1 <?xml version="1.0" encoding="UTF-8"?> 2 <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> 3 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> 4 <head> 5 <title>Android 4.2 Compatibility Definition</title> 6 <link rel="stylesheet" type="text/css" href="cdd.css"/> 7 </head> 8 <body> 9 <h1>Android 4.2 Compatibility Definition</h1> 10 <!-- 11 <span style="color: red; font-weight: bold;"><h2>Revision 1</h2></span><br/> 12 <span style="color: red;">Last updated: October 17, 2012</span> 13 --> 14 <p><b><font color="red">Revision 2</font></b><br/> 15 Last updated: Feb 17, 2013 16 </p> 17 <p>Copyright © 2012, Google Inc. All rights reserved.<br/> 18 <a href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> 19 </p> 20 21 <h2> Table of Contents</h2> 22 <div style="margin-left: 2em;"> 23 <a href="#section-1">1. Introduction</a><br/> 24 <a href="#section-2">2. Resources</a><br/> 25 <a href="#section-3">3. Software</a><br/> 26 <div style="margin-left: 2em;"> 27 <a href="#section-3.1">3.1. Managed API Compatibility</a><br/> 28 <a href="#section-3.2">3.2. Soft API Compatibility</a><br/> 29 <div style="margin-left: 2em;"> 30 <a href="#section-3.2.1">3.2.1. Permissions</a><br/> 31 <a href="#section-3.2.2">3.2.2. Build Parameters</a><br/> 32 <a href="#section-3.2.3">3.2.3. Intent Compatibility</a><br/> 33 <div style="margin-left: 2em;"> 34 <a href="#section-3.2.3.1">3.2.3.1. Core Application Intents</a><br/> 35 <a href="#section-3.2.3.2">3.2.3.2. Intent Overrides</a><br/> 36 <a href="#section-3.2.3.3">3.2.3.3. Intent Namespaces</a><br/> 37 <a href="#section-3.2.3.4">3.2.3.4. Broadcast Intents</a><br/> 38 </div> 39 </div> 40 <a href="#section-3.3">3.3. Native API Compatibility</a><br/> 41 <div style="margin-left: 2em;"> 42 <a href="#section-3.3.1">3.3.1 Application Binary Interfaces</a><br/> 43 </div> 44 <a href="#section-3.4">3.4. Web Compatibility</a><br/> 45 <div style="margin-left: 2em;"> 46 <a href="#section-3.4.1">3.4.1. WebView Compatibility</a><br/> 47 <a href="#section-3.4.2">3.4.2. Browser Compatibility</a><br/> 48 </div> 49 <a href="#section-3.5">3.5. API Behavioral Compatibility</a><br/> 50 <a href="#section-3.6">3.6. API Namespaces</a><br/> 51 <a href="#section-3.7">3.7. Virtual Machine Compatibility</a><br/> 52 <a href="#section-3.8">3.8. User Interface Compatibility</a><br/> 53 <div style="margin-left: 2em;"> 54 <a href="#section-3.8.1">3.8.1. Widgets</a><br/> 55 <a href="#section-3.8.2">3.8.2. Notifications</a><br/> 56 <a href="#section-3.8.3">3.8.3. Search</a><br/> 57 <a href="#section-3.8.4">3.8.4. Toasts</a><br/> 58 <a href="#section-3.8.5">3.8.5. Themes</a><br/> 59 <a href="#section-3.8.6">3.8.6. Live Wallpapers</a><br/> 60 <a href="#section-3.8.7">3.8.7. Recent Application Display</a><br/> 61 <a href="#section-3.8.8">3.8.8. Input Management Settings</a><br/> 62 <a href="#section-3.8.9">3.8.9. Lock and Home Screen Widgets</a><br/> 63 <a href="#section-3.8.10">3.8.10. Lock Screen Media Remote Control</a><br/> 64 <a href="#section-3.8.11">3.8.11. Dreams</a><br/> 65 </div> 66 <a href="#section-3.9">3.9 Device Administration</a><br/> 67 <a href="#section-3.10">3.10 Accessibility</a><br/> 68 <a href="#section-3.11">3.11 Text-to-Speech</a><br/> 69 </div> 70 <a href="#section-4">4. Application Packaging Compatibility</a><br/> 71 <a href="#section-5">5. Multimedia Compatibility</a><br/> 72 <div style="margin-left: 2em;"> 73 <a href="#section-5.1">5.1. Media Codecs</a><br/> 74 <a href="#section-5.2">5.2. Video Encoding</a><br/> 75 <a href="#section-5.3">5.3. Video Decoding</a><br/> 76 <a href="#section-5.4">5.4. Audio Recording</a><br/> 77 <a href="#section-5.5">5.5. Audio Latency</a><br/> 78 <a href="#section-5.6">5.6. Network Protocols</a><br/> 79 </div> 80 <a href="#section-6">6. Developer Tools and Options Compatibility</a><br/> 81 <div style="margin-left: 2em;"> 82 <a href="#section-6.1">6.1. Developer Tools</a><br/> 83 <a href="#section-6.2">6.2. Developer Options</a><br/> 84 </div> 85 <a href="#section-7">7. Hardware Compatibility</a><br/> 86 <div style="margin-left: 2em;"> 87 <a href="#section-7.1">7.1. Display and Graphics</a><br/> 88 <div style="margin-left: 2em;"> 89 <a href="#section-7.1.1">7.1.1. Screen Configuration</a><br/> 90 <a href="#section-7.1.2">7.1.2. Display Metrics</a><br/> 91 <a href="#section-7.1.3">7.1.3. Screen Orientation</a><br/> 92 <a href="#section-7.1.4">7.1.4. 2D and 3D Graphics Accleration</a><br/> 93 <a href="#section-7.1.5">7.1.5. Legacy Application Compatibility Mode</a><br/> 94 <a href="#section-7.1.6">7.1.6. Screen Types</a><br/> 95 <a href="#section-7.1.7">7.1.7. Screen Technology</a><br/> 96 <a href="#section-7.1.8">7.1.8. External Displays</a><br/> 97 </div> 98 <a href="#section-7.2">7.2. Input Devices</a><br/> 99 <div style="margin-left: 2em;"> 100 <a href="#section-7.2.1">7.2.1. Keyboard</a><br/> 101 <a href="#section-7.2.2">7.2.2. Non-touch Navigation</a><br/> 102 <a href="#section-7.2.3">7.2.3. Navigation keys</a><br/> 103 <a href="#section-7.2.4">7.2.4. Touchscreen input</a><br/> 104 </div> 105 <a href="#section-7.3">7.3. Sensors</a><br/> 106 <div style="margin-left: 2em;"> 107 <a href="#section-7.3.1">7.3.1. Accelerometer</a><br/> 108 <a href="#section-7.3.2">7.3.2. Magnetometer</a><br/> 109 <a href="#section-7.3.3">7.3.3. GPS</a><br/> 110 <a href="#section-7.3.4">7.3.4. Gyroscope</a><br/> 111 <a href="#section-7.3.5">7.3.5. Barometer</a><br/> 112 <a href="#section-7.3.6">7.3.6. Thermometer</a><br/> 113 <a href="#section-7.3.7">7.3.7. Photometer</a><br/> 114 <a href="#section-7.3.8">7.3.8. Proximity Sensor</a><br/> 115 </div> 116 <a href="#section-7.4">7.4. Data Connectivity</a><br/> 117 <div style="margin-left: 2em;"> 118 <a href="#section-7.4.1">7.4.1. Telephony</a><br/> 119 <a href="#section-7.4.2">7.4.2. IEEE 802.11 (WiFi)</a><br/> 120 <div style="margin-left: 2em;"> 121 <a href="#section-7.4.2.1">7.4.2.1. WiFi Direct</a><br/> 122 </div> 123 <a href="#section-7.4.3">7.4.3. Bluetooth</a><br/> 124 <a href="#section-7.4.4">7.4.4. Near-Field Communications</a><br/> 125 <a href="#section-7.4.5">7.4.5. Minimum Network Capability</a><br/> 126 </div> 127 <a href="#section-7.5">7.5. Cameras</a><br/> 128 <div style="margin-left: 2em;"> 129 <a href="#section-7.5.1">7.5.1. Rear-Facing Camera</a><br/> 130 <a href="#section-7.5.2">7.5.2. Front-Facing Camera</a><br/> 131 <a href="#section-7.5.3">7.5.3. Camera API Behavior</a><br/> 132 <a href="#section-7.5.4">7.5.4. Camera Orientation</a><br/> 133 </div> 134 <a href="#section-7.6">7.6. Memory and Storage</a><br/> 135 <div style="margin-left: 2em;"> 136 <a href="#section-7.6.1">7.6.1. Minimum Memory and Storage</a><br/> 137 <a href="#section-7.6.2">7.6.2. Application Shared Storage</a><br/> 138 </div> 139 <a href="#section-7.7">7.7. USB</a><br/> 140 </div> 141 <a href="#section-8">8. Performance Compatibility</a><br/> 142 <a href="#section-9">9. Security Model Compatibility</a><br/> 143 <div style="margin-left: 2em;"> 144 <a href="#section-9.1">9.1. Permissions</a><br/> 145 <a href="#section-9.2">9.2. UID and Process Isolation</a><br/> 146 <a href="#section-9.3">9.3. Filesystem Permissions</a><br/> 147 <a href="#section-9.4">9.4. Alternate Execution Environments</a><br/> 148 <a href="#section-9.5">9.5. Multi-User Support</a><br/> 149 <a href="#section-9.6">9.6. Premium SMS Warning</a><br/> 150 </div> 151 <a href="#section-10">10. Software Compatibility Testing</a><br/> 152 <div style="margin-left: 2em;"> 153 <a href="#section-10.1">10.1. Compatibility Test Suite</a><br/> 154 <a href="#section-10.2">10.2. CTS Verifier</a><br/> 155 <a href="#section-10.3">10.3. Reference Applications</a><br/> 156 </div> 157 <a href="#section-11">11. Updatable Software</a><br/> 158 <a href="#section-12">12. Contact Us</a><br/> 159 <a href="#appendix-A">Appendix A - Bluetooth Test Procedure</a><br/> 160 </div> 161 162 <div style="page-break-before: always;"></div> 163 164 <a name="section-1"></a><h2>1. Introduction</h2> 165 <p>This document enumerates the requirements that must be met in order for 166 devices to be compatible with Android 4.2.</p> 167 <p>The use of "must", "must not", "required", "shall", "shall not", "should", 168 "should not", "recommended", "may" and "optional" is per the IETF standard 169 defined in RFC2119 [<a href="#resources01">Resources, 1</a>].</p> 170 <p>As used in this document, a "device implementer" or "implementer" is a 171 person or organization developing a hardware/software solution running Android 172 4.2. A "device implementation" or "implementation" is the hardware/software 173 solution so developed.</p> 174 <p>To be considered compatible with Android 4.2, device implementations 175 MUST meet the requirements presented in this Compatibility Definition, 176 including any documents incorporated via reference.</p> 177 <p>Where this definition or the software tests described in <a 178 href="#section-10">Section 10</a> is silent, ambiguous, or incomplete, it is 179 the responsibility of the device implementer to ensure compatibility with 180 existing implementations.</p> 181 <p>For this reason, the Android Open Source Project [<a 182 href="#resources03">Resources, 3</a>] is both the reference and preferred 183 implementation of Android. Device implementers are strongly encouraged to base 184 their implementations to the greatest extent possible on the "upstream" source 185 code available from the Android Open Source Project. While some components can 186 hypothetically be replaced with alternate implementations this practice is 187 strongly discouraged, as passing the software tests will become substantially 188 more difficult. It is the implementer's responsibility to ensure full 189 behavioral compatibility with the standard Android implementation, including 190 and beyond the Compatibility Test Suite. Finally, note that certain component 191 substitutions and modifications are explicitly forbidden by this document.</p> 192 <a name="section-2"></a><h2>2. Resources</h2> 193 <ol> 194 <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> 195 <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> 196 <a name="resources03"></a><li>Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></li> 197 <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> 198 <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> 199 <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> 200 <a name="resources07"></a><li>Android 4.2 allowed version strings: <a href="http://source.android.com/compatibility/4.2/versions.html">http://source.android.com/compatibility/4.2/versions.html</a></li> 201 <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> 202 <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> 203 <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> 204 <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> 205 <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> 206 <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> 207 <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> 208 <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> 209 <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> 210 <a name="resources17"></a><li>Dalvik Virtual Machine specification: available in the Android source code, at dalvik/docs</li> 211 <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> 212 <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> 213 <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> 214 <a name="resources21"></a><li>Status Bar icon style guide: <a href="http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html">http://developer.android.com/guide/practices/ui_guidelines/icon_design_status_bar.html</a></li> 215 <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> 216 <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> 217 <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> 218 <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> 219 <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> 220 <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> 221 <a name="resources28"></a><li>DevicePolicyManager reference: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html</a></li> 222 <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> 223 <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> 224 <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> 225 <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> 226 <a name="resources33"></a><li>Reference tool documentation (for adb, aapt, ddms, systrace): <a href="http://developer.android.com/guide/developing/tools/index.html">http://developer.android.com/guide/developing/tools/index.html</a></li> 227 <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> 228 <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> 229 <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> 230 <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> 231 <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> 232 <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> 233 <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> 234 <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> 235 <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> 236 <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> 237 <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> 238 <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> 239 <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> 240 <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> 241 <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> 242 <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> 243 <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> 244 <a name="resources51"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></li> 245 <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> 246 <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> 247 <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> 248 <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> 249 <a name="resources56"></a><li>Android DownloadManager: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></li> 250 <a name="resources57"></a><li>Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></li> 251 <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> 252 <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> 253 <a name="resources60"></a><li>NFC Connection Handover: <a href="http://www.nfc-forum.org/specs/spec_list/#conn_handover/">http://www.nfc-forum.org/specs/spec_list/#conn_handover</a></li> 254 <a name="resources61"></a><li>Bluetooth Secure Simple Pairing Using NFC: <a href="http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf">http://www.nfc-forum.org/resources/AppDocs/NFCForum_AD_BTSSP_1_0.pdf</a></li> 255 <a name="resources62"></a><li>Wifi Multicast API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html</a></li> 256 <a name="resources63"></a><li>Action Assist: <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST</a></li> 257 <a name="resources64"></a><li>USB Charging Specification: <a href="http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf">http://www.usb.org/developers/devclass_docs/USB_Battery_Charging_1.2.pdf</a></li> 258 <a name="resources65"></a><li>Android Beam: <a href="http://developer.android.com/guide/topics/nfc/nfc.html">http://developer.android.com/guide/topics/nfc/nfc.html</a></li> 259 <a name="resources66"></a><li>Android USB Audio: <a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO</a></li> 260 <a name="resources67"></a><li>Android NFC Sharing Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS</a></li> 261 <a name="resources68"></a><li>Wifi Direct (Wifi P2P): <a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html</a></li> 262 <a name="resources69"></a><li>Lock and Home Screen Widget: <a href="http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html">http://developer.android.com/reference/android/appwidget/AppWidgetProviderInfo.html</a></li> 263 <a name="resources70"></a><li>UserManager reference: <a href="http://developer.android.com/reference/android/os/UserManager.html">http://developer.android.com/reference/android/os/UserManager.html</a></li> 264 <a name="resources71"></a><li>External Storage reference: <a href="http://source.android.com/tech/storage">http://source.android.com/tech/storage</a></li> 265 <a name="resources72"></a><li>External Storage APIs: <a href="http://developer.android.com/reference/android/os/Environment.html">http://developer.android.com/reference/android/os/Environment.html</a></li> 266 <a name="resources73"></a><li>SMS Short Code: <a href="http://en.wikipedia.org/wiki/Short_code">http://en.wikipedia.org/wiki/Short_code</a></li> 267 <a name="resources74"></a><li>Media Remote Control Client: <a href="http://developer.android.com/reference/android/media/RemoteControlClient.html">http://developer.android.com/reference/android/media/RemoteControlClient.html</a></li> 268 <a name="resources75"></a><li>Display Manager: <a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">http://developer.android.com/reference/android/hardware/display/DisplayManager.html</a></li> 269 <a name="resources76"></a><li>Dreams: <a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">http://developer.android.com/reference/android/service/dreams/DreamService.html</a></li> 270 <a name="resources77"></a><li>Android Application Development-Related Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS</a></li> 271 </ol> 272 <a name="resources78"></a><li>Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">http://developer.android.com/reference/android/hardware/Camera.Parameters.html</a></li> 273 <p>Many of these resources are derived directly or indirectly from the Android 274 4.2 SDK, and will be functionally identical to the information in that SDK's 275 documentation. In any cases where this Compatibility Definition or the 276 Compatibility Test Suite disagrees with the SDK documentation, the SDK 277 documentation is considered authoritative. Any technical details provided in 278 the references included above are considered by inclusion to be part of this 279 Compatibility Definition.