1 <html devsite> 2 <head> 3 <title>Android 4.0 Compatibility Definition</title> 4 <link rel="stylesheet" type="text/css" href="cdd.css"/> 5 </head> 6 <body> 7 <!-- 8 <span style="color: red; font-weight: bold;"><h2>DRAFT 3</h2></span><br/> 9 <span style="color: red;">Last updated: November 17, 2012</span> 10 --> 11 <p>Revision 4<br/> 12 Last updated: April 21, 2013 13 </p> 14 <p>Copyright © 2012, Google Inc. All rights reserved.<br/> 15 <a href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> 16 </p> 17 18 <h2> Table of Contents</h2> 19 <div style="margin-left: 2em;"> 20 <a href="#section-1">1. Introduction</a><br/> 21 <a href="#section-2">2. Resources</a><br/> 22 <a href="#section-3">3. Software</a><br/> 23 <div style="margin-left: 2em;"> 24 <a href="#section-3.1">3.1. Managed API Compatibility</a><br/> 25 <a href="#section-3.2">3.2. Soft API Compatibility</a><br/> 26 <div style="margin-left: 2em;"> 27 <a href="#section-3.2.1">3.2.1. Permissions</a><br/> 28 <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/> 29 <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/> 30 <div style="margin-left: 2em;"> 31 <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/> 32 <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/> 33 <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/> 34 <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/> 35 </div> 36 </div> 37 <a href="#section-3.3">3.3. Native API Compatibility</a><br/> 38 <div style="margin-left: 2em;"> 39 <a href="#section-3.3.1">3.3.1 Application Binary Interfaces</a><br/> 40 </div> 41 <a href="#section-3.4">3.4. Web Compatibility</a><br/> 42 <div style="margin-left: 2em;"> 43 <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/> 44 <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/> 45 </div> 46 <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/> 47 <a href="#section-3.6">3.6. API Namespaces</a><br/> 48 <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/> 49 <a href="#section-3.8">3.8. User Interface Compatibility</a><br/> 50 <div style="margin-left: 2em;"> 51 <a href="#section-3.8.1">3.8.1. Widgets</a><br/> 52 <a href="#section-3.8.2">3.8.2. Notifications</a><br/> 53 <a href="#section-3.8.3">3.8.3. Search</a><br/> 54 <a href="#section-3.8.4">3.8.4. Toasts</a><br/> 55 <a href="#section-3.8.5">3.8.5. Themes</a><br/> 56 <a href="#section-3.8.6">3.8.6. Live Wallpapers</a><br/> 57 <a href="#section-3.8.7">3.8.7. Recent Application Display</a><br/> 58 <a href="#section-3.8.8">3.8.8. Input Management Settings</a><br/> 59 </div> 60 <a href="#section-3.9">3.9 Device Administration</a><br/> 61 <a href="#section-3.10">3.10 Accessibility</a><br/> 62 <a href="#section-3.11">3.11 Text-to-Speech</a><br/> 63 </div> 64 <a href="#section-4">4. Application Packaging Compatibility</a><br/> 65 <a href="#section-5">5. Multimedia Compatibility</a><br/> 66 <div style="margin-left: 2em;"> 67 <a href="#section-5.1">5.1. Media Codecs</a><br/> 68 <a href="#section-5.2">5.2. Video Encoding</a><br/> 69 <a href="#section-5.3">5.3. Audio Recording</a><br/> 70 <a href="#section-5.4">5.4. Audio Latency</a><br/> 71 <a href="#section-5.5">5.5. Network Protocols</a><br/> 72 </div> 73 <a href="#section-6">6. Developer Tool Compatibility</a><br/> 74 <a href="#section-7">7. Hardware Compatibility</a><br/> 75 <div style="margin-left: 2em;"> 76 <a href="#section-7.1">7.1. Display and Graphics</a><br/> 77 <div style="margin-left: 2em;"> 78 <a href="#section-7.1.1">7.1.1. Screen Configuration</a><br/> 79 <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/> 80 <a href="#section-7.1.3">7.1.3. Screen Orientation</a><br/> 81 <a href="#section-7.1.4">7.1.4. 2D and 3D Graphics Accleration</a><br/> 82 <a href="#section-7.1.5">7.1.5. Legacy Application Compatibility Mode</a><br/> 83 <a href="#section-7.1.6">7.1.6. Screen Types</a><br/> 84 <a href="#section-7.1.7">7.1.7. Screen Technology</a><br/> 85 </div> 86 <a href="#section-7.2">7.2. Input Devices</a><br/> 87 <div style="margin-left: 2em;"> 88 <a href="#section-7.2.1">7.2.1. Keyboard</a><br/> 89 <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/> 90 <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/> 91 <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/> 92 <a href="#section-7.2.5">7.2.5. Fake touch input</a><br/> 93 <a href="#section-7.2.6">7.2.6. Microphone</a><br/> 94 </div> 95 <a href="#section-7.3">7.3. Sensors</a><br/> 96 <div style="margin-left: 2em;"> 97 <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/> 98 <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/> 99 <a href="#section-7.3.3">7.3.3. GPS</a><br/> 100 <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/> 101 <a href="#section-7.3.5">7.3.5. Barometer</a><br/> 102 <a href="#section-7.3.6">7.3.6. Thermometer</a><br/> 103 <a href="#section-7.3.7">7.3.7. Photometer</a><br/> 104 <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/> 105 </div> 106 <a href="#section-7.4">7.4. Data Connectivity</a><br/> 107 <div style="margin-left: 2em;"> 108 <a href="#section-7.4.1">7.4.1. Telephony</a><br/> 109 <a href="#section-7.4.2">7.4.2. IEEE 802.11 (WiFi)</a><br/> 110 <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/> 111 <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/> 112 <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/> 113 </div> 114 <a href="#section-7.5">7.5. Cameras</a><br/> 115 <div style="margin-left: 2em;"> 116 <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/> 117 <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/> 118 <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/> 119 <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/> 120 </div> 121 <a href="#section-7.6">7.6. Memory and Storage</a><br/> 122 <div style="margin-left: 2em;"> 123 <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/> 124 <a href="#section-7.6.2">7.6.2. Application Shared Storage</a><br/> 125 </div> 126 <a href="#section-7.7">7.7. USB</a><br/> 127 </div> 128 <a href="#section-8">8. Performance Compatibility</a><br/> 129 <a href="#section-9">9. Security Model Compatibility</a><br/> 130 <div style="margin-left: 2em;"> 131 <a href="#section-9.1">9.1. Permissions</a><br/> 132 <a href="#section-9.2">9.2. UID and Process Isolation</a><br/> 133 <a href="#section-9.3">9.3. Filesystem Permissions</a><br/> 134 <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/> 135 </div> 136 <a href="#section-10">10. Software Compatibility Testing</a><br/> 137 <div style="margin-left: 2em;"> 138 <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/> 139 <a href="#section-10.2">10.2. CTS Verifier</a><br/> 140 <a href="#section-10.3">10.3. Reference Applications</a><br/> 141 </div> 142 <a href="#section-11">11. Updatable Software</a><br/> 143 <a href="#section-12">12. Contact Us</a><br/> 144 <a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/> 145 </div> 146 147 <div style="page-break-before: always;"></div> 148 149 <a name="section-1"></a><h2>1. Introduction</h2> 150 <p>This document enumerates the requirements that must be met in order for 151 devices to be compatible with Android 4.0.</p> 152 <p>The use of "must", "must not", "required", "shall", "shall not", "should", 153 "should not", "recommended", "may" and "optional" is per the IETF standard 154 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 155 <p>As used in this document, a "device implementer" or "implementer" is a 156 person or organization developing a hardware/software solution running Android 157 4.0. A "device implementation" or "implementation" is the hardware/software 158 solution so developed.</p> 159 <p>To be considered compatible with Android 4.0, device implementations 160 MUST meet the requirements presented in this Compatibility Definition, 161 including any documents incorporated via reference.</p> 162 <p>Where this definition or the software tests described in <a 163 href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is 164 the responsibility of the device implementer to ensure compatibility with 165 existing implementations.</p> 166 <p>For this reason, the Android Open Source Project [<a 167 href="#resources03">Resources, 3</a>] is both the reference and preferred 168 implementation of Android. Device implementers are strongly encouraged to base 169 their implementations to the greatest extent possible on the "upstream" source 170 code available from the Android Open Source Project. While some components can 171 hypothetically be replaced with alternate implementations this practice is 172 strongly discouraged, as passing the software tests will become substantially 173 more difficult. It is the implementer's responsibility to ensure full 174 behavioral compatibility with the standard Android implementation, including 175 and beyond the Compatibility Test Suite. Finally, note that certain component 176 substitutions and modifications are explicitly forbidden by this document.</p> 177 <a name="section-2"></a><h2>2. Resources</h2> 178 <ol> 179 <a name="resources01"></a><li>IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></li> 180 <a name="resources02"></a><li>Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></li> 181 <a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 182 <a name="resources04"></a><li>API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></li> 183 <a name="resources05"></a><li>Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></li> 184 <a name="resources06"></a><li>android.os.Build reference: <a href="http://developer.android.com/reference/android/os/Build.html">http://developer.android.com/reference/android/os/Build.html</a></li> 185 <a name="resources07"></a><li>Android 4.0 allowed version strings: <a href="http://source.android.com/compatibility/4.0/versions.html">http://source.android.com/compatibility/4.0/versions.html</a></li> 186 <a name="resources08"></a><li>Renderscript: <a href="http://developer.android.com/guide/topics/graphics/renderscript.html">http://developer.android.com/guide/topics/graphics/renderscript.html</a></li> 187 <a name="resources09"></a><li>Hardware Acceleration: <a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">http://developer.android.com/guide/topics/graphics/hardware-accel.html</a></li> 188 <a name="resources10"></a><li>android.webkit.WebView class: <a href="http://developer.android.com/reference/android/webkit/WebView.html">http://developer.android.com/reference/android/webkit/WebView.html</a></li> 189 <a name="resources11"></a><li>HTML5: <a href="http://www.whatwg.org/specs/web-apps/current-work/multipage/">http://www.whatwg.org/specs/web-apps/current-work/multipage/</a></li> 190 <a name="resources12"></a><li>HTML5 offline capabilities: <a href="http://dev.w3.org/html5/spec/Overview.html#offline">http://dev.w3.org/html5/spec/Overview.html#offline</a></li> 191 <a name="resources13"></a><li>HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></li> 192 <a name="resources14"></a><li>HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></li> 193 <a name="resources15"></a><li>HTML5/W3C webdatabase API: <a href="http://www.w3.org/TR/webdatabase/">http://www.w3.org/TR/webdatabase/</a></li> 194 <a name="resources16"></a><li>HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></li> 195 <a name="resources17"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 196 <a name="resources18"></a><li>AppWidgets: <a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">http://developer.android.com/guide/practices/ui_guidelines/widget_design.html</a></li> 197 <a name="resources19"></a><li>Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></li> 198 <a name="resources20"></a><li>Application Resources: <a href="http://code.google.com/android/reference/available-resources.html">http://code.google.com/android/reference/available-resources.html</a></li> 199 <a name="resources21"></a><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design.html#statusbarstructure">http://developer.android.com/guide/practices/ui_guideline /icon_design.html#statusbarstructure</a></li> 200 <a name="resources22"></a><li>Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></li> 201 <a name="resources23"></a><li>Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></li> 202 <a name="resources24"></a><li>Themes: <a href="http://developer.android.com/guide/topics/ui/themes.html">http://developer.android.com/guide/topics/ui/themes.html</a></li> 203 <a name="resources25"></a><li>R.style class: <a href="http://developer.android.com/reference/android/R.style.html">http://developer.android.com/reference/android/R.style.html</a></li> 204 <a name="resources26"></a><li>Live Wallpapers: <a href="http://developer.android.com/resources/articles/live-wallpapers.html">http://developer.android.com/resources/articles/live-wallpapers.html</a></li> 205 <a name="resources27"></a><li>Android Device Administration: <a href="http://developer.android.com/guide/topics/admin/device-admin.html">http://developer.android.com/guide/topics/admin/device-admin.html</a></li> 206 <a name="resources28"></a><li>android.app.admin.DevicePolicyManager class: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html</a></li> 207 <a name="resources29"></a><li>Android Accessibility Service APIs: <a href="http://developer.android.com/reference/android/accessibilityservice/package-summary.html">http://developer.android.com/reference/android/accessibilityservice/package-summary.html</a></li> 208 <a name="resources30"></a><li>Android Accessibility APIs: <a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">http://developer.android.com/reference/android/view/accessibility/package-summary.html</a></li> 209 <a name="resources31"></a><li>Eyes Free project: <a href="http://http://code.google.com/p/eyes-free">http://code.google.com/p/eyes-free</a></li> 210 <a name="resources32"></a><li>Text-To-Speech APIs: <a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">http://developer.android.com/reference/android/speech/tts/package-summary.html</a></li> 211 <a name="resources33"></a><li>Reference tool documentation (for adb, aapt, ddms): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li> 212 <a name="resources34"></a><li>Android apk file description: <a href="http://developer.android.com/guide/topics/fundamentals.html">http://developer.android.com/guide/topics/fundamentals.html</a></li> 213 <a name="resources35"></a><li>Manifest files: <a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">http://developer.android.com/guide/topics/manifest/manifest-intro.html</a></li> 214 <a name="resources36"></a><li>Monkey testing tool: <a href="http://developer.android.com/guide/developing/tools/monkey.html">http://developer.android.com/guide/developing/tools/monkey.html</a></li> 215 <a name="resources37"></a><li>Android android.content.pm.PackageManager class and Hardware Features List: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">http://developer.android.com/reference/android/content/pm/PackageManager.html</a></li> 216 <a name="resources38"></a><li>Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></li> 217 <a name="resources39"></a><li>android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></li> 218 <a name="resources40"></a><li>android.content.res.Configuration: <a href="http://developer.android.com/reference/android/content/res/Configuration.html">http://developer.android.com/reference/android/content/res/Configuration.html</a></li> 219 <a name="resources41"></a><li>android.hardware.SensorEvent: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></li> 220 <a name="resources42"></a><li>Bluetooth API: <a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">http://developer.android.com/reference/android/bluetooth/package-summary.html</a></li> 221 <a name="resources43"></a><li>NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></li> 222 <a name="resources44"></a><li>MIFARE MF1S503X: <a href="http://www.nxp.com/documents/data_sheet/MF1S503x.pdf">http://www.nxp.com/documents/data_sheet/MF1S503x.pdf</a></li> 223 <a name="resources45"></a><li>MIFARE MF1S703X: <a href="http://www.nxp.com/documents/data_sheet/MF1S703x.pdf">http://www.nxp.com/documents/data_sheet/MF1S703x.pdf</a></li> 224 <a name="resources46"></a><li>MIFARE MF0ICU1: <a href="http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf">http://www.nxp.com/documents/data_sheet/MF0ICU1.pdf</a></li> 225 <a name="resources47"></a><li>MIFARE MF0ICU2: <a href="http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf">http://www.nxp.com/documents/short_data_sheet/MF0ICU2_SDS.pdf</a></li> 226 <a name="resources48"></a><li>MIFARE AN130511: <a href="http://www.nxp.com/documents/application_note/AN130511.pdf">http://www.nxp.com/documents/application_note/AN130511.pdf</a></li> 227 <a name="resources49"></a><li>MIFARE AN130411: <a href="http://www.nxp.com/documents/application_note/AN130411.pdf">http://www.nxp.com/documents/application_note/AN130411.pdf</a></li> 228 <a name="resources50"></a><li>Camera orientation API: <a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)</a></li> 229 <a name="resources51"></a><li>android.hardware.Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li> 230 <a name="resources52"></a><li>Android Open Accessories: <a href="http://developer.android.com/guide/topics/usb/accessory.html">http://developer.android.com/guide/topics/usb/accessory.html</a></li> 231 <a name="resources53"></a><li>USB Host API: <a href="http://developer.android.com/guide/topics/usb/host.html">http://developer.android.com/guide/topics/usb/host.html</a></li> 232 <a name="resources54"></a><li>Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/security.html">http://developer.android.com/guide/topics/security/security.html</a></li> 233 <a name="resources55"></a><li>Apps for Android: <a href="http://code.google.com/p/apps-for-android">http://code.google.com/p/apps-for-android</a></li> 234 <a name="resources56"></a><li>android.app.DownloadManager class: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></li> 235 <a name="resources57"></a><li>Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></li> 236 <a name="resources58"></a><li>Android Media Formats: <a href="http://developer.android.com/guide/appendix/media-formats.html">http://developer.android.com/guide/appendix/media-formats.html</a></li> 237 <a name="resources59"></a><li>HTTP Live Streaming Draft Protocol: <a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">http://tools.ietf.org/html/draft-pantos-http-live-streaming-03</a></li> 238 <a name="resources60"></a><li>Motion Event API: <a href="http://developer.android.com/reference/android/view/MotionEvent.html">http://developer.android.com/reference/android/view/MotionEvent.html</a></li> 239 <a name="resources61"></a><li>Touch Input Configuration: <a href="http://source.android.com/tech/input/touch-devices.html">http://source.android.com/tech/input/touch-devices.html</a></li> 240 </ol> 241 242 <p>Many of these resources are derived directly or indirectly from the Android 243 4.0 SDK, and will be functionally identical to the information in that SDK's 244 documentation. In any cases where this Compatibility Definition or the 245 Compatibility Test Suite disagrees with the SDK documentation, the SDK 246 documentation is considered authoritative. Any technical details provided in 247 the references included above are considered by inclusion to be part of this 248 Compatibility Definition.</p> 249 250 <a name="section-3"></a><h2>3. Software</h2> 251 <a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3> 252 <p>The managed (Dalvik-based) execution environment is the primary vehicle for 253 Android applications. The Android application programming interface (API) is 254 the set of Android platform interfaces exposed to applications running in the 255 managed VM environment. Device implementations MUST provide complete 256 implementations, including all documented behaviors, of any documented API 257 exposed by the Android 4.0 SDK [<a href="#resources04">Resources, 4</a>].</p> 258 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 259 or signatures, deviate from the documented behavior, or include no-ops, except 260 where specifically allowed by this Compatibility Definition.</p> 261 <p>This Compatibility Definition permits some types of hardware for which 262 Android includes APIs to be omitted by device implementations. In such cases, 263 the APIs MUST still be present and behave in a reasonable way. See 264 <a href="#section-7">Section 7</a> for specific requirements for this scenario. 265 </p> 266 267 <a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3> 268 <p>In addition to the managed APIs from Section 3.1, Android also includes a 269 significant runtime-only "soft" API, in the form of such things such as 270 Intents, permissions, and similar aspects of Android applications that cannot 271 be enforced at application compile time.</p> 272 <a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4> 273 <p>Device implementers MUST support and enforce all permission constants as 274 documented by the Permission reference page [<a 275 href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional 276 requirements related to the Android security model.</p> 277 <a name="section-3.2.3"></a><h4>3.2.3. Build Parameters</h4> 278 <p>The Android APIs include a number of constants on the <code>android.os.Build</code> 279 class [<a href="#resources06">Resources, 6</a>] that are intended to describe 280 the current device. To provide consistent, meaningful values across device 281 implementations, the table below includes additional restrictions on the 282 formats of these values to which device implementations MUST conform.</p> 283 <table> 284 <tbody> 285 <tr> 286 <td><b>Parameter</b></td> 287 <td><b>Comments</b></td> 288 </tr> 289 <tr> 290 <td>android.os.Build.VERSION.RELEASE</td> 291 <td>The version of the currently-executing Android system, in human-readable 292 format. This field MUST have one of the string values defined in [<a 293 href="#resources07">Resources, 7</a>].</td> 294 </tr> 295 <tr> 296 <td>android.os.Build.VERSION.SDK</td> 297 <td>The version of the currently-executing Android system, in a format 298 accessible to third-party application code. For Android 4.0.1 - 4.0.2, this 299 field MUST have the integer value 14. For Android 4.0.3 or greater, this field 300 MUST have the integer value 15.</td> 301 </tr> 302 <tr> 303 <td>android.os.Build.VERSION.SDK_INT</td> 304 <td>The version of the currently-executing Android system, in a format 305 accessible to third-party application code. For Android 4.0.1 - 4.0.2, this 306 field MUST have the integer value 14. For Android 4.0.3 or greater, this field 307 MUST have the integer value 15.</td> 308 </tr> 309 <tr> 310 <td>android.os.Build.VERSION.INCREMENTAL</td> 311 <td>A value chosen by the device implementer designating the specific build of 312 the currently-executing Android system, in human-readable format. This value 313 MUST NOT be re-used for different builds made available to end users. A typical use 314 of this field is to indicate which build number or source-control change 315 identifier was used to generate the build. There are no requirements on the 316 specific format of this field, except that it MUST NOT be null or the empty 317 string ("").</td> 318 </tr> 319 <tr> 320 <td>android.os.Build.BOARD</td> 321 <td>A value chosen by the device implementer identifying the specific internal 322 hardware used by the device, in human-readable format. A possible use of this 323 field is to indicate the specific revision of the board powering the device. 324 The value of this field MUST be encodable as 7-bit ASCII and match the regular expression 325 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 326 </tr> 327 <tr> 328 <td>android.os.Build.BRAND</td> 329 <td>A value chosen by the device implementer identifying the name of the 330 company, organization, individual, etc. who produced the device, in 331 human-readable format. A possible use of this field is to indicate the OEM 332 and/or carrier who sold the device. The value of this field MUST be 333 encodable as 7-bit ASCII and match the regular expression 334 <code>"^[a-zA-Z0-9.,_-]+$"</code>. 335 </td> 336 </tr> 337 <tr> 338 <td>android.os.Build.CPU_ABI</td> 339 <td>The name of the instruction set (CPU type + ABI convention) of native code. 340 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>. 341 </td> 342 </tr> 343 <tr> 344 <td>android.os.Build.CPU_ABI2</td> 345 <td>The name of the second instruction set (CPU type + ABI convention) of native code. 346 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>. 347 </td> 348 </tr> 349 <tr> 350 <td>android.os.Build.DEVICE</td> 351 <td>A value chosen by the device implementer identifying the specific 352 configuration or revision of the body (sometimes called "industrial design") 353 of the device. The value of this field MUST be encodable as 7-bit ASCII and 354 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 355 </tr> 356 <tr> 357 <td>android.os.Build.FINGERPRINT</td> 358 <td>A string that uniquely identifies this build. It SHOULD be reasonably 359 human-readable. It MUST follow this template: 360 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 361 For example: 362 <br/><code>acme/mydevice/generic:4.0/IRK77/3359:userdebug/test-keys</code><br/> 363 The fingerprint MUST NOT include whitespace characters. If other fields included in the 364 template above have whitespace characters, they MUST be replaced in the build 365 fingerprint with another character, such as the underscore ("_") character. 366 The value of this field MUST be encodable as 7-bit ASCII.</td> 367 </tr> 368 <tr> 369 <td>android.os.Build.HARDWARE</td> 370 <td>The name of the hardware (from the kernel command line or /proc). It SHOULD be 371 reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and 372 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 373 </tr> 374 <tr> 375 <td>android.os.Build.HOST</td> 376 <td>A string that uniquely identifies the host the build was built on, in 377 human readable format. There are no requirements on the specific format of 378 this field, except that it MUST NOT be null or the empty string ("").</td> 379 </tr> 380 <tr> 381 <td>android.os.Build.ID</td> 382 <td>An identifier chosen by the device implementer to refer to a specific 383 release, in human readable format. This field can be the same as 384 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 385 meaningful for end users to distinguish between software builds. The value of 386 this field MUST be encodable as 7-bit ASCII and match the regular expression 387 <code>"^[a-zA-Z0-9.,_-]+$"</code>. 388 </td> 389 </tr> 390 <tr> 391 <td>android.os.Build.MANUFACTURER</td> 392 <td>The trade name of the Original Equipment Manufacturer (OEM) of the product. 393 There are no requirements on the specific format of this field, except that it 394 MUST NOT be null or the empty string ("").</td> 395 </tr> 396 <tr> 397 <td>android.os.Build.MODEL</td> 398 <td>A value chosen by the device implementer containing the name of the device 399 as known to the end user. This SHOULD be the same name under which the device 400 is marketed and sold to end users. There are no requirements on the specific 401 format of this field, except that it MUST NOT be null or the empty string 402 ("").</td> 403 </tr> 404 <tr> 405 <td>android.os.Build.PRODUCT</td> 406 <td>A value chosen by the device implementer containing the development name 407 or code name of the product (SKU). MUST be human-readable, but is not necessarily 408 intended for view by end users. The value of this field MUST be encodable as 7-bit 409 ASCII and match the regular expression 410 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 411 </tr> 412 <tr> 413 <td>android.os.Build.SERIAL</td> 414 <td>A hardware serial number, if available. The value of this field MUST be encodable 415 as 7-bit ASCII and match the regular expression 416 <code>"^([a-zA-Z0-9]{0,20})$"</code>.</td> 417 </tr> 418 <tr> 419 <td>android.os.Build.TAGS</td> 420 <td>A comma-separated list of tags chosen by the device implementer that 421 further distinguish the build. For example, "unsigned,debug". The value of 422 this field MUST be encodable as 7-bit ASCII and match the regular expression 423 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 424 </tr> 425 <tr> 426 <td>android.os.Build.TIME</td> 427 <td>A value representing the timestamp of when the build occurred.</td> 428 </tr> 429 <tr> 430 <td>android.os.Build.TYPE</td> 431 <td>A value chosen by the device implementer specifying the runtime 432 configuration of the build. This field SHOULD have one of the values 433 corresponding to the three typical Android runtime configurations: "user", 434 "userdebug", or "eng". The value of this field MUST be 435 encodable as 7-bit ASCII and match the regular expression 436 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 437 </tr> 438 <tr> 439 <td>android.os.Build.USER</td> 440 <td>A name or user ID of the user (or automated user) that generated the 441 build. There are no requirements on the specific format of this field, except 442 that it MUST NOT be null or the empty string ("").</td> 443 </tr> 444 </tbody> 445 </table> 446 <a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4> 447 <p> 448 Device implementations MUST honor Android's loose-coupling Intent system, as 449 described in the sections below. By "honored", it is meant that the device 450 implementer MUST provide an Android Activity or Service that specifies a 451 matching Intent filter and binds to and implements correct behavior for each 452 specified Intent pattern.</p> 453 <a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4> 454 <p>The Android upstream project defines a number of core applications, such as 455 contacts, calendar, photo gallery, music player, and so on. Device implementers 456 MAY replace these applications with alternative versions.</p> 457 <p>However, any such alternative versions MUST honor the same Intent patterns 458 provided by the upstream project. For example, if a device contains an 459 alternative music player, it must still honor the Intent pattern issued by 460 third-party applications to pick a song.</p> 461 <p>The following applications are considered core Android system 462 applications:</p> 463 <ul> 464 <li>Desk Clock</li> 465 <li>Browser</li> 466 <li>Calendar</li> 467 <li>Contacts</li> 468 <!--<li>Email</li>--> 469 <li>Gallery</li> 470 <li>GlobalSearch</li> 471 <li>Launcher</li> 472 <!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 473 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> --> 474 <!-- <li>Messaging (AKA "Mms")</li> --> 475 <li>Music</li> 476 <!-- <li>Phone</li> --> 477 <li>Settings</li> 478 <!-- <li>SoundRecorder</li> --> 479 </ul> 480 <p>The core Android system applications include various Activity, or Service 481 components that are considered "public". That is, the attribute 482 "android:exported" may be absent, or may have the value "true".</p> 483 <p>For every Activity or Service defined 484 in one of the core Android system apps that is not marked as non-public via an 485 android:exported attribute with the value "false", device implementations MUST 486 include a compontent of the same type implementing the same Intent filter 487 patterns as the core Android system app.</p> 488 <p>In other words, a device implementation MAY replace core Android system 489 apps; however, if it does, the device implementation MUST support all Intent 490 patterns defined by each core Android system app being replaced.</p> 491 <a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4> 492 <p>As Android is an extensible platform, device implementations MUST allow each 493 Intent pattern referenced in Section 3.2.3.2 to be overridden by third-party 494 applications. The upstream Android open source implementation allows this by 495 default; device implementers MUST NOT attach special privileges to system 496 applications' use of these Intent patterns, or prevent third-party 497 applications from binding to and assuming control of these patterns. This 498 prohibition specifically includes but is not limited to disabling the 499 "Chooser" user interface which allows the user to select between multiple 500 applications which all handle the same Intent pattern.</p> 501 <a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4> 502 <p>Device implementations MUST NOT include any Android component that honors any 503 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 504 key string in the android.* or com.android.* namespace. Device implementers 505 MUST NOT include any Android components that honor any new Intent or Broadcast 506 Intent patterns using an ACTION, CATEGORY, or other key string in a package 507 space belonging to another organization. Device implementers MUST NOT alter or 508 extend any of the Intent patterns used by the core apps listed in Section 509 3.2.3.1. Device implementations MAY include Intent patterns using 510 namespaces clearly and obviously associated with their own organization.</p> 511 <p>This prohibition is analogous to that specified for Java language classes 512 in Section 3.6.</p> 513 <a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4> 514 <p>Third-party applications rely on the platform to broadcast certain Intents 515 to notify them of changes in the hardware or software environment. 516 Android-compatible devices MUST broadcast the public broadcast Intents in 517 response to appropriate system events. Broadcast Intents are described in the 518 SDK documentation.</p> 519 520 <a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3> 521 <a name="section-3.3.1"></a><h4>3.3.1 Application Binary Interfaces</h4> 522 <p>Managed code running in Dalvik can call into native code provided in the 523 application .apk file as an ELF .so file compiled for the appropriate device 524 hardware architecture. As native code is highly dependent on the underlying 525 processor technology, Android defines a number of Application Binary 526 Interfaces (ABIs) in the Android NDK, in the file 527 <code>docs/CPU-ARCH-ABIS.txt</code>. If a device implementation is compatible 528 with one or more defined ABIs, it SHOULD implement compatibility with the 529 Android NDK, as below.</p> 530 <p>If a device implementation includes support for an Android ABI, it:</p> 531 <ul> 532 <li>MUST include support for code running in the managed environment to call 533 into native code, using the standard Java Native Interface (JNI) 534 semantics.