to 911 either portrait or landscape screen orientation. That is, the device must 912 respect the application's request for a specific screen orientation. Device 913 implementations MAY select either portrait or landscape orientation as the 914 default.</p> 915 <p>Devices MUST report the correct value for the device's current orientation, 916 whenever queried via the android.content.res.Configuration.orientation, 917 android.view.Display.getOrientation(), or other APIs.</p> 918 919 <h3>8.5. Touchscreen input</h3> 920 <p>Device implementations:</p> 921 <ul> 922 <li>MUST have a touchscreen</li> 923 <li>MAY have either capacative or resistive touchscreen</li> 924 <li>MUST report the value of <code>android.content.res.Configuration</code> 925 [<a href="#resources24">Resources, 24</a>] 926 reflecting corresponding to the type of the specific touchscreen on the 927 device</li> 928 </ul> 929 930 <h3>8.6. USB</h3> 931 <p>Device implementations:</p> 932 <ul> 933 <li>MUST implement a USB client, connectable to a USB host with a standard 934 USB-A port</li> 935 <li>MUST implement the Android Debug Bridge over USB (as described in Section 936 7)</li> 937 <li>MUST implement the USB mass storage specification, to allow a host 938 connected to the device to access the contents of the /sdcard volume </li> 939 <li>SHOULD use the micro USB form factor on the device side</li> 940 <li>MAY include a non-standard port on the device side, but if so MUST ship 941 with a cable capable of connecting the custom pinout to standard USB-A 942 port</li> 943 </ul> 944 945 <h3>8.7. Navigation keys</h3> 946 <p>The Home, Menu and Back functions are essential to the Android navigation 947 paradigm. Device implementations MUST make these functions available to the 948 user at all times, regardless of application state. These functions SHOULD be 949 implemented via dedicated buttons. They MAY be implemented using software, 950 gestures, touch panel, etc., but if so they MUST be always accessible and not 951 obscure or interfere with the available application display area.</p> 952 <p>Device implementers SHOULD also provide a dedicated search key. Device 953 implementers MAY also provide send and end keys for phone calls.</p> 954 955 <h3>8.8. Wireless Data Networking</h3> 956 <p>Device implementations MUST include support for wireless high-speed data 957 networking. Specifically, device implementations MUST include support for at 958 least one wireless data standard capable of 200Kbit/sec or greater. Examples of 959 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, etc.</p> 960 <p>If a device implementation includes a particular modality for which the 961 Android SDK includes an API (that is, WiFi, GSM, or CDMA), the implementation 962 MUST support the API.</p> 963 <p>Devices MAY implement more than one form of wireless data connectivity. 964 Devices MAY implement wired data connectivity (such as Ethernet), but MUST 965 nonetheless include at least one form of wireless connectivity, as above.</p> 966 <h3>8.9. Camera</h3> 967 <p>Device implementations MUST include a camera. The included camera:</p> 968 <ul> 969 <li>MUST have a resolution of at least 2 megapixels</li> 970 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented 971 in the camera driver (transparent to application software)</li> 972 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 973 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 974 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 975 registered on a Camera preview surface, unless the application has explicitly 976 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 977 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 978 object. Note that this constraint does not apply to the device's built-in 979 system camera application, but only to third-party applications using 980 <code>Camera.PreviewCallback</code>.</li> 981 </ul> 982 <p>Device implementations MUST implement the following behaviors for the 983 camera-related APIs:</p> 984 <ol> 985 <li>If an application has never called 986 android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST 987 use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to 988 application callbacks.</li> 989 <li>If an application registers an android.hardware.Camera.PreviewCallback 990 instance and the system calls the onPreviewFrame() method when the preview 991 format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() 992 must further be in the NV21 encoding format. (This is the format used natively 993 by the 7k hardware family.) That is, NV21 MUST be the default.</li> 994 </ol> 995 <p>Device implementations MUST implement the full Camera API included in the 996 Android 2.1 SDK documentation [<a href="#resources26">Resources, 26</a>]), 997 regardless of whether the device includes hardware autofocus or other 998 capabilities. For instance, cameras that lack autofocus MUST still call any 999 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 1000 this has no relevance to a non-autofocus camera.)