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 2.1 Compatibility Definition</title> 6 <link rel="stylesheet" type="text/css" href="cdd.css"/> 7 </head> 8 <body> 9 <div><img src="header.jpg" alt="Android logo"/></div> 10 <h1>Android 2.1 Compatibility Definition</h1> 11 <p>Copyright © 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>1. Introduction</h2> 16 <p>This document enumerates the requirements that must be met in order for 17 mobile phones to be compatible with Android 2.1.</p> 18 <p>The use of "must", "must not", "required", "shall", "shall not", "should", 19 "should not", "recommended", "may" and "optional" is per the IETF standard 20 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 21 <p>As used in this document, a "device implementer" or "implementer" is a 22 person or organization developing a hardware/software solution running Android 23 2.1. A "device implementation" or "implementation" is the hardware/software 24 solution so developed.</p> 25 <p>To be considered compatible with Android 2.1, device implementations:</p> 26 <ul> 27 <li>MUST meet the requirements presented in this Compatibility Definition, 28 including any documents incorporated via reference.</li> 29 <li>MUST pass the most recent version of the Android Compatibility Test Suite 30 (CTS) available at the time of the device implementation's software is 31 completed. (The CTS is available as part of the Android Open Source Project [<a 32 href="#resources02">Resources, 2</a>].) The CTS tests many, but not all, of the 33 components outlined in this document.</li> 34 </ul> 35 <p>Where this definition or the CTS is silent, ambiguous, or incomplete, it is 36 the responsibility of the device implementer to ensure compatibility with 37 existing implementations. For this reason, the Android Open Source Project [<a 38 href="#resources03">Resources, 3</a>] is both the reference and preferred 39 implementation of Android. Device implementers are strongly encouraged to base 40 their implementations on the "upstream" source code available from the Android 41 Open Source Project. While some components can hypothetically be replaced with 42 alternate implementations this practice is strongly discouraged, as passing 43 the CTS tests will become substantially more difficult. It is the 44 implementer's responsibility to ensure full behavioral compatibility with the 45 standard Android implementation, including and beyond the Compatibility Test 46 Suite. Finally, note that certain component substitutions and modifications 47 are explicitly forbidden by this document.</p> 48 49 <a name="resources"/><h2>2. Resources</h2> 50 <ol> 51 <a name="resources01"/><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li> 52 <a name="resources02"/><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li> 53 <a name="resources03"/><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 54 <a name="resources04"/><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li> 55 <a name="resources05"/><li>Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li> 56 <a name="resources06"/><li>android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li> 57 <a name="resources07"/><li>Android 2.1 allowed version strings: <a href="http://source.android.com/compatibility/2.1/versions.xhtml">http://source.android.com/compatibility/2.1/versions.xhtml</a></li> 58 <a name="resources08"/><li>android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li> 59 <a name="resources09"/><li>HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li> 60 <a name="resources10"/><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 61 <a name="resources11"/><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li> 62 <a name="resources12"/><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li> 63 <a name="resources13"/><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li> 64 <a name="resources14"/><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design.html#statusbarstructure">http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure</a></li> 65 <a name="resources15"/><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li> 66 <a name="resources16"/><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li> 67 <a name="resources17"/><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li> 68 <a name="resources18"/><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li> 69 <a name="resources19"/><li>Reference tool documentation (for adb, aapt, ddms): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li> 70 <a name="resources20"/><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li> 71 <a name="resources21"/><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li> 72 <a name="resources22"/><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li> 73 <a name="resources23"/><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li> 74 <a name="resources24"/><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li> 75 <a name="resources25"/><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li> 76 <a name="resources26"/><li>android.hardware.Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li> 77 <a name="resources27"/><li>Sensor coordinate space: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li> 78 <a name="resources28"/><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li> 79 <a name="resources29"/><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li> 80 </ol> 81 <p>Many of these resources are derived directly or indirectly from the Android 82 2.1 SDK, and will be functionally identical to the information in that SDK's 83 documentation. In any cases where this Compatibility Definition or the 84 Compatibility Test Suite disagrees with the SDK documentation, the SDK 85 documentation is considered authoritative. Any technical details provided in 86 the references included above are considered by inclusion to be part of this 87 Compatibility Definition.</p> 88 89 <h2>3. Software</h2> 90 <p>The Android platform includes a set of managed APIs, a set of native APIs, 91 and a body of so-called "soft" APIs such as the Intent system and 92 web-application APIs. This section details the hard and soft APIs that are 93 integral to compatibility, as well as certain other relevant technical and 94 user interface behaviors. Device implementations MUST comply with all the 95 requirements in this section.</p> 96 97 <h3>3.1. Managed API Compatibility</h3> 98 <p>The managed (Dalvik-based) execution environment is the primary vehicle for 99 Android applications. The Android application programming interface (API) is 100 the set of Android platform interfaces exposed to applications running in the 101 managed VM environment. Device implementations MUST provide complete 102 implementations, including all documented behaviors, of any documented API 103 exposed by the Android 2.1 SDK [<a href="#resources04">Resources, 4</a>].</p> 104 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 105 or signatures, deviate from the documented behavior, or include no-ops, except 106 where specifically allowed by this Compatibility Definition.</p> 107 108 <h3>3.2. Soft API Compatibility</h3> 109 <p>In addition to the managed APIs from Section 3.1, Android also includes a 110 significant runtime-only "soft" API, in the form of such things such as 111 Intents, permissions, and similar aspects of Android applications that cannot 112 be enforced at application compile time. This section details the "soft" APIs 113 and system behaviors required for compatibility with Android 2.1. Device 114 implementations MUST meet all the requirements presented in this section.</p> 115 <h4>3.2.1. Permissions</h4> 116 <p>Device implementers MUST support and enforce all permission constants as 117 documented by the Permission reference page [<a 118 href="#resources05">Resources, 5</a>]. Note that Section 10 lists addtional 119 requirements related to the Android security model.