</li> 535 <li>MUST be source-compatible (i.e. header compatible) and binary-compatible 536 (for the ABI) with each required library in the list below</li> 537 <li>MUST accurately report the native Application Binary Interface (ABI) 538 supported by the device, via the <code>android.os.Build.CPU_ABI</code> 539 API</li> 540 <li>MUST report only those ABIs documented in the latest version of the 541 Android NDK, in the file <code>docs/CPU-ARCH-ABIS.txt</code></li> 542 <li>SHOULD be built using the source code and header files available in the 543 upstream Android open source project</li> 544 </ul> 545 <p>The following native code APIs MUST be available to apps that include 546 native code:</p> 547 <ul> 548 <li>libc (C library)</li> 549 <li>libm (math library)</li> 550 <li>Minimal support for C++</li> 551 <li>JNI interface</li> 552 <li>liblog (Android logging)</li> 553 <li>libz (Zlib compression)</li> 554 <li>libdl (dynamic linker)</li> 555 <li>libGLESv1_CM.so (OpenGL ES 1.0)</li> 556 <li>libGLESv2.so (OpenGL ES 2.0)</li> 557 <li>libEGL.so (native OpenGL surface management)</li> 558 <li>libjnigraphics.so</li> 559 <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li> 560 <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li> 561 <li>libandroid.so (native Android activity support)</li> 562 <li>Support for OpenGL, as described below</li> 563 </ul> 564 <p>Note that future releases of the Android NDK may introduce support for 565 additional ABIs. If a device implementation is not compatible with an existing 566 predefined ABI, it MUST NOT report support for any ABI at all.</p> 567 <p>Native code compatibility is challenging. For this reason, it should be 568 repeated that device implementers are VERY strongly encouraged to use the 569 upstream implementations of the libraries listed above to help ensure 570 compatibility.</p> 571 572 <a name="section-3.4"></a><h3>3.4. Web Compatibility</h3> 573 <a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4> 574 <p>The Android Open Source implementation uses the WebKit rendering engine to 575 implement the <code>android.webkit.WebView</code>. Because it is not feasible 576 to develop a comprehensive test suite for a web rendering system, device 577 implementers MUST use the specific upstream build of WebKit in the WebView 578 implementation. Specifically:</p> 579 <ul> 580 <li>Device implementations' <code>android.webkit.WebView</code> 581 implementations MUST be based on the 534.30 WebKit build from the upstream 582 Android Open Source tree for Android 4.0. This build includes a specific set 583 of functionality and security fixes for the WebView. Device implementers MAY 584 include customizations to the WebKit implementation; however, any such 585 customizations MUST NOT alter the behavior of the WebView, including rendering 586 behavior.</li> 587 <li>The user agent string reported by the WebView MUST be in this format:<br/> 588 <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.0 Mobile Safari/534.30</code> 589 <ul> 590 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 591 <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> 592 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 593 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 594 </ul> 595 </li> 596 </ul> 597 <p>The WebView component SHOULD include support for as much of HTML5 [<a 598 href="#resources11">Resources, 11</a>] as possible. 599 Minimally, device implementations MUST support each of these APIs associated 600 with HTML5 in the WebView:</p> 601 <ul> 602 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li> 603 <li>the <video> tag [<a href="#resources13">Resources, 13</a>]</li> 604 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li> 605 </ul> 606 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage 607 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the 608 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note 609 that as the web development standards bodies are transitioning to favor 610 IndexedDB over webstorage, IndexedDB is expected to become a required 611 component in a future version of Android.</i></p> 612 <p>HTML5 APIs, like all JavaScript APIs, MUST be disabled by default in a 613 WebView, unless the developer explicitly enables them via the usual Android 614 APIs.</p> 615 616 <a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4> 617 <p>Device implementations MUST include a standalone Browser application for 618 general user web browsing. The standalone Browser MAY be based on a 619 browser technology other than WebKit. However, even if an alternate Browser 620 application is used, the <code>android.webkit.WebView</code> component 621 provided to third-party applications MUST be based on WebKit, as described in 622 Section 3.4.1.</p> 623 <p>Implementations MAY ship a custom user agent string in the standalone 624 Browser application.</p> 625 <p>The standalone Browser application (whether based on the upstream 626 WebKit Browser application or a third-party replacement) SHOULD include support 627 for as much of HTML5 [<a href="#resources11">Resources, 11</a>] as possible. 628 Minimally, device implementations MUST support each of these APIs associated 629 with HTML5:</p> 630 <ul> 631 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li> 632 <li>the <video> tag [<a href="#resources13">Resources, 13</a>]</li> 633 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li> 634 </ul> 635 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage 636 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the 637 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note 638 that as the web development standards bodies are transitioning to favor 639 IndexedDB over webstorage, IndexedDB is expected to become a required 640 component in a future version of Android.</i></p> 641 642 <a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3> 643 <p>The behaviors of each of the API types (managed, soft, native, and web) 644 must be consistent with the preferred implementation of the upstream Android 645 open source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 646 of compatibility are:</p> 647 <ul> 648 <li>Devices MUST NOT change the behavior or semantics of a standard Intent</li> 649 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a 650 particular type of system component (such as Service, Activity, 651 ContentProvider, etc.)</li> 652 <li>Devices MUST NOT change the semantics of a standard permission</li> 653 </ul> 654 <p>The above list is not comprehensive. The Compatibility Test Suite (CTS) 655 tests significant portions of the platform for behavioral compatibility, but 656 not all. It is the responsibility of the implementer to ensure behavioral 657 compatibility with the Android Open Source Project. For this reason, device 658 implementers SHOULD use the source code available via the Android Open Source 659 Project where possible, rather than re-implement significant parts of the 660 system.</p> 661 662 663 <a name="section-3.6"></a><h3>3.6. API Namespaces</h3> 664 <p>Android follows the package and class namespace conventions defined by the 665 Java programming language. To ensure compatibility with third-party 666 applications, device implementers MUST NOT make any prohibited modifications 667 (see below) to these package namespaces:</p> 668 <ul> 669 <li>java.*</li> 670 <li>javax.*</li> 671 <li>sun.*</li> 672 <li>android.*</li> 673 <li>com.android.*</li> 674 </ul> 675 <p>Prohibited modifications include:</p> 676 <ul> 677 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 678 Android platform by changing any method or class signatures, or by removing 679 classes or class fields.</li> 680 <li>Device implementers MAY modify the underlying implementation of the APIs, 681 but such modifications MUST NOT impact the stated behavior and Java-language 682 signature of any publicly exposed APIs.</li> 683 <li>Device implementers MUST NOT add any publicly exposed elements (such as 684 classes or interfaces, or fields or methods to existing classes or interfaces) 685 to the APIs above.</li> 686 </ul> 687 <p>A "publicly exposed element" is any construct which is not decorated with 688 the "@hide" marker as used in the upstream Android source code. In other 689 words, device implementers MUST NOT expose new APIs or alter existing APIs in 690 the namespaces noted above. Device implementers MAY make internal-only 691 modifications, but those modifications MUST NOT be advertised or otherwise 692 exposed to developers.</p> 693 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 694 namespace owned by or referring to another organization. For instance, device 695 implementers MUST NOT add APIs to the com.google.* or similar namespace; only 696 Google may do so. Similarly, Google MUST NOT add APIs to other companies' 697 namespaces. Additionally, if a device implementation includes custom APIs 698 outside the standard Android namespace, those APIs MUST be packaged in an 699 Android shared library so that only apps that explicitly use them (via the 700 <code><uses-library></code> mechanism) are affected by the increased 701 memory usage of such APIs.</p> 702 <p>If a device implementer proposes to improve one of the package namespaces 703 above (such as by adding useful new functionality to an existing API, or 704 adding a new API), the implementer SHOULD visit source.android.com and begin 705 the process for contributing changes and code, according to the information on 706 that site.</p> 707 <p>Note that the restrictions above correspond to standard conventions for 708 naming APIs in the Java programming language; this section simply aims to 709 reinforce those conventions and make them binding through inclusion in this 710 compatibility definition.</p> 711 712 <a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3> 713 <p>Device implementations MUST support the full Dalvik Executable (DEX) 714 bytecode specification and Dalvik Virtual Machine semantics [<a 715 href="#resources17">Resources, 17</a>].</p> 716 <p>Device implementations MUST configure Dalvik to allocate memory in 717 accordance with the upstream Android platform, and as specified by the following 718 table. (See <a href="#section-7.1.1">Section 7.1.1</a> for screen size and screen 719 density definitions.)</p> 720 721 <p>Note that memory values specified below are considered minimum values, 722 and device implementations MAY allocate more memory per application.</p> 723 <table> 724 <tbody> 725 <tr> 726 <td><b>Screen Size</b></td> 727 <td><b>Screen Density</b></td> 728 <td><b>Application Memory</b></td> 729 </tr> 730 <tr> 731 <td>small / normal / large</td> 732 <td>ldpi / mdpi</td> 733 <td>16MB</td> 734 </tr> 735 <tr> 736 <td>small / normal / large</td> 737 <td>tvdpi / hdpi</td> 738 <td>32MB</td> 739 </tr> 740 <tr> 741 <td>small / normal / large</td> 742 <td>xhdpi</td> 743 <td>64MB</td> 744 </tr> 745 <tr> 746 <td>xlarge</td> 747 <td>mdpi</td> 748 <td>32MB</td> 749 </tr> 750 <tr> 751 <td>xlarge</td> 752 <td>tvdpi / hdpi</td> 753 <td>64MB</td> 754 </tr> 755 <tr> 756 <td>xlarge</td> 757 <td>xhdpi</td> 758 <td>128MB</td> 759 </tr> 760 </tbody> 761 </table> 762 763 <a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3> 764 <a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4> 765 <p>Android defines a component type and corresponding API and lifecycle that 766 allows applications to expose an "AppWidget" to the end user [<a 767 href="#resources18">Resources, 18</a>]. 768 The Android Open Source reference release includes a Launcher application that 769 includes user interface affordances allowing the user to add, view, and remove 770 AppWidgets from the home screen.</p> 771 <p>Device implementations MAY substitute an alternative to the reference Launcher 772 (i.e. home screen). Alternative Launchers SHOULD include built-in support for 773 AppWidgets, and expose user interface affordances to add, configure, view, and 774 remove AppWidgets directly within the Launcher. Alternative Launchers MAY omit 775 these user interface elements; however, if they are omitted, the device 776 implementation MUST provide a separate application accessible from the Launcher 777 that allows users to add, configure, view, and remove AppWidgets.</p> 778 <p>Device implementations MUST be capable of rendering widgets that are 4 x 4 779 in the standard grid size. (See the App Widget Design Guidelines in the Android 780 SDK documentation [<a 781 href="#resources18">Resources, 18</a>] for details.</p> 782 <a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4> 783 <p>Android includes APIs that allow developers to notify users of notable 784 events [<a href="#resources19">Resources, 19</a>], using hardware and software 785 features of the device.</p> 786 <p>Some APIs allow applications to perform notifications or attract attention 787 using hardware, specifically sound, vibration, and light. Device implementations 788 MUST support notifications that use hardware features, as described in the SDK 789 documentation, and to the extent possible with the device implementation 790 hardware. For instance, if a device implementation includes a vibrator, it 791 MUST correctly implement the vibration APIs. If a device implementation lacks 792 hardware, the corresponding APIs MUST be implemented as no-ops. Note that this 793 behavior is further detailed in <a href="#section-7">Section 7.</a></p> 794 <p>Additionally, the implementation MUST correctly render all resources 795 (icons, sound files, etc.) provided for in the APIs [<a 796 href="#resources20">Resources, 20</a>], or in the 797 Status/System Bar icon style guide [<a href="#resources21">Resources, 21</a>]. 798 Device implementers MAY provide an alternative user experience for 799 notifications than that provided by the reference Android Open Source 800 implementation; however, such alternative notification systems MUST support 801 existing notification resources, as above.</p> 802 <p>Android 4.0 includes support for rich notifications, such as interactive 803 Views for ongoing notifications. Device implementations MUST properly display 804 and execute rich notifications, as documented in the Android APIs.</p> 805 <a name="section-3.8.3"></a><h4>3.8.3. Search</h4> 806 <p>Android includes APIs [<a href="#resources22">Resources, 22</a>] that allow 807 developers to incorporate search into their applications, and expose their 808 application's data into the global system search. Generally speaking, this 809 functionality consists of a single, system-wide user interface that allows users 810 to enter queries, displays suggestions as users type, and displays results. The 811 Android APIs allow developers to reuse this interface to provide search within 812 their own apps, and allow developers to supply results to the common global 813 search user interface.</p> 814 <p>Device implementations MUST include a single, shared, system-wide search 815 user interface capable of real-time suggestions in response to user input. 816 Device implementations MUST implement the APIs that allow developers to reuse 817 this user interface to provide search within their own applications. Device 818 implementations MUST implement the APIs that allow third-party applications to 819 add suggestions to the search box when it is run in global search mode. If no 820 third-party applications are installed that make use of this functionality, 821 the default behavior SHOULD be to display web search engine results and 822 suggestions.</p> 823 <a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4> 824 <p>Applications can use the "Toast" API (defined in [<a 825 href="#resources23">Resources, 23</a>]) to 826 display short non-modal strings to the end user, that disappear after a brief 827 period of time. Device implementations MUST display Toasts from applications 828 to end users in some high-visibility manner.</p> 829 830 <a name="section-3.8.5"></a><h4>3.8.5. Themes</h4> 831 <p>Android provides "themes" as a mechanism for applications to apply styles 832 across an entire Activity or application. Android 3.0 introduced a new "Holo" 833 or "holographic" theme as a set of defined styles for application developers to 834 use if they want to match the Holo theme look and feel as defined by the Android 835 SDK [<a href="#resources24">Resources, 24</a>]. Device implementations MUST NOT 836 alter any of the Holo theme attributes exposed to applications 837 [<a href="#resources25">Resources, 25</a>].</p> 838 <p>Android 4.0 introduces a new "Device Default" theme as a set of defined 839 styles for application developers to use if they want to match the look and feel 840 of the device theme as defined by the device implementer. Device implementations 841 MAY modify the DeviceDefault theme attributes exposed to applications 842 [<a href="#resources25">Resources, 25</a>].</p> 843 844 <a name="section-3.8.6"></a><h4>3.8.6. Live Wallpapers</h4> 845 <p>Android defines a component type and corresponding API and lifecycle that 846 allows applications to expose one or more "Live Wallpapers" to the end user 847 [<a href="#resources26">Resources, 26</a>]. Live Wallpapers are animations, 848 patterns, or similar images with limited input capabilities that display as a 849 wallpaper, behind other applications.</p> 850 <p>Hardware is considered capable of reliably running live wallpapers if it 851 can run all live wallpapers, with no limitations on functionality, at a 852 reasonable framerate with no adverse affects on other applications. If 853 limitations in the hardware cause wallpapers and/or applications to crash, 854 malfunction, consume excessive CPU or battery power, or run at unacceptably 855 low frame rates, the hardware is considered incapable of running live 856 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 857 context to render their content. Live wallpaper will not run reliably on 858 hardware that does not support multiple OpenGL contexts because the live 859 wallpaper use of an OpenGL context may conflict with other applications that 860 also use an OpenGL context.</p> 861 <p>Device implementations capable of running live wallpapers reliably as 862 described above SHOULD implement live wallpapers. Device implementations 863 determined to not run live wallpapers reliably as described above MUST NOT 864 implement live wallpapers.