</p> 1001 <p>Device implementations MUST recognize and honor each parameter name defined 1002 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 1003 underlying hardware supports the feature. If the device hardware does not 1004 support a feature, the API must behave as documented. Conversely, Device 1005 implementations MUST NOT honor or recognize string constants passed 1006 to the <code>android.hardware.Camera.setParameters()</code> method other than 1007 those documented as constants on the 1008 <code>android.hardware.Camera.Parameters</code>, unless the constants are 1009 prefixed with a string indicating the name of the device implementer. That is, 1010 device implementations MUST support all standard Camera parameters if the 1011 hardware allows, and MUST NOT support custom Camera parameter types unless 1012 the parameter names are clearly indicated via a string prefix to be non-standard.</p> 1013 1014 <h3>8.10. Accelerometer</h3> 1015 <p>Device implementations MUST include a 3-axis accelerometer and MUST be able 1016 to deliver events at 50 Hz or greater. The coordinate system used by the 1017 accelerometer MUST comply with the Android sensor coordinate system as detailed 1018 in the Android APIs (see [<a href="#resources27">Resources, 27</a>]).</p> 1019 1020 <h3>8.11. Compass</h3> 1021 <p>Device implementations MUST include a 3-axis compass and MUST be able to 1022 deliver events 10 Hz or greater. The coordinate system used by the compass 1023 MUST comply with the Android sensor coordinate system as defined in the Android 1024 API (see [<a href="#resources27">Resources, 27</a>]).</p> 1025 1026 <h3>8.12. GPS</h3> 1027 <p>Device implementations MUST include a GPS, and SHOULD include some form of 1028 "assisted GPS" technique to minimize GPS lock-on time.</p> 1029 1030 <h3>8.13. Telephony</h3> 1031 <p>Android 2.1 MAY be used on devices that do not include telephony hardware. 1032 That is, Android 2.1 is compatible with devices that are not phones. 1033 However, if a device implementation does include GSM or CDMA telephony, it 1034 MUST implement the full support for the API for that technology. Device 1035 implementations that do not include telephony hardware MUST implement the full 1036 APIs as no-ops.</p> 1037 <p>See also Section 8.8, Wireless Data Networking.</p> 1038 1039 <h3>8.14. Memory and Storage</h3> 1040 <p>Device implementations MUST have at least 92MB of memory available to the 1041 kernel and userspace. The 92MB MUST be in addition to any memory dedicated to 1042 hardware components such as radio, memory, and so on that is not under the 1043 kernel's control.</p> 1044 <p>Device implementations MUST have at least 150MB of non-volatile storage 1045 available for user data. That is, the <code>/data</code> partition must be at 1046 least 150MB.</p> 1047 <div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div> 1048 1049 <h3>8.15. Application Shared Storage</h3> 1050 <p>Device implementations MUST offer shared storage for applications. The 1051 shared storage provided MUST be at least 2GB in size.</p> 1052 <p>Device implementations MUST be configured with shared storage mounted by 1053 default, "out of the box". If the shared storage is not mounted on the Linux 1054 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 1055 from <code>/sdcard</code> to the actual mount point.</p> 1056 <p>Device implementations MUST enforce as documented the 1057 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 1058 shared storage. Shared storage MUST otherwise be writable by any application 1059 that obtains that permission.</p> 1060 <p>Device implementations MAY have hardware for user-accessible removable 1061 storage, such as a Secure Digital card. Alternatively, device implementations 1062 MAY allocate internal (non-removable) storage as shared storage for apps.</p> 1063 <p>Regardless of the form of shared storage used, the shared storage MUST 1064 implement USB mass storage, as described in Section 8.6. As shipped out of the 1065 box, the shared storage MUST be mounted with the FAT filesystem.</p> 1066 <p>It is illustrative to consider two common examples. If a device 1067 implementation includes an SD card slot to satisfy the shared storage 1068 requirement, a FAT-formatted SD card 2GB in size or larger MUST be included 1069 with the device as sold to users, and MUST be mounted by default. 1070 Alternatively, if a device implementation uses internal fixed storage to 1071 satisfy this requirement, that storage MUST be 2GB in size or larger and 1072 mounted on <code>/sdcard</code> (or <code>/sdcard</code> MUST be a symbolic 1073 link to the physical location if it is mounted elsewhere.)</p> 1074 <div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div> 1075 1076 <h3>8.16. Bluetooth</h3> 1077 <p>Device implementations MUST include a Bluetooth transceiver. Device 1078 implementations MUST enable the RFCOMM-based Bluetooth API as described in the 1079 SDK documentation [<a href="#resources29">Resources, 29</a>]. Device 1080 implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, 1081 AVRCP, OBEX, etc. as appropriate for the device.</p> 1082 <div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div> 1083 1084 <h2>9. Performance Compatibility</h2> 1085 <p>One of the goals of the Android Compatibility Program is to enable 1086 consistent application experience to consumers. Compatible implementations 1087 must ensure not only that applications simply run correctly on the device, but 1088 that they do so with reasonable performance and overall good user experience. 