</p> 280 281 <a name="section-3"></a><h2>3. Software</h2> 282 <a name="section-3.1"></a><h3>3.1. Managed API Compatibility</h3> 283 <p>The managed (Dalvik-based) execution environment is the primary vehicle for 284 Android applications. The Android application programming interface (API) is 285 the set of Android platform interfaces exposed to applications running in the 286 managed VM environment. Device implementations MUST provide complete 287 implementations, including all documented behaviors, of any documented API 288 exposed by the Android 4.2 SDK [<a href="#resources04">Resources, 4</a>].</p> 289 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces 290 or signatures, deviate from the documented behavior, or include no-ops, except 291 where specifically allowed by this Compatibility Definition.</p> 292 <p>This Compatibility Definition permits some types of hardware for which 293 Android includes APIs to be omitted by device implementations. In such cases, 294 the APIs MUST still be present and behave in a reasonable way. See 295 <a href="#section-7">Section 7</a> for specific requirements for this scenario. 296 </p> 297 298 <a name="section-3.2"></a><h3>3.2. Soft API Compatibility</h3> 299 <p>In addition to the managed APIs from Section 3.1, Android also includes a 300 significant runtime-only "soft" API, in the form of such things such as 301 Intents, permissions, and similar aspects of Android applications that cannot 302 be enforced at application compile time.</p> 303 <a name="section-3.2.1"></a><h4>3.2.1. Permissions</h4> 304 <p>Device implementers MUST support and enforce all permission constants as 305 documented by the Permission reference page [<a 306 href="#resources05">Resources, 5</a>]. Note that Section 10 lists additional 307 requirements related to the Android security model.</p> 308 <a name="section-3.2.2"></a><h4>3.2.2. Build Parameters</h4> 309 <p>The Android APIs include a number of constants on the <code>android.os.Build</code> 310 class [<a href="#resources06">Resources, 6</a>] that are intended to describe 311 the current device. To provide consistent, meaningful values across device 312 implementations, the table below includes additional restrictions on the 313 formats of these values to which device implementations MUST conform.</p> 314 <table> 315 <tbody> 316 <tr> 317 <td><b>Parameter</b></td> 318 <td><b>Comments</b></td> 319 </tr> 320 <tr> 321 <td>android.os.Build.VERSION.RELEASE</td> 322 <td>The version of the currently-executing Android system, in human-readable 323 format. This field MUST have one of the string values defined in [<a 324 href="#resources07">Resources, 7</a>].</td> 325 </tr> 326 <tr> 327 <td>android.os.Build.VERSION.SDK</td> 328 <td>The version of the currently-executing Android system, in a format 329 accessible to third-party application code. For Android 4.2, this 330 field MUST have the integer value 17.</td> 331 </tr> 332 <tr> 333 <td>android.os.Build.VERSION.SDK_INT</td> 334 <td>The version of the currently-executing Android system, in a format 335 accessible to third-party application code. For Android 4.2, this 336 field MUST have the integer value 17.</td> 337 </tr> 338 <tr> 339 <td>android.os.Build.VERSION.INCREMENTAL</td> 340 <td>A value chosen by the device implementer designating the specific build of 341 the currently-executing Android system, in human-readable format. This value 342 MUST NOT be re-used for different builds made available to end users. A typical use 343 of this field is to indicate which build number or source-control change 344 identifier was used to generate the build. There are no requirements on the 345 specific format of this field, except that it MUST NOT be null or the empty 346 string ("").</td> 347 </tr> 348 <tr> 349 <td>android.os.Build.BOARD</td> 350 <td>A value chosen by the device implementer identifying the specific internal 351 hardware used by the device, in human-readable format. A possible use of this 352 field is to indicate the specific revision of the board powering the device. 353 The value of this field MUST be encodable as 7-bit ASCII and match the regular expression 354 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 355 </tr> 356 <tr> 357 <td>android.os.Build.BRAND</td> 358 <td>A value chosen by the device implementer identifying the name of the 359 company, organization, individual, etc. who produced the device, in 360 human-readable format. A possible use of this field is to indicate the OEM 361 and/or carrier who sold the device. The value of this field MUST be 362 encodable as 7-bit ASCII and match the regular expression 363 <code>"^[a-zA-Z0-9.,_-]+$"</code>. 364 </td> 365 </tr> 366 <tr> 367 <td>android.os.Build.CPU_ABI</td> 368 <td>The name of the instruction set (CPU type + ABI convention) of native code. 369 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>. 370 </td> 371 </tr> 372 <tr> 373 <td>android.os.Build.CPU_ABI2</td> 374 <td>The name of the second instruction set (CPU type + ABI convention) of native code. 375 See <a href="#section-3.3">Section 3.3: Native API Compatibility</a>. 376 </td> 377 </tr> 378 <tr> 379 <td>android.os.Build.DEVICE</td> 380 <td>A value chosen by the device implementer identifying the specific 381 configuration or revision of the body (sometimes called "industrial design") 382 of the device. The value of this field MUST be encodable as 7-bit ASCII and 383 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 384 </tr> 385 <tr> 386 <td>android.os.Build.FINGERPRINT</td> 387 <td>A string that uniquely identifies this build. It SHOULD be reasonably 388 human-readable. It MUST follow this template: 389 <br/><code>$(BRAND)/$(PRODUCT)/$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</code><br/> 390 For example: 391 <br/><code>acme/mydevice/generic:4.2/JRN53/3359:userdebug/test-keys</code><br/> 392 The fingerprint MUST NOT include whitespace characters. If other fields included in the 393 template above have whitespace characters, they MUST be replaced in the build 394 fingerprint with another character, such as the underscore ("_") character. 395 The value of this field MUST be encodable as 7-bit ASCII.</td> 396 </tr> 397 <tr> 398 <td>android.os.Build.HARDWARE</td> 399 <td>The name of the hardware (from the kernel command line or /proc). It SHOULD be 400 reasonably human-readable. The value of this field MUST be encodable as 7-bit ASCII and 401 match the regular expression <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 402 </tr> 403 <tr> 404 <td>android.os.Build.HOST</td> 405 <td>A string that uniquely identifies the host the build was built on, in 406 human readable format. There are no requirements on the specific format of 407 this field, except that it MUST NOT be null or the empty string ("").</td> 408 </tr> 409 <tr> 410 <td>android.os.Build.ID</td> 411 <td>An identifier chosen by the device implementer to refer to a specific 412 release, in human readable format. This field can be the same as 413 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently 414 meaningful for end users to distinguish between software builds. The value of 415 this field MUST be encodable as 7-bit ASCII and match the regular expression 416 <code>"^[a-zA-Z0-9.,_-]+$"</code>. 417 </td> 418 </tr> 419 <tr> 420 <td>android.os.Build.MANUFACTURER</td> 421 <td>The trade name of the Original Equipment Manufacturer (OEM) of the product. 422 There are no requirements on the specific format of this field, except that it 423 MUST NOT be null or the empty string ("").</td> 424 </tr> 425 <tr> 426 <td>android.os.Build.MODEL</td> 427 <td>A value chosen by the device implementer containing the name of the device 428 as known to the end user. This SHOULD be the same name under which the device 429 is marketed and sold to end users. There are no requirements on the specific 430 format of this field, except that it MUST NOT be null or the empty string 431 ("").</td> 432 </tr> 433 <tr> 434 <td>android.os.Build.PRODUCT</td> 435 <td>A value chosen by the device implementer containing the development name 436 or code name of the product (SKU). MUST be human-readable, but is not necessarily 437 intended for view by end users. The value of this field MUST be encodable as 7-bit 438 ASCII and match the regular expression 439 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 440 </tr> 441 <tr> 442 <td>android.os.Build.SERIAL</td> 443 <td>A hardware serial number, if available. The value of this field MUST be encodable 444 as 7-bit ASCII and match the regular expression 445 <code>"^([a-zA-Z0-9]{0,20})$"</code>.</td> 446 </tr> 447 <tr> 448 <td>android.os.Build.TAGS</td> 449 <td>A comma-separated list of tags chosen by the device implementer that 450 further distinguish the build. For example, "unsigned,debug". The value of 451 this field MUST be encodable as 7-bit ASCII and match the regular expression 452 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 453 </tr> 454 <tr> 455 <td>android.os.Build.TIME</td> 456 <td>A value representing the timestamp of when the build occurred.</td> 457 </tr> 458 <tr> 459 <td>android.os.Build.TYPE</td> 460 <td>A value chosen by the device implementer specifying the runtime 461 configuration of the build. This field SHOULD have one of the values 462 corresponding to the three typical Android runtime configurations: "user", 463 "userdebug", or "eng". The value of this field MUST be 464 encodable as 7-bit ASCII and match the regular expression 465 <code>"^[a-zA-Z0-9.,_-]+$"</code>.</td> 466 </tr> 467 <tr> 468 <td>android.os.Build.USER</td> 469 <td>A name or user ID of the user (or automated user) that generated the 470 build. There are no requirements on the specific format of this field, except 471 that it MUST NOT be null or the empty string ("").</td> 472 </tr> 473 </tbody> 474 </table> 475 <a name="section-3.2.3"></a><h4>3.2.3. Intent Compatibility</h4> 476 <p> 477 Device implementations MUST honor Android's loose-coupling Intent system, as 478 described in the sections below. By "honored", it is meant that the device 479 implementer MUST provide an Android Activity or Service that specifies a 480 matching Intent filter and binds to and implements correct behavior for each 481 specified Intent pattern.</p> 482 <a name="section-3.2.3.1"></a><h4>3.2.3.1. Core Application Intents</h4> 483 <p>The Android upstream project defines a number of core applications, such as 484 contacts, calendar, photo gallery, music player, and so on. Device implementers 485 MAY replace these applications with alternative versions.</p> 486 <p>However, any such alternative versions MUST honor the same Intent patterns 487 provided by the upstream project. For example, if a device contains an 488 alternative music player, it must still honor the Intent pattern issued by 489 third-party applications to pick a song.</p> 490 <p>The following applications are considered core Android system 491 applications:</p> 492 <ul> 493 <li>Desk Clock</li> 494 <li>Browser</li> 495 <li>Calendar</li> 496 <li>Contacts</li> 497 <!--<li>Email</li>--> 498 <li>Gallery</li> 499 <li>GlobalSearch</li> 500 <li>Launcher</li> 501 <!-- <li>LivePicker (that is, the Live Wallpaper picker application; MAY be omitted 502 if the device does not support Live Wallpapers, per Section 3.8.5.)</li> --> 503 <!-- <li>Messaging (AKA "Mms")</li> --> 504 <li>Music</li> 505 <!-- <li>Phone</li> --> 506 <li>Settings</li> 507 <!-- <li>SoundRecorder</li> --> 508 </ul> 509 <p>The core Android system applications include various Activity, or Service 510 components that are considered "public". That is, the attribute 511 "android:exported" may be absent, or may have the value "true".</p> 512 <p>For every Activity or Service defined 513 in one of the core Android system apps that is not marked as non-public via an 514 android:exported attribute with the value "false", device implementations MUST 515 include a compontent of the same type implementing the same Intent filter 516 patterns as the core Android system app.</p> 517 <p>In other words, a device implementation MAY replace core Android system 518 apps; however, if it does, the device implementation MUST support all Intent 519 patterns defined by each core Android system app being replaced.</p> 520 <a name="section-3.2.3.2"></a><h4>3.2.3.2. Intent Overrides</h4> 521 <p>As Android is an extensible platform, device implementations MUST allow each 522 Intent pattern referenced in Section 3.2.3.2 to be overridden by third-party 523 applications. The upstream Android open source implementation allows this by 524 default; device implementers MUST NOT attach special privileges to system 525 applications' use of these Intent patterns, or prevent third-party 526 applications from binding to and assuming control of these patterns. This 527 prohibition specifically includes but is not limited to disabling the 528 "Chooser" user interface which allows the user to select between multiple 529 applications which all handle the same Intent pattern.</p> 530 <p>However, device implementations MAY provide default activities for specific 531 URI patterns (eg. http://play.google.com) if the default activity provides a 532 more specific filter for the data URI. For example, an intent filter specifying 533 the data URI "http://www.android.com" is more specific than the browser filter 534 for "http://". Device implementations MUST provide a user interface for users 535 to modify the default activity for intents.</p> 536 537 <a name="section-3.2.3.3"></a><h4>3.2.3.3. Intent Namespaces</h4> 538 <p>Device implementations MUST NOT include any Android component that honors any 539 new Intent or Broadcast Intent patterns using an ACTION, CATEGORY, or other 540 key string in the android.* or com.android.* namespace. Device implementers 541 MUST NOT include any Android components that honor any new Intent or Broadcast 542 Intent patterns using an ACTION, CATEGORY, or other key string in a package 543 space belonging to another organization. Device implementers MUST NOT alter or 544 extend any of the Intent patterns used by the core apps listed in Section 545 3.2.3.1. Device implementations MAY include Intent patterns using 546 namespaces clearly and obviously associated with their own organization.