</p> 865 <a name="section-3.8.7"></a><h4>3.8.7. Recent Application Display</h4> 866 <p>The upstream Android 4.0 source code includes a user interface for 867 displaying recent applications using a thumbnail image of the application's 868 graphical state at the moment the user last left the application. Device 869 implementations MAY alter or eliminate this user interface; however, a future 870 version of Android is planned to make more extensive use of this 871 functionality. Device implementations are strongly encouraged to use the 872 upstream Android 4.0 user interface (or a similar thumbnail-based interface) 873 for recent applications, or else they may not be compatible with a future 874 version of Android.</p> 875 <a name="section-3.8.8"></a><h4>3.8.8. Input Management Settings</h4> 876 <p>Android 4.0 includes support for Input Management Engines. The Android 4.0 877 APIs allow custom app IMEs to specify user-tunable settings. Device 878 implementations MUST include a way for the user to access IME settings at all 879 times when an IME that provides such user settings is displayed.</p> 880 881 <a name="section-3.9"></a><h3>3.9 Device Administration</h3> 882 <p>Android 4.0 includes features that allow security-aware applications 883 to perform device administration functions at the system level, such as enforcing 884 password policies or performing remote wipe, through the Android Device 885 Administration API [<a href="#resources27">Resources, 27</a>]. Device 886 implementations MUST provide an implementation of the <code>DevicePolicyManager 887 </code> class [<a href="#resources28">Resources, 28</a>], and SHOULD support 888 the full range of device administration policies defined in the Android SDK 889 documentation [<a href="#resources27">Resources, 27</a>].</p> 890 891 <p>If device implementations do not support the full range of device administration 892 policies, they MUST NOT allow device administration applications to be enabled. 893 Specifically, if a device does not support all device administration policies, 894 the device implementation MUST respond to the 895 <code>android.app.admin.DevicePolicyManager.ACTION_ADD_DEVICE_ADMIN</code> intent, 896 but MUST dislpay a message notifying the user that the device does not support 897 device administration.</p> 898 899 <a name="section-3.10"></a><h3>3.10 Accessibility</h3> 900 <p>Android 4.0 provides an accessibility layer that helps users with disabilities 901 to navigate their devices more easily. In addition, Android 4.0 provides 902 platform APIs that enable accessibility service implementations to receive 903 callbacks for user and system events and generate alternate feedback mechanisms, 904 such as text-to-speech, haptic feedback, and trackball/d-pad navigation 905 [<a href="#resources29">Resources, 29</a>]. Device implementations MUST provide an 906 implementation of the Android accessibility framework consistent with the 907 default Android implementation. Specifically, device implementations MUST meet 908 the following requirements.</p> 909 <ul> 910 <li>Device implementations MUST support third party accessibility service 911 implementations through the <code>android.accessibilityservice</code> 912 APIs [<a href="#resources30">Resources, 30</a>].</li> 913 <li>Device implementations MUST generate <code>AccessibilityEvent</code>s 914 and deliver these events to all registered <code>AccessibilityService 915 </code> implementations in a manner consistent with the default Android 916 implementation.</li> 917 <li>Device implementations MUST provide a user-accessible mechanism to enable 918 and disable accessibility services, and MUST display this interface in 919 response to the 920 <code>android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS</code> 921 intent.</li> 922 </ul> 923 <p>Additionally, device implementations SHOULD provide an implementation 924 of an accessibility service on the device, and SHOULD provide a mechanism 925 for users to enable the accessibility service during device setup. An open 926 source implementation of an accessibility service is available from the Eyes 927 Free project [<a href="#resources31">Resources, 31</a>].</p> 928 929 <a name="section-3.11"></a><h3>3.11 Text-to-Speech</h3> 930 <p>Android 4.0 includes APIs that allow applications to make use of 931 text-to-speech (TTS) services, and allows service providers to provide 932 implementations of TTS services [<a href="#resources32">Resources, 32</a>]. 933 Device implementations MUST meet these requirements related to the Android TTS 934 framework:</p> 935 <ul> 936 <li>Device implementations MUST support the Android TTS framework APIs and 937 SHOULD include a TTS engine supporting the languages available on the 938 device. Note that the upstream Android open source software includes a 939 full-featured TTS engine implementation.</li> 940 <li>Device implementations MUST support installation of third-party TTS 941 engines.</li> 942 <li>Device implementations MUST provide a user-accessible interface that allows 943 users to select a TTS engine for use at the system level.</li> 944 </ul> 945 946 <a name="section-4"></a><h2>4. Application Packaging Compatibility</h2> 947 <p>Device implementations MUST install and run Android ".apk" files as 948 generated by the "aapt" tool included in the official Android SDK [<a 949 href="#resources33">Resources, 33</a>].</p> 950 <p>Devices implementations MUST NOT extend either the .apk [<a 951 href="#resources34">Resources, 34</a>], Android Manifest [<a 952 href="#resources35">Resources, 35</a>], 953 Dalvik bytecode [<a href="#resources17">Resources, 17</a>], or renderscript 954 bytecode formats in such a way that would prevent those files from installing 955 and running correctly on other compatible devices. Device implementers SHOULD 956 use the reference upstream implementation of Dalvik, and the reference 957 implementation's package management system.</p> 958 959 <a name="section-5"></a><h2>5. Multimedia Compatibility</h2> 960 <p>Device implementations MUST include at least one form of audio output, such as 961 speakers, headphone jack, external speaker connection, etc.</p> 962 <a name="section-5.1"></a><h3>5.1. Media Codecs</h3> 963 <p>Device implementations MUST support the core media formats specified 964 in the Android SDK documentation [<a href="#resources58">Resources, 58</a>] except 965 where explicitly permitted in this document. Specifically, device implementations 966 MUST support the media formats, encoders, decoders, file types and container 967 formats defined in the tables below. All of these codecs are provided as 968 software implementations in the preferred Android implementation from the Android 969 Open Source Project.</p> 970 971 <p><strong>Please note that neither Google nor the Open Handset Alliance make any 972 representation that these codecs are unencumbered by third-party patents. 973 Those intending to use this source code in hardware or software products are 974 advised that implementations of this code, including in open source software 975 or shareware, may require patent licenses from the relevant patent 976 holders.</strong></p> 977 978 <p>Note that these tables do not list specific bitrate requirements for 979 most video codecs because current device hardware does not necessarily support 980 bitrates that map exactly to the required bitrates specified by the relevant 981 standards. Instead, device implementations SHOULD support the highest bitrate 982 practical on the hardware, up to the limits defined by the specifications.</p> 983 <div style="page-break-before: always;"></div> 984 <table> 985 <tbody> 986 987 <tr> 988 <th>Type</th> 989 <th>Format / Codec</th> 990 <th>Encoder</th> 991 <th>Decoder</th> 992 <th>Details</th> 993 <th>File Type(s) / Container Formats</th> 994 </tr> 995 996 <tr> 997 <td rowspan="10">Audio</td> 998 <td>AAC LC/LTP</td> 999 <td style="text-align: center;">REQUIRED<br/> 1000 <small>Required for device implementations that include microphone hardware 1001 and define <code>android.hardware.microphone</code>.</small></td> 1002 <td style="text-align: center;">REQUIRED</td> 1003 <td rowspan="3">Mono/Stereo content in any combination of standard bit 1004 rates up to 160 kbps and sampling rates from 8 to 48kHz</td> 1005 <td rowspan="3"> 1006 <ul> 1007 <li>3GPP (.3gp)</li> 1008 <li>MPEG-4 (.mp4, .m4a)</li> 1009 <li>ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)</li> 1010 <li>MPEG-TS (.ts, not seekable, Android 3.0+)</li> 1011 </ul> 1012 </td> 1013 </tr> 1014 <tr> 1015 <td>HE-AACv1 (AAC+)</td> 1016 <td> </td> 1017 <td style="text-align: center;">REQUIRED</td> 1018 </tr> 1019 1020 <tr> 1021 <td>HE-AACv2 (enhanced AAC+)</td> 1022 <td> </td> 1023 <td style="text-align: center;">REQUIRED</td> 1024 </tr> 1025 1026 <tr> 1027 <td>AMR-NB</td> 1028 <td style="text-align: center;">REQUIRED<br/> 1029 <small>Required for device implementations that include microphone hardware 1030 and define <code>android.hardware.microphone</code>.</small></td> 1031 <td style="text-align: center;">REQUIRED</td> 1032 <td>4.75 to 12.2 kbps sampled @ 8kHz</td> 1033 <td>3GPP (.3gp) 1034 </td> 1035 </tr> 1036 1037 <tr> 1038 <td>AMR-WB</td> 1039 <td style="text-align: center;">REQUIRED<br/> 1040 <small>Required for device implementations that include microphone hardware 1041 and define <code>android.hardware.microphone</code>.</small></td> 1042 <td style="text-align: center;">REQUIRED</td> 1043 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 1044 <td>3GPP (.3gp)</td> 1045 </tr> 1046 1047 <tr> 1048 <td>FLAC</td> 1049 <td> </td> 1050 <td style="text-align: center;">REQUIRED<br/><small>(Android 3.1+)</small></td> 1051 <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 1052 kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz 1053 downsampler does not include a low-pass filter). 16-bit recommended; 1054 no dither applied for 24-bit. 1055 </td> 1056 <td>FLAC (.flac) only</td> 1057 </tr> 1058 1059 <tr> 1060 <td>MP3</td> 1061 <td> </td> 1062 <td style="text-align: center;">REQUIRED</td> 1063 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR) 1064 </td> 1065 <td>MP3 (.mp3)</td> 1066 </tr> 1067 1068 <tr> 1069 <td>MIDI</td> 1070 <td> </td> 1071 <td style="text-align: center;">REQUIRED</td> 1072 <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> 1073 <td> 1074 <ul> 1075 <li>Type 0 and 1 (.mid, .xmf, .mxmf)</li> 1076 <li>RTTTL/RTX (.rtttl, .rtx)</li> 1077 <li>OTA (.ota)</li> 1078 <li>iMelody (.imy)</li> 1079 </ul> 1080 </td> 1081 </tr> 1082 1083 <tr> 1084 <td>Vorbis</td> 1085 <td> </td> 1086 <td style="text-align: center;">REQUIRED</td> 1087 <td> </td> 1088 <td> 1089 <ul> 1090 <li>Ogg (.ogg)</li> 1091 <li>Matroska (.mkv)</li> 1092 </ul> 1093 </td> 1094 </tr> 1095 1096 <tr> 1097 <td>PCM/WAVE</td> 1098 <td> </td> 1099 <td style="text-align: center;">REQUIRED</td> 1100 <td>8- and 16-bit linear PCM (rates up to limit of hardware)</td> 1101 <td>WAVE (.wav)</td> 1102 </tr> 1103 1104 <tr> 1105 <td rowspan="5">Image</td> 1106 <td>JPEG</td> 1107 <td style="text-align: center;">REQUIRED</td> 1108 <td style="text-align: center;">REQUIRED</td> 1109 <td>Base+progressive</td> 1110 <td>JPEG (.jpg)</td> 1111 </tr> 1112 1113 <tr> 1114 <td>GIF</td> 1115 <td> </td> 1116 <td style="text-align: center;">REQUIRED</td> 1117 <td> </td> 1118 <td>GIF (.gif)</td> 1119 </tr> 1120 1121 <tr> 1122 <td>PNG</td> 1123 <td style="text-align: center;">REQUIRED</td> 1124 <td style="text-align: center;">REQUIRED</td> 1125 <td> </td> 1126 <td>PNG (.png)</td> 1127 </tr> 1128 1129 <tr> 1130 <td>BMP</td> 1131 <td> </td> 1132 <td style="text-align: center;">REQUIRED</td> 1133 <td> </td> 1134 <td>BMP (.bmp)</td> 1135 </tr> 1136 1137 1138 <tr> 1139 <td>WEBP</td> 1140 <td style="text-align: center;">REQUIRED</td> 1141 <td style="text-align: center;">REQUIRED</td> 1142 <td> </td> 1143 <td>WebP (.webp)</td> 1144 </tr> 1145 1146 <tr> 1147 <td rowspan="4">Video</td> 1148 <td>H.263</td> 1149 <td style="text-align: center;">REQUIRED<br/> 1150 <small>Required for device implementations that include camera hardware 1151 and define <code>android.hardware.camera</code> or 1152 <code>android.hardware.camera.front</code>.</small></td> 1153 <td style="text-align: center;">REQUIRED</td> 1154 <td> </td> 1155 <td> 1156 <ul> 1157 <li>3GPP (.3gp)</li> 1158 <li>MPEG-4 (.mp4)</li> 1159 </ul> 1160 </td> 1161 </tr> 1162 1163 <tr> 1164 <td>H.264 AVC</td> 1165 <td style="text-align: center;">REQUIRED<br/> 1166 <small>Required for device implementations that include camera hardware 1167 and define <code>android.hardware.camera</code> or 1168 <code>android.hardware.camera.front</code>.</small></td> 1169 <td style="text-align: center;">REQUIRED</td> 1170 <td>Baseline Profile (BP)</td> 1171 <td> 1172 <ul> 1173 <li>3GPP (.3gp)</li> 1174 <li>MPEG-4 (.mp4)</li> 1175 <li>MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li> 1176 </ul> 1177 </td> 1178 </tr> 1179 1180 <tr> 1181 <td>MPEG-4 SP</td> 1182 <td> </td> 1183 <td style="text-align: center;">REQUIRED</td> 1184 <td> </td> 1185 <td>3GPP (.3gp)</td> 1186 </tr> 1187 1188 <tr> 1189 <td>VP8</td> 1190 <td> </td> 1191 <td style="text-align: center;">REQUIRED<br/><small>(Android 2.3.3+)</small></td> 1192 <td> </td> 1193 <td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv, Android 4.0+)</td> 1194 </tr> 1195 1196 </tbody></table> 1197 1198 <a name="section-5.2"></a><h3>5.2 Video Encoding</h3> 1199 <p>Android device implementations that include a rear-facing camera and declare 1200 <code>android.hardware.camera</code> SHOULD support the following video encoding 1201 profiles.</p> 1202 <table> 1203 <thead> 1204 <tr> 1205 <th> </th> 1206 <th>SD (Low quality)</th> 1207 <th>SD (High quality)</th> 1208 <th>HD (When supported by hardware)</th> 1209 </tr> 1210 </thead> 1211 <tbody> 1212 <tr> 1213 <th>Video codec</th> 1214 <td>H.264 Baseline Profile</td> 1215 <td>H.264 Baseline Profile</td> 1216 <td>H.264 Baseline Profile</td> 1217 </tr> 1218 <tr> 1219 <th>Video resolution</th> 1220 <td>176 x 144 px</td> 1221 <td>480 x 360 px</td> 1222 <td>1280 x 720 px</td> 1223 </tr> 1224 <tr> 1225 <th>Video frame rate</th> 1226 <td>12 fps</td> 1227 <td>30 fps</td> 1228 <td>30 fps</td> 1229 </tr> 1230 <tr> 1231 <th>Video bitrate</th> 1232 <td>56 Kbps</td> 1233 <td>500 Kbps or higher</td> 1234 <td>2 Mbps or higher</td> 1235 </tr> 1236 <tr> 1237 <th>Audio codec</th> 1238 <td>AAC-LC</td> 1239 <td>AAC-LC</td> 1240 <td>AAC-LC</td> 1241 </tr> 1242 <tr> 1243 <th>Audio channels</th> 1244 <td>1 (mono)</td> 1245 <td>2 (stereo)</td> 1246 <td>2 (stereo)</td> 1247 </tr> 1248 <tr> 1249 <th>Audio bitrate</th> 1250 <td>24 Kbps</td> 1251 <td>128 Kbps</td> 1252 <td>192 Kbps</td> 1253 </tr> 1254 </tbody> 1255 </table> 1256 1257 <a name="section-5.3"></a><h3>5.3. Audio Recording</h3> 1258 <p>When an application has used the <code>android.media.AudioRecord</code> API to 1259 start recording an audio stream, device implementations that include microphone 1260 hardware and declare <code>android.hardware.microphone</code> MUST sample and 1261 record audio with each of these behaviors:</p> 1262 <ul> 1263 <li>The device SHOULD exhibit approximately flat amplitude versus frequency 1264 characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz</li> 1265 <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level 1266 (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li> 1267 <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least 1268 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li> 1269 <li>Total harmonic distortion SHOULD be less than 1% from 100 Hz to 4000 Hz at 1270 90 dB SPL input level.</li> 1271 </ul> 1272 <p>In addition to the above recording specifications, when an application has 1273 started recording an audio stream using the 1274 <code>android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION</code> audio 1275 source:</p> 1276 <ul> 1277 <li>Noise reduction processing, if present, MUST be disabled.</li> 1278 <li>Automatic gain control, if present, MUST be disabled.</li> 1279 </ul> 1280 <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD" 1281 for Android 4.0, the Compatibility Definition for a future version is planned 1282 to change these to "MUST". That is, these requirements are optional in Android 1283 4.0 but <b>will be required</b> by a future version. Existing and new devices 1284 that run Android 4.0 are <b>very strongly encouraged to meet 1285 these requirements in Android 4.0</b>, or they will not be able to attain 1286 Android compatibility when upgraded to the future version.</p> 1287 1288 <a name="section-5.4"></a><h3>5.4. Audio Latency</h3> 1289 <p>Audio latency is broadly defined as the interval between when an 1290 application requests an audio playback or record operation, and when the 1291 device implementation actually begins the operation. Many classes of 1292 applications rely on short latencies, to achieve real-time effects such sound 1293 effects or VOIP communication. Device implementations that include microphone 1294 hardware and declare <code>android.hardware.microphone</code> SHOULD meet all 1295 audio latency requirements outlined in this section. See <a href="#section-7"> 1296 Section 7</a> for details on the conditions under which microphone hardware may 1297 be omitted by device implementations.