1089 Device implementations MUST meet the key performance metrics of an Android 2.1 1090 compatible device defined in the table below:</p> 1091 <table><tbody><tr> 1092 <td><b>Metric</b></td> 1093 <td><b>Performance Threshold</b></td> 1094 <td><b>Comments</b></td> 1095 </tr> 1096 <tr> 1097 <td>Application Launch Time</td> 1098 <td>The following applications should launch within the specified time.<ul> 1099 <li>Browser: less than 1300ms</li> 1100 <li>MMS/SMS: less than 700ms</li> 1101 <li>AlarmClock: less than 650ms</li> 1102 </ul></td> 1103 <td>The launch time is measured as the total time to 1104 complete loading the default activity for the application, including the time 1105 it takes to start the Linux process, load the Android package into the Dalvik 1106 VM, and call onCreate.</td> 1107 </tr> 1108 <tr> 1109 <td>Simultaneous Applications</td> 1110 <td>When multiple applications have been launched, re-launching an 1111 already-running application after it has been launched must take less than the 1112 original launch time.</td> 1113 <td> </td> 1114 </tr> 1115 </tbody> 1116 </table> 1117 1118 <h2>10. Security Model Compatibility</h2> 1119 <p>Device implementations MUST implement a security model consistent with the 1120 Android platform security model as defined in Security and Permissions 1121 reference document in the APIs [<a href="#resources28">Resources, 28</a>] in the 1122 Android developer documentation. Device implementations MUST support 1123 installation of self-signed applications without requiring any additional 1124 permissions/certificates from any third parties/authorities. Specifically, 1125 compatible devices MUST support the security mechanisms described in the 1126 follow sub-sections.</p> 1127 <h3>10.1. Permissions</h3> 1128 <p>Device implementations MUST support the Android permissions model as 1129 defined in the Android developer documentation [<a 1130 href="#resources28">Resources, 28</a>]. Specifically, 1131 implementations MUST enforce each permission defined as described in the SDK 1132 documentation; no permissions may be omitted, altered, or ignored. 1133 Implementations MAY add additional permissions, provided the new permission ID 1134 strings are not in the android.* namespace.</p> 1135 <h3>10.2. UID and Process Isolation</h3> 1136 <p>Device implementations MUST support the Android application sandbox model, 1137 in which each application runs as a unique Unix-style UID and in a separate 1138 process. Device implementations MUST support running multiple applications as 1139 the same Linux user ID, provided that the applications are properly signed and 1140 constructed, as defined in the Security and Permissions reference [<a 1141 href="#resources28">Resources, 28</a>].</p> 1142 <h3>10.3. Filesystem Permissions</h3> 1143 <p>Device implementations MUST support the Android file access permissions 1144 model as defined in as defined in the Security and Permissions reference [<a 1145 href="#resources28">Resources, 28</a>].</p> 1146 1147 <h2>11. Compatibility Test Suite</h2> 1148 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 1149 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source 1150 Project, using the final shipping software on the device. Additionally, device 1151 implementers SHOULD use the reference implementation in the Android Open 1152 Source tree as much as possible, and MUST ensure compatibility in cases of 1153 ambiguity in CTS and for any reimplementations of parts of the reference 1154 source code.</p> 1155 <p>The CTS is designed to be run on an actual device. Like any software, the 1156 CTS may itself contain bugs. The CTS will be versioned independently of this 1157 Compatibility Definition, and multiple revisions of the CTS may be released 1158 for Android 2.1. Device implementations MUST pass the latest CTS version 1159 available at the time the device software is completed.</p> 1160 1161 <h2>12. Updatable Software</h2> 1162 <p>Device implementations MUST include a mechanism to replace the entirety of 1163 the system software. The mechanism need not perform "live" upgrades -- that 1164 is, a device restart MAY be required.</p> 1165 <p>Any method can be used, provided that it can replace the entirety of the 1166 software preinstalled on the device. For instance, any of the following 1167 approaches will satisfy this requirement:</p> 1168 <ul> 1169 <li>Over-the-air (OTA) downloads with offline update via reboot</li> 1170 <li>"Tethered" updates over USB from a host PC</li> 1171 <li>"Offline" updates via a reboot and update from a file on removable 1172 storage</li> 1173 </ul> 1174 <p>The update mechanism used MUST support updates without wiping user data. 1175 Note that the upstream Android software includes an update mechanism that 1176 satisfies this requirement.</p> 1177 <p>If an error is found in a device implementation after it has been released 1178 but within its reasonable product lifetime that is determined in consultation 1179 with the Android Compatibility Team to affect the compatibility of thid-party 1180 applications, the device implementer MUST correct the error via a software 1181 update available that can be applied per the mechanism just described.</p> 1182 1183 <h2>13. Contact Us</h2> 1184 <p>You can contact the document authors at <a 1185 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for 1186 clarifications and to bring up any issues that you think the document does not 1187 cover.</p> 1188 </body> 1189 </html> 1190