</p> 547 <p>This prohibition is analogous to that specified for Java language classes 548 in Section 3.6.</p> 549 <a name="section-3.2.3.4"></a><h4>3.2.3.4. Broadcast Intents</h4> 550 <p>Third-party applications rely on the platform to broadcast certain Intents 551 to notify them of changes in the hardware or software environment. 552 Android-compatible devices MUST broadcast the public broadcast Intents in 553 response to appropriate system events. Broadcast Intents are described in the 554 SDK documentation.</p> 555 556 <a name="section-3.3"></a><h3>3.3. Native API Compatibility</h3> 557 <a name="section-3.3.1"></a><h4>3.3.1 Application Binary Interfaces</h4> 558 <p>Managed code running in Dalvik can call into native code provided in the 559 application .apk file as an ELF .so file compiled for the appropriate device 560 hardware architecture. As native code is highly dependent on the underlying 561 processor technology, Android defines a number of Application Binary 562 Interfaces (ABIs) in the Android NDK, in the file 563 <code>docs/CPU-ARCH-ABIS.html</code>. If a device implementation is compatible 564 with one or more defined ABIs, it SHOULD implement compatibility with the 565 Android NDK, as below.</p> 566 <p>If a device implementation includes support for an Android ABI, it:</p> 567 <ul> 568 <li>MUST include support for code running in the managed environment to call 569 into native code, using the standard Java Native Interface (JNI) 570 semantics.</li> 571 <li>MUST be source-compatible (i.e. header compatible) and binary-compatible 572 (for the ABI) with each required library in the list below</li> 573 <li>MUST accurately report the native Application Binary Interface (ABI) 574 supported by the device, via the <code>android.os.Build.CPU_ABI</code> 575 API</li> 576 <li>MUST report only those ABIs documented in the latest version of the 577 Android NDK, in the file <code>docs/CPU-ARCH-ABIS.txt</code></li> 578 <li>SHOULD be built using the source code and header files available in the 579 upstream Android open source project</li> 580 </ul> 581 <p>The following native code APIs MUST be available to apps that include 582 native code:</p> 583 <ul> 584 <li>libc (C library)</li> 585 <li>libm (math library)</li> 586 <li>Minimal support for C++</li> 587 <li>JNI interface</li> 588 <li>liblog (Android logging)</li> 589 <li>libz (Zlib compression)</li> 590 <li>libdl (dynamic linker)</li> 591 <li>libGLESv1_CM.so (OpenGL ES 1.0)</li> 592 <li>libGLESv2.so (OpenGL ES 2.0)</li> 593 <li>libEGL.so (native OpenGL surface management)</li> 594 <li>libjnigraphics.so</li> 595 <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li> 596 <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li> 597 <li>libandroid.so (native Android activity support)</li> 598 <li>Support for OpenGL, as described below</li> 599 </ul> 600 <p>Note that future releases of the Android NDK may introduce support for 601 additional ABIs. If a device implementation is not compatible with an existing 602 predefined ABI, it MUST NOT report support for any ABI at all.</p> 603 <p>Native code compatibility is challenging. For this reason, it should be 604 repeated that device implementers are VERY strongly encouraged to use the 605 upstream implementations of the libraries listed above to help ensure 606 compatibility.</p> 607 608 <a name="section-3.4"></a><h3>3.4. Web Compatibility</h3> 609 <a name="section-3.4.1"></a><h4>3.4.1. WebView Compatibility</h4> 610 <p>The Android Open Source implementation uses the WebKit rendering engine to 611 implement the <code>android.webkit.WebView</code>. Because it is not feasible 612 to develop a comprehensive test suite for a web rendering system, device 613 implementers MUST use the specific upstream build of WebKit in the WebView 614 implementation. Specifically:</p> 615 <ul> 616 <li>Device implementations' <code>android.webkit.WebView</code> 617 implementations MUST be based on the 534.30 WebKit build from the upstream 618 Android Open Source tree for Android 4.2. This build includes a specific set 619 of functionality and security fixes for the WebView. Device implementers MAY 620 include customizations to the WebKit implementation; however, any such 621 customizations MUST NOT alter the behavior of the WebView, including rendering 622 behavior.</li> 623 <li>The user agent string reported by the WebView MUST be in this format:<br/> 624 <code>Mozilla/5.0 (Linux; U; Android $(VERSION); $(LOCALE); $(MODEL) Build/$(BUILD)) AppleWebKit/534.30 (KHTML, like Gecko) Version/4.2 Mobile Safari/534.30</code> 625 <ul> 626 <li>The value of the $(VERSION) string MUST be the same as the value for <code>android.os.Build.VERSION.RELEASE</code></li> 627 <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> 628 <li>The value of the $(MODEL) string MUST be the same as the value for <code>android.os.Build.MODEL</code></li> 629 <li>The value of the $(BUILD) string MUST be the same as the value for <code>android.os.Build.ID</code></li> 630 <li>Device implementations MAY omit <code>Mobile</code> in the user agent string</li> 631 </ul> 632 </li> 633 </ul> 634 <p>The WebView component SHOULD include support for as much of HTML5 [<a 635 href="#resources11">Resources, 11</a>] as possible. 636 Minimally, device implementations MUST support each of these APIs associated 637 with HTML5 in the WebView:</p> 638 <ul> 639 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li> 640 <li>the <video> tag [<a href="#resources13">Resources, 13</a>]</li> 641 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li> 642 </ul> 643 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage 644 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the 645 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note 646 that as the web development standards bodies are transitioning to favor 647 IndexedDB over webstorage, IndexedDB is expected to become a required 648 component in a future version of Android.</i></p> 649 <p>HTML5 APIs, like all JavaScript APIs, MUST be disabled by default in a 650 WebView, unless the developer explicitly enables them via the usual Android 651 APIs.</p> 652 653 <a name="section-3.4.2"></a><h4>3.4.2. Browser Compatibility</h4> 654 <p>Device implementations MUST include a standalone Browser application for 655 general user web browsing. The standalone Browser MAY be based on a 656 browser technology other than WebKit. However, even if an alternate Browser 657 application is used, the <code>android.webkit.WebView</code> component 658 provided to third-party applications MUST be based on WebKit, as described in 659 Section 3.4.1.</p> 660 <p>Implementations MAY ship a custom user agent string in the standalone 661 Browser application.</p> 662 <p>The standalone Browser application (whether based on the upstream 663 WebKit Browser application or a third-party replacement) SHOULD include support 664 for as much of HTML5 [<a href="#resources11">Resources, 11</a>] as possible. 665 Minimally, device implementations MUST support each of these APIs associated 666 with HTML5:</p> 667 <ul> 668 <li>application cache/offline operation [<a href="#resources12">Resources, 12</a>]</li> 669 <li>the <video> tag [<a href="#resources13">Resources, 13</a>]</li> 670 <li>geolocation [<a href="#resources14">Resources, 14</a>]</li> 671 </ul> 672 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage 673 API [<a href="#resources15">Resources, 15</a>], and SHOULD support the 674 HTML5/W3C IndexedDB API [<a href="#resources16">Resources, 16</a>]. <i>Note 675 that as the web development standards bodies are transitioning to favor 676 IndexedDB over webstorage, IndexedDB is expected to become a required 677 component in a future version of Android.</i></p> 678 679 <a name="section-3.5"></a><h3>3.5. API Behavioral Compatibility</h3> 680 <p>The behaviors of each of the API types (managed, soft, native, and web) 681 must be consistent with the preferred implementation of the upstream Android 682 open source project [<a href="#resources03">Resources, 3</a>]. Some specific areas 683 of compatibility are:</p> 684 <ul> 685 <li>Devices MUST NOT change the behavior or semantics of a standard Intent</li> 686 <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a 687 particular type of system component (such as Service, Activity, 688 ContentProvider, etc.)</li> 689 <li>Devices MUST NOT change the semantics of a standard permission</li> 690 </ul> 691 <p>The above list is not comprehensive. The Compatibility Test Suite (CTS) 692 tests significant portions of the platform for behavioral compatibility, but 693 not all. It is the responsibility of the implementer to ensure behavioral 694 compatibility with the Android Open Source Project. For this reason, device 695 implementers SHOULD use the source code available via the Android Open Source 696 Project where possible, rather than re-implement significant parts of the 697 system.</p> 698 699 700 <a name="section-3.6"></a><h3>3.6. API Namespaces</h3> 701 <p>Android follows the package and class namespace conventions defined by the 702 Java programming language. To ensure compatibility with third-party 703 applications, device implementers MUST NOT make any prohibited modifications 704 (see below) to these package namespaces:</p> 705 <ul> 706 <li>java.*</li> 707 <li>javax.*</li> 708 <li>sun.*</li> 709 <li>android.*</li> 710 <li>com.android.*</li> 711 </ul> 712 <p>Prohibited modifications include:</p> 713 <ul> 714 <li>Device implementations MUST NOT modify the publicly exposed APIs on the 715 Android platform by changing any method or class signatures, or by removing 716 classes or class fields.</li> 717 <li>Device implementers MAY modify the underlying implementation of the APIs, 718 but such modifications MUST NOT impact the stated behavior and Java-language 719 signature of any publicly exposed APIs.</li> 720 <li>Device implementers MUST NOT add any publicly exposed elements (such as 721 classes or interfaces, or fields or methods to existing classes or interfaces) 722 to the APIs above.</li> 723 </ul> 724 <p>A "publicly exposed element" is any construct which is not decorated with 725 the "@hide" marker as used in the upstream Android source code. In other 726 words, device implementers MUST NOT expose new APIs or alter existing APIs in 727 the namespaces noted above. Device implementers MAY make internal-only 728 modifications, but those modifications MUST NOT be advertised or otherwise 729 exposed to developers.</p> 730 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a 731 namespace owned by or referring to another organization. For instance, device 732 implementers MUST NOT add APIs to the com.google.* or similar namespace; only 733 Google may do so. Similarly, Google MUST NOT add APIs to other companies' 734 namespaces. Additionally, if a device implementation includes custom APIs 735 outside the standard Android namespace, those APIs MUST be packaged in an 736 Android shared library so that only apps that explicitly use them (via the 737 <code><uses-library></code> mechanism) are affected by the increased 738 memory usage of such APIs.</p> 739 <p>If a device implementer proposes to improve one of the package namespaces 740 above (such as by adding useful new functionality to an existing API, or 741 adding a new API), the implementer SHOULD visit source.android.com and begin 742 the process for contributing changes and code, according to the information on 743 that site.</p> 744 <p>Note that the restrictions above correspond to standard conventions for 745 naming APIs in the Java programming language; this section simply aims to 746 reinforce those conventions and make them binding through inclusion in this 747 compatibility definition.</p> 748 749 <a name="section-3.7"></a><h3>3.7. Virtual Machine Compatibility</h3> 750 <p>Device implementations MUST support the full Dalvik Executable (DEX) 751 bytecode specification and Dalvik Virtual Machine semantics [<a 752 href="#resources17">Resources, 17</a>].</p> 753 <p>Device implementations MUST configure Dalvik to allocate memory in 754 accordance with the upstream Android platform, and as specified by the following 755 table. (See <a href="#section-7.1.1">Section 7.1.1</a> for screen size and screen 756 density definitions.)</p> 757 758 <p>Note that memory values specified below are considered minimum values, 759 and device implementations MAY allocate more memory per application.</p> 760 <table> 761 <tbody> 762 <tr> 763 <td><b>Screen Size</b></td> 764 <td><b>Screen Density</b></td> 765 <td><b>Application Memory</b></td> 766 </tr> 767 <tr> 768 <td>small / normal / large</td> 769 <td>ldpi / mdpi</td> 770 <td>16MB</td> 771 </tr> 772 <tr> 773 <td>small / normal / large</td> 774 <td>tvdpi / hdpi</td> 775 <td>32MB</td> 776 </tr> 777 <tr> 778 <td>small / normal / large</td> 779 <td>xhdpi</td> 780 <td>64MB</td> 781 </tr> 782 <tr> 783 <td>xlarge</td> 784 <td>mdpi</td> 785 <td>32MB</td> 786 </tr> 787 <tr> 788 <td>xlarge</td> 789 <td>tvdpi / hdpi</td> 790 <td>64MB</td> 791 </tr> 792 <tr> 793 <td>xlarge</td> 794 <td>xhdpi</td> 795 <td>128MB</td> 796 </tr> 797 </tbody> 798 </table> 799 800 <a name="section-3.8"></a><h3>3.8. User Interface Compatibility</h3> 801 <a name="section-3.8.1"></a><h4>3.8.1. Widgets</h4> 802 <p>Android defines a component type and corresponding API and lifecycle that 803 allows applications to expose an "AppWidget" to the end user [<a 804 href="#resources18">Resources, 18</a>]. 805 The Android Open Source reference release includes a Launcher application that 806 includes user interface affordances allowing the user to add, view, and remove 807 AppWidgets from the home screen.</p> 808 <p>Device implementations MAY substitute an alternative to the reference Launcher 809 (i.e. home screen). Alternative Launchers SHOULD include built-in support for 810 AppWidgets, and expose user interface affordances to add, configure, view, and 811 remove AppWidgets directly within the Launcher. Alternative Launchers MAY omit 812 these user interface elements; however, if they are omitted, the device 813 implementation MUST provide a separate application accessible from the Launcher 814 that allows users to add, configure, view, and remove AppWidgets.</p> 815 <p>Device implementations MUST be capable of rendering widgets that are 4 x 4 816 in the standard grid size. (See the App Widget Design Guidelines in the Android 817 SDK documentation [<a href="#resources18">Resources, 18</a>] for details.</p> 818 <p> 819 <a name="section-3.8.2"></a><h4>3.8.2. Notifications</h4> 820 <p>Android includes APIs that allow developers to notify users of notable 821 events [<a href="#resources19">Resources, 19</a>], using hardware and software 822 features of the device.</p> 823 <p>Some APIs allow applications to perform notifications or attract attention 824 using hardware, specifically sound, vibration, and light. Device implementations 825 MUST support notifications that use hardware features, as described in the SDK 826 documentation, and to the extent possible with the device implementation 827 hardware. For instance, if a device implementation includes a vibrator, it 828 MUST correctly implement the vibration APIs. If a device implementation lacks 829 hardware, the corresponding APIs MUST be implemented as no-ops. Note that this 830 behavior is further detailed in <a href="#section-7">Section 7.</a></p> 831 <p>Additionally, the implementation MUST correctly render all resources 832 (icons, sound files, etc.) provided for in the APIs [<a 833 href="#resources20">Resources, 20</a>], or in the 834 Status/System Bar icon style guide [<a href="#resources21">Resources, 21</a>]. 835 Device implementers MAY provide an alternative user experience for 836 notifications than that provided by the reference Android Open Source 837 implementation; however, such alternative notification systems MUST support 838 existing notification resources, as above.