</p> 1298 <p>For the purposes of this section:</p> 1299 <ul> 1300 <li>"cold output latency" is defined to be the interval between when an 1301 application requests audio playback and when sound begins playing, when 1302 the audio system has been idle and powered down prior to the request</li> 1303 <li>"warm output latency" is defined to be the interval between when an 1304 application requests audio playback and when sound begins playing, when 1305 the audio system has been recently used but is currently idle (that is, 1306 silent)</li> 1307 <li>"continuous output latency" is defined to be the interval between when an 1308 application issues a sample to be played and when the speaker physically 1309 plays the corresponding sound, while the device is currently playing back 1310 audio</li> 1311 <li>"cold input latency" is defined to be the interval between when an 1312 application requests audio recording and when the first sample is 1313 delivered to the application via its callback, when the audio system and 1314 microphone has been idle and powered down prior to the request</li> 1315 <li>"continuous input latency" is defined to be when an ambient sound occurs 1316 and when the sample corresponding to that sound is delivered to a 1317 recording application via its callback, while the device is in recording 1318 mode</li> 1319 </ul> 1320 <p>Using the above definitions, device implementations SHOULD exhibit each of 1321 these properties:</p> 1322 <ul> 1323 <li>cold output latency of 100 milliseconds or less</li> 1324 <li>warm output latency of 10 milliseconds or less</li> 1325 <li>continuous output latency of 45 milliseconds or less</li> 1326 <li>cold input latency of 100 milliseconds or less</li> 1327 <li>continuous input latency of 50 milliseconds or less</li> 1328 </ul> 1329 <p><b>Note:</b> while the requirements outlined above are stated as "SHOULD" 1330 for Android 4.0, the Compatibility Definition for a future version is planned 1331 to change these to "MUST". That is, these requirements are optional in Android 1332 4.0 but <b>will be required</b> by a future version. Existing and new devices 1333 that run Android 4.0 are <b>very strongly encouraged to meet 1334 these requirements in Android 4.0</b>, or they will not be able to attain 1335 Android compatibility when upgraded to the future version.</p> 1336 <p>If a device implementation meets the requirements of this section, it MAY 1337 report support for low-latency audio, by reporting the feature 1338 "android.hardware.audio.low-latency" via the 1339 <code>android.content.pm.PackageManager</code> class. [<a 1340 href="#resources37">Resources, 37</a>] Conversely, if the device 1341 implementation does not meet these requirements it MUST NOT report support for 1342 low-latency audio.</p> 1343 1344 <a name="section-5.5"></a><h3>5.5. Network Protocols</h3> 1345 <p>Devices MUST support the media network protocols for audio and video playback 1346 as specified in the Android SDK documentation 1347 [<a href="#resources58">Resources, 58</a>]. Specifically, devices MUST support 1348 the following media network protocols:</p> 1349 <ul> 1350 <li>RTSP (RTP, SDP)</li> 1351 <li>HTTP(S) progressive streaming</li> 1352 <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="#resources59">Resources, 59</a>]</li> 1353 </ul> 1354 <a name="section-6"></a><h2>6. Developer Tool Compatibility</h2> 1355 <p>Device implementations MUST support the Android Developer Tools provided in 1356 the Android SDK. Specifically, Android-compatible devices MUST be compatible 1357 with:</p> 1358 <ul> 1359 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources33">Resources, 33</a>]<br/> 1360 Device implementations MUST support all <code>adb</code> functions as 1361 documented in the Android SDK. The device-side <code>adb</code> daemon MUST 1362 be inactive by default, and there MUST be a user-accessible mechanism to turn 1363 on the Android Debug Bridge.</li> 1364 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources33">Resources, 33</a>]<br/> 1365 Device implementations MUST support all <code>ddms</code> features as documented in the 1366 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 1367 <code>ddms</code> SHOULD be inactive by default, 1368 but MUST be supported whenever the user has activated the Android Debug 1369 Bridge, as above.</li> 1370 <li><b>Monkey</b> [<a href="#resources36">Resources, 36</a>]<br/> 1371 Device implementations MUST include the Monkey framework, and make it 1372 available for applications to use.</li> 1373 </ul> 1374 <p>Most Linux-based systems and Apple Macintosh systems recognize Android 1375 devices using the standard Android SDK tools, without additional support; 1376 however Microsoft Windows systems typically require a driver for new Android 1377 devices. (For instance, new vendor IDs and sometimes new device IDs require 1378 custom USB drivers for Windows systems.) If a device implementation is 1379 unrecognized by the <code>adb</code> tool as provided in the standard Android 1380 SDK, device implementers MUST provide Windows drivers allowing developers to 1381 connect to the device using the <code>adb</code> protocol. These drivers MUST 1382 be provided for Windows XP, Windows Vista, and Windows 7, in both 32-bit and 1383 64-bit versions.</p> 1384 1385 <a name="section-7"></a><h2>7. Hardware Compatibility</h2> 1386 <p>If a device includes a particular hardware component that has a 1387 corresponding API for third-party developers, the device implementation MUST 1388 implement that API as described in the Android SDK documentation. If an API in 1389 the SDK interacts with a hardware component that is stated to be optional and 1390 the device implementation does not possess that component:</p> 1391 <ul> 1392 <li>complete class definitions (as documented by the SDK) for the component's 1393 APIs MUST still be present</li> 1394 <li>the API's behaviors MUST be implemented as no-ops in some reasonable 1395 fashion</li> 1396 <li>API methods MUST return null values where permitted by the SDK 1397 documentation</li> 1398 <li>API methods MUST return no-op implementations of classes where null 1399 values are not permitted by the SDK documentation</li> 1400 <li>API methods MUST NOT throw exceptions not documented by the SDK 1401 documentation</li> 1402 </ul> 1403 <p>A typical example of a scenario where these requirements apply is the 1404 telephony API: even on non-phone devices, these APIs must be implemented as 1405 reasonable no-ops.</p> 1406 <p>Device implementations MUST accurately report accurate hardware configuration 1407 information via the <code>getSystemAvailableFeatures()</code> and 1408 <code>hasSystemFeature(String)</code> methods on the 1409 <code>android.content.pm.PackageManager</code> class. [<a 1410 href="#resources37">Resources, 37</a>]</p> 1411 1412 <a name="section-7.1"></a><h3>7.1. Display and Graphics</h3> 1413 <p>Android 4.0 includes facilities that automatically adjust application 1414 assets and UI layouts appropriately for the device, to ensure that third-party 1415 applications run well on a variety of hardware configurations [<a 1416 href="#resources38">Resources, 38</a>]. Devices MUST properly implement these 1417 APIs and behaviors, as detailed in this section.</p> 1418 1419 <p>The units referenced by the requirements in this section are defined as follows:</p> 1420 <ul> 1421 <li>"Physical diagonal size" is the distance in inches between two opposing 1422 corners of the illuminated portion of the display.</li> 1423 <li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a 1424 linear horizontal or vertical span of 1". Where dpi values are listed, both 1425 horizontal and vertical dpi must fall within the range.</li> 1426 <li>"Aspect ratio" is the ratio of the longer dimension of the screen to the 1427 shorter dimension. For example, a display of 480x854 pixels would be 854 / 480 1428 = 1.779, or roughly "16:9".</li> 1429 <li>A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a 1430 160 dpi screen, calculated as: 1431 <code>pixels = dps * (density / 160)</code>.</li> 1432 </ul> 1433 1434 1435 <a name="section-7.1.1"></a><h4>7.1.1. Screen Configuration</h4> 1436 1437 <p style="font-weight:bold;">Screen Size</p> 1438 <p>The Android UI framework supports a variety of different screen sizes, and 1439 allows applications to query the device screen size (aka "screen layout") via 1440 <code>android.content.res.Configuration.screenLayout</code> with the 1441 <code>SCREENLAYOUT_SIZE_MASK</code>. Device implementations MUST report the 1442 correct screen size as defined in the Android SDK documentation 1443 [<a href="#resources38">Resources, 38</a>] and determined by the upstream 1444 Android platform. Specifically, device implementations must report the correct 1445 screen size according to the following logical density-independent pixel (dp) 1446 screen dimensions.</p> 1447 <ul> 1448 <li>Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')</li> 1449 <li>Devices that report screen size 'normal' MUST have screen sizes of at least 1450 470 dp x 320 dp</li> 1451 <li>Devices that report screen size 'large' MUST have screen sizes of at least 1452 640 dp x 480 dp</li> 1453 <li>Devices that report screen size 'xlarge' MUST have screen sizes of at least 1454 960 dp x 720 dp</li> 1455 </ul> 1456 <p>In addition, devices MUST have screen sizes of at least 2.5 inches in 1457 physical diagonal size.</p> 1458 1459 <p>Devices MUST NOT change their reported screen size at any time.</p> 1460 <p>Applications optionally indicate which screen sizes they support via the 1461 <code><supports-screens></code> attribute in the AndroidManifest.xml 1462 file. Device implementations MUST correctly honor applications' stated support 1463 for small, normal, large, and xlarge screens, as described in the Android 1464 SDK documentation.</p> 1465 1466 <p style="font-weight:bold;">Screen Aspect Ratio</p> 1467 <p>The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).</p> 1468 1469 <p style="font-weight:bold;">Screen Density</p> 1470 <p>The Android UI framework defines a set of standard logical densities to 1471 help application developers target application resources. Device 1472 implementations MUST report one of the following logical Android framework 1473 densities through the <code>android.util.DisplayMetrics</code> APIs, and MUST 1474 execute applications at this standard density. 1475 <ul> 1476 <li>120 dpi, known as 'ldpi'</li> 1477 <li>160 dpi, known as 'mdpi'</li> 1478 <li>213 dpi, known as 'tvdpi'</li> 1479 <li>240 dpi, known as 'hdpi'</li> 1480 <li>320 dpi, known as 'xhdpi'</li> 1481 </ul> 1482 Device implementations SHOULD define the standard Android framework density 1483 that is numerically closest to the physical density of the screen, unless that 1484 logical density pushes the reported screen size below the minimum supported. 1485 If the standard Android framework density that is numerically closest to the 1486 physical density results in a screen size that is smaller than the smallest 1487 supported compatible screen size (320 dp width), device implementations SHOULD 1488 report the next lowest standard Android framework density.</p> 1489 1490 <a name="section-7.1.2"></a><h4>7.1.2. Display Metrics</h4> 1491 <p>Device implementations MUST report correct values for all display metrics 1492 defined in <code>android.util.DisplayMetrics</code> [<a 1493 href="#resources39">Resources, 39</a>].</p> 1494 1495 <a name="section-7.1.3"></a><h4>7.1.3. Screen Orientation</h4> 1496 <p>Devices MUST support dynamic orientation by applications to 1497 either portrait or landscape screen orientation. That is, the device must 1498 respect the application's request for a specific screen orientation. Device 1499 implementations MAY select either portrait or landscape orientation as the 1500 default.</p> 1501 <p>Devices MUST report the correct value for the device's current orientation, 1502 whenever queried via the android.content.res.Configuration.orientation, 1503 android.view.Display.getOrientation(), or other APIs.</p> 1504 <p>Devices MUST NOT change the reported screen size or density when changing 1505 orientation.</p> 1506 <p>Devices MUST report which screen orientations they support ( 1507 <code>android.hardware.screen.portrait</code> and/or 1508 <code>android.hardware.screen.landscape</code>) and MUST report at least one 1509 supported orientation. For example, a device with a fixed-orientation 1510 landscape screen, such as a television or laptop, MUST only report 1511 <code>android.hardware.screen.landscape</code>.</p> 1512 1513 <a name="section-7.1.4"></a><h4>7.1.4. 2D and 3D Graphics Acceleration</h4> 1514 <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied 1515 and detailed in the Android SDK documentations. Device implementations MUST 1516 also support Android Renderscript, as detailed in the Android SDK 1517 documentation [<a href="#resources08">Resources, 8</a>].</p> 1518 <p>Device implementations MUST also correctly identify themselves as 1519 supporting OpenGL ES 1.0 and 2.0. That is:</p> 1520 <ul> 1521 <li>The managed APIs (such as via the <code>GLES10.getString()</code> method) 1522 MUST report support for OpenGL ES 1.0 and 2.0</li> 1523 <li>The native C/C++ OpenGL APIs (that is, those available to apps via 1524 libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for 1525 OpenGL ES 1.0 and 2.0.</li> 1526 </ul> 1527 <p>Device implementations MAY implement any desired OpenGL ES extensions. 1528 However, device implementations MUST report via the OpenGL ES managed and 1529 native APIs all extension strings that they do support, and conversely MUST 1530 NOT report extension strings that they do not support.</p> 1531 <p>Note that Android 4.0 includes support for applications to optionally 1532 specify that they require specific OpenGL texture compression formats. These 1533 formats are typically vendor-specific. Device implementations are not required 1534 by Android 4.0 to implement any specific texture compression format. However, 1535 they SHOULD accurately report any texture compression formats that they do 1536 support, via the <code>getString()</code> method in the OpenGL API.</p> 1537 1538 <p>Android 3.0 introduced a mechanism for applications to declare that they 1539 wanted to enable hardware acceleration for 2D graphics at the Application, 1540 Activity, Window or View level through the use of a manifest tag 1541 <code>android:hardwareAccelerated</code> or direct API calls 1542 [<a href="#resources09">Resources, 9</a>].</p> 1543 <p>In Android 4.0, device implementations MUST enable hardware acceleration by 1544 default, and MUST disable hardware acceleration if the developer so requests 1545 by setting <code>android:hardwareAccelerated="false"</code> or disabling 1546 hardware acceleration directly through the Android View APIs.</p> 1547 <p>In addition, device implementations MUST exhibit behavior consistent with the 1548 Android SDK documentation on hardware acceleration 1549 [<a href="#resources09">Resources, 9</a>].</p> 1550 <p>Android 4.0 includes a <code>TextureView</code> object that lets developers 1551 directly integrate hardware-accelerated OpenGL ES textures as rendering targets 1552 in a UI hierarchy. Device implementations MUST support the <code>TextureView 1553 </code> API, and MUST exhibit consistent behavior with the upstream Android 1554 implementation.</p> 1555 1556 <a name="section-7.1.5"></a><h4>7.1.5. Legacy Application Compatibility Mode</h4> 1557 <p>Android 4.0 specifies a "compatibility mode" in which the framework 1558 operates in an 'normal' screen size equivalent (320dp width) mode for the benefit 1559 of legacy applications not developed for old versions of Android that pre-date 1560 screen-size independence. Device implementations MUST include support for legacy 1561 application compatibility mode as implemented by the upstream Android open source 1562 code. That is, device implementations MUST NOT alter the triggers or thresholds at 1563 which compatibility mode is activated, and MUST NOT alter the behavior of the 1564 compatibility mode itself.</p> 1565 1566 <a name="section-7.1.6"></a><h4>7.1.6. Screen Types</h4> 1567 <p>Device implementation screens are classified as one of two types:</p> 1568 <ul> 1569 <li>Fixed-pixel display implementations: the screen is a single panel that supports only a 1570 single pixel width and height. Typically the screen is physically integrated with 1571 the device. Examples include mobile phones, tablets, and so on.</li> 1572 <li>Variable-pixel display implementations: the device implementation either has no 1573 embedded screen and includes a video output port such as VGA or HDMI for 1574 display, or has an embedded screen that can change pixel dimensions. Examples 1575 include televisions, set-top boxes, and so on.</li> 1576 </ul> 1577 <p style="font-weight: bold;">Fixed-Pixel Device Implementations</p> 1578 <p>Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided 1579 that they meet the requirements defined this Compatibility Definition.</p> 1580 <p>Fixed-pixel implementations MAY include a video output port for use with an 1581 external display. However, if that display is ever used for running apps, the 1582 device MUST meet the following requirements:</p> 1583 <ul> 1584 <li>The device MUST report the same screen configuration and display metrics, as detailed 1585 in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.</li> 1586 <li>The device MUST report the same logical density as the fixed-pixel display.</li> 1587 <li>The device MUST report screen dimensions that are the same as, or very close to, 1588 the fixed-pixel display.