</p> 120 <h4>3.2.2. Build Parameters</h4> 121 <p>The Android APIs include a number of constants on the <code>android.os.Build</code> 122 class [<a href="#resources06">Resources, 6</a>] that are intended to describe 123 the current device. To provide consistent, meaningful values across device 124 implementations, the table below includes additional restrictions on the 125 formats of these values to which device implementations MUST conform.</p> 126 <table> 127 <tbody> 128 <tr> 129 <td><b>Parameter</b></td> 130 <td><b>Comments</b></td> 131 </tr> 132 <tr> 133 <td>android.os.Build.VERSION.RELEASE</td> 134 <td>The version of the currently-executing Android system, in human-readable 135 format. This field MUST have one of the string values defined in [<a 136 href="#resources07">Resources, 7</a>].</td> 137 </tr> 138 <tr> 139 <td>android.os.Build.VERSION.SDK</td> 140 <td>The version of the currently-executing Android system, in a format 141 accessible to third-party application code. For Android 2.1, this field MUST have 142 the integer value 7.</td> 143 </tr> 144 <tr> 145 <td>android.os.Build.VERSION.INCREMENTAL</td> 146 <td>A value chosen by the device implementer designating the specific build of 147 the currently-executing Android system, in human-readable format. This value 148 MUST NOT be re-used for different builds shipped to end users. A typical use 149 of this field is to indicate which build number or source-control change 150 identifier was used to generate the build. There are no requirements on the 151 specific format of this field, except that it MUST NOT be null or the empty 152 string ("").</td> 153 </tr> 154 <tr> 155 <td>android.os.Build.BOARD</td> 156 <td>A value chosen by the device implementer identifying the specific internal 157 hardware used by the device, in human-readable format. A possible use of this 158 field is to indicate the specific revision of the board powering the device. 159 There are no requirements on the specific format of this field, except that it 160 MUST NOT be null or the empty string ("").</td> 161 </tr> 162 <tr> 163 <td>android.os.Build.BRAND</td> 164 <td>A value chosen by the device implementer identifying the name of the 165 company, organization, individual, etc. who produced the device, in 166 human-readable format. A possible use of this field is to indicate the OEM 167 and/or carrier who sold the device. There are no requirements on the specific 168 format of this field, except that it MUST NOT be null or the empty string 169 ("").</td> 170 </tr> 171 <tr> 172 <td>android.os.Build.DEVICE</td> 173 <td>A value chosen by the device implementer identifying the specific 174 configuration or revision of the body (sometimes called "industrial design") 175 of the device. There are no requirements on the specific format of this field, 176 except that it MUST NOT be null or the empty string ("").</td> 177 </tr> 178 <tr> 179 <td>android.os.Build.FINGERPRINT</td> 180 <td>A string that uniquely identifies this build. It SHOULD be reasonably 181 human-readable. It MUST follow this template: 182 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE)/$(BOARD):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 183 For example: 184 <br/><code>acme/mydevice/generic/generic:2.1-update1/ERC77/3359:userdebug/test-keys</code><br/> 185 The fingerprint MUST NOT include spaces. If other fields included in the 186 template above have spaces, they SHOULD be replaced with the ASCII underscore 187 ("_") character in the fingerprint.</td> 188 </tr> 189 <tr> 190 <td>android.os.Build.HOST</td> 191 <td>A string that uniquely identifies the host the build was built on, in 192 human readable format. There are no requirements on the specific format of 193 this field, except that it MUST NOT be null or the empty string ("").</td> 194 </tr> 195 <tr> 196 <td>android.os.Build.ID</td> 197 <td>An identifier chosen by the device implementer to refer to a specific 198 release, in human readable format. This field can be the same as 199 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 200 meaningful for end users to distinguish between software builds. There are no 201 requirements on the specific format of this field, except that it MUST NOT be 202 null or the empty string ("").</td> 203 </tr> 204 <tr> 205 <td>android.os.Build.MODEL</td> 206 <td>A value chosen by the device implementer containing the name of the device 207 as known to the end user. This SHOULD be the same name under which the device 208 is marketed and sold to end users. There are no requirements on the specific 209 format of this field, except that it MUST NOT be null or the empty string 210 ("").</td> 211 </tr> 212 <tr> 213 <td>android.os.Build.PRODUCT</td> 214 <td>A value chosen by the device implementer containing the development name 215 or code name of the device. MUST be human-readable, but is not necessarily 216 intended for view by end users. There are no requirements on the specific 217 format of this field, except that it MUST NOT be null or the empty string 218 ("").</td> 219 </tr> 220 <tr> 221 <td>android.os.Build.TAGS</td> 222 <td>A comma-separated list of tags chosen by the device implementer that 223 further distinguish the build. For example, "unsigned,debug". This field MUST 224 NOT be null or the empty string (""), but a single tag (such as "release") is 225 fine.</td> 226 </tr> 227 <tr> 228 <td>android.os.Build.TIME</td> 229 <td>A value representing the timestamp of when the build occurred.</td> 230 </tr> 231 <tr> 232 <td>android.os.Build.TYPE</td> 233 <td>A value chosen by the device implementer specifying the runtime 234 configuration of the build. This field SHOULD have one of the values 235 corresponding to the three typical Android runtime configurations: "user", 236 "userdebug", or "eng".</td> 237 </tr> 238 <tr> 239 <td>android.os.Build.USER</td> 240 <td>A name or user ID of the user (or automated user) that generated the 241 build. There are no requirements on the specific format of this field, except 242 that it MUST NOT be null or the empty string ("").</td> 243 </tr> 244 </tbody> 245 </table> 246 <h4>3.2.3. Intent Compatibility</h4> 247 <p>Android uses Intents to achieve loosely-coupled integration between 248 applications. This section describes requirements related to the Intent 249 patterns that MUST be honored by device implementations. By "honored", it is 250 meant that the device implementer MUST provide an Android Activity or Service 251 that specifies a matching Intent filter and binds to and implements correct 252 behavior for each specified Intent pattern.</p> 253 <h4>3.2.3.1. Core Application Intents</h4> 254 <p>The Android upstream project defines a number of core applications, such as 255 a phone dialer, calendar, contacts book, music player, and so on. Device 256 implementers MAY replace these applications with alternative versions.</p> 257 <p>However, any such alternative versions MUST honor the same Intent patterns 258 provided by the upstream project. For example, if a device contains an 259 alternative music player, it must still honor the Intent pattern issued by 260 third-party applications to pick a song.</p> 261 <p>The following applications are considered core Android system 262 applications:</p> 263 <ul> 264 <li>Desk Clock</li> 265 <li>Browser</li> 266 <li>Calendar</li> 267 <li>Calculator</li> 268 <li>Camera</li> 269 <li>Contacts</li> 270 <li>Email</li> 271 <li>Gallery</li> 272 <li>GlobalSearch</li> 273 <li>Launcher</li> 274 <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 275 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> 276 <li>Messaging (AKA "Mms")</li> 277 <li>Music</li> 278 <li>Phone</li> 279 <li>Settings</li> 280 <li>SoundRecorder</li> 281 </ul> 282 <p>The core Android system applications include various Activity, or Service 283 components that are considered "public". 