</p> 839 <p>Android 4.2 includes support for rich notifications, such as interactive 840 Views for ongoing notifications. Device implementations MUST properly display 841 and execute rich notifications, as documented in the Android APIs.</p> 842 <a name="section-3.8.3"></a><h4>3.8.3. Search</h4> 843 <p>Android includes APIs [<a href="#resources22">Resources, 22</a>] that allow 844 developers to incorporate search into their applications, and expose their 845 application's data into the global system search. Generally speaking, this 846 functionality consists of a single, system-wide user interface that allows users 847 to enter queries, displays suggestions as users type, and displays results. The 848 Android APIs allow developers to reuse this interface to provide search within 849 their own apps, and allow developers to supply results to the common global 850 search user interface.</p> 851 <p>Device implementations MUST include a single, shared, system-wide search 852 user interface capable of real-time suggestions in response to user input. 853 Device implementations MUST implement the APIs that allow developers to reuse 854 this user interface to provide search within their own applications. Device 855 implementations MUST implement the APIs that allow third-party applications to 856 add suggestions to the search box when it is run in global search mode. If no 857 third-party applications are installed that make use of this functionality, 858 the default behavior SHOULD be to display web search engine results and 859 suggestions.</p> 860 <a name="section-3.8.4"></a><h4>3.8.4. Toasts</h4> 861 <p>Applications can use the "Toast" API (defined in [<a 862 href="#resources23">Resources, 23</a>]) to 863 display short non-modal strings to the end user, that disappear after a brief 864 period of time. Device implementations MUST display Toasts from applications 865 to end users in some high-visibility manner.</p> 866 867 <a name="section-3.8.5"></a><h4>3.8.5. Themes</h4> 868 <p>Android provides "themes" as a mechanism for applications to apply styles 869 across an entire Activity or application. Android 4.2 includes a "Holo" 870 or "holographic" theme as a set of defined styles for application developers to 871 use if they want to match the Holo theme look and feel as defined by the Android 872 SDK [<a href="#resources24">Resources, 24</a>]. Device implementations MUST NOT 873 alter any of the Holo theme attributes exposed to applications 874 [<a href="#resources25">Resources, 25</a>].</p> 875 <p>Android 4.2 includes a new "Device Default" theme as a set of defined 876 styles for application developers to use if they want to match the look and feel 877 of the device theme as defined by the device implementer. Device implementations 878 MAY modify the DeviceDefault theme attributes exposed to applications 879 [<a href="#resources25">Resources, 25</a>].</p> 880 881 <a name="section-3.8.6"></a><h4>3.8.6. Live Wallpapers</h4> 882 <p>Android defines a component type and corresponding API and lifecycle that 883 allows applications to expose one or more "Live Wallpapers" to the end user 884 [<a href="#resources26">Resources, 26</a>]. Live Wallpapers are animations, 885 patterns, or similar images with limited input capabilities that display as a 886 wallpaper, behind other applications.</p> 887 <p>Hardware is considered capable of reliably running live wallpapers if it 888 can run all live wallpapers, with no limitations on functionality, at a 889 reasonable framerate with no adverse affects on other applications. If 890 limitations in the hardware cause wallpapers and/or applications to crash, 891 malfunction, consume excessive CPU or battery power, or run at unacceptably 892 low frame rates, the hardware is considered incapable of running live 893 wallpaper. As an example, some live wallpapers may use an Open GL 1.0 or 2.0 894 context to render their content. Live wallpaper will not run reliably on 895 hardware that does not support multiple OpenGL contexts because the live 896 wallpaper use of an OpenGL context may conflict with other applications that 897 also use an OpenGL context.</p> 898 <p>Device implementations capable of running live wallpapers reliably as 899 described above SHOULD implement live wallpapers. Device implementations 900 determined to not run live wallpapers reliably as described above MUST NOT 901 implement live wallpapers.</p> 902 <a name="section-3.8.7"></a><h4>3.8.7. Recent Application Display</h4> 903 <p>The upstream Android 4.2 source code includes a user interface for 904 displaying recent applications using a thumbnail image of the application's 905 graphical state at the moment the user last left the application. Device 906 implementations MAY alter or eliminate this user interface; however, a future 907 version of Android is planned to make more extensive use of this 908 functionality. Device implementations are strongly encouraged to use the 909 upstream Android 4.2 user interface (or a similar thumbnail-based interface) 910 for recent applications, or else they may not be compatible with a future 911 version of Android.</p> 912 <a name="section-3.8.8"></a><h4>3.8.8. Input Management Settings</h4> 913 <p>Android 4.2 includes support for Input Management Engines. The Android 4.2 914 APIs allow custom app IMEs to specify user-tunable settings. Device 915 implementations MUST include a way for the user to access IME settings at all 916 times when an IME that provides such user settings is displayed.</p> 917 918 <a name="section-3.8.9"></a><h4>3.8.9. Lock and Home Screen Widgets</h4> 919 <p>Android 4.2 includes support for application widgets that users can embed in the home screen or the lock screen 920 (See the App Widget Design Guidelines in the Android SDK documentation [<a href="#resources69">Resources, 69</a>] for details). 921 Application widgets allow quick access to application data and services without launching a new activity. Widgets declare support 922 for usage on the home screen or the lock screen by declaring the <code>android:widgetCategory</code> manifest tag that tells the system 923 where the widget can be placed. Specifically, device implementations MUST meet the following requirements.</p> 924 <ul> 925 <li>Device implementations MUST support application widgets on the home screen.</li> 926 <li>Device implementations SHOULD support lock screen. If device implementations include support for lock screen 927 then device implementations MUST support application widgets on the lock screen.</li> 928 </ul> 929 930 <a name="section-3.8.10"></a><h4>3.8.10. Lock Screen Media Remote Control</h4> 931 <p>Android 4.2 includes support for Remote Control API that lets media applications integrate with playback controls 932 that are displayed in a remote view like the device lock screen[<a href="#resources74">Resources, 74</a>]. Device implementations MUST 933 include support for embedding remote controls in the device lock screen. 934 </p> 935 <a name="section-3.8.11"></a><h4>3.8.11. Dreams</h4> 936 <p>Android 4.2 includes support for interactive screensavers called Dreams [<a href="#resources76">Resources, 76</a>]. 937 Dreams allows users to interact with applications when a charging device is idle, or docked in a desk dock. Device implementations 938 MUST include support for Dreams and provide a settings option for users to configure Dreams.</p> 939 940 <a name="section-3.9"></a><h3>3.9 Device Administration</h3> 941 <p>Android 4.2 includes features that allow security-aware applications 942 to perform device administration functions at the system level, such as enforcing 943 password policies or performing remote wipe, through the Android Device 944 Administration API [<a href="#resources27">Resources, 27</a>]. Device 945 implementations MUST provide an implementation of the <code>DevicePolicyManager 946 </code> class [<a href="#resources28">Resources, 28</a>], and SHOULD support 947 the full range of device administration policies defined in the Android SDK 948 documentation [<a href="#resources27">Resources, 27</a>]. 949 </p> 950 <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD" 951 for Android 4.2, device implementations that support lock screen MUST support device policies to manage widgets 952 on the lock screen as defined in the Android SDK documentation [<a href="#resources27">Resources, 27</a>]. 953 </p> 954 <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD" 955 for Android 4.2, the Compatibility Definition for a future version is planned 956 to change these to "MUST". That is, these requirements are optional in Android 957 4.2 but <b>will be required</b> by a future version. Existing and new devices 958 that run Android 4.2 are <b>very strongly encouraged to meet 959 these requirements in Android 4.2</b>, or they will not be able to attain 960 Android compatibility when upgraded to the future version.</p> 961 962 <a name="section-3.10"></a><h3>3.10 Accessibility</h3> 963 <p>Android 4.2 provides an accessibility layer that helps users with disabilities 964 to navigate their devices more easily. In addition, Android 4.2 provides 965 platform APIs that enable accessibility service implementations to receive 966 callbacks for user and system events and generate alternate feedback mechanisms, 967 such as text-to-speech, haptic feedback, and trackball/d-pad navigation 968 [<a href="#resources29">Resources, 29</a>]. Device implementations MUST provide an 969 implementation of the Android accessibility framework consistent with the 970 default Android implementation. Specifically, device implementations MUST meet 971 the following requirements.</p> 972 <ul> 973 <li>Device implementations MUST support third party accessibility service 974 implementations through the <code>android.accessibilityservice</code> 975 APIs [<a href="#resources30">Resources, 30</a>].</li> 976 <li>Device implementations MUST generate <code>AccessibilityEvents</code> 977 and deliver these events to all registered <code>AccessibilityService 978 </code> implementations in a manner consistent with the default Android 979 implementation.</li> 980 <li>Device implementations MUST provide a user-accessible mechanism to enable 981 and disable accessibility services, and MUST display this interface in 982 response to the 983 <code>android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS</code> 984 intent.</li> 985 </ul> 986 <p>Additionally, device implementations SHOULD provide an implementation 987 of an accessibility service on the device, and SHOULD provide a mechanism 988 for users to enable the accessibility service during device setup. An open 989 source implementation of an accessibility service is available from the Eyes 990 Free project [<a href="#resources31">Resources, 31</a>].</p> 991 992 <a name="section-3.11"></a><h3>3.11 Text-to-Speech</h3> 993 <p>Android 4.2 includes APIs that allow applications to make use of 994 text-to-speech (TTS) services, and allows service providers to provide 995 implementations of TTS services [<a href="#resources32">Resources, 32</a>]. 996 Device implementations MUST meet these requirements related to the Android TTS 997 framework:</p> 998 <ul> 999 <li>Device implementations MUST support the Android TTS framework APIs and 1000 SHOULD include a TTS engine supporting the languages available on the 1001 device. Note that the upstream Android open source software includes a 1002 full-featured TTS engine implementation.</li> 1003 <li>Device implementations MUST support installation of third-party TTS 1004 engines.</li> 1005 <li>Device implementations MUST provide a user-accessible interface that allows 1006 users to select a TTS engine for use at the system level.</li> 1007 </ul> 1008 1009 <a name="section-4"></a><h2>4. Application Packaging Compatibility</h2> 1010 <p>Device implementations MUST install and run Android ".apk" files as 1011 generated by the "aapt" tool included in the official Android SDK [<a 1012 href="#resources33">Resources, 33</a>].</p> 1013 <p>Devices implementations MUST NOT extend either the .apk [<a 1014 href="#resources34">Resources, 34</a>], Android Manifest [<a 1015 href="#resources35">Resources, 35</a>], 1016 Dalvik bytecode [<a href="#resources17">Resources, 17</a>], or renderscript 1017 bytecode formats in such a way that would prevent those files from installing 1018 and running correctly on other compatible devices. Device implementers SHOULD 1019 use the reference upstream implementation of Dalvik, and the reference 1020 implementation's package management system.</p> 1021 1022 <a name="section-5"></a><h2>5. Multimedia Compatibility</h2> 1023 <p>Device implementations MUST include at least one form of audio output, such as 1024 speakers, headphone jack, external speaker connection, etc.</p> 1025 <a name="section-5.1"></a><h3>5.1. Media Codecs</h3> 1026 <p>Device implementations MUST support the core media formats specified 1027 in the Android SDK documentation [<a href="#resources58">Resources, 58</a>] except 1028 where explicitly permitted in this document. Specifically, device implementations 1029 MUST support the media formats, encoders, decoders, file types and container 1030 formats defined in the tables below. All of these codecs are provided as 1031 software implementations in the preferred Android implementation from the Android 1032 Open Source Project.</p> 1033 1034 <p><strong>Please note that neither Google nor the Open Handset Alliance make any 1035 representation that these codecs are unencumbered by third-party patents. 1036 Those intending to use this source code in hardware or software products are 1037 advised that implementations of this code, including in open source software 1038 or shareware, may require patent licenses from the relevant patent 1039 holders.</strong></p> 1040 1041 <p>Note that these tables do not list specific bitrate requirements for 1042 most video codecs because current device hardware does not necessarily support 1043 bitrates that map exactly to the required bitrates specified by the relevant 1044 standards. Instead, device implementations SHOULD support the highest bitrate 1045 practical on the hardware, up to the limits defined by the specifications.</p> 1046 <div style="page-break-before: always;"></div> 1047 <table> 1048 <tbody> 1049 1050 <tr> 1051 <th>Type</th> 1052 <th>Format / Codec</th> 1053 <th>Encoder</th> 1054 <th>Decoder</th> 1055 <th>Details</th> 1056 <th>File Type(s) / Container Formats</th> 1057 </tr> 1058 1059 <tr> 1060 <td rowspan="11">Audio</td> 1061 <td>MPEG-4 AAC Profile (AAC LC)</td> 1062 <td style="text-align: center;">REQUIRED<br/> 1063 <small>Required for device implementations that include microphone hardware 1064 and define <code>android.hardware.microphone</code>.</small></td> 1065 <td style="text-align: center;">REQUIRED</td> 1066 <td rowspan="1"> Support for mono/stereo/5.0/5.1* content with standard sampling rates from 8 to 48 kHz.</td> 1067 <td rowspan="4"> 1068 <ul> 1069 <li>3GPP (.3gp)</li> 1070 <li>MPEG-4 (.mp4, .m4a)</li> 1071 <li>ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not supported)</li> 1072 <li>MPEG-TS (.ts, not seekable, Android 3.0+)</li> 1073 </ul> 1074 </td> 1075 </tr> 1076 1077 <tr> 1078 <td>MPEG-4 HE AAC Profile (AAC+)</td> 1079 <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td> 1080 <td style="text-align: center;">REQUIRED</td> 1081 <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td> 1082 </tr> 1083 1084 <tr> 1085 <td>MPEG-4 HE AAC v2 Profile (enhanced AAC+)</td> 1086 <td> </td> 1087 <td style="text-align: center;">REQUIRED</td> 1088 <td>Support for mono/stereo/5.0/5.1* content with standard sampling rates from 16 to 48 kHz.</td> 1089 </tr> 1090 1091 <tr> 1092 <td>MPEG-4 Audio Object Type ER AAC ELD (Enhanced Low Delay AAC)</td> 1093 <td>REQUIRED for device implementations that include microphone hardware and define android.hardware.microphone</td> 1094 <td style="text-align: center;">REQUIRED</td> 1095 <td>Support for mono/stereo content with standard 1096 sampling rates from 16 to 48 kHz.</td> 1097 </tr> 1098 1099 <tr> 1100 <td>AMR-NB</td> 1101 <td style="text-align: center;">REQUIRED<br/> 1102 <small>Required for device implementations that include microphone hardware 1103 and define <code>android.hardware.microphone</code>.