</li> 1589 </ul> 1590 <p>For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is 1591 considered a fixed-pixel large mdpi display implementation. If it contains a video 1592 output port that displays at 720p or 1080p, the device implementation MUST scale the output so that 1593 applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display 1594 or video output port is in use.</p> 1595 1596 <p style="font-weight: bold;">Variable-Pixel Device Implementations</p> 1597 <p>Variable-pixel device implementations MUST support one or both of 1280x720, 1598 or 1920x1080 (that is, 720p or 1080p). Device implementations with 1599 variable-pixel displays MUST NOT support any other screen configuration or 1600 mode. Device implementations with variable-pixel screens MAY change screen 1601 configuration or mode at runtime or boot-time. For example, a user of a 1602 set-top box may replace a 720p display with a 1080p display, and the device 1603 implementation may adjust accordingly.</p> 1604 1605 <p>Additionally, variable-pixel device implementations MUST report the following 1606 configuration buckets for these pixel dimensions:</p> 1607 <ul> 1608 <li>1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi) 1609 density</li> 1610 <li>1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi) 1611 density</li> 1612 </ul> 1613 <p>For clarity, device implementations with variable pixel dimensions are 1614 restricted to 720p or 1080p in Android 4.0, and MUST be configured to report 1615 screen size and density buckets as noted above.</p> 1616 1617 <a name="section-7.1.7"></a><h4>7.1.7. Screen Technology</h4> 1618 <p>The Android platform includes APIs that allow applications to render rich 1619 graphics to the display. Devices MUST support all of these APIs as defined by 1620 the Android SDK unless specifically allowed in this document. Specifically:</p> 1621 <ul> 1622 <li>Devices MUST support displays capable of rendering 16-bit color graphics and 1623 SHOULD support displays capable of 24-bit color graphics.</li> 1624 <li>Devices MUST support displays capable of rendering animations.</li> 1625 <li>The display technology used MUST have a pixel aspect ratio (PAR) between 1626 0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with 1627 a 10% tolerance.</li> 1628 </ul> 1629 1630 <a name="section-7.2"></a><h3>7.2. Input Devices</h3> 1631 <a name="section-7.2.1"></a><h4>7.2.1. Keyboard</h4> 1632 <p>Device implementations:</p> 1633 <ul> 1634 <li>MUST include support for the Input Management Framework (which allows third 1635 party developers to create Input Management Engines - i.e. soft keyboard) as 1636 detailed at <a href="http://developer.android.com">http://developer.android.com</a> 1637 </li> 1638 <li>MUST provide at least one soft keyboard implementation (regardless of whether 1639 a hard keyboard is present)</li> 1640 <li>MAY include additional soft keyboard implementations</li> 1641 <li>MAY include a hardware keyboard</li> 1642 <li>MUST NOT include a hardware keyboard that does not match one of the 1643 formats specified in <code>android.content.res.Configuration.keyboard</code> 1644 [<a href="#resources40">Resources, 40</a>] (that is, QWERTY, or 12-key)</li> 1645 </ul> 1646 <a name="section-7.2.2"></a><h4>7.2.2. Non-touch Navigation</h4> 1647 <p>Device implementations:</p> 1648 <ul> 1649 <li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad, 1650 or wheel)</li> 1651 <li>MUST report the correct value for 1652 <code>android.content.res.Configuration.navigation</code> 1653 [<a href="#resources40">Resources, 40</a>]</li> 1654 <li>MUST provide a reasonable alternative user interface mechanism for the 1655 selection and editing of text, compatible with Input Management Engines. The 1656 upstream Android open source software includes a selection mechanism suitable 1657 for use with devices that lack non-touch navigation inputs.</li> 1658 </ul> 1659 <a name="section-7.2.3"></a><h4>7.2.3. Navigation keys</h4> 1660 <p>The Home, Menu and Back functions are essential to the Android navigation 1661 paradigm. Device implementations MUST make these functions available to the 1662 user at all times when running applications. These functions MAY be implemented 1663 via dedicated physical buttons (such as mechanical or capacitive touch buttons), 1664 or MAY be implemented using dedicated software keys, gestures, touch panel, etc. 1665 Android 4.0 supports both implementations.</p> 1666 1667 <p>Device implementations MAY use a distinct portion of the screen to display 1668 the navigation keys, but if so, MUST meet these requirements:</p> 1669 1670 <ul> 1671 <li>Device implementation navigation keys MUST use a distinct portion of the 1672 screen, not available to applications, and MUST NOT obscure or otherwise 1673 interfere with the portion of the screen available to applications.</li> 1674 <li>Device implementations MUST make available a portion of the display to 1675 applications that meets the requirements defined in 1676 <a href="section-7.1.1">Section 7.1.1</a>.</li> 1677 <li>Device implementations MUST display the navigation keys when applications 1678 do not specify a system UI mode, or specify 1679 <code>SYSTEM_UI_FLAG_VISIBLE</code>.</li> 1680 <li>Device implementations MUST present the navigation keys in an unobtrusive 1681 "low profile" (eg. dimmed) mode when applications specify 1682 <code>SYSTEM_UI_FLAG_LOW_PROFILE</code>.</li> 1683 <li>Device implementations MUST hide the navigation keys when applications 1684 specify <code>SYSTEM_UI_FLAG_HIDE_NAVIGATION</code>.</li> 1685 <li>Device implementation MUST present a Menu key to applications when 1686 targetSdkVersion <= 10 and SHOULD NOT present a Menu key when the 1687 targetSdkVersion > 10.</li> 1688 </ul> 1689 1690 <a name="section-7.2.4"></a><h4>7.2.4. Touchscreen input</h4> 1691 <p>Device implementations:</p> 1692 <ul> 1693 <li>MUST have a pointer input system of some kind (either mouse-like, or touch)</li> 1694 <li>MAY have a touchscreen of any modality (such as capacitive or resistive)</li> 1695 <li>SHOULD support fully independently tracked pointers, if a touchscreen supports multiple pointers</li> 1696 <li>MUST report the value of <code>android.content.res.Configuration.touchscreen</code> [<a href="#resources40">Resources, 40</a>] 1697 corresponding to the type of the specific touchscreen on the device</li> 1698 </ul> 1699 1700 <p>Android 4.0 includes support for a variety of touch screens, touch pads, and fake touch input devices. 1701 Touch screen based device implementations are associated with a display [<a href="#resources61">Resources, 61</a>] 1702 such that the user has the impression of directly manipulating items on screen. Since the user is directly touching the screen, 1703 the system does not require any additional affordances to indicate the objects being manipulated. 1704 In contrast, a fake touch interface provides a user input system that approximates a subset of touchscreen capabilities. 1705 For example, a mouse or remote control that drives an on-screen cursor approximates touch, but requires the user to first 1706 point or focus then click. Numerous input devices like the mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, 1707 and multi-touch trackpad can support fake touch interactions. Android 4.0 includes the feature constant <code>android.hardware.faketouch</code>, 1708 which corresponds to a high-fidelity non-touch (that is, pointer-based) input device such as a mouse or trackpad that can adequately emulate touch-based 1709 input (including basic gesture support), and indicates that the device supports an emulated subset of touchscreen 1710 functionality. Device implementations that declare the fake touch feature MUST meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p> 1711 1712 <p>Device implementations MUST report the correct feature corresponding to the type of input used. Device implementations that 1713 include a touchscreen (single-touch or better) MUST also report the platform feature constant <code>android.hardware.faketouch</code>. 1714 Device implementations that do not include a touchscreen (and rely on a pointer device only) MUST NOT report any touchscreen feature, and MUST report only 1715 <code>android.hardware.faketouch</code> if they meet the fake touch requirements in <a href="section 7.2.5">Section 7.2.5</a>.</p> 1716 1717 <a name="section-7.2.5"></a><h4>7.2.5. Fake touch input</h4> 1718 <p>Device implementations that declare support for <code>android.hardware.faketouch</code></p> 1719 <ul> 1720 <li> MUST report the absolute X and Y screen positions of the pointer location and display a visual pointer on the screen[<a href="#resources60">Resources, 60</a>] </li> 1721 <li> MUST report touch event with the action code [<a href="#resources60">Resources, 60</a>] that specifies the state change 1722 that occurs on the pointer going <code>down</code> or <code>up</code> on the screen [<a href="#resources60">Resources, 60</a>] </li> 1723 <li> MUST support pointer <code>down</code> and <code>up</code> on an object on the screen, which allows users to emulate tap on an object on the screen</li> 1724 <li> MUST support pointer <code>down</code>, pointer <code>up</code>, pointer <code>down</code> then pointer <code>up</code> in the same place on an object on the screen 1725 within a time threshold, which allows users to emulate double tap on an object on the screen [<a href="#resources60">Resources, 60</a>]</li> 1726 <li>MUST support pointer <code>down</code> on an arbitrary point on the screen, pointer move to any other arbitrary point on the screen, 1727 followed by a pointer <code>up</code>, which allows users to emulate a touch drag</li> 1728 <li> MUST support pointer <code>down</code> then allow users to quickly move the object to a different position on the screen 1729 and then pointer <code>up</code> on the screen, which allows users to fling an object on the screen</li> 1730 </ul> 1731 1732 <p>Devices that declare support for <code>android.hardware.faketouch.multitouch.distinct</code> MUST meet the requirements for 1733 faketouch above, and MUST also support distinct tracking of two or more independent pointer inputs.</p> 1734 1735 <a name="section-7.2.6"></a><h4>7.2.6. Microphone</h4> 1736 <p>Device implementations MAY omit a microphone. However, if a device 1737 implementation omits a microphone, it MUST NOT report the 1738 <code>android.hardware.microphone</code> feature constant, and must implement 1739 the audio recording API as no-ops, per <a href="section-7">Section 7</a>. 1740 Conversely, device implementations that do possess a microphone:</p> 1741 <ul> 1742 <li>MUST report the <code>android.hardware.microphone</code> feature 1743 constant</li> 1744 <li>SHOULD meet the audio quality requirements in <a 1745 href="section-5.3">Section 5.3</a></li> 1746 <li>SHOULD meet the audio latency requirements in <a 1747 href="section-5.4">Section 5.4</a></li> 1748 </ul> 1749 1750 <a name="section-7.3"></a><h3>7.3. Sensors</h3> 1751 <p>Android 4.0 includes APIs for accessing a variety of sensor types. Devices 1752 implementations generally MAY omit these sensors, as provided for in the 1753 following subsections. If a device includes a particular sensor type that has a 1754 corresponding API for third-party developers, the device implementation MUST 1755 implement that API as described in the Android SDK documentation. For example, 1756 device implementations:</p> 1757 <ul> 1758 <li>MUST accurately report the presence or absence of sensors per the 1759 <code>android.content.pm.PackageManager</code> class. [<a 1760 href="#resources37">Resources, 37</a>]</li> 1761 <li>MUST return an accurate list of supported sensors via the 1762 <code>SensorManager.getSensorList()</code> and similar methods</li> 1763 <li>MUST behave reasonably for all other sensor APIs (for example, by 1764 returning true or false as appropriate when applications attempt to register 1765 listeners, not calling sensor listeners when the corresponding sensors are not 1766 present; etc.)</li> 1767 <li>MUST report all sensor measurements using the relevant International System 1768 of Units (i.e. metric) values for each sensor type as defined in the Android SDK 1769 documentation [<a href="#resources41">Resources, 41</a>]</li> 1770 </ul> 1771 <p>The list above is not comprehensive; the documented behavior of the Android 1772 SDK is to be considered authoritative.</p> 1773 <p>Some sensor types are synthetic, meaning they can be derived from data 1774 provided by one or more other sensors. (Examples include the orientation 1775 sensor, and the linear acceleration sensor.) Device implementations SHOULD 1776 implement these sensor types, when they include the prerequisite physical 1777 sensors.</p> 1778 <p>The Android 4.0 APIs introduce a notion of a "streaming" sensor, which is 1779 one that returns data continuously, rather than only when the data changes. 1780 Device implementations MUST continuously provide periodic data samples for any 1781 API indicated by the Android 4.0 SDK documentation to be a streaming 1782 sensor.</p> 1783 <a name="section-7.3.1"></a><h4>7.3.1. Accelerometer</h4> 1784 <p>Device implementations SHOULD include a 3-axis accelerometer. If a device 1785 implementation does include a 3-axis accelerometer, it:</p> 1786 <ul> 1787 <li>MUST be able to deliver events at 50 Hz or greater</li> 1788 <li>MUST comply with the Android sensor coordinate system as detailed 1789 in the Android APIs (see [<a href="#resources41">Resources, 41</a>])</li> 1790 <li>MUST be capable of measuring from freefall up to twice gravity (2g) or 1791 more on any three-dimensional vector</li> 1792 <li>MUST have 8-bits of accuracy or more</li> 1793 <li>MUST have a standard deviation no greater than 0.05 m/s^2</li> 1794 </ul> 1795 <a name="section-7.3.2"></a><h4>7.3.2. Magnetometer</h4> 1796 <p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.) 1797 If a device does include a 3-axis magnetometer, it:</p> 1798 <ul> 1799 <li>MUST be able to deliver events at 10 Hz or greater</li> 1800 <li>MUST comply with the Android sensor coordinate system as detailed 1801 in the Android APIs (see [<a href="#resources41">Resources, 41</a>]).</li> 1802 <li>MUST be capable of sampling a range of field strengths adequate to cover the 1803 geomagnetic field</li> 1804 <li>MUST have 8-bits of accuracy or more</li> 1805 <li>MUST have a standard deviation no greater than 0.5 µT</li> 1806 </ul> 1807 <a name="section-7.3.3"></a><h4>7.3.3. GPS</h4> 1808 <p>Device implementations SHOULD include a GPS receiver. If a device 1809 implementation does include a GPS receiver, it SHOULD include 1810 some form of "assisted GPS" technique to minimize GPS lock-on time.</p> 1811 <a name="section-7.3.4"></a><h4>7.3.4. Gyroscope</h4> 1812 <p>Device implementations SHOULD include a gyroscope (i.e. angular change 1813 sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis 1814 accelerometer is also included. If a device implementation includes a 1815 gyroscope, it:</p> 1816 <ul> 1817 <li>MUST be temperature compensated</li> 1818 <li>MUST be capable of measuring orientation changes up to 5.5*Pi 1819 radians/second (that is, approximately 1,000 degrees per second)</li> 1820 <li>MUST be able to deliver events at 100 Hz or greater</li> 1821 <li>MUST have 12-bits of accuracy or more</li> 1822 <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s). 1823 The variance is allowed to vary with the sampling rate, but must be constrained by this value. 1824 In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no 1825 greater than 1e-7 rad^2/s^2. </li> 1826 <li>MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.</li> 1827 </ul> 1828 <a name="section-7.3.5"></a><h4>7.3.5. Barometer</h4> 1829 <p>Device implementations MAY include a barometer (i.e. ambient air pressure 1830 sensor.) If a device implementation includes a barometer, it:</p> 1831 <ul> 1832 <li>MUST be able to deliver events at 5 Hz or greater</li> 1833 <li>MUST have adequate precision to enable estimating altitude</li> 1834 </ul> 1835 <a name="section-7.3.6"></a><h4>7.3.7. Thermometer</h4> 1836 <p>Device implementations MAY but SHOULD NOT include a thermometer (i.e. 1837 temperature sensor.) If a device implementation does include a thermometer, it 1838 MUST measure the temperature of the device CPU. It MUST NOT measure any other 1839 temperature. (Note that this sensor type is deprecated in the Android 4.0 1840 APIs.)</p> 1841 <a name="section-7.3.7"></a><h4>7.3.7. Photometer</h4> 1842 <p>Device implementations MAY include a photometer (i.e. ambient light 1843 sensor.)</p> 1844 <a name="section-7.3.8"></a><h4>7.3.8. Proximity Sensor</h4> 1845 <p>Device implementations MAY include a proximity sensor. If a device 1846 implementation does include a proximity sensor, it MUST measure the proximity 1847 of an object in the same direction as the screen. That is, the proximity 1848 sensor MUST be oriented to detect objects close to the screen, as the 1849 primary intent of this sensor type is to detect a phone in use by the 1850 user. If a device implementation includes a proximity sensor with any other 1851 orientation, it MUST NOT be accessible through this API. If a device 1852 implementation has a proximity sensor, it MUST be have 1-bit of accuracy or 1853 more.