284 That is, the attribute "android:exported" may be absent, or may have the value 285 "true".</p> 286 <p>For every Activity or Service defined 287 in one of the core Android system apps that is not marked as non-public via an 288 android:exported attribute with the value "false", device implementations MUST 289 include a compontent of the same type implementing the same Intent filter 290 patterns as the core Android system app.</p> 291 <p>In other words, a device implementation MAY replace core Android system 292 apps; however, if it does, the device implementation MUST support all Intent 293 patterns defined by each core Android system app being replaced.</p> 294 <h4>3.2.3.2. Intent Overrides</h4> 295 <p>As Android is an extensible platform, device implementers MUST allow each 296 Intent pattern defined in core system apps to be overridden by third-party 297 applications. The upstream Android open source project allows this by default; 298 device implementers MUST NOT attach special privileges to system applications' 299 use of these Intent patterns, or prevent third-party applications from binding 300 to and assuming control of these patterns. This prohibition specifically 301 includes but is not limited to disabling the "Chooser" user interface which 302 allows the user to select between multiple applications which all handle the 303 same Intent pattern.</p> 304 <div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div> 305 <h4>3.2.3.3. Intent Namespaces</h4> 306 <p>Device implementers MUST NOT include any Android component that honors any 307 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 308 key string in the android.* namespace. Device implementers MUST NOT include 309 any Android components that honor any new Intent or Broadcast Intent patterns 310 using an ACTION, CATEGORY, or other key string in a package space belonging to 311 another organization. Device implementers MUST NOT alter or extend any of the 312 Intent patterns used by the core apps listed in Section 3.2.3.1.</p> 313 <p>This prohibition is analogous to that specified for Java language classes 314 in Section 3.6.</p> 315 <h4>3.2.3.4. Broadcast Intents</h4> 316 <p>Third-party applications rely on the platform to broadcast certain Intents 317 to notify them of changes in the hardware or software environment. 318 Android-compatible devices MUST broadcast the public broadcast Intents in 319 response to appropriate system events. Broadcast Intents are described in the 320 SDK documentation.</p> 321 322 <h3>3.3. Native API Compatibility</h3> 323 <p>Managed code running in Dalvik can call into native code provided in the 324 application .apk file as an ELF .so file compiled for the appropriate device 325 hardware architecture. Device implementations MUST include support for code 326 running in the managed environment to call into native code, using the 327 standard Java Native Interface (JNI) semantics. The following APIs MUST be 328 available to native code:</p> 329 <ul> 330 <li>libc (C library)</li> 331 <li>libm (math library)</li> 332 <li>JNI interface</li> 333 <li>libz (Zlib compression)</li> 334 <li>liblog (Android logging)</li> 335 <li>Minimal support for C++</li> 336 <li>Support for OpenGL, as described below</li> 337 </ul> 338 <p>Device implementations MUST support OpenGL ES 1.0. Devices that lack 339 hardware acceleration MUST implement OpenGL ES 1.0 using a software renderer. 340 Device implementations SHOULD implement as much of OpenGL ES 1.1 as the device 341 hardware supports. Device implementations SHOULD provide an implementation 342 for OpenGL ES 2.0, if the hardware is capable of reasonable performance on 343 those APIs.</p> 344 <p>These libraries MUST be source-compatible (i.e. header compatible) and 345 binary-compatible (for a given processor architecture) with the versions 346 provided in Bionic by the Android Open Source project. Since the Bionic 347 implementations are not fully compatible with other implementations such as 348 the GNU C library, device implementers SHOULD use the Android implementation. 349 If device implementers use a different implementation of these libraries, they 350 MUST ensure header, binary, and behavioral compatibility.</p> 351 <p>Device implementations MUST accurately report the native Application Binary 352 Interface (ABI) supported by the device, via the 353 <code>android.os.Build.CPU_ABI</code> API. The ABI MUST be one of the entries 354 documented in the latest version of the Android NDK, in the file 355 <code>docs/CPU-ARCH-ABIS.txt</code>. Note that additional releases of the 356 Android NDK may introduce support for additional ABIs.</p> 357 <p>Native code compatibility is challenging. For this reason, it should be 358 repeated that device implementers are VERY strongly encouraged to use the 359 upstream implementations of the libraries listed above, to help ensure 360 compatibility.</p> 361 362 <h3>3.4. Web API Compatibility</h3> 363 <p>Many developers and applications rely on the behavior of the 364 <code>android.webkit.WebView</code> class [<a 365 href="#resources08">Resources, 8</a>] 366 for their user interfaces, so the WebView implementation must be 367 compatible across Android implementations. The Android Open Source 368 implementation uses the WebKit rendering engine to implement the 369 WebView.</p> 370 <p>Because it is not feasible to develop a comprehensive test suite for a web 371 browser, device implementers MUST use the specific upstream build of WebKit in 372 the WebView implementation. Specifically:</p> 373 <ul> 374 <li>WebView MUST use the 530.17 WebKit build from the upstream Android Open 375 Source tree for Android 2.1. This build includes a specific set of functionality 376 and security fixes for the WebView.</li> 377 <li>The user agent string reported by the WebView MUST be in this format:<br/> 378 <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/530.17 (KHTML, like Gecko) Version/4.0 Mobile Safari/530.17</code> 379 <ul> 380 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 381 <li>The value of the $(LOCALE) string SHOULD follow the ISO conventions for country code and language, and SHOULD refer to the current configured locale of the device</li> 382 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 383 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 384 </ul></li> 385 </ul> 386 <p>Implementations MAY ship a custom user agent string in the standalone 387 Browser application. What's more, the standalone Browser MAY be based on an 388 alternate browser technology (such as Firefox, Opera, etc.) However, even if an 389 alternate Browser application is shipped, the WebView component provided to 390 third-party applications MUST be based on WebKit, as above.</p> 391 <p>The WebView configuration MUST include support for the HTML5 database, 392 application cache, and geolocation APIs [<a href="#resources09">Resources, 393 9</a>]. The WebView MUST include support for 394 the HTML5 <code><video></code> tag in 395 some form. The standalone Browser application (whether based on the upstream 396 WebKit Browser application or a third-party replacement) MUST include support 397 for the same HTML5 features just listed for WebView.</p> 398 399 <h3>3.5. API Behavioral Compatibility</h3> 400 <p>The behaviors of each of the API types (managed, soft, native, and web) 401 must be consistent with the preferred implementation of the upstream Android 402 open-source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 403 of compatibility are:</p> 404 <ul> 405 <li>Devices MUST NOT change the behavior or meaning of a standard Intent</li> 406 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular type of system component (such as Service, Activity, ContentProvider, etc.)