</small></td> 1104 <td style="text-align: center;">REQUIRED</td> 1105 <td>4.75 to 12.2 kbps sampled @ 8kHz</td> 1106 <td>3GPP (.3gp) 1107 </td> 1108 </tr> 1109 1110 <tr> 1111 <td>AMR-WB</td> 1112 <td style="text-align: center;">REQUIRED<br/> 1113 <small>Required for device implementations that include microphone hardware 1114 and define <code>android.hardware.microphone</code>.</small></td> 1115 <td style="text-align: center;">REQUIRED</td> 1116 <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16kHz</td> 1117 <td>3GPP (.3gp)</td> 1118 </tr> 1119 1120 <tr> 1121 <td>FLAC</td> 1122 <td> </td> 1123 <td style="text-align: center;">REQUIRED<br/><small>(Android 3.1+)</small></td> 1124 <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 1125 kHz is recommended on devices with 44.1 kHz output, as the 48 to 44.1 kHz 1126 downsampler does not include a low-pass filter). 16-bit recommended; 1127 no dither applied for 24-bit. 1128 </td> 1129 <td>FLAC (.flac) only</td> 1130 </tr> 1131 1132 <tr> 1133 <td>MP3</td> 1134 <td> </td> 1135 <td style="text-align: center;">REQUIRED</td> 1136 <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bit-rate (VBR) 1137 </td> 1138 <td>MP3 (.mp3)</td> 1139 </tr> 1140 1141 <tr> 1142 <td>MIDI</td> 1143 <td> </td> 1144 <td style="text-align: center;">REQUIRED</td> 1145 <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> 1146 <td> 1147 <ul> 1148 <li>Type 0 and 1 (.mid, .xmf, .mxmf)</li> 1149 <li>RTTTL/RTX (.rtttl, .rtx)</li> 1150 <li>OTA (.ota)</li> 1151 <li>iMelody (.imy)</li> 1152 </ul> 1153 </td> 1154 </tr> 1155 1156 <tr> 1157 <td>Vorbis</td> 1158 <td> </td> 1159 <td style="text-align: center;">REQUIRED</td> 1160 <td> </td> 1161 <td> 1162 <ul> 1163 <li>Ogg (.ogg)</li> 1164 <li>Matroska (.mkv)</li> 1165 </ul> 1166 </td> 1167 </tr> 1168 1169 <tr> 1170 <td>PCM/WAVE</td> 1171 <td style="text-align: center;">REQUIRED</td> 1172 <td style="text-align: center;">REQUIRED</td> 1173 <td>8-bit and 16-bit linear PCM** (rates up to limit of hardware).Devices MUST support sampling rates 1174 for raw PCM recording at 8000,16000 and 44100 Hz frequencies</td> 1175 <td>WAVE (.wav)</td> 1176 </tr> 1177 1178 <tr> 1179 <td rowspan="5">Image</td> 1180 <td>JPEG</td> 1181 <td style="text-align: center;">REQUIRED</td> 1182 <td style="text-align: center;">REQUIRED</td> 1183 <td>Base+progressive</td> 1184 <td>JPEG (.jpg)</td> 1185 </tr> 1186 1187 <tr> 1188 <td>GIF</td> 1189 <td> </td> 1190 <td style="text-align: center;">REQUIRED</td> 1191 <td> </td> 1192 <td>GIF (.gif)</td> 1193 </tr> 1194 1195 <tr> 1196 <td>PNG</td> 1197 <td style="text-align: center;">REQUIRED</td> 1198 <td style="text-align: center;">REQUIRED</td> 1199 <td> </td> 1200 <td>PNG (.png)</td> 1201 </tr> 1202 1203 <tr> 1204 <td>BMP</td> 1205 <td> </td> 1206 <td style="text-align: center;">REQUIRED</td> 1207 <td> </td> 1208 <td>BMP (.bmp)</td> 1209 </tr> 1210 1211 1212 <tr> 1213 <td>WEBP</td> 1214 <td style="text-align: center;">REQUIRED</td> 1215 <td style="text-align: center;">REQUIRED</td> 1216 <td> </td> 1217 <td>WebP (.webp)</td> 1218 </tr> 1219 1220 <tr> 1221 <td rowspan="4">Video</td> 1222 <td>H.263</td> 1223 <td style="text-align: center;">REQUIRED<br/> 1224 <small>Required for device implementations that include camera hardware 1225 and define <code>android.hardware.camera</code> or 1226 <code>android.hardware.camera.front</code>.</small></td> 1227 <td style="text-align: center;">REQUIRED</td> 1228 <td> </td> 1229 <td> 1230 <ul> 1231 <li>3GPP (.3gp)</li> 1232 <li>MPEG-4 (.mp4)</li> 1233 </ul> 1234 </td> 1235 </tr> 1236 1237 <tr> 1238 <td>H.264 AVC</td> 1239 <td style="text-align: center;">REQUIRED<br/> 1240 <small>Required for device implementations that include camera hardware 1241 and define <code>android.hardware.camera</code> or 1242 <code>android.hardware.camera.front</code>.</small></td> 1243 <td style="text-align: center;">REQUIRED</td> 1244 <td>Baseline Profile (BP)</td> 1245 <td> 1246 <ul> 1247 <li>3GPP (.3gp)</li> 1248 <li>MPEG-4 (.mp4)</li> 1249 <li>MPEG-TS (.ts, AAC audio only, not seekable, Android 3.0+)</li> 1250 </ul> 1251 </td> 1252 </tr> 1253 1254 <tr> 1255 <td>MPEG-4 SP</td> 1256 <td> </td> 1257 <td style="text-align: center;">REQUIRED</td> 1258 <td> </td> 1259 <td>3GPP (.3gp)</td> 1260 </tr> 1261 1262 <tr> 1263 <td>VP8</td> 1264 <td> </td> 1265 <td style="text-align: center;">REQUIRED<br/><small>(Android 2.3.3+)</small></td> 1266 <td> </td> 1267 <td><a href="http://www.webmproject.org/">WebM</a> (.webm) and Matroska (.mkv, Android 4.0+)</td> 1268 </tr> 1269 1270 </tbody></table> 1271 *Note: Only downmix of 5.0/5.1 content is required; recording or rendering more than 2 channels is optional. 1272 **Note: 16-bit linear PCM capture is mandatory. 8-bit linear PCM capture is not mandatory. 1273 1274 <a name="section-5.2"></a><h3>5.2 Video Encoding</h3> 1275 <p>Android device implementations that include a rear-facing camera and declare 1276 <code>android.hardware.camera</code> SHOULD support the following video encoding 1277 profiles.</p> 1278 <table> 1279 <thead> 1280 <tr> 1281 <th> </th> 1282 <th>SD (Low quality)</th> 1283 <th>SD (High quality)</th> 1284 <th>HD (When supported by hardware)</th> 1285 </tr> 1286 </thead> 1287 <tbody> 1288 <tr> 1289 <th>Video codec</th> 1290 <td>H.264 Baseline Profile</td> 1291 <td>H.264 Baseline Profile</td> 1292 <td>H.264 Baseline Profile</td> 1293 </tr> 1294 <tr> 1295 <th>Video resolution</th> 1296 <td>176 x 144 px</td> 1297 <td>480 x 360 px</td> 1298 <td>1280 x 720 px</td> 1299 </tr> 1300 <tr> 1301 <th>Video frame rate</th> 1302 <td>12 fps</td> 1303 <td>30 fps</td> 1304 <td>30 fps</td> 1305 </tr> 1306 <tr> 1307 <th>Video bitrate</th> 1308 <td>56 Kbps</td> 1309 <td>500 Kbps or higher</td> 1310 <td>2 Mbps or higher</td> 1311 </tr> 1312 <tr> 1313 <th>Audio codec</th> 1314 <td>AAC-LC</td> 1315 <td>AAC-LC</td> 1316 <td>AAC-LC</td> 1317 </tr> 1318 <tr> 1319 <th>Audio channels</th> 1320 <td>1 (mono)</td> 1321 <td>2 (stereo)</td> 1322 <td>2 (stereo)</td> 1323 </tr> 1324 <tr> 1325 <th>Audio bitrate</th> 1326 <td>24 Kbps</td> 1327 <td>128 Kbps</td> 1328 <td>192 Kbps</td> 1329 </tr> 1330 </tbody> 1331 </table> 1332 1333 <a name="section-5.3"></a><h3>5.3 Video Decoding</h3> 1334 <p>Android device implementations SHOULD support the following VP8 video decoding profiles.</p> 1335 <div style="page-break-before: always;"></div> 1336 <table> 1337 <thead> 1338 <tr> 1339 <th> </th> 1340 <th>SD (Low quality)</th> 1341 <th>SD (High quality)</th> 1342 <th>HD 720p <br/> (When supported by hardware)</th> 1343 <th>HD 1080p <br/>(When supported by hardware)</th> 1344 </tr> 1345 </thead> 1346 <tbody> 1347 <tr> 1348 <th>Video resolution</th> 1349 <td>320 x 180 px</td> 1350 <td>640 x 360 px</td> 1351 <td>1280 x 720 px</td> 1352 <td>1920 x 1080 px</td> 1353 </tr> 1354 <tr> 1355 <th>Video frame rate</th> 1356 <td>30 fps</td> 1357 <td>30 fps</td> 1358 <td>30 fps</td> 1359 <td>30 fps</td> 1360 </tr> 1361 <tr> 1362 <th>Video bitrate</th> 1363 <td>800 Kbps</td> 1364 <td>2 Mbps</td> 1365 <td>8 Mbps</td> 1366 <td>20 Mbps</td> 1367 </tr> 1368 </tbody> 1369 </table> 1370 <a name="section-5.4"></a><h3>5.4. Audio Recording</h3> 1371 <p>When an application has used the <code>android.media.AudioRecord</code> API to 1372 start recording an audio stream, device implementations that include microphone 1373 hardware and declare <code>android.hardware.microphone</code> MUST sample and 1374 record audio with each of these behaviors:</p> 1375 <ul> 1376 <li>The device SHOULD exhibit approximately flat amplitude versus frequency 1377 characteristics; specifically, ±3 dB, from 100 Hz to 4000 Hz</li> 1378 <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level 1379 (SPL) source at 1000 Hz yields RMS of 2500 for 16-bit samples.</li> 1380 <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least 1381 a 30 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.</li> 1382 <li>Total harmonic distortion SHOULD be less than 1% for 1Khz at 90 dB SPL input level.</li> 1383 </ul> 1384 <p>In addition to the above recording specifications, when an application has 1385 started recording an audio stream using the 1386 <code>android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION</code> audio 1387 source:</p> 1388 <ul> 1389 <li>Noise reduction processing, if present, MUST be disabled.</li> 1390 <li>Automatic gain control, if present, MUST be disabled.</li> 1391 </ul> 1392 <p><b>Note:</b> while some of the requirements outlined above are stated as "SHOULD" 1393 for Android 4.2, the Compatibility Definition for a future version is planned 1394 to change these to "MUST". That is, these requirements are optional in Android 1395 4.2 but <b>will be required</b> by a future version. Existing and new devices 1396 that run Android 4.2 are <b>very strongly encouraged to meet 1397 these requirements in Android 4.2</b>, or they will not be able to attain 1398 Android compatibility when upgraded to the future version.</p> 1399 1400 <a name="section-5.5"></a><h3>5.5. Audio Latency</h3> 1401 <p>Audio latency is the time delay as an audio signal passes through a system. 1402 Many classes of 1403 applications rely on short latencies, to achieve real-time effects such sound 1404 effects or VOIP communication.</p> 1405 <p>For the purposes of this section:</p> 1406 <ul> 1407 <li>"output latency" is defined as the interval between when an application 1408 writes a frame of PCM-coded data and when the corresponding sound can be heard 1409 by an external listener or observed by a transducer</li> 1410 <li>"cold output latency" is defined as the output latency for the first frame, when 1411 the audio output system has been idle and powered down prior to the request</li> 1412 <li>"continuous output latency" is defined as the output latency for subsequent frames, 1413 after the device is already playing audio</li> 1414 <li>"input latency" is the interval between when an external sound is presented 1415 to the device and when an application reads the corresponding frame of PCM-coded data</li> 1416 <li>"cold input latency" is defined as the sum of lost input time 1417 and the input latency for the first frame, when 1418 the audio input system has been idle and powered down prior to the request</li> 1419 <li>"continuous input latency" is defined as the input latency for subsequent frames, 1420 while the device is already capturing audio</li> 1421 <li>"OpenSL ES PCM buffer queue API" is the set of PCM-related OpenSL ES APIs within Android NDK; 1422 see <i>NDK_root</i><code>/docs/opensles/index.html</code></li> 1423 </ul> 1424 <p>Per <a href="#section-5">Section 5</a>, 1425 all compatible device implementations MUST include at least one form of audio output. 1426 Device implementations SHOULD meet or exceed these output latency requirements:</p> 1427 <ul> 1428 <li>cold output latency of 100 milliseconds or less</li> 1429 <li>continuous output latency of 45 milliseconds or less</li> 1430 </ul> 1431 <p>If a device implementation meets the requirements of this section 1432 after any initial calibration 1433 when using the OpenSL ES PCM buffer queue API, 1434 for continuous output latency and cold output latency 1435 over at least one supported audio output device, it MAY 1436 report support for low-latency audio, by reporting the feature 1437 "android.hardware.audio.low-latency" via the 1438 <code>android.content.pm.PackageManager</code> class. [<a 1439 href="#resources37">Resources, 37</a>] Conversely, if the device 1440 implementation does not meet these requirements it MUST NOT report support for 1441 low-latency audio.</p> 1442 <p> 1443 Per <a href="#section-7.2.5">Section 7.2.5</a>, 1444 microphone hardware may be omitted by device implementations.</p> 1445 <p> 1446 Device implementations that include microphone 1447 hardware and declare <code>android.hardware.microphone</code> SHOULD 1448 meet these input audio latency requirements:</p> 1449 <ul> 1450 <li>cold input latency of 100 milliseconds or less</li> 1451 <li>continuous input latency of 50 milliseconds or less</li> 1452 </ul> 1453 1454 <a name="section-5.6"></a><h3>5.6. Network Protocols</h3> 1455 <p>Devices MUST support the media network protocols for audio and video playback 1456 as specified in the Android SDK documentation 1457 [<a href="#resources58">Resources, 58</a>]. Specifically, devices MUST support 1458 the following media network protocols:</p> 1459 <ul> 1460 <li>RTSP (RTP, SDP)</li> 1461 <li>HTTP(S) progressive streaming</li> 1462 <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="#resources59">Resources, 59</a>]</li> 1463 </ul> 1464 <a name="section-6"></a><h2>6. Developer Tools and Options Compatibility</h2> 1465 1466 <a name="section-6.1"></a><h3>6.1 Developer Tools</h3> 1467 <p>Device implementations MUST support the Android Developer Tools provided in the Android SDK. 1468 Specifically, Android-compatible devices MUST be compatible with:</p> 1469 <ul> 1470 <li><b>Android Debug Bridge (known as adb)</b> [<a href="#resources33">Resources, 33</a>]<br/> 1471 Device implementations MUST support all <code>adb</code> functions as 1472 documented in the Android SDK. The device-side <code>adb</code> daemon MUST 1473 be inactive by default, and there MUST be a user-accessible mechanism to turn 1474 on the Android Debug Bridge.</li> 1475 <p>Android 4.2.2 includes support for secure adb. Secure adb enables adb on known authenticated hosts. 1476 Existing and new devices that run Android 4.2.2 are <b>very strongly encouraged to meet 1477 this requirement in Android 4.2</b>, or they will not be able to attain 1478 Android compatibility when upgraded to the future version.</p> 1479 <li><b>Dalvik Debug Monitor Service (known as ddms)</b> [<a href="#resources33">Resources, 33</a>]<br/> 1480 Device implementations MUST support all <code>ddms</code> features as documented in the 1481 Android SDK. As <code>ddms</code> uses <code>adb</code>, support for 1482 <code>ddms</code> SHOULD be inactive by default, 1483 but MUST be supported whenever the user has activated the Android Debug 1484 Bridge, as above.</li> 1485 <li><b>Monkey</b> [<a href="#resources36">Resources, 36</a>]<br/> 1486 Device implementations MUST include the Monkey framework, and make it 1487 available for applications to use.</li> 1488 <li><b>SysTrace</b> [<a href="#resources33">Resources, 33</a>]<br/> 1489 Device implementations MUST support systrace tool as documented in the Android SDK. 1490 Systrace must be inactive by default, and there MUST be a user-accessible mechanism to turn 1491 on Systrace.</li> 1492 </ul> 1493 <p>Most Linux-based systems and Apple Macintosh systems recognize Android 1494 devices using the standard Android SDK tools, without additional support; 1495 however Microsoft Windows systems typically require a driver for new Android 1496 devices. (For instance, new vendor IDs and sometimes new device IDs require 1497 custom USB drivers for Windows systems.) If a device implementation is 1498 unrecognized by the <code>adb</code> tool as provided in the standard Android 1499 SDK, device implementers MUST provide Windows drivers allowing developers to 1500 connect to the device using the <code>adb</code> protocol. These drivers MUST 1501 be provided for Windows XP, Windows Vista, Windows 7, and Windows 8, in both 32-bit and 1502 64-bit versions.</p> 1503 1504 <a name="section-6.2"></a><h3>6.2 Developer Options</h3> 1505 <p>Android 4.2 includes support for developers to configure application development-related settings. 1506 Device implementations MUST honor the android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show 1507 application development-related settings [<a href="#resources77">Resources, 77</a>]. The upstream Android 1508 implementation hides the Developer Options menu by default, and enables users to launch Developer Options 1509 after pressing seven (7) times on the Settings > About Device > Build Number menu item. Device implementations 1510 MUST provide a consistent experience for Developer Options. Specifically, device implementations MUST hide 1511 Developer Options by default and MUST provide a mechanism to enable Developer Options that is consistent with 1512 the upstream Android implementation.