</p> 1854 1855 <a name="section-7.4"></a><h3>7.4. Data Connectivity</h3> 1856 <a name="section-7.4.1"></a><h4>7.4.1. Telephony</h4> 1857 <p>"Telephony" as used by the Android 4.0 APIs and this document refers 1858 specifically to hardware related to placing voice calls and sending SMS 1859 messages via a GSM or CDMA network. While these voice calls may or may not be 1860 packet-switched, they are for the purposes of Android 4.0 considered 1861 independent of any data connectivity that may be implemented using the same 1862 network. In other words, the Android "telephony" functionality and APIs refer 1863 specifically to voice calls and SMS; for instance, device implementations that 1864 cannot place calls or send/receive SMS messages MUST NOT report the 1865 "android.hardware.telephony" feature or any sub-features, regardless of 1866 whether they use a cellular network for data connectivity.</p> 1867 <p>Android 4.0 MAY be used on devices that do not include telephony hardware. 1868 That is, Android 4.0 is compatible with devices that are not phones. 1869 However, if a device implementation does include GSM or CDMA telephony, it 1870 MUST implement full support for the API for that technology. Device 1871 implementations that do not include telephony hardware MUST implement the full 1872 APIs as no-ops.</p> 1873 <a name="section-7.4.2"></a><h4>7.4.2. IEEE 802.11 (WiFi)</h4> 1874 <p>Android 4.0 device implementations SHOULD include support for one or more 1875 forms of 802.11 (b/g/a/n, etc.) If a device implementation does include 1876 support for 802.11, it MUST implement the corresponding Android API.</p> 1877 <a name="section-7.4.3"></a><h4>7.4.3. Bluetooth</h4> 1878 <p>Device implementations SHOULD include a Bluetooth transceiver. Device 1879 implementations that do include a Bluetooth transceiver MUST enable the 1880 RFCOMM-based Bluetooth API as described in the SDK documentation [<a 1881 href="#resources42">Resources, 42</a>]. Device implementations SHOULD 1882 implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as 1883 appropriate for the device.</p> 1884 <p>The Compatibility Test Suite includes cases that cover basic operation of 1885 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 1886 protocol between devices, it cannot be fully tested by unit tests running on a 1887 single device. Consequently, device implementations MUST also pass the 1888 human-driven Bluetooth test procedure described in Appendix A.</p> 1889 <a name="section-7.4.4"></a><h4>7.4.4. Near-Field Communications</h4> 1890 <p>Device implementations SHOULD include a transceiver and related hardware 1891 for Near-Field Communications (NFC). If a device implementation does include 1892 NFC hardware, then it:</p> 1893 <ul> 1894 <li>MUST report the android.hardware.nfc feature from the 1895 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method. 1896 [<a href="#resources37">Resources, 37</a>]</li> 1897 <li>MUST be capable of reading and writing NDEF messages via the following NFC 1898 standards: 1899 <ul> 1900 <li>MUST be capable of acting as an NFC Forum reader/writer 1901 (as defined by the NFC Forum technical specification 1902 NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards: 1903 <ul> 1904 <li>NfcA (ISO14443-3A)</li> 1905 <li>NfcB (ISO14443-3B) </li> 1906 <li>NfcF (JIS 6319-4)</li> 1907 <li>IsoDep (ISO 14443-4)</li> 1908 <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li> 1909 </ul> 1910 </li> 1911 </ul> 1912 </li> 1913 <li>SHOULD be capable of reading and writing NDEF messages via the following 1914 NFC standards. Note that while the NFC standards below are stated as 1915 "SHOULD" for Android 4.0, the Compatibility Definition for a future 1916 version is planned to change these to "MUST". That is, these stanards are 1917 optional in Android 4.0 but <b>will be required</b> in future versions. 1918 Existing and new devices that run Android 4.0 are <b>very strongly 1919 encouraged to meet these requirements in Android 4.0</b> so they will be 1920 able to upgrade to the future platform releases. 1921 <ul> 1922 <li>NfcV (ISO 15693)</li> 1923 </ul> 1924 </li> 1925 <li>MUST be capable of transmitting and receiving data via the following 1926 peer-to-peer standards and protocols: 1927 <ul> 1928 <li>ISO 18092</li> 1929 <li>LLCP 1.0 (defined by the NFC Forum)</li> 1930 <li>SDP 1.0 (defined by the NFC Forum)</li> 1931 <li>NDEF Push Protocol [<a href="#resources43">Resources, 43</a>]</li> 1932 <li>SNEP 1.0 (defined by the NFC Forum)</li> 1933 </ul> 1934 </li> 1935 <li>MUST include support for Android Beam: 1936 <ul> 1937 <li>MUST implement the SNEP default server. Valid NDEF messages received 1938 by the default SNEP server MUST be dispatched to applications using 1939 the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam 1940 in settings MUST NOT disable dispatch of incoming NDEF message.</li> 1941 <li>MUST implement the NPP server. Messages received by the NPP server MUST 1942 be processed the same way as the SNEP default server.</li> 1943 <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to 1944 the default SNEP server when Android Beam is enabled. If no default 1945 SNEP server is found then the client MUST attempt to send to an NPP 1946 server.</li> 1947 <li>MUST allow foreground activities to set the outbound P2P NDEF message 1948 using android.nfc.NfcAdapter.setNdefPushMessage, and 1949 android.nfc.NfcAdapter.setNdefPushMessageCallback, and 1950 android.nfc.NfcAdapter.enableForegroundNdefPush.</li> 1951 <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', 1952 before sending outbound P2P NDEF messages.</li> 1953 <li>SHOULD enable Android Beam by default</li> 1954 </ul> 1955 </li> 1956 <li>MUST poll for all supported technologies while in NFC discovery mode.</li> 1957 <li>SHOULD be in NFC discovery mode while the device is awake with the screen active 1958 and the lock-screen unlocked.</li> 1959 </ul> 1960 1961 <p>(Note that publicly available links are not available for the JIS, ISO, and 1962 NFC Forum specifications cited above.)</p> 1963 <p>Additionally, device implementations MAY include reader/writer support for 1964 the following MIFARE technologies.</p> 1965 <ul> 1966 <li>MIFARE Classic (NXP MF1S503x [<a href="#resources44">Resources, 44</a>], 1967 MF1S703x [<a href="#resources44">Resources, 44</a>])</li> 1968 <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources46">Resources, 46</a>], 1969 MF0ICU2 [<a href="#resources46">Resources, 46</a>])</li> 1970 <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources48">Resources, 48</a>], 1971 AN130411 [<a href="#resources49">Resources, 49</a>])</li> 1972 </ul> 1973 <p>Note that Android 4.0 includes APIs for these MIFARE types. If a 1974 device implementation supports MIFARE in the reader/writer role, it:</p> 1975 <ul> 1976 <li>MUST implement the corresponding Android APIs as documented by the 1977 Android SDK</li> 1978 <li>MUST report the feature com.nxp.mifare from the 1979 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method. 1980 [<a href="#resources37">Resources, 37</a>] Note that this is not a standard 1981 Android feature, and as such does not appear as a constant on the 1982 <code>PackageManager</code> class.</li> 1983 <li>MUST NOT implement the corresponding Android APIs nor report the 1984 com.nxp.mifare feature unless it also implements general NFC support as 1985 described in this section</li> 1986 </ul> 1987 <p>If a device implementation does not include NFC hardware, it MUST NOT 1988 declare the android.hardware.nfc feature from the 1989 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a 1990 href="#resources37">Resources, 37</a>], and MUST implement the Android 4.0 NFC 1991 API as a no-op.</p> 1992 <p>As the classes <code>android.nfc.NdefMessage</code> and 1993 <code>android.nfc.NdefRecord</code> represent a protocol-independent data 1994 representation format, device implementations MUST implement these APIs even 1995 if they do not include support for NFC or declare the android.hardware.nfc 1996 feature.</p> 1997 <a name="section-7.4.5"></a><h4>7.4.5. Minimum Network Capability</h4> 1998 <p>Device implementations MUST include support for one or more forms of data 1999 networking. Specifically, device implementations MUST include support for at 2000 least one data standard capable of 200Kbit/sec or greater. Examples of 2001 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, 2002 Ethernet, etc.</p> 2003 <p>Device implementations where a physical networking standard (such as 2004 Ethernet) is the primary data connection SHOULD also include support for at 2005 least one common wireless data standard, such as 802.11 (WiFi).</p> 2006 <p>Devices MAY implement more than one form of data connectivity.</p> 2007 2008 2009 <a name="section-7.5"></a><h3>7.5. Cameras</h3> 2010 <p>Device implementations SHOULD include a rear-facing camera, and MAY include 2011 a front-facing camera. A rear-facing camera is a camera located on the side of 2012 the device opposite the display; that is, it images scenes on the far side of 2013 the device, like a traditional camera. A front-facing camera is a camera 2014 located on the same side of the device as the display; that is, a camera 2015 typically used to image the user, such as for video conferencing and similar 2016 applications.</p> 2017 <a name="section-7.5.1"></a><h4>7.5.1. Rear-Facing Camera</h4> 2018 <p>Device implementations SHOULD include a rear-facing camera. If a device 2019 implementation includes a rear-facing camera, it:</p> 2020 <ul> 2021 <li>MUST have a resolution of at least 2 megapixels</li> 2022 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented 2023 in the camera driver (transparent to application software)</li> 2024 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 2025 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 2026 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 2027 registered on a Camera preview surface, unless the application has explicitly 2028 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 2029 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 2030 object. Note that this constraint does not apply to the device's built-in 2031 system camera application, but only to third-party applications using 2032 <code>Camera.PreviewCallback</code>.</li> 2033 </ul> 2034 <a name="section-7.5.2"></a><h4>7.5.2. Front-Facing Camera</h4> 2035 <p>Device implementations MAY include a front-facing camera. If a device 2036 implementation includes a front-facing camera, it:</p> 2037 <ul> 2038 <li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li> 2039 <li>MUST NOT use a front-facing camera as the default for the Camera API. 2040 That is, the camera API in Android 4.0 has specific support for front-facing 2041 cameras, and device implementations MUST NOT configure the API to to treat a 2042 front-facing camera as the default rear-facing camera, even if it is the only 2043 camera on the device.</li> 2044 <li>MAY include features (such as auto-focus, flash, etc.) 2045 available to rear-facing cameras as described in Section 7.5.1.</li> 2046 <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a 2047 CameraPreview, as follows:</li> 2048 <ul> 2049 <li>If the device implementation is capable of being rotated by user (such as 2050 automatically via an accelerometer or manually via user input), the camera 2051 preview MUST be mirrored horizontally relative to the device's current 2052 orientation.</li> 2053 <li>If the current application has explicitly requested that the Camera 2054 display be rotated via a call to the 2055 <code>android.hardware.Camera.setDisplayOrientation()</code> [<a 2056 href="#resources50">Resources, 50</a>] method, the camera preview MUST be 2057 mirrored horizontally relative to the orientation specified by the 2058 application.</li> 2059 <li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li> 2060 </ul> 2061 <li>MUST mirror the image displayed by the postview in the same manner as 2062 the camera preview image stream. (If the device implementation does not 2063 support postview, this requirement obviously does not apply.)</li> 2064 <li>MUST NOT mirror the final captured still image or video streams returned 2065 to application callbacks or committed to media storage</li> 2066 </ul> 2067 <a name="section-7.5.3"></a><h4>7.5.3. Camera API Behavior</h4> 2068 <p>Device implementations MUST implement the following behaviors for the 2069 camera-related APIs, for both front- and rear-facing cameras:</p> 2070 <ol> 2071 <li>If an application has never called 2072 <code>android.hardware.Camera.Parameters.setPreviewFormat(int)</code>, then the 2073 device MUST use <code>android.hardware.PixelFormat.YCbCr_420_SP</code> for 2074 preview data provided to application callbacks.</li> 2075 <li>If an application registers an <code>android.hardware.Camera.PreviewCallback 2076 </code> instance and the system calls the <code>onPreviewFrame()</code> method 2077 when the preview format is YCbCr_420_SP, the data in the <code>byte[]</code> 2078 passed into <code>onPreviewFrame()</code> must further be in the NV21 encoding 2079 format. That is, NV21 MUST be the default.</li> 2080 <li>Device implementations MUST support the YV12 format (as denoted by the 2081 <code>android.graphics.ImageFormat.YV12</code> constant) for camera previews 2082 for both front- and rear-facing cameras. (The hardware video decoder and camera 2083 may use any native pixel format, but the device implementation MUST support conversion 2084 to YV12.)</li> 2085 </ol> 2086 <p>Device implementations MUST implement the full Camera API included in the 2087 Android 4.0 SDK documentation [<a href="#resources51">Resources, 51</a>]), 2088 regardless of whether the device includes hardware autofocus or other 2089 capabilities. For instance, cameras that lack autofocus MUST still call any 2090 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 2091 this has no relevance to a non-autofocus camera.) Note that this does apply 2092 to front-facing cameras; for instance, even though most front-facing cameras 2093 do not support autofocus, the API callbacks must still be "faked" as 2094 described.</p> 2095 <p>Device implementations MUST recognize and honor each parameter name defined 2096 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 2097 underlying hardware supports the feature. If the device hardware does not 2098 support a feature, the API must behave as documented. Conversely, Device 2099 implementations MUST NOT honor or recognize string constants passed 2100 to the <code>android.hardware.Camera.setParameters()</code> method other than 2101 those documented as constants on the 2102 <code>android.hardware.Camera.Parameters</code>. That is, 2103 device implementations MUST support all standard Camera parameters if the 2104 hardware allows, and MUST NOT support custom Camera parameter types.</p> 2105 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_PICTURE</code> 2106 intent whenever a new picture is taken by the camera and the entry of the picture 2107 has been added to the media store.</p> 2108 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_VIDEO</code> 2109 intent whenever a new video is recorded by the camera and the entry of the picture 2110 has been added to the media store.</p> 2111 <a name="section-7.5.4"></a><h4>7.5.4. Camera Orientation</h4> 2112 <p>Both front- and rear-facing cameras, if present, MUST be oriented so that 2113 the long dimension of the camera aligns with the screen's long dimention. That 2114 is, when the device is held in the landscape orientation, cameras MUST 2115 capture images in the landscape orientation. This applies regardless of the 2116 device's natural orientation; that is, it applies to landscape-primary devices 2117 as well as portrait-primary devices.</p> 2118 2119 2120 <a name="section-7.6"></a><h3>7.6. Memory and Storage</h3> 2121 <a name="section-7.6.1"></a><h4>7.6.1. Minimum Memory and Storage</h4> 2122 <p>Device implementations MUST have at least 340MB of memory available to the 2123 kernel and userspace. The 340MB MUST be in addition to any memory dedicated to 2124 hardware components such as radio, video, and so on that is not under the 2125 kernel's control.</p> 2126 <p>Device implementations MUST have at least 350MB of non-volatile storage 2127 available for application private data. That is, the <code>/data</code> partition MUST be at 2128 least 350MB.</p> 2129 <p>The Android APIs include a Download Manager that applications may use to 2130 download data files [<a href="#resources56">Resources, 56</a>]. The device 2131 implementation of the Download Manager MUST be capable of downloading individual 2132 files of at least 100MB in size to the default "cache" location.</p> 2133 <a name="section-7.6.2"></a><h4>7.6.2. Application Shared Storage</h4> 2134 <p>Device implementations MUST offer shared storage for applications. The 2135 shared storage provided MUST be at least 1GB in size.</p> 2136 <p>Device implementations MUST be configured with shared storage mounted by 2137 default, "out of the box". If the shared storage is not mounted on the Linux 2138 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 2139 from <code>/sdcard</code> to the actual mount point.</p> 2140 <p>Device implementations MUST enforce as documented the 2141 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 2142 shared storage. Shared storage MUST otherwise be writable by any application 2143 that obtains that permission.</p> 2144 <p>Device implementations MAY have hardware for user-accessible removable 2145 storage, such as a Secure Digital card. Alternatively, device implementations 2146 MAY allocate internal (non-removable) storage as shared storage for apps.