</li> 407 <li>Devices MUST NOT change the semantics of a particular permission</li> 408 </ul> 409 <p>The above list is not comprehensive, and the onus is on device implementers 410 to ensure behavioral compatibility. For this reason, device implementers 411 SHOULD use the source code available via the Android Open Source Project where 412 possible, rather than re-implement significant parts of the system.</p> 413 <p>The Compatibility Test Suite (CTS) tests significant portions of the 414 platform for behavioral compatibility, but not all. It is the responsibility 415 of the implementer to ensure behavioral compatibility with the Android Open 416 Source Project.</p> 417 418 <h3>3.6. API Namespaces</h3> 419 <p>Android follows the package and class namespace conventions defined by the 420 Java programming language. To ensure compatibility with third-party 421 applications, device implementers MUST NOT make any prohibited modifications 422 (see below) to these package namespaces:</p> 423 <ul> 424 <li>java.*</li> 425 <li>javax.*</li> 426 <li>sun.*</li> 427 <li>android.*</li> 428 <li>com.android.*</li> 429 </ul> 430 <p>Prohibited modifications include:</p> 431 <ul> 432 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 433 Android platform by changing any method or class signatures, or by removing 434 classes or class fields.</li> 435 <li>Device implementers MAY modify the underlying implementation of the APIs, 436 but such modifications MUST NOT impact the stated behavior and Java-language 437 signature of any publicly exposed APIs.</li> 438 <li>Device implementers MUST NOT add any publicly exposed elements (such as 439 classes or interfaces, or fields or methods to existing classes or interfaces) 440 to the APIs above.</li> 441 </ul> 442 <p>A "publicly exposed element" is any construct which is not decorated with 443 the "@hide" marker in the upstream Android source code. In other words, device 444 implementers MUST NOT expose new APIs or alter existing APIs in the namespaces 445 noted above. Device implementers MAY make internal-only modifications, but 446 those modifications MUST NOT be advertised or otherwise exposed to 447 developers.</p> 448 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 449 namespace owned by or referring to another organization. For instance, device 450 implementers MUST NOT add APIs to the com.google.* or similar namespace; only 451 Google may do so. Similarly, Google MUST NOT add APIs to other companies' 452 namespaces.</p> 453 <p>If a device implementer proposes to improve one of the package namespaces 454 above (such as by adding useful new functionality to an existing API, or 455 adding a new API), the implementer SHOULD visit source.android.com and begin 456 the process for contributing changes and code, according to the information on 457 that site.</p> 458 <p>Note that the restrictions above correspond to standard conventions for 459 naming APIs in the Java programming language; this section simply aims to 460 reinforce those conventions and make them binding through inclusion in this 461 compatibility definition.</p> 462 463 <h3>3.7. Virtual Machine Compatibility</h3> 464 <p>Device implementations MUST support the full Dalvik Executable (DEX) 465 bytecode specification and Dalvik Virtual Machine semantics [<a 466 href="#resources10">Resources, 10</a>].</p> 467 <p>Device implementations MUST configure Dalvik to allocate at least 16MB of 468 memory to each application on devices with screens classified as medium- or 469 low-density. Device implementations MUST configure Dalvik to allocate at least 470 24MB of memory to each application on devices with screens classified as 471 high-density. Note that device implementations MAY allocate more memory than 472 these figures, but are not required to.</p> 473 474 <h3>3.8. User Interface Compatibility</h3> 475 <p>The Android platform includes some developer APIs that allow developers to 476 hook into the system user interface. Device implementations MUST incorporate 477 these standard UI APIs into custom user interfaces they develop, as explained 478 below.</p> 479 <h4>3.8.1. Widgets</h4> 480 <p>Android defines a component type and corresponding API and lifecycle that 481 allows applications to expose an "AppWidget" to the end user [<a 482 href="#resources11">Resources, 11</a>]. 483 The Android Open Source reference release includes a Launcher application that 484 includes user interface elements allowing the user to add, view, and remove 485 AppWidgets from the home screen.</p> 486 <p>Device implementers MAY substitute an alternative to the reference Launcher 487 (i.e. home screen). Alternative Launchers SHOULD include built-in support for 488 AppWidgets, and expose user interface elements to add, configure, view, and remove 489 AppWidgets directly within the Launcher. Alternative Launchers MAY omit these 490 user interface elements; however, if they are omitted, the device implementer 491 MUST provide a separate application accessible from the Launcher that allows 492 users to add, configure, view, and remove AppWidgets.</p> 493 <h4>3.8.2. Notifications</h4> 494 <p>Android includes APIs that allow developers to notify users of notable 495 events [<a href="#resources12">Resources, 12</a>]. Device implementers MUST provide support for each 496 class of notification so defined; specifically: sounds, vibration, light and 497 status bar.</p> 498 <p>Additionally, the implementation MUST correctly render all resources 499 (icons, sound files, etc.) provided for in the APIs [<a 500 href="#resources13">Resources, 13</a>], or in the 501 Status Bar icon style guide [<a href="#resources14">Resources, 14</a>]. Device implementers MAY provide 502 an alternative user experience for notifications than that provided by the 503 reference Android Open Source implementation; however, such alternative 504 notification systems MUST support existing notification resources, as 505 above.</p> 506 <h4>3.8.3. Search</h4> 507 <p>Android includes APIs [<a href="#resources15">Resources, 15</a>] that allow developers to incorporate 508 search into their applications, and expose their application's data into the 509 global system search. Generally speaking, this functionality consists of a 510 single, system-wide user interface that allows users to enter queries, 511 displays suggestions as users type, and displays results. The Android APIs 512 allow developers to reuse this interface to provide search within their own 513 apps, and allow developers to supply results to the common global search user 514 interface.</p> 515 <p>Device implementations MUST include a single, shared, system-wide search 516 user interface capable of real-time suggestions in response to user input. 517 Device implementations MUST implement the APIs that allow developers to reuse 518 this user interface to provide search within their own applications. Device 519 implementations MUST implement the APIs that allow third-party applications to 520 add suggestions to the search box when it is run in global search mode. If no 521 third-party applications are installed that make use of this functionality, 522 the default behavior SHOULD be to display web search engine results and 523 suggestions.</p> 524 <p>Device implementations MAY ship alternate search user interfaces, but 525 SHOULD include a hard or soft dedicated search button, that can be used at any 526 time within any app to invoke the search framework, with the behavior provided 527 for in the API documentation.</p> 528 <h4>3.8.4. Toasts</h4> 529 <p>Applications can use the "Toast" API (defined in [<a 530 href="#resources16">Resources, 16</a>]) to 531 display short non-modal strings to the end user, that disappear after a brief 532 period of time. Device implementations MUST display Toasts from applications 533 to end users in some high-visibility manner.</p> 534 <h4>3.8.5. Live Wallpapers</h4> 535 <p>Android defines a component type and corresponding API and lifecycle that 536 allows applications to expose one or more "Live Wallpapers" to the end user 537 [<a href="#resources17">Resources, 17</a>]. Live Wallpapers are animations, 538 patterns, or similar images with limited input capabilities that display as a 539 wallpaper, behind other applications.</p> 540 <p>Hardware is considered capable of reliably running live wallpapers if it 541 can run all live wallpapers, with no limitations on functionality, at a 542 reasonable framerate with no adverse affects on other applications. If 543 limitations in the hardware cause wallpapers and/or applications to crash, 544 malfunction, consume excessive CPU or battery power, or run at unacceptably 545 low frame rates, the hardware is considered incapable of running live 546 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 547 context to render their content. Live wallpaper will not run reliably on 548 hardware that does not support multiple OpenGL contexts because the live 549 wallpaper use of an OpenGL context may conflict with other applications that 550 also use an OpenGL context. </p> 551 <p>Device implemenations capable of running live wallpapers reliably as 552 described above SHOULD implement live wallpapers. Device implementations 553 determined to not run live wallpapers reliably as described above MUST NOT 554 implement live wallpapers.</p> 555 556 <h2>4. Reference Software Compatibility</h2> 557 <p>Device implementers MUST test implementation compatibility using the 558 following open-source applications:</p> 559 <ul> 560 <li>Calculator (included in SDK)</li> 561 <li>Lunar Lander (included in SDK)</li> 562 <li>The "Apps for Android" applications [<a href="#resources18">Resources, 18</a>].</li> 563 </ul> 564 <p>Each app above MUST launch and behave correctly on the implementation, for 565 the implementation to be considered compatible.</p> 566 <p>Additionally, device implementations MUST test each menu item (including all 567 sub-menus) of each of these smoke-test applications:</p> 568 <ul> 569 <li>ApiDemos (included in SDK)</li> 570 <li>ManualSmokeTests (included in CTS)</li> 571 </ul> 572 <p>Each test case in the applications above MUST run correctly on the device 573 implementation.</p> 574 575 <h2>5. Application Packaging Compatibility</h2> 576 <p>Device implementations MUST install and run Android ".apk" files as 577 generated by the "aapt" tool included in the official Android SDK [<a 578 href="#resources19">Resources, 19</a>].</p> 579 <p>Devices implementations MUST NOT extend either the .apk [<a 580 href="#resources20">Resources, 20</a>], Android Manifest [<a 581 href="#resources21">Resources, 21</a>], 582 or Dalvik bytecode [<a href="#resources10">Resources, 10</a>] formats in such 583 a way that would prevent those files from 584 installing and running correctly on other compatible devices. Device 585 implementers SHOULD use the reference upstream implementation of Dalvik, and 586 the reference implementation's package management system.</p> 587 588 <h2>6. Multimedia Compatibility</h2> 589 <p>Device implemenations MUST support the following multimedia codecs. All of 590 these codecs are provided as software implementations in the preferred Android 591 implementation from the Android Open Source Project.</p> 592 <p>Please note that neither Google nor the Open Handset Alliance make any 593 representation that these codecs are unencumbered by third-party patents. 594 Those intending to use this source code in hardware or software products are 595 advised that implementations of this code, including in open source software 596 or shareware, may require patent licenses from the relevant patent 597 holders.</p> 598 <table><tbody> 599 <tr> 600 <td rowspan="11"><b>Audio</b></td> 601 </tr> 602 <tr> 603 <td><b>Name</b></td> 604 <td><b>Encoder</b></td> 605 <td><b>Decoder</b></td> 606 <td><b>Details</b></td> 607 <td><b>File/Container Format</b></td> 608 </tr> 609 <tr> 610 <td>AAC LC/LTP</td> 611 <td> </td> 612 <td>X</td> 613 <td rowspan="3">Mono/Stereo content in any combination of standard bit rates up to 160 kbps and sampling rates between 8 to 48kHz</td> 614 <td rowspan="3">3GPP (.3gp) and MPEG-4 (.mp4, .m4a). No support for raw AAC (.aac)</td> 615 </tr> 616 <tr> 617 <td>HE-AACv1 (AAC+)</td> 618 <td> </td> 619 <td>X</td> 620 </tr> 621 <tr> 622 <td>HE-AACv2 (enhanced AAC+)</td> 623 <td> </td> 624 <td>X</td> 625 </tr> 626 <tr> 627 <td>AMR-NB</td> 628 <td>X</td> 629 <td>X</td> 630 <td>4.75 to 12.2 kbps sampled @ 8kHz</td> 631 <td>3GPP (.3gp)</td> 632 </tr> 633 <tr> 634 <td>AMR-WB</td> 635 <td> </td> 636 <td>X</td> 637 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 638 <td>3GPP (.3gp)</td> 639 </tr> 640 <tr> 641 <td>MP3</td> 642 <td> </td> 643 <td>X</td> 644 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR)</td> 645 <td>MP3 (.mp3)</td> 646 </tr> 647 <tr> 648 <td>MIDI</td> 649 <td> </td> 650 <td>X</td> 651 <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for ringtone formats RTTTL/RTX, OTA, and iMelody</td> 652 <td>Type 0 and 1 (.mid, .xmf, .mxmf). Also RTTTL/RTX (.rtttl, .rtx), OTA (.ota), and iMelody (.imy)</td> 653 </tr> 654 <tr> 655 <td>Ogg Vorbis</td> 656 <td> </td> 657 <td>X</td> 658 <td> </td> 659 <td>Ogg (.ogg)</td> 660 </tr> 661 <tr> 662 <td>PCM</td> 663 <td> </td> 664 <td>X</td> 665 <td>8- and 16-bit linear PCM (rates up to limit of hardware)</td> 666 <td>WAVE (.wav)</td> 667 </tr> 668 <tr> 669 <td rowspan="5"><b>Image</b></td> 670 </tr> 671 <tr> 672 <td>JPEG</td> 673 <td>X</td> 674 <td>X</td> 675 <td>base+progressive</td> 676 <td> </td> 677 </tr> 678 <tr> 679 <td>GIF</td> 680 <td> </td> 681 <td>X</td> 682 <td> </td> 683 <td> </td> 684 </tr> 685 <tr> 686 <td>PNG</td> 687 <td>X</td> 688 <td>X</td> 689 <td> </td> 690 <td> </td> 691 </tr> 692 <tr> 693 <td>BMP</td> 694 <td> </td> 695 <td>X</td> 696 <td> </td> 697 <td> </td> 698 </tr> 699 <tr> 700 <td rowspan="4"><b>Video</b></td> 701 </tr> 702 <tr> 703 <td>H.263</td> 704 <td>X</td> 705 <td>X</td> 706 <td> </td> 707 <td>3GPP (.3gp) files</td> 708 </tr> 709 <tr> 710 <td>H.264</td> 711 <td> </td> 712 <td>X</td> 713 <td> </td> 714 <td>3GPP (.3gp) and MPEG-4 (.mp4) files</td> 715 </tr> 716 <tr> 717 <td>MPEG4 Simple Profile</td> 718 <td> </td> 719 <td>X</td> 720 <td> </td> 721 <td>3GPP (.3gp) file</td> 722 </tr> 723 </tbody> 724 </table> 725 <p>Note that the table above does not list specific bitrate requirements for 726 most video codecs. The reason for this is that in practice, current device 727 hardware does not necessarily support bitrates that map exactly to the 728 required bitrates specified by the relevant standards. Instead, device 729 implementations SHOULD support the highest bitrate practical on the hardware, 730 up to the limits defined by the specifications.</p> 731 732 <h2>7. Developer Tool Compatibility</h2> 733 <p>Device implemenations MUST support the Android Developer Tools provided in 734 the Android SDK. Specifically, Android-compatible devices MUST be compatible 735 with:</p> 736 <ul> 737 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources19">Resources, 19</a>]<br/> 738 Device implementations MUST support all <code>adb</code> functions as 739 documented in the Android SDK. The device-side <code>adb</code> daemon SHOULD 740 be inactive by default, but there MUST be a user-accessible mechanism to turn 741 on the Android Debug Bridge.</li> 742 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources19">Resources, 19</a>]<br/> 743 Device implementations MUST support all <code>ddms</code> features as documented in the 744 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 745 <code>ddms</code> SHOULD be inactive by default, 746 but MUST be supported whenever the user has activated the Android Debug 747 Bridge, as above.</li> 748 <li><b>Monkey</b> [<a href="#resources22">Resources, 22</a>]<br/> 749 Device implementations MUST include the Monkey framework, and make it 750 available for applications to use.</li> 751 </ul> 752 753 <h2>8. Hardware Compatibility</h2> 754 <p>Android is intended to support device implementers creating innovative form 755 factors and configurations. At the same time Android developers expect 756 certain hardware, sensors and APIs across all Android device. This section 757 lists the hardware features that all Android 2.1 compatible devices must 758 support.</p> 759 <p>If a device includes a particular hardware component that has a 760 corresponding API for third-party developers, the device implementation MUST 761 implement that API as defined in the Android SDK documentation. If an API in 762 the SDK interacts with a hardware component that is stated to be optional and the device 763 implementation does not possess that component:</p> 764 <ul> 765 <li>class definitions for the component's APIs MUST be present</li> 766 <li>the API's behaviors MUST be implemented as no-ops in some reasonable fashion</li> 767 <li>API methods MUST return null values where permitted by the SDK documentation</li> 768 <li>API methods MUST return no-op implementations of classes where null values are not permitted by the SDK documentation</li> 769 </ul> 770 <p>A typical example of a scenario where these requirements apply is the 771 telephony API: even on non-phone devices, these APIs must be implemented as 772 reasonable no-ops.</p> 773 <p>Device implementations MUST accurate report accurate hardware configuration 774 information via the <code>getSystemAvailableFeatures()</code> and 775 <code>hasSystemFeature(String)</code> methods on the 776 <code>android.content.pm.PackageManager</code> class.</p> 777 778 <h3>8.1. Display</h3> 779 <p>Android 2.1 includes facilities that perform certain automatic scaling and 780 transformation operations under some circumstances, to ensure that third-party 781 applications run reasonably well on a variety of hardware configurations [<a 782 href="#resources23">Resources, 23</a>]. Devices MUST properly implement these 783 behaviors, as detailed in this section.</p> 784 <p>For Android 2.1, this are the most common display configurations:</p> 785 <table><tbody> 786 <tr> 787 <td>Screen Type</td> 788 <td>Width (Pixels)</td> 789 <td>Height (Pixels)</td> 790 <td>Diagonal Length Range (inches)</td> 791 <td>Screen Size Group</td> 792 <td>Screen Density Group</td> 793 </tr> 794 <tr> 795 <td>QVGA</td> 796 <td>240</td> 797 <td>320</td> 798 <td>2.6 - 3.0</td> 799 <td>Small</td> 800 <td>Low</td> 801 </tr> 802 <tr> 803 <td>WQVGA</td> 804 <td>240</td> 805 <td>400</td> 806 <td>3.2 - 3.5</td> 807 <td>Normal</td> 808 <td>Low</td> 809 </tr> 810 <tr> 811 <td>FWQVGA</td> 812 <td>240</td> 813 <td>432</td> 814 <td>3.5 - 3.8</td> 815 <td>Normal</td> 816 <td>Low</td> 817 </tr> 818 <tr> 819 <td>HVGA</td> 820 <td>320</td> 821 <td>480</td> 822 <td>3.0 - 3.5</td> 823 <td>Normal</td> 824 <td>Medium</td> 825 </tr> 826 <tr> 827 <td>WVGA</td> 828 <td>480</td> 829 <td>800</td> 830 <td>3.3 - 4.0</td> 831 <td>Normal</td> 832 <td>High</td> 833 </tr> 834 <tr> 835 <td>FWVGA</td> 836 <td>480</td> 837 <td>854</td> 838 <td>3.5 - 4.0</td> 839 <td>Normal</td> 840 <td>High</td> 841 </tr> 842 <tr> 843 <td>WVGA </td> 844 <td>480 </td> 845 <td>800 </td> 846 <td>4.8 - 5.5 </td> 847 <td>Large </td> 848 <td>Medium</td> 849 </tr> 850 <tr> 851 <td>FWVGA</td> 852 <td>480</td> 853 <td>854</td> 854 <td>5.0 - 5.8</td> 855 <td>Large</td> 856 <td>Medium</td> 857 </tr> 858 </tbody></table> 859 860 <p>Device implementations corresponding to one of the standard configurations 861 above MUST be configured to report the indicated screen size to applications 862 via the <code>android.content.res.Configuration</code> [<a href="#resources24">Resources, 863 24</a>] class.</p> 864 <p>Some .apk packages have manifests that do not identify them as supporting a 865 specific density range. When running such applications, the following 866 constraints apply:</p> 867 <ul> 868 <li>Device implementations MUST interpret resources in a .apk that lack a 869 density qualifier as defaulting to "medium" (known as "mdpi" in the SDK 870 documentation.)</li> 871 <li>When operating on a "low" density screen, device implementations MUST 872 scale down medium/mdpi assets by a factor of 0.75.</li> 873 <li>When operating on a "high" density screen, device implementations MUST 874 scale up medium/mdpi assets by a factor of 1.5.</li> 875 <li>Device implementations MUST NOT scale assets within a density range, and 876 MUST scale assets by exactly these factors between density ranges.</li> 877 </ul> 878 879 <h4>8.1.2. Non-Standard Display Configurations</h4> 880 <p>Display configurations that do not match one of the standard configurations 881 listed in Section 8.1.1 require additional consideration and work to be 882 compatible. Device implementers MUST contact Android Compatibility Team as 883 provided for in Section 12 to obtain classifications for screen-size bucket, 884 density, and scaling factor. When provided with this information, device 885 implementations MUST implement them as specified.</p> 886 <p>Note that some display configurations (such as very large or very small 887 screens, and some aspect ratios) are fundamentally incompatible with Android 888 2.1; therefore device implementers are encouraged to contact Android 889 Compatibility Team as early as possible in the development process.</p> 890 <h4>8.1.3. Display Metrics</h4> 891 <p>Device implementations MUST report correct valuesfor all display metrics 892 defined in <code>android.util.DisplayMetrics</code> [<a 893 href="#resources25">Resources, 25</a>].</p> 894 895 <h3>8.2. Keyboard</h3> 896 <p>Device implementations:</p> 897 <ul> 898 <li>MUST include support for the Input Management Framework (which allows third party developers to create Input Management Engines -- i.e. soft keyboard) as detailed at developer.android.com</li> 899 <li>MUST provide at least one soft keyboard implementation (regardless of whether a hard keyboard is present)</li> 900 <li>MAY include additional soft keyboard implementations</li> 901 <li>MAY include a hardware keyboard</li> 902 <li>MUST NOT include a hardware keyboard that does not match one of the 903 formats specified in <code>android.content.res.Configuration.keyboard</code> 904 [<a href="#resources24">Resources, 24</a>] (that is, QWERTY, or 12-key)</li> 905 </ul> 906 <h3>8.3. Non-touch Navigation</h3> 907 <p>Device implementations:</p> 908 <ul> 909 <li>MAY omit a non-touch navigation options (that is, may omit a trackball, d-pad, or wheel)</li> 910 <li>MUST report the correct value for 911 <code>android.content.res.Configuration.navigation</code> [<a href="#resources24">Resources, 24</a>]</li> 912 </ul> 913 <h3>8.4. Screen Orientation</h3> 914 <p>Compatible devices MUST support dynamic orientation by applications to 915 either portrait or landscape screen orientation. That is, the device must 916 respect the application's request for a specific screen orientation. Device 917 implementations MAY select either portrait or landscape orientation as the 918 default.</p> 919 <p>Devices MUST report the correct value for the device's current orientation, 920 whenever queried via the android.content.res.Configuration.orientation, 921 android.view.Display.getOrientation(), or other APIs.</p> 922 923 <h3>8.5. Touchscreen input</h3> 924 <p>Device implementations:</p> 925 <ul> 926 <li>MUST have a touchscreen</li> 927 <li>MAY have either capacative or resistive touchscreen</li> 928 <li>MUST report the value of <code>android.content.res.Configuration</code> 929 [<a href="#resources24">Resources, 24</a>] 930 reflecting corresponding to the type of the specific touchscreen on the 931 device</li> 932 </ul> 933 934 <h3>8.6. USB</h3> 935 <p>Device implementations:</p> 936 <ul> 937 <li>MUST implement a USB client, connectable to a USB host with a standard 938 USB-A port</li> 939 <li>MUST implement the Android Debug Bridge over USB (as described in Section 940 7)</li> 941 <li>MUST implement the USB mass storage specification, to allow a host 942 connected to the device to access the contents of the /sdcard volume </li> 943 <li>SHOULD use the micro USB form factor on the device side</li> 944 <li>MAY include a non-standard port on the device side, but if so MUST ship 945 with a cable capable of connecting the custom pinout to standard USB-A 946 port</li> 947 </ul> 948 949 <h3>8.7. Navigation keys</h3> 950 <p>The Home, Menu and Back functions are essential to the Android navigation 951 paradigm. Device implementations MUST make these functions available to the 952 user at all times, regardless of application state. These functions SHOULD be 953 implemented via dedicated buttons. They MAY be implemented using software, 954 gestures, touch panel, etc., but if so they MUST be always accessible and not 955 obscure or interfere with the available application display area.</p> 956 <p>Device implementers SHOULD also provide a dedicated search key. Device 957 implementers MAY also provide send and end keys for phone calls.</p> 958 959 <h3>8.8. Wireless Data Networking</h3> 960 <p>Device implementations MUST include support for wireless high-speed data 961 networking. Specifically, device implementations MUST include support for at 962 least one wireless data standard capable of 200Kbit/sec or greater. Examples of 963 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, etc.</p> 964 <p>If a device implementation includes a particular modality for which the 965 Android SDK includes an API (that is, WiFi, GSM, or CDMA), the implementation 966 MUST support the API.</p> 967 <p>Devices MAY implement more than one form of wireless data connectivity. 968 Devices MAY implement wired data connectivity (such as Ethernet), but MUST 969 nonetheless include at least one form of wireless connectivity, as above.</p> 970 <h3>8.9. Camera</h3> 971 <p>Device implementations MUST include a camera. The included camera:</p> 972 <ul> 973 <li>MUST have a resolution of at least 2 megapixels</li> 974 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented 975 in the camera driver (transparent to application software)</li> 976 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 977 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 978 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 979 registered on a Camera preview surface, unless the application has explicitly 980 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 981 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 982 object. Note that this constraint does not apply to the device's built-in 983 system camera application, but only to third-party applications using 984 <code>Camera.PreviewCallback</code>.</li> 985 </ul> 986 <p>Device implementations MUST implement the following behaviors for the 987 camera-related APIs:</p> 988 <ol> 989 <li>If an application has never called 990 android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST 991 use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to 992 application callbacks.</li> 993 <li>If an application registers an android.hardware.Camera.PreviewCallback 994 instance and the system calls the onPreviewFrame() method when the preview 995 format is YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() 996 must further be in the NV21 encoding format. (This is the format used natively 997 by the 7k hardware family.) That is, NV21 MUST be the default.</li> 998 </ol> 999 <p>Device implementations MUST implement the full Camera API included in the 1000 Android 2.1 SDK documentation [<a href="#resources26">Resources, 26</a>]), 1001 regardless of whether the device includes hardware autofocus or other 1002 capabilities. For instance, cameras that lack autofocus MUST still call any 1003 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 1004 this has no relevance to a non-autofocus camera.)</p> 1005 <p>Device implementations MUST recognize and honor each parameter name defined 1006 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 1007 underlying hardware supports the feature. If the device hardware does not 1008 support a feature, the API must behave as documented. Conversely, Device 1009 implementations MUST NOT honor or recognize string constants passed 1010 to the <code>android.hardware.Camera.setParameters()</code> method other than 1011 those documented as constants on the 1012 <code>android.hardware.Camera.Parameters</code>, unless the constants are 1013 prefixed with a string indicating the name of the device implementer. That is, 1014 device implementations MUST support all standard Camera parameters if the 1015 hardware allows, and MUST NOT support custom Camera parameter types unless 1016 the parameter names are clearly indicated via a string prefix to be non-standard.</p> 1017 1018 <h3>8.10. Accelerometer</h3> 1019 <p>Device implementations MUST include a 3-axis accelerometer and MUST be able 1020 to deliver events at 50 Hz or greater. The coordinate system used by the 1021 accelerometer MUST comply with the Android sensor coordinate system as detailed 1022 in the Android APIs (see [<a href="#resources27">Resources, 27</a>]).</p> 1023 1024 <h3>8.11. Compass</h3> 1025 <p>Device implementations MUST include a 3-axis compass and MUST be able to 1026 deliver events 10 Hz or greater. The coordinate system used by the compass 1027 MUST comply with the Android sensor coordinate system as defined in the Android 1028 API (see [<a href="#resources27">Resources, 27</a>]).</p> 1029 1030 <h3>8.12. GPS</h3> 1031 <p>Device implementations MUST include a GPS, and SHOULD include some form of 1032 "assisted GPS" technique to minimize GPS lock-on time.</p> 1033 1034 <h3>8.13. Telephony</h3> 1035 <p>Android 2.1 MAY be used on devices that do not include telephony hardware. 1036 That is, Android 2.1 is compatible with devices that are not phones. 1037 However, if a device implementation does include GSM or CDMA telephony, it 1038 MUST implement the full support for the API for that technology. Device 1039 implementations that do not include telephony hardware MUST implement the full 1040 APIs as no-ops.</p> 1041 <p>See also Section 8.8, Wireless Data Networking.</p> 1042 1043 <h3>8.14. Memory and Storage</h3> 1044 <p>Device implementations MUST have at least 92MB of memory available to the 1045 kernel and userspace. The 92MB MUST be in addition to any memory dedicated to 1046 hardware components such as radio, memory, and so on that is not under the 1047 kernel's control.</p> 1048 <p>Device implementations MUST have at least 150MB of non-volatile storage 1049 available for user data. That is, the <code>/data</code> partition must be at 1050 least 150MB.</p> 1051 <div class="cdd-erratum">Note: this section was modified by Erratum EX6580.</div> 1052 1053 <h3>8.15. Application Shared Storage</h3> 1054 <p>Device implementations MUST offer shared storage for applications. The 1055 shared storage provided MUST be at least 2GB in size.</p> 1056 <p>Device implementations MUST be configured with shared storage mounted by 1057 default, "out of the box". If the shared storage is not mounted on the Linux 1058 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 1059 from <code>/sdcard</code> to the actual mount point.</p> 1060 <p>Device implementations MUST enforce as documented the 1061 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 1062 shared storage. Shared storage MUST otherwise be writable by any application 1063 that obtains that permission.</p> 1064 <p>Device implementations MAY have hardware for user-accessible removable 1065 storage, such as a Secure Digital card. Alternatively, device implementations 1066 MAY allocate internal (non-removable) storage as shared storage for apps.</p> 1067 <p>Regardless of the form of shared storage used, the shared storage MUST 1068 implement USB mass storage, as described in Section 8.6. As shipped out of the 1069 box, the shared storage MUST be mounted with the FAT filesystem.</p> 1070 <p>It is illustrative to consider two common examples. If a device 1071 implementation includes an SD card slot to satisfy the shared storage 1072 requirement, a FAT-formatted SD card 2GB in size or larger MUST be included 1073 with the device as sold to users, and MUST be mounted by default. 1074 Alternatively, if a device implementation uses internal fixed storage to 1075 satisfy this requirement, that storage MUST be 2GB in size or larger and 1076 mounted on <code>/sdcard</code> (or <code>/sdcard</code> MUST be a symbolic 1077 link to the physical location if it is mounted elsewhere.)</p> 1078 <div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div> 1079 1080 <h3>8.16. Bluetooth</h3> 1081 <p>Device implementations MUST include a Bluetooth transceiver. Device 1082 implementations MUST enable the RFCOMM-based Bluetooth API as described in the 1083 SDK documentation [<a href="#resources29">Resources, 29</a>]. Device 1084 implementations SHOULD implement relevant Bluetooth profiles, such as A2DP, 1085 AVRCP, OBEX, etc. as appropriate for the device.</p> 1086 <div class="cdd-erratum">Note: this section was added by Erratum EX6580.</div> 1087 1088 <h2>9. Performance Compatibility</h2> 1089 <p>One of the goals of the Android Compatibility Program is to enable 1090 consistent application experience to consumers. Compatible implementations 1091 must ensure not only that applications simply run correctly on the device, but 1092 that they do so with reasonable performance and overall good user experience. 1093 Device implementations MUST meet the key performance metrics of an Android 2.1 1094 compatible device defined in the table below:</p> 1095 <table><tbody><tr> 1096 <td><b>Metric</b></td> 1097 <td><b>Performance Threshold</b></td> 1098 <td><b>Comments</b></td> 1099 </tr> 1100 <tr> 1101 <td>Application Launch Time</td> 1102 <td>The following applications should launch within the specified time.<ul> 1103 <li>Browser: less than 1300ms</li> 1104 <li>MMS/SMS: less than 700ms</li> 1105 <li>AlarmClock: less than 650ms</li> 1106 </ul></td> 1107 <td>The launch time is measured as the total time to 1108 complete loading the default activity for the application, including the time 1109 it takes to start the Linux process, load the Android package into the Dalvik 1110 VM, and call onCreate.</td> 1111 </tr> 1112 <tr> 1113 <td>Simultaneous Applications</td> 1114 <td>When multiple applications have been launched, re-launching an 1115 already-running application after it has been launched must take less than the 1116 original launch time.</td> 1117 <td> </td> 1118 </tr> 1119 </tbody> 1120 </table> 1121 1122 <h2>10. Security Model Compatibility</h2> 1123 <p>Device implementations MUST implement a security model consistent with the 1124 Android platform security model as defined in Security and Permissions 1125 reference document in the APIs [<a href="#resources28">Resources, 28</a>] in the 1126 Android developer documentation. Device implementations MUST support 1127 installation of self-signed applications without requiring any additional 1128 permissions/certificates from any third parties/authorities. Specifically, 1129 compatible devices MUST support the security mechanisms described in the 1130 follow sub-sections.</p> 1131 <h3>10.1. Permissions</h3> 1132 <p>Device implementations MUST support the Android permissions model as 1133 defined in the Android developer documentation [<a 1134 href="#resources28">Resources, 28</a>]. Specifically, 1135 implementations MUST enforce each permission defined as described in the SDK 1136 documentation; no permissions may be omitted, altered, or ignored. 1137 Implementations MAY add additional permissions, provided the new permission ID 1138 strings are not in the android.* namespace.</p> 1139 <h3>10.2. UID and Process Isolation</h3> 1140 <p>Device implementations MUST support the Android application sandbox model, 1141 in which each application runs as a unique Unix-style UID and in a separate 1142 process. Device implementations MUST support running multiple applications as 1143 the same Linux user ID, provided that the applications are properly signed and 1144 constructed, as defined in the Security and Permissions reference [<a 1145 href="#resources28">Resources, 28</a>].</p> 1146 <h3>10.3. Filesystem Permissions</h3> 1147 <p>Device implementations MUST support the Android file access permissions 1148 model as defined in as defined in the Security and Permissions reference [<a 1149 href="#resources28">Resources, 28</a>].</p> 1150 1151 <h2>11. Compatibility Test Suite</h2> 1152 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 1153 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source 1154 Project, using the final shipping software on the device. Additionally, device 1155 implementers SHOULD use the reference implementation in the Android Open 1156 Source tree as much as possible, and MUST ensure compatibility in cases of 1157 ambiguity in CTS and for any reimplementations of parts of the reference 1158 source code.</p> 1159 <p>The CTS is designed to be run on an actual device. Like any software, the 1160 CTS may itself contain bugs. The CTS will be versioned independently of this 1161 Compatibility Definition, and multiple revisions of the CTS may be released 1162 for Android 2.1. Device implementations MUST pass the latest CTS version 1163 available at the time the device software is completed.</p> 1164 1165 <h2>12. Updatable Software</h2> 1166 <p>Device implementations MUST include a mechanism to replace the entirety of 1167 the system software. The mechanism need not perform "live" upgrades -- that 1168 is, a device restart MAY be required.</p> 1169 <p>Any method can be used, provided that it can replace the entirety of the 1170 software preinstalled on the device. For instance, any of the following 1171 approaches will satisfy this requirement:</p> 1172 <ul> 1173 <li>Over-the-air (OTA) downloads with offline update via reboot</li> 1174 <li>"Tethered" updates over USB from a host PC</li> 1175 <li>"Offline" updates via a reboot and update from a file on removable 1176 storage</li> 1177 </ul> 1178 <p>The update mechanism used MUST support updates without wiping user data. 1179 Note that the upstream Android software includes an update mechanism that 1180 satisfies this requirement.</p> 1181 <p>If an error is found in a device implementation after it has been released 1182 but within its reasonable product lifetime that is determined in consultation 1183 with the Android Compatibility Team to affect the compatibility of thid-party 1184 applications, the device implementer MUST correct the error via a software 1185 update available that can be applied per the mechanism just described.</p> 1186 1187 <h2>13. Contact Us</h2> 1188 <p>You can contact the document authors at <a 1189 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for 1190 clarifications and to bring up any issues that you think the document does not 1191 cover.</p> 1192 </body> 1193 </html> 1194