</p> 1513 1514 <a name="section-7"></a><h2>7. Hardware Compatibility</h2> 1515 <p>If a device includes a particular hardware component that has a 1516 corresponding API for third-party developers, the device implementation MUST 1517 implement that API as described in the Android SDK documentation. If an API in 1518 the SDK interacts with a hardware component that is stated to be optional and 1519 the device implementation does not possess that component:</p> 1520 <ul> 1521 <li>complete class definitions (as documented by the SDK) for the component's 1522 APIs MUST still be present</li> 1523 <li>the API's behaviors MUST be implemented as no-ops in some reasonable 1524 fashion</li> 1525 <li>API methods MUST return null values where permitted by the SDK 1526 documentation</li> 1527 <li>API methods MUST return no-op implementations of classes where null 1528 values are not permitted by the SDK documentation</li> 1529 <li>API methods MUST NOT throw exceptions not documented by the SDK 1530 documentation</li> 1531 </ul> 1532 <p>A typical example of a scenario where these requirements apply is the 1533 telephony API: even on non-phone devices, these APIs must be implemented as 1534 reasonable no-ops.</p> 1535 <p>Device implementations MUST accurately report accurate hardware configuration 1536 information via the <code>getSystemAvailableFeatures()</code> and 1537 <code>hasSystemFeature(String)</code> methods on the 1538 <code>android.content.pm.PackageManager</code> class. [<a 1539 href="#resources37">Resources, 37</a>]</p> 1540 1541 <a name="section-7.1"></a><h3>7.1. Display and Graphics</h3> 1542 <p>Android 4.2 includes facilities that automatically adjust application 1543 assets and UI layouts appropriately for the device, to ensure that third-party 1544 applications run well on a variety of hardware configurations [<a 1545 href="#resources38">Resources, 38</a>]. Devices MUST properly implement these 1546 APIs and behaviors, as detailed in this section.</p> 1547 1548 <p>The units referenced by the requirements in this section are defined as follows:</p> 1549 <ul> 1550 <li>"Physical diagonal size" is the distance in inches between two opposing 1551 corners of the illuminated portion of the display.</li> 1552 <li>"dpi" (meaning "dots per inch") is the number of pixels encompassed by a 1553 linear horizontal or vertical span of 1". Where dpi values are listed, both 1554 horizontal and vertical dpi must fall within the range.</li> 1555 <li>"Aspect ratio" is the ratio of the longer dimension of the screen to the 1556 shorter dimension. For example, a display of 480x854 pixels would be 854 / 480 1557 = 1.779, or roughly "16:9".</li> 1558 <li>A "density-independent pixel" or ("dp") is the virtual pixel unit normalized to a 1559 160 dpi screen, calculated as: 1560 <code>pixels = dps * (density / 160)</code>.</li> 1561 </ul> 1562 1563 1564 <a name="section-7.1.1"></a><h4>7.1.1. Screen Configuration</h4> 1565 1566 <p style="font-weight:bold;">Screen Size</p> 1567 <p>The Android UI framework supports a variety of different screen sizes, and 1568 allows applications to query the device screen size (aka "screen layout") via 1569 <code>android.content.res.Configuration.screenLayout</code> with the 1570 <code>SCREENLAYOUT_SIZE_MASK</code>. Device implementations MUST report the 1571 correct screen size as defined in the Android SDK documentation 1572 [<a href="#resources38">Resources, 38</a>] and determined by the upstream 1573 Android platform. Specifically, device implementations must report the correct 1574 screen size according to the following logical density-independent pixel (dp) 1575 screen dimensions.</p> 1576 <ul> 1577 <li>Devices MUST have screen sizes of at least 426 dp x 320 dp ('small')</li> 1578 <li>Devices that report screen size 'normal' MUST have screen sizes of at least 1579 480 dp x 320 dp</li> 1580 <li>Devices that report screen size 'large' MUST have screen sizes of at least 1581 640 dp x 480 dp</li> 1582 <li>Devices that report screen size 'xlarge' MUST have screen sizes of at least 1583 960 dp x 720 dp</li> 1584 </ul> 1585 <p>In addition, devices MUST have screen sizes of at least 2.5 inches in 1586 physical diagonal size.</p> 1587 1588 <p>Devices MUST NOT change their reported screen size at any time.</p> 1589 <p>Applications optionally indicate which screen sizes they support via the 1590 <code><supports-screens></code> attribute in the AndroidManifest.xml 1591 file. Device implementations MUST correctly honor applications' stated support 1592 for small, normal, large, and xlarge screens, as described in the Android 1593 SDK documentation.</p> 1594 1595 <p style="font-weight:bold;">Screen Aspect Ratio</p> 1596 <p>The aspect ratio MUST be between 1.3333 (4:3) and 1.85 (16:9).</p> 1597 1598 <p style="font-weight:bold;">Screen Density</p> 1599 <p>The Android UI framework defines a set of standard logical densities to 1600 help application developers target application resources. Device 1601 implementations MUST report one of the following logical Android framework 1602 densities through the <code>android.util.DisplayMetrics</code> APIs, and MUST 1603 execute applications at this standard density. 1604 <ul> 1605 <li>120 dpi, known as 'ldpi'</li> 1606 <li>160 dpi, known as 'mdpi'</li> 1607 <li>213 dpi, known as 'tvdpi'</li> 1608 <li>240 dpi, known as 'hdpi'</li> 1609 <li>320 dpi, known as 'xhdpi'</li> 1610 <li>480 dpi, known as 'xxhdpi'</li> 1611 </ul> 1612 Device implementations SHOULD define the standard Android framework density 1613 that is numerically closest to the physical density of the screen, unless that 1614 logical density pushes the reported screen size below the minimum supported. 1615 If the standard Android framework density that is numerically closest to the 1616 physical density results in a screen size that is smaller than the smallest 1617 supported compatible screen size (320 dp width), device implementations SHOULD 1618 report the next lowest standard Android framework density.</p> 1619 1620 <a name="section-7.1.2"></a><h4>7.1.2. Display Metrics</h4> 1621 <p>Device implementations MUST report correct values for all display metrics 1622 defined in <code>android.util.DisplayMetrics</code> [<a 1623 href="#resources39">Resources, 39</a>].</p> 1624 1625 <a name="section-7.1.3"></a><h4>7.1.3. Screen Orientation</h4> 1626 <p>Devices MUST support dynamic orientation by applications to 1627 either portrait or landscape screen orientation. That is, the device must 1628 respect the application's request for a specific screen orientation. Device 1629 implementations MAY select either portrait or landscape orientation as the 1630 default.</p> 1631 <p>Devices MUST report the correct value for the device's current orientation, 1632 whenever queried via the android.content.res.Configuration.orientation, 1633 android.view.Display.getOrientation(), or other APIs.</p> 1634 <p>Devices MUST NOT change the reported screen size or density when changing 1635 orientation.</p> 1636 <p>Devices MUST report which screen orientations they support ( 1637 <code>android.hardware.screen.portrait</code> and/or 1638 <code>android.hardware.screen.landscape</code>) and MUST report at least one 1639 supported orientation. For example, a device with a fixed-orientation 1640 landscape screen, such as a television or laptop, MUST only report 1641 <code>android.hardware.screen.landscape</code>.</p> 1642 1643 <a name="section-7.1.4"></a><h4>7.1.4. 2D and 3D Graphics Acceleration</h4> 1644 <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied 1645 and detailed in the Android SDK documentations. Device implementations MUST 1646 also support Android Renderscript, as detailed in the Android SDK 1647 documentation [<a href="#resources08">Resources, 8</a>].</p> 1648 <p>Device implementations MUST also correctly identify themselves as 1649 supporting OpenGL ES 1.0 and 2.0. That is:</p> 1650 <ul> 1651 <li>The managed APIs (such as via the <code>GLES10.getString()</code> method) 1652 MUST report support for OpenGL ES 1.0 and 2.0</li> 1653 <li>The native C/C++ OpenGL APIs (that is, those available to apps via 1654 libGLES_v1CM.so, libGLES_v2.so, or libEGL.so) MUST report support for 1655 OpenGL ES 1.0 and 2.0.</li> 1656 </ul> 1657 <p>Device implementations MAY implement any desired OpenGL ES extensions. 1658 However, device implementations MUST report via the OpenGL ES managed and 1659 native APIs all extension strings that they do support, and conversely MUST 1660 NOT report extension strings that they do not support.</p> 1661 <p>Note that Android 4.2 includes support for applications to optionally 1662 specify that they require specific OpenGL texture compression formats. These 1663 formats are typically vendor-specific. Device implementations are not required 1664 by Android 4.2 to implement any specific texture compression format. However, 1665 they SHOULD accurately report any texture compression formats that they do 1666 support, via the <code>getString()</code> method in the OpenGL API.</p> 1667 1668 <p>Android 4.2 includes a mechanism for applications to declare that they 1669 wanted to enable hardware acceleration for 2D graphics at the Application, 1670 Activity, Window or View level through the use of a manifest tag 1671 <code>android:hardwareAccelerated</code> or direct API calls 1672 [<a href="#resources09">Resources, 9</a>].</p> 1673 <p>In Android 4.2, device implementations MUST enable hardware acceleration by 1674 default, and MUST disable hardware acceleration if the developer so requests 1675 by setting <code>android:hardwareAccelerated="false"</code> or disabling 1676 hardware acceleration directly through the Android View APIs.</p> 1677 <p>In addition, device implementations MUST exhibit behavior consistent with the 1678 Android SDK documentation on hardware acceleration 1679 [<a href="#resources09">Resources, 9</a>].</p> 1680 <p>Android 4.2 includes a <code>TextureView</code> object that lets developers 1681 directly integrate hardware-accelerated OpenGL ES textures as rendering targets 1682 in a UI hierarchy. Device implementations MUST support the <code>TextureView 1683 </code> API, and MUST exhibit consistent behavior with the upstream Android 1684 implementation.</p> 1685 1686 <a name="section-7.1.5"></a><h4>7.1.5. Legacy Application Compatibility Mode</h4> 1687 <p>Android 4.2 specifies a "compatibility mode" in which the framework 1688 operates in an 'normal' screen size equivalent (320dp width) mode for the benefit 1689 of legacy applications not developed for old versions of Android that pre-date 1690 screen-size independence. Device implementations MUST include support for legacy 1691 application compatibility mode as implemented by the upstream Android open source 1692 code. That is, device implementations MUST NOT alter the triggers or thresholds at 1693 which compatibility mode is activated, and MUST NOT alter the behavior of the 1694 compatibility mode itself.</p> 1695 1696 <a name="section-7.1.6"></a><h4>7.1.6. Screen Types</h4> 1697 <p>Device implementation screens are classified as one of two types:</p> 1698 <ul> 1699 <li>Fixed-pixel display implementations: the screen is a single panel that supports only a 1700 single pixel width and height. Typically the screen is physically integrated with 1701 the device. Examples include mobile phones, tablets, and so on.</li> 1702 <li>Variable-pixel display implementations: the device implementation either has no 1703 embedded screen and includes a video output port such as VGA, HDMI or a wireless port 1704 for display, or has an embedded screen that can change pixel dimensions. Examples 1705 include televisions, set-top boxes, and so on.</li> 1706 </ul> 1707 <p style="font-weight: bold;">Fixed-Pixel Device Implementations</p> 1708 <p>Fixed-pixel device implementations MAY use screens of any pixel dimensions, provided 1709 that they meet the requirements defined this Compatibility Definition.</p> 1710 <p>Fixed-pixel implementations MAY include a video output port for use with an 1711 external display. However, if that display is ever used for running apps, the 1712 device MUST meet the following requirements:</p> 1713 <ul> 1714 <li>The device MUST report the same screen configuration and display metrics, as detailed 1715 in Sections 7.1.1 and 7.1.2, as the fixed-pixel display.</li> 1716 <li>The device MUST report the same logical density as the fixed-pixel display.</li> 1717 <li>The device MUST report screen dimensions that are the same as, or very close to, 1718 the fixed-pixel display.</li> 1719 </ul> 1720 <p>For example, a tablet that is 7" diagonal size with a 1024x600 pixel resolution is 1721 considered a fixed-pixel large mdpi display implementation. If it contains a video 1722 output port that displays at 720p or 1080p, the device implementation MUST scale the output so that 1723 applications are only executed in a large mdpi window, regardless of whether the fixed-pixel display 1724 or video output port is in use.</p> 1725 1726 <p style="font-weight: bold;">Variable-Pixel Device Implementations</p> 1727 <p>Variable-pixel device implementations MUST support one or both of 1280x720, 1728 or 1920x1080 (that is, 720p or 1080p). Device implementations with 1729 variable-pixel displays MUST NOT support any other screen configuration or 1730 mode. Device implementations with variable-pixel screens MAY change screen 1731 configuration or mode at runtime or boot-time. For example, a user of a 1732 set-top box may replace a 720p display with a 1080p display, and the device 1733 implementation may adjust accordingly.</p> 1734 1735 <p>Additionally, variable-pixel device implementations MUST report the following 1736 configuration buckets for these pixel dimensions:</p> 1737 <ul> 1738 <li>1280x720 (also known as 720p): 'large' screen size, 'tvdpi' (213 dpi) 1739 density</li> 1740 <li>1920x1080 (also known as 1080p): 'large' screen size, 'xhdpi' (320 dpi) 1741 density</li> 1742 </ul> 1743 <p>For clarity, device implementations with variable pixel dimensions are 1744 restricted to 720p or 1080p in Android 4.2, and MUST be configured to report 1745 screen size and density buckets as noted above.</p> 1746 1747 <a name="section-7.1.7"></a><h4>7.1.7. Screen Technology</h4> 1748 <p>The Android platform includes APIs that allow applications to render rich 1749 graphics to the display. Devices MUST support all of these APIs as defined by 1750 the Android SDK unless specifically allowed in this document. Specifically:</p> 1751 <ul> 1752 <li>Devices MUST support displays capable of rendering 16-bit color graphics and 1753 SHOULD support displays capable of 24-bit color graphics.</li> 1754 <li>Devices MUST support displays capable of rendering animations.</li> 1755 <li>The display technology used MUST have a pixel aspect ratio (PAR) between 1756 0.9 and 1.1. That is, the pixel aspect ratio MUST be near square (1.0) with 1757 a 10% tolerance.</li> 1758 </ul> 1759 <a name="section-7.1.8"></a><h4>7.1.8. External Displays</h4> 1760 <p>Android 4.2 includes support for secondary display to enable media sharing capabilities and 1761 developer APIs for accessing external displays. If a device supports an external display either via 1762 a wired, wireless or an embedded additional display connection then the device implementation MUST 1763 implement the display manager API as described in the Android SDK documentation [<a href="#resources75">Resources, 75</a>]. 1764 Device implementations that support secure video output and are capable of supporting secure surfaces MUST declare support 1765 for <code>Display.SECURE_FLAG</code>. Specifically, device implementations that declare support for <code>Display.SECURE_FLAG</code>, 1766 MUST support <b>HDCP 2.x or higher</b> for Miracast wireless displays or <b>HDCP 1.2 or higher</b> for wired displays. The upstream 1767 Android open source implementation includes support for wireless (Miracast) and wired (HDMI) displays that satisfies this requirement.