</p> 2147 <p>Regardless of the form of shared storage used, device implementations MUST 2148 provide some mechanism to access the contents of shared storage from a host 2149 computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device 2150 implementations MAY use USB mass storage, but SHOULD use Media Transfer 2151 Protocol. If the device implementation supports Media Transfer Protocol:</p> 2152 <ul> 2153 <li>The device implementation SHOULD be compatible with the reference Android 2154 MTP host, Android File Transfer [<a href="#resources57">Resources, 57</a>].</li> 2155 <li>The device implementation SHOULD report a USB device class of <code>0x00</code>.</li> 2156 <li>The device implementation SHOULD report a USB interface name of 'MTP'.</li> 2157 </ul> 2158 <p>If the device implementation lacks USB ports, it MUST provide a host 2159 computer with access to the contents of shared storage by some other means, 2160 such as a network file system.</p> 2161 <p>It is illustrative to consider two common examples. If a device 2162 implementation includes an SD card slot to satisfy the shared storage 2163 requirement, a FAT-formatted SD card 1GB in size or larger MUST be included 2164 with the device as sold to users, and MUST be mounted by default. 2165 Alternatively, if a device implementation uses internal fixed storage to 2166 satisfy this requirement, that storage MUST be 1GB in size or larger 2167 and mounted on <code>/sdcard</code> (or <code>/sdcard</code> 2168 MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p> 2169 <p>Device implementations that include multiple shared storage paths (such as 2170 both an SD card slot and shared internal storage) SHOULD modify the core 2171 applications such as the media scanner and ContentProvider to transparently 2172 support files placed in both locations.</p> 2173 2174 <a name="section-7.7"></a><h3>7.7. USB</h3> 2175 <p>Device implementations SHOULD include a USB client port, and SHOULD include 2176 a USB host port.</p> 2177 <p>If a device implementation includes a USB client port:</p> 2178 <ul> 2179 <li>the port MUST be connectable to a USB host with a standard USB-A port</li> 2180 <li>the port SHOULD use the micro USB form factor on the device side</li> 2181 <li>it MUST allow a host connected to the device to access the contents of the 2182 shared storage volume using either USB mass storage or Media Transfer 2183 Protocol</li> 2184 <li>it MUST implement the Android Open Accessory API and specification as documented 2185 in the Android SDK documentation, and MUST declare support for the hardware 2186 feature <code>android.hardware.usb.accessory</code> [<a href="#resources52">Resources, 2187 51</a>]</li> 2188 </ul> 2189 2190 <p>If a device implementation includes a USB host port:</p> 2191 <ul> 2192 <li>it MAY use a non-standard port form factor, but if so MUST ship with a 2193 cable or cables adapting the port to standard USB-A</li> 2194 <li>it MUST implement the Android USB host API as documented in the Android 2195 SDK, and MUST declare support for the hardware feature 2196 <code>android.hardware.usb.host</code> [<a href="#resources53">Resources, 2197 52</a>]</li> 2198 </ul> 2199 <p>Device implementations MUST implement the Android Debug Bridge. If a device 2200 implementation omits a USB client port, it MUST implement the Android Debug 2201 Bridge via local-area network (such as Ethernet or 802.11)</p> 2202 2203 <a name="section-8"></a><h2>8. Performance Compatibility</h2> 2204 <p>Device implementations MUST meet the key performance metrics of an Android 2205 4.0 compatible device defined in the table below:</p> 2206 <table><tbody><tr> 2207 <td><b>Metric</b></td> 2208 <td><b>Performance Threshold</b></td> 2209 <td><b>Comments</b></td> 2210 </tr> 2211 <tr> 2212 <td>Application Launch Time</td> 2213 <td>The following applications should launch within the specified time.<ul> 2214 <li>Browser: less than 1300ms</li> 2215 <li>Contacts: less than 700ms</li> 2216 <li>Settings: less than 700ms</li> 2217 </ul></td> 2218 <td>The launch time is measured as the total time to 2219 complete loading the default activity for the application, including the time 2220 it takes to start the Linux process, load the Android package into the Dalvik 2221 VM, and call onCreate.</td> 2222 </tr> 2223 <tr> 2224 <td>Simultaneous Applications</td> 2225 <td>When multiple applications have been launched, re-launching an 2226 already-running application after it has been launched must take less than the 2227 original launch time.</td> 2228 <td> </td> 2229 </tr> 2230 </tbody> 2231 </table> 2232 2233 <a name="section-9"></a><h2>9. Security Model Compatibility</h2> 2234 <p>Device implementations MUST implement a security model consistent with the 2235 Android platform security model as defined in Security and Permissions 2236 reference document in the APIs [<a href="#resources54">Resources, 54</a>] in the 2237 Android developer documentation. Device implementations MUST support 2238 installation of self-signed applications without requiring any additional 2239 permissions/certificates from any third parties/authorities. Specifically, 2240 compatible devices MUST support the security mechanisms described in the 2241 follow sub-sections.</p> 2242 <a name="section-9.1"></a><h3>9.1. Permissions</h3> 2243 <p>Device implementations MUST support the Android permissions model as 2244 defined in the Android developer documentation [<a 2245 href="#resources54">Resources, 54</a>]. Specifically, 2246 implementations MUST enforce each permission defined as described in the SDK 2247 documentation; no permissions may be omitted, altered, or ignored. 2248 Implementations MAY add additional permissions, provided the new permission ID 2249 strings are not in the android.* namespace.</p> 2250 <a name="section-9.2"></a><h3>9.2. UID and Process Isolation</h3> 2251 <p>Device implementations MUST support the Android application sandbox model, 2252 in which each application runs as a unique Unix-style UID and in a separate 2253 process. Device implementations MUST support running multiple applications as 2254 the same Linux user ID, provided that the applications are properly signed and 2255 constructed, as defined in the Security and Permissions reference [<a 2256 href="#resources54">Resources, 54</a>].</p> 2257 <a name="section-9.3"></a><h3>9.3. Filesystem Permissions</h3> 2258 <p>Device implementations MUST support the Android file access permissions 2259 model as defined in as defined in the Security and Permissions reference [<a 2260 href="#resources54">Resources, 54</a>].</p> 2261 <a name="section-9.4"></a><h3>9.4. Alternate Execution Environments</h3> 2262 <p>Device implementations MAY include runtime environments that execute 2263 applications using some other software or technology than the Dalvik virtual 2264 machine or native code. However, such alternate execution environments MUST 2265 NOT compromise the Android security model or the security of installed Android 2266 applications, as described in this section.</p> 2267 <p>Alternate runtimes MUST themselves be Android applications, and abide by 2268 the standard Android security model, as described elsewhere in Section 9.</p> 2269 <p>Alternate runtimes MUST NOT be granted access to resources protected by 2270 permissions not requested in the runtime's AndroidManifest.xml file via the 2271 <code><uses-permission></code> mechanism.</p> 2272 <p>Alternate runtimes MUST NOT permit applications to make use of features 2273 protected by Android permissions restricted to system applications.</p> 2274 <p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p> 2275 <ul> 2276 <li>Alternate runtimes SHOULD install apps via the PackageManager into 2277 separate Android sandboxes (that is, Linux user IDs, etc.)</li> 2278 <li>Alternate runtimes MAY provide a single Android sandbox shared by all 2279 applications using the alternate runtime.</li> 2280 <li>Alternate runtimes and installed applications using an alternate runtime 2281 MUST NOT reuse the sandbox of any other app installed on the device, except 2282 through the standard Android mechanisms of shared user ID and signing 2283 certificate</li> 2284 <li>Alternate runtimes MUST NOT launch with, grant, or be granted access to 2285 the sandboxes corresponding to other Android applications.</li> 2286 </ul> 2287 <p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other 2288 applications any privileges of the superuser (root), or of any other user ID.</p> 2289 <p>The .apk files of alternate runtimes MAY be included in the system image of 2290 a device implementation, but MUST be signed with a key distinct 2291 from the key used to sign other applications included with the device 2292 implementation.</p> 2293 <p>When installing applications, alternate runtimes MUST obtain user consent 2294 for the Android permissions used by the application. That is, if an 2295 application needs to make use of a device resource for which there is a 2296 corresponding Android permission (such as Camera, GPS, etc.), the alternate 2297 runtime MUST inform the user that the application will be able to access 2298 that resource. If the runtime environment does not record application 2299 capabilities in this manner, the runtime environment MUST list all 2300 permissions held by the runtime itself when installing any application 2301 using that runtime.</p> 2302 2303 <a name="section-10"></a><h2>10. Software Compatibility Testing</h2> 2304 <p>Device implementations MUST pass all tests described in this section.</p> 2305 <p>However, note that no software test package is fully comprehensive. For 2306 this reason, device implementers are very strongly encouraged to make the 2307 minimum number of changes as possible to the reference and preferred 2308 implementation of Android 4.0 available from the Android Open Source Project. 2309 This will minimize the risk of introducing bugs that create incompatibilities 2310 requiring rework and potential device updates.</p> 2311 <a name="section-10.1"></a><h3>10.1. Compatibility Test Suite</h3> 2312 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 2313 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source 2314 Project, using the final shipping software on the device. Additionally, device 2315 implementers SHOULD use the reference implementation in the Android Open 2316 Source tree as much as possible, and MUST ensure compatibility in cases of 2317 ambiguity in CTS and for any reimplementations of parts of the reference 2318 source code.</p> 2319 <p>The CTS is designed to be run on an actual device. Like any software, the 2320 CTS may itself contain bugs. The CTS will be versioned independently of this 2321 Compatibility Definition, and multiple revisions of the CTS may be released 2322 for Android 4.0. Device implementations MUST pass the latest CTS version 2323 available at the time the device software is completed.</p> 2324 <a name="section-10.2"></a><h3>10.2. CTS Verifier</h3> 2325 <p>Device implementations MUST correctly execute all applicable cases in the 2326 CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, 2327 and is intended to be run by a human operator to test functionality that 2328 cannot be tested by an automated system, such as correct functioning of a 2329 camera and sensors.</p> 2330 <p>The CTS Verifier has tests for many kinds of hardware, including some 2331 hardware that is optional. Device implementations MUST pass all tests for 2332 hardware which they possess; for instance, if a device possesses an 2333 accelerometer, it MUST correctly execute the Accelerometer test case in the 2334 CTS Verifier. Test cases for features noted as optional by this Compatibility 2335 Definition Document MAY be skipped or omitted.</p> 2336 <p>Every device and every build MUST correctly run the CTS Verifier, as noted 2337 above. However, since many builds are very similar, device implementers are 2338 not expected to explicitly run the CTS Verifier on builds that differ only in 2339 trivial ways. Specifically, device implementations that differ from an 2340 implementation that has passed the CTS Verfier only by the set of included 2341 locales, branding, etc. MAY omit the CTS Verifier test.</p> 2342 <a name="section-10.3"></a><h3>10.3. Reference Applications</h3> 2343 <p>Device implementers MUST test implementation compatibility using the 2344 following open source applications:</p> 2345 <ul> 2346 <li>The "Apps for Android" applications [<a href="#resources55">Resources, 55</a>].</li> 2347 <li>Replica Island (available in Android Market)</li> 2348 </ul> 2349 <p>Each app above MUST launch and behave correctly on the implementation, for 2350 the implementation to be considered compatible.</p> 2351 2352 2353 <a name="section-11"></a><h2>11. Updatable Software</h2> 2354 <p>Device implementations MUST include a mechanism to replace the entirety of 2355 the system software. The mechanism need not perform "live" upgrades - that 2356 is, a device restart MAY be required.</p> 2357 <p>Any method can be used, provided that it can replace the entirety of the 2358 software preinstalled on the device. For instance, any of the following 2359 approaches will satisfy this requirement:</p> 2360 <ul> 2361 <li>Over-the-air (OTA) downloads with offline update via reboot</li> 2362 <li>"Tethered" updates over USB from a host PC</li> 2363 <li>"Offline" updates via a reboot and update from a file on removable 2364 storage</li> 2365 </ul> 2366 <p>The update mechanism used MUST support updates without wiping user data. 2367 That is, the update mechanism MUST preserve application private data 2368 and application shared data. Note that the upstream Android software includes 2369 an update mechanism that satisfies this requirement.</p> 2370 <p>If an error is found in a device implementation after it has been released 2371 but within its reasonable product lifetime that is determined in consultation 2372 with the Android Compatibility Team to affect the compatibility of third-party 2373 applications, the device implementer MUST correct the error via a software 2374 update available that can be applied per the mechanism just described.</p> 2375 2376 <a name="section-12"></a><h2>12. Contact Us</h2> 2377 <p>You can contact the document authors at <a 2378 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for 2379 clarifications and to bring up any issues that you think the document does not 2380 cover.</p> 2381 2382 <div style="page-break-before: always;"></div> 2383 2384 <a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2> 2385 <p>The Compatibility Test Suite includes cases that cover basic operation of 2386 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 2387 protocol between devices, it cannot be fully tested by unit tests running on a 2388 single device. Consequently, device implementations MUST also pass the 2389 human-operated Bluetooth test procedure described below.</p> 2390 <p>The test procedure is based on the BluetoothChat sample app included in the 2391 Android open source project tree. The procedure requires two devices:</p> 2392 <ul> 2393 <li>a candidate device implementation running the software build to be tested</li> 2394 <li>a separate device implementation already known to be compatible, and of a 2395 model from the device implementation being tested - that is, a "known 2396 good" device implementation</li> 2397 </ul> 2398 <p>The test procedure below refers to these devices as the "candidate" and "known 2399 good" devices, respectively.</p> 2400 <h3>Setup and Installation</h3> 2401 <ol> 2402 <li>Build BluetoothChat.apk via 'make samples' from an Android source code tree.</li> 2403 <li>Install BluetoothChat.apk on the known-good device.</li> 2404 <li>Install BluetoothChat.apk on the candidate device.</li> 2405 </ol> 2406 <h3>Test Bluetooth Control by Apps</h3> 2407 <ol> 2408 <li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled.</li> 2409 <li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth.</li> 2410 </ol> 2411 <h3>Test Pairing and Communication</h3> 2412 <ol> 2413 <li>Launch the Bluetooth Chat app on both devices.</li> 2414 <li>Make the known-good device discoverable from within BluetoothChat (using the Menu).</li> 2415 <li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device.</li> 2416 <li>Send 10 or more messages from each device, and verify that the other device receives them correctly.</li> 2417 <li>Close the BluetoothChat app on both devices by pressing <b>Home</b>.</li> 2418 <li>Unpair each device from the other, using the device Settings app.</li> 2419 </ol> 2420 <h3>Test Pairing and Communication in the Reverse Direction</h3> 2421 <ol> 2422 <li>Launch the Bluetooth Chat app on both devices.</li> 2423 <li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li> 2424 <li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li> 2425 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 2426 <li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li> 2427 </ol> 2428 <h3>Test Re-Launches</h3> 2429 <ol> 2430 <li>Re-launch the Bluetooth Chat app on both devices.</li> 2431 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 2432 </ol> 2433 <p>Note: the above tests have some cases which end a test section by using 2434 Home, and some using Back. These tests are not redundant and are not optional: 2435 the objective is to verify that the Bluetooth API and stack works correctly 2436 both when Activities are explicitly terminated (via the user pressing Back, 2437 which calls finish()), and implicitly sent to background (via the user 2438 pressing Home.) Each test sequence MUST be performed as described.</p> 2439 2440 <div id="footerContent" xmlns:pdf="http://whatever"> 2441 <pdf:pagenumber/> 2442 </div> 2443 </body> 2444 </html> 2445