</p> 1768 1769 <a name="section-7.2"></a><h3>7.2. Input Devices</h3> 1770 <a name="section-7.2.1"></a><h4>7.2.1. Keyboard</h4> 1771 <p>Device implementations:</p> 1772 <ul> 1773 <li>MUST include support for the Input Management Framework (which allows third 1774 party developers to create Input Management Engines - i.e. soft keyboard) as 1775 detailed at <a href="http://developer.android.com">http://developer.android.com</a> 1776 </li> 1777 <li>MUST provide at least one soft keyboard implementation (regardless of whether 1778 a hard keyboard is present)</li> 1779 <li>MAY include additional soft keyboard implementations</li> 1780 <li>MAY include a hardware keyboard</li> 1781 <li>MUST NOT include a hardware keyboard that does not match one of the 1782 formats specified in <code>android.content.res.Configuration.keyboard</code> 1783 [<a href="#resources40">Resources, 40</a>] (that is, QWERTY, or 12-key)</li> 1784 </ul> 1785 <a name="section-7.2.2"></a><h4>7.2.2. Non-touch Navigation</h4> 1786 <p>Device implementations:</p> 1787 <ul> 1788 <li>MAY omit a non-touch navigation option (that is, may omit a trackball, d-pad, 1789 or wheel)</li> 1790 <li>MUST report the correct value for 1791 <code>android.content.res.Configuration.navigation</code> 1792 [<a href="#resources40">Resources, 40</a>]</li> 1793 <li>MUST provide a reasonable alternative user interface mechanism for the 1794 selection and editing of text, compatible with Input Management Engines. The 1795 upstream Android open source implementation includes a selection mechanism suitable 1796 for use with devices that lack non-touch navigation inputs.</li> 1797 </ul> 1798 <a name="section-7.2.3"></a><h4>7.2.3. Navigation keys</h4> 1799 <p>The Home, Menu and Back functions are essential to the Android navigation 1800 paradigm. Device implementations MUST make these functions available to the 1801 user at all times when running applications. These functions MAY be implemented 1802 via dedicated physical buttons (such as mechanical or capacitive touch buttons), 1803 or MAY be implemented using dedicated software keys, gestures, touch panel, etc. 1804 Android 4.2 supports both implementations.</p> 1805 1806 <p>Android 4.2 includes support for assist action [<a href="#resources63">Resources, 63</a>]. 1807 Device implementations MUST make the assist action available to the user at all times when running applications. 1808 This function MAY be implemented via hardware or software keys.</p> 1809 1810 <p>Device implementations MAY use a distinct portion of the screen to display 1811 the navigation keys, but if so, MUST meet these requirements:</p> 1812 1813 <ul> 1814 <li>Device implementation navigation keys MUST use a distinct portion of the 1815 screen, not available to applications, and MUST NOT obscure or otherwise 1816 interfere with the portion of the screen available to applications.</li> 1817 <li>Device implementations MUST make available a portion of the display to 1818 applications that meets the requirements defined in 1819 <a href="section-7.1.1">Section 7.1.1</a>.</li> 1820 <li>Device implementations MUST display the navigation keys when applications 1821 do not specify a system UI mode, or specify 1822 <code>SYSTEM_UI_FLAG_VISIBLE</code>.</li> 1823 <li>Device implementations MUST present the navigation keys in an unobtrusive 1824 "low profile" (eg. dimmed) mode when applications specify 1825 <code>SYSTEM_UI_FLAG_LOW_PROFILE</code>.</li> 1826 <li>Device implementations MUST hide the navigation keys when applications 1827 specify <code>SYSTEM_UI_FLAG_HIDE_NAVIGATION</code>.</li> 1828 <li>Device implementation MUST present a Menu key to applications when 1829 targetSdkVersion <= 10 and SHOULD NOT present a Menu key when the 1830 targetSdkVersion > 10.</li> 1831 </ul> 1832 1833 <a name="section-7.2.4"></a><h4>7.2.4. Touchscreen input</h4> 1834 <p>Device implementations:</p> 1835 <ul> 1836 <li>MUST have a pointer input system of some kind (either mouse-like, or 1837 touch)</li> 1838 <li>MAY have a touchscreen of any modality (such as capacitive or resistive)</li> 1839 <li>SHOULD support fully independently tracked pointers, if a touchscreen 1840 supports multiple pointers</li> 1841 <li>MUST report the value of <code>android.content.res.Configuration</code> 1842 [<a href="#resources40">Resources, 39</a>] 1843 reflecting corresponding to the type of the specific touchscreen on the 1844 device</li> 1845 </ul> 1846 <p>Device implementations MUST report the correct feature corresponding to the 1847 type of input used. Note that Android 4.2 includes the feature 1848 <code>android.hardware.faketouch</code>, which corresponds to a high-fidelity 1849 non-touch (that is, pointer-based) input device such as a mouse or trackpad that 1850 can adequately emulate touch-based input (including basic gesture support), 1851 and indicates that the device supports an emulated subset of touchscreen 1852 functionality. 1853 Device implementations that include a touchscreen (single-touch or better) 1854 MUST also report android.hardware.faketouch. Device implementations that do 1855 not include a touchscreen (and rely on a pointer device only) MUST NOT report 1856 any touchscreen feature, and MUST report only 1857 <code>android.hardware.faketouch</code>.</p> 1858 <a name="section-7.2.5"></a><h4>7.2.5. Microphone</h4> 1859 <p>Device implementations MAY omit a microphone. However, if a device 1860 implementation omits a microphone, it MUST NOT report the 1861 <code>android.hardware.microphone</code> feature constant, and must implement 1862 the audio recording API as no-ops, per <a href="section-7">Section 7</a>. 1863 Conversely, device implementations that do possess a microphone:</p> 1864 <ul> 1865 <li>MUST report the <code>android.hardware.microphone</code> feature constant</li> 1866 <li>SHOULD meet the audio quality requirements in <a href="section-5.4">Section 5.4</a></li> 1867 <li>SHOULD meet the audio latency requirements in <a href="section-5.5">Section 5.5</a></li> 1868 </ul> 1869 1870 <a name="section-7.3"></a><h3>7.3. Sensors</h3> 1871 <p>Android 4.2 includes APIs for accessing a variety of sensor types. Devices 1872 implementations generally MAY omit these sensors, as provided for in the 1873 following subsections. If a device includes a particular sensor type that has a 1874 corresponding API for third-party developers, the device implementation MUST 1875 implement that API as described in the Android SDK documentation. For example, 1876 device implementations:</p> 1877 <ul> 1878 <li>MUST accurately report the presence or absence of sensors per the 1879 <code>android.content.pm.PackageManager</code> class. [<a 1880 href="#resources37">Resources, 37</a>]</li> 1881 <li>MUST return an accurate list of supported sensors via the 1882 <code>SensorManager.getSensorList()</code> and similar methods</li> 1883 <li>MUST behave reasonably for all other sensor APIs (for example, by 1884 returning true or false as appropriate when applications attempt to register 1885 listeners, not calling sensor listeners when the corresponding sensors are not 1886 present; etc.)</li> 1887 <li>MUST report all sensor measurements using the relevant International System 1888 of Units (i.e. metric) values for each sensor type as defined in the Android SDK 1889 documentation [<a href="#resources41">Resources, 41</a>]</li> 1890 </ul> 1891 <p>The list above is not comprehensive; the documented behavior of the Android 1892 SDK is to be considered authoritative.</p> 1893 <p>Some sensor types are synthetic, meaning they can be derived from data 1894 provided by one or more other sensors. (Examples include the orientation 1895 sensor, and the linear acceleration sensor.) Device implementations SHOULD 1896 implement these sensor types, when they include the prerequisite physical 1897 sensors.</p> 1898 <p>The Android 4.2 includes a notion of a "streaming" sensor, which is 1899 one that returns data continuously, rather than only when the data changes. 1900 Device implementations MUST continuously provide periodic data samples for any 1901 API indicated by the Android 4.2 SDK documentation to be a streaming 1902 sensor. Note that the device implementations MUST ensure that the sensor stream must not 1903 prevent the device CPU from entering a suspend state or waking up from a suspend state.</p> 1904 1905 <a name="section-7.3.1"></a><h4>7.3.1. Accelerometer</h4> 1906 <p>Device implementations SHOULD include a 3-axis accelerometer. If a device 1907 implementation does include a 3-axis accelerometer, it:</p> 1908 <ul> 1909 <li>SHOULD be able to deliver events at 120 Hz or greater. Note that while the 1910 accelerometer frequency above is stated as "SHOULD" for Android 4.2, the Compatibility Definition 1911 for a future version is planned to change these to "MUST". That is, these standards are 1912 optional in Android 4.2 but <b>will be required</b> in future versions. Existing and 1913 new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements 1914 in Android 4.2</b> so they will be able to upgrade to the future platform releases 1915 </li> 1916 <li>MUST comply with the Android sensor coordinate system as detailed 1917 in the Android APIs (see [<a href="#resources41">Resources, 41</a>])</li> 1918 <li>MUST be capable of measuring from freefall up to twice gravity (2g) or 1919 more on any three-dimensional vector</li> 1920 <li>MUST have 8-bits of accuracy or more</li> 1921 <li>MUST have a standard deviation no greater than 0.05 m/s^2</li> 1922 </ul> 1923 <a name="section-7.3.2"></a><h4>7.3.2. Magnetometer</h4> 1924 <p>Device implementations SHOULD include a 3-axis magnetometer (i.e. compass.) 1925 If a device does include a 3-axis magnetometer, it:</p> 1926 <ul> 1927 <li>MUST be able to deliver events at 10 Hz or greater</li> 1928 <li>MUST comply with the Android sensor coordinate system as detailed 1929 in the Android APIs (see [<a href="#resources41">Resources, 41</a>]).</li> 1930 <li>MUST be capable of sampling a range of field strengths adequate to cover the 1931 geomagnetic field</li> 1932 <li>MUST have 8-bits of accuracy or more</li> 1933 <li>MUST have a standard deviation no greater than 0.5 µT</li> 1934 </ul> 1935 <a name="section-7.3.3"></a><h4>7.3.3. GPS</h4> 1936 <p>Device implementations SHOULD include a GPS receiver. If a device 1937 implementation does include a GPS receiver, it SHOULD include 1938 some form of "assisted GPS" technique to minimize GPS lock-on time.</p> 1939 <a name="section-7.3.4"></a><h4>7.3.4. Gyroscope</h4> 1940 <p>Device implementations SHOULD include a gyroscope (i.e. angular change 1941 sensor.) Devices SHOULD NOT include a gyroscope sensor unless a 3-axis 1942 accelerometer is also included. If a device implementation includes a 1943 gyroscope, it:</p> 1944 <ul> 1945 <li>MUST be temperature compensated</li> 1946 <li>MUST be capable of measuring orientation changes up to 5.5*Pi 1947 radians/second (that is, approximately 1,000 degrees per second)</li> 1948 <li>SHOULD be able to deliver events at 200 Hz or greater. Note that while the 1949 gyroscope frequency above is stated as "SHOULD" for Android 4.2, the Compatibility Definition 1950 for a future version is planned to change these to "MUST". That is, these standards are 1951 optional in Android 4.2 but <b>will be required</b> in future versions. Existing and 1952 new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements 1953 in Android 4.2</b> so they will be able to upgrade to the future platform releases 1954 </li> 1955 <li>MUST have 12-bits of accuracy or more</li> 1956 <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz, or rad^2 / s). 1957 The variance is allowed to vary with the sampling rate, but must be constrained by this value. 1958 In other words, if you measure the variance of the gyro at 1 Hz sampling rate it should be no 1959 greater than 1e-7 rad^2/s^2. </li> 1960 <li>MUST have timestamps as close to when the hardware event happened as possible. The constant latency must be removed.</li> 1961 </ul> 1962 <a name="section-7.3.5"></a><h4>7.3.5. Barometer</h4> 1963 <p>Device implementations MAY include a barometer (i.e. ambient air pressure 1964 sensor.) If a device implementation includes a barometer, it:</p> 1965 <ul> 1966 <li>MUST be able to deliver events at 5 Hz or greater</li> 1967 <li>MUST have adequate precision to enable estimating altitude</li> 1968 <li>MUST be temperature compensated</li> 1969 </ul> 1970 <a name="section-7.3.6"></a><h4>7.3.7. Thermometer</h4> 1971 <p>Device implementations MAY but SHOULD NOT include a thermometer (i.e. 1972 temperature sensor.) If a device implementation does include a thermometer, it 1973 MUST measure the temperature of the device CPU. It MUST NOT measure any other 1974 temperature. (Note that this sensor type is deprecated in the Android 4.2 1975 APIs.)</p> 1976 <a name="section-7.3.7"></a><h4>7.3.7. Photometer</h4> 1977 <p>Device implementations MAY include a photometer (i.e. ambient light 1978 sensor.)</p> 1979 <a name="section-7.3.8"></a><h4>7.3.8. Proximity Sensor</h4> 1980 <p>Device implementations MAY include a proximity sensor. If a device 1981 implementation does include a proximity sensor, it MUST measure the proximity 1982 of an object in the same direction as the screen. That is, the proximity 1983 sensor MUST be oriented to detect objects close to the screen, as the 1984 primary intent of this sensor type is to detect a phone in use by the 1985 user. If a device implementation includes a proximity sensor with any other 1986 orientation, it MUST NOT be accessible through this API. If a device 1987 implementation has a proximity sensor, it MUST be have 1-bit of accuracy or 1988 more.</p> 1989 1990 <a name="section-7.4"></a><h3>7.4. Data Connectivity</h3> 1991 <a name="section-7.4.1"></a><h4>7.4.1. Telephony</h4> 1992 <p>"Telephony" as used by the Android 4.2 APIs and this document refers 1993 specifically to hardware related to placing voice calls and sending SMS 1994 messages via a GSM or CDMA network. While these voice calls may or may not be 1995 packet-switched, they are for the purposes of Android 4.2 considered 1996 independent of any data connectivity that may be implemented using the same 1997 network. In other words, the Android "telephony" functionality and APIs refer 1998 specifically to voice calls and SMS; for instance, device implementations that 1999 cannot place calls or send/receive SMS messages MUST NOT report the 2000 "android.hardware.telephony" feature or any sub-features, regardless of 2001 whether they use a cellular network for data connectivity.</p> 2002 <p>Android 4.2 MAY be used on devices that do not include telephony hardware. 2003 That is, Android 4.2 is compatible with devices that are not phones. 2004 However, if a device implementation does include GSM or CDMA telephony, it 2005 MUST implement full support for the API for that technology. Device 2006 implementations that do not include telephony hardware MUST implement the full 2007 APIs as no-ops.</p> 2008 <a name="section-7.4.2"></a><h4>7.4.2. IEEE 802.11 (WiFi)</h4> 2009 <p>Android 4.2 device implementations SHOULD include support for one or more 2010 forms of 802.11 (b/g/a/n, etc.) If a device implementation does include 2011 support for 802.11, it MUST implement the corresponding Android API.</p> 2012 <p>Device implementations MUST implement the multicast API as described in 2013 the SDK documentation [<a href="#resources62">Resources, 62</a>]. Device 2014 implementations that do include Wifi support MUST support multicast DNS (mDNS). 2015 Device implementations MUST not filter mDNS packets (224.0.0.251) at any time 2016 of operation including when the screen is not in an active state.</p> 2017 2018 <a name="section-7.4.2.1"></a><h4>7.4.2.1. WiFi Direct</h4> 2019 <p>Device implementations SHOULD include support for Wifi direct (Wifi peer-to-peer). 2020 If a device implementation does include support for Wifi direct, it MUST implement the corresponding 2021 Android API as described in the SDK documentation [<a href="#resources68">Resources, 68</a>]. 2022 If a device implementation includes support for Wifi direct, then it:</p> 2023 <ul> 2024 <li>MUST support regular Wifi operation</li> 2025 <li>SHOULD support concurrent wifi and wifi Direct operation</li> 2026 </ul> 2027 2028 <a name="section-7.4.3"></a><h4>7.4.3. Bluetooth</h4> 2029 <p>Device implementations SHOULD include a Bluetooth transceiver. Device 2030 implementations that do include a Bluetooth transceiver MUST enable the 2031 RFCOMM-based Bluetooth API as described in the SDK documentation [<a 2032 href="#resources42">Resources, 42</a>]. Device implementations SHOULD 2033 implement relevant Bluetooth profiles, such as A2DP, AVRCP, OBEX, etc. as 2034 appropriate for the device.</p> 2035 <p>The Compatibility Test Suite includes cases that cover basic operation of 2036 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 2037 protocol between devices, it cannot be fully tested by unit tests running on a 2038 single device. Consequently, device implementations MUST also pass the 2039 human-driven Bluetooth test procedure described in Appendix A.</p> 2040 2041 <a name="section-7.4.4"></a><h4>7.4.4. Near-Field Communications</h4> 2042 <p>Device implementations SHOULD include a transceiver and related hardware 2043 for Near-Field Communications (NFC). If a device implementation does include 2044 NFC hardware, then it:</p> 2045 <ul> 2046 <li>MUST report the android.hardware.nfc feature from the 2047 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method. 2048 [<a href="#resources37">Resources, 37</a>]</li> 2049 <li>MUST be capable of reading and writing NDEF messages via the following NFC 2050 standards: 2051 <ul> 2052 <li>MUST be capable of acting as an NFC Forum reader/writer 2053 (as defined by the NFC Forum technical specification 2054 NFCForum-TS-DigitalProtocol-1.0) via the following NFC standards: 2055 <ul> 2056 <li>NfcA (ISO14443-3A)</li> 2057 <li>NfcB (ISO14443-3B) </li> 2058 <li>NfcF (JIS 6319-4)</li> 2059 <li>IsoDep (ISO 14443-4)</li> 2060 <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li> 2061 </ul> 2062 </li> 2063 </ul> 2064 </li> 2065 <li>SHOULD be capable of reading and writing NDEF messages via the following 2066 NFC standards. Note that while the NFC standards below are stated as 2067 "SHOULD" for Android 4.2, the Compatibility Definition for a future 2068 version is planned to change these to "MUST". That is, these standards are 2069 optional in Android 4.2 but <b>will be required</b> in future versions. 2070 Existing and new devices that run Android 4.2 are <b>very strongly 2071 encouraged to meet these requirements in Android 4.2</b> so they will be 2072 able to upgrade to the future platform releases. 2073 <ul> 2074 <li>NfcV (ISO 15693)</li> 2075 </ul> 2076 </li> 2077 <li>MUST be capable of transmitting and receiving data via the following 2078 peer-to-peer standards and protocols: 2079 <ul> 2080 <li>ISO 18092</li> 2081 <li>LLCP 1.0 (defined by the NFC Forum)</li> 2082 <li>SDP 1.0 (defined by the NFC Forum)</li> 2083 <li>NDEF Push Protocol [<a href="#resources43">Resources, 43</a>]</li> 2084 <li>SNEP 1.0 (defined by the NFC Forum)</li> 2085 </ul> 2086 </li> 2087 <li>MUST include support for Android Beam [<a href="#resources65">Resources, 65</a>]: 2088 <ul> 2089 <li>MUST implement the SNEP default server. Valid NDEF messages received 2090 by the default SNEP server MUST be dispatched to applications using 2091 the android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam 2092 in settings MUST NOT disable dispatch of incoming NDEF message.</li> 2093 <li>Device implementations MUST honor the android.settings.NFCSHARING_SETTINGS intent 2094 to show NFC sharing settings [<a href="#resources67">Resources, 67</a>].</li> 2095 <li>MUST implement the NPP server. Messages received by the NPP server MUST 2096 be processed the same way as the SNEP default server.</li> 2097 <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to 2098 the default SNEP server when Android Beam is enabled. If no default 2099 SNEP server is found then the client MUST attempt to send to an NPP 2100 server.</li> 2101 <li>MUST allow foreground activities to set the outbound P2P NDEF message 2102 using android.nfc.NfcAdapter.setNdefPushMessage, and 2103 android.nfc.NfcAdapter.setNdefPushMessageCallback, and 2104 android.nfc.NfcAdapter.enableForegroundNdefPush.</li> 2105 <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', 2106 before sending outbound P2P NDEF messages.</li> 2107 <li>SHOULD enable Android Beam by default</li> 2108 <li>MUST support NFC Connection handover to Bluetooth when the device supports Bluetooth Object Push Profile. 2109 Device implementations must support connection handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, 2110 by implementing the "Connection Handover version 1.2" [<a href="#resources60">Resources, 60</a>] 2111 and "Bluetooth Secure Simple Pairing Using NFC version 1.0" [<a href="#resources61">Resources, 61</a>] 2112 specs from the NFC Forum. Such an implementation SHOULD use SNEP GET 2113 requests for exchanging the handover request / select records over NFC, and it MUST 2114 use the Bluetooth Object Push Profile for the actual Bluetooth data transfer.</li> 2115 </ul> 2116 </li> 2117 <li>MUST poll for all supported technologies while in NFC discovery mode.</li> 2118 <li>SHOULD be in NFC discovery mode while the device is awake with the screen active 2119 and the lock-screen unlocked.</li> 2120 </ul> 2121 2122 <p>(Note that publicly available links are not available for the JIS, ISO, and 2123 NFC Forum specifications cited above.)</p> 2124 <p>Additionally, device implementations MAY include reader/writer support for 2125 the following MIFARE technologies.</p> 2126 <ul> 2127 <li>MIFARE Classic (NXP MF1S503x [<a href="#resources44">Resources, 44</a>], 2128 MF1S703x [<a href="#resources44">Resources, 44</a>])</li> 2129 <li>MIFARE Ultralight (NXP MF0ICU1 [<a href="#resources46">Resources, 46</a>], 2130 MF0ICU2 [<a href="#resources46">Resources, 46</a>])</li> 2131 <li>NDEF on MIFARE Classic (NXP AN130511 [<a href="#resources48">Resources, 48</a>], 2132 AN130411 [<a href="#resources49">Resources, 49</a>])</li> 2133 </ul> 2134 <p>Note that Android 4.2 includes APIs for these MIFARE types. If a 2135 device implementation supports MIFARE in the reader/writer role, it:</p> 2136 <ul> 2137 <li>MUST implement the corresponding Android APIs as documented by the 2138 Android SDK</li> 2139 <li>MUST report the feature com.nxp.mifare from the 2140 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method. 2141 [<a href="#resources37">Resources, 37</a>] Note that this is not a standard 2142 Android feature, and as such does not appear as a constant on the 2143 <code>PackageManager</code> class.</li> 2144 <li>MUST NOT implement the corresponding Android APIs nor report the 2145 com.nxp.mifare feature unless it also implements general NFC support as 2146 described in this section</li> 2147 </ul> 2148 <p>If a device implementation does not include NFC hardware, it MUST NOT 2149 declare the android.hardware.nfc feature from the 2150 <code>android.content.pm.PackageManager.hasSystemFeature()</code> method [<a 2151 href="#resources37">Resources, 37</a>], and MUST implement the Android 4.2 NFC 2152 API as a no-op.</p> 2153 <p>As the classes <code>android.nfc.NdefMessage</code> and 2154 <code>android.nfc.NdefRecord</code> represent a protocol-independent data 2155 representation format, device implementations MUST implement these APIs even 2156 if they do not include support for NFC or declare the android.hardware.nfc 2157 feature.</p> 2158 <a name="section-7.4.5"></a><h4>7.4.5. Minimum Network Capability</h4> 2159 <p>Device implementations MUST include support for one or more forms of data 2160 networking. Specifically, device implementations MUST include support for at 2161 least one data standard capable of 200Kbit/sec or greater. Examples of 2162 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g, 2163 Ethernet, etc.</p> 2164 <p>Device implementations where a physical networking standard (such as 2165 Ethernet) is the primary data connection SHOULD also include support for at 2166 least one common wireless data standard, such as 802.11 (WiFi).</p> 2167 <p>Devices MAY implement more than one form of data connectivity.</p> 2168 2169 2170 <a name="section-7.5"></a><h3>7.5. Cameras</h3> 2171 <p>Device implementations SHOULD include a rear-facing camera, and MAY include 2172 a front-facing camera. A rear-facing camera is a camera located on the side of 2173 the device opposite the display; that is, it images scenes on the far side of 2174 the device, like a traditional camera. A front-facing camera is a camera 2175 located on the same side of the device as the display; that is, a camera 2176 typically used to image the user, such as for video conferencing and similar 2177 applications.</p> 2178 <a name="section-7.5.1"></a><h4>7.5.1. Rear-Facing Camera</h4> 2179 <p>Device implementations SHOULD include a rear-facing camera. If a device 2180 implementation includes a rear-facing camera, it:</p> 2181 <ul> 2182 <li>MUST have a resolution of at least 2 megapixels</li> 2183 <li>SHOULD have either hardware auto-focus, or software auto-focus implemented 2184 in the camera driver (transparent to application software)</li> 2185 <li>MAY have fixed-focus or EDOF (extended depth of field) hardware</li> 2186 <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST 2187 NOT be lit while an android.hardware.Camera.PreviewCallback instance has been 2188 registered on a Camera preview surface, unless the application has explicitly 2189 enabled the flash by enabling the <code>FLASH_MODE_AUTO</code> or 2190 <code>FLASH_MODE_ON</code> attributes of a <code>Camera.Parameters</code> 2191 object. Note that this constraint does not apply to the device's built-in 2192 system camera application, but only to third-party applications using 2193 <code>Camera.PreviewCallback</code>.</li> 2194 </ul> 2195 <a name="section-7.5.2"></a><h4>7.5.2. Front-Facing Camera</h4> 2196 <p>Device implementations MAY include a front-facing camera. If a device 2197 implementation includes a front-facing camera, it:</p> 2198 <ul> 2199 <li>MUST have a resolution of at least VGA (that is, 640x480 pixels)</li> 2200 <li>MUST NOT use a front-facing camera as the default for the Camera API. 2201 That is, the camera API in Android 4.2 has specific support for front-facing 2202 cameras, and device implementations MUST NOT configure the API to to treat a 2203 front-facing camera as the default rear-facing camera, even if it is the only 2204 camera on the device.</li> 2205 <li>MAY include features (such as auto-focus, flash, etc.) 2206 available to rear-facing cameras as described in Section 7.5.1.</li> 2207 <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a 2208 CameraPreview, as follows:</li> 2209 <ul> 2210 <li>If the device implementation is capable of being rotated by user (such as 2211 automatically via an accelerometer or manually via user input), the camera 2212 preview MUST be mirrored horizontally relative to the device's current 2213 orientation.</li> 2214 <li>If the current application has explicitly requested that the Camera 2215 display be rotated via a call to the 2216 <code>android.hardware.Camera.setDisplayOrientation()</code> [<a 2217 href="#resources50">Resources, 50</a>] method, the camera preview MUST be 2218 mirrored horizontally relative to the orientation specified by the 2219 application.</li> 2220 <li>Otherwise, the preview MUST be mirrored along the device's default horizontal axis.</li> 2221 </ul> 2222 <li>MUST mirror the image displayed by the postview in the same manner as 2223 the camera preview image stream. (If the device implementation does not 2224 support postview, this requirement obviously does not apply.)</li> 2225 <li>MUST NOT mirror the final captured still image or video streams returned 2226 to application callbacks or committed to media storage</li> 2227 </ul> 2228 <a name="section-7.5.3"></a><h4>7.5.3. Camera API Behavior</h4> 2229 <p>Device implementations MUST implement the following behaviors for the 2230 camera-related APIs, for both front- and rear-facing cameras:</p> 2231 <ol> 2232 <li>If an application has never called 2233 <code>android.hardware.Camera.Parameters.setPreviewFormat(int)</code>, then the 2234 device MUST use <code>android.hardware.PixelFormat.YCbCr_420_SP</code> for 2235 preview data provided to application callbacks.</li> 2236 <li>If an application registers an <code>android.hardware.Camera.PreviewCallback 2237 </code> instance and the system calls the <code>onPreviewFrame()</code> method 2238 when the preview format is YCbCr_420_SP, the data in the <code>byte[]</code> 2239 passed into <code>onPreviewFrame()</code> must further be in the NV21 encoding 2240 format. That is, NV21 MUST be the default.</li> 2241 <li>Device implementations MUST support the YV12 format (as denoted by the 2242 <code>android.graphics.ImageFormat.YV12</code> constant) for camera previews 2243 for both front- and rear-facing cameras. (The hardware video encoder and camera 2244 may use any native pixel format, but the device implementation MUST support conversion 2245 to YV12.)</li> 2246 </ol> 2247 <p>Device implementations MUST implement the full Camera API included in the 2248 Android 4.2 SDK documentation [<a href="#resources51">Resources, 51</a>]), 2249 regardless of whether the device includes hardware autofocus or other 2250 capabilities. For instance, cameras that lack autofocus MUST still call any 2251 registered <code>android.hardware.Camera.AutoFocusCallback</code> instances (even though 2252 this has no relevance to a non-autofocus camera.) Note that this does apply 2253 to front-facing cameras; for instance, even though most front-facing cameras 2254 do not support autofocus, the API callbacks must still be "faked" as 2255 described.</p> 2256 <p>Device implementations MUST recognize and honor each parameter name defined 2257 as a constant on the <code>android.hardware.Camera.Parameters</code> class, if the 2258 underlying hardware supports the feature. If the device hardware does not 2259 support a feature, the API must behave as documented. Conversely, Device 2260 implementations MUST NOT honor or recognize string constants passed 2261 to the <code>android.hardware.Camera.setParameters()</code> method other than 2262 those documented as constants on the 2263 <code>android.hardware.Camera.Parameters</code>. That is, 2264 device implementations MUST support all standard Camera parameters if the 2265 hardware allows, and MUST NOT support custom Camera parameter types. 2266 For instance, device implementations that support image capture using high dynamic range (HDR) 2267 imaging techniques MUST support camera parameter <code>Camera.SCENE_MODE_HDR</code> 2268 [<a href="#resources78">Resources, 78</a>]).</p> 2269 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_PICTURE</code> 2270 intent whenever a new picture is taken by the camera and the entry of the picture 2271 has been added to the media store.</p> 2272 <p>Device implementations MUST broadcast the <code>Camera.ACTION_NEW_VIDEO</code> 2273 intent whenever a new video is recorded by the camera and the entry of the picture 2274 has been added to the media store.</p> 2275 <a name="section-7.5.4"></a><h4>7.5.4. Camera Orientation</h4> 2276 <p>Both front- and rear-facing cameras, if present, MUST be oriented so that 2277 the long dimension of the camera aligns with the screen's long dimention. That 2278 is, when the device is held in the landscape orientation, cameras MUST 2279 capture images in the landscape orientation. This applies regardless of the 2280 device's natural orientation; that is, it applies to landscape-primary devices 2281 as well as portrait-primary devices.</p> 2282 2283 <a name="section-7.6"></a><h3>7.6. Memory and Storage</h3> 2284 <a name="section-7.6.1"></a><h4>7.6.1. Minimum Memory and Storage</h4> 2285 <p>Device implementations MUST have at least 340MB of memory available to the 2286 kernel and userspace. The 340MB MUST be in addition to any memory dedicated to 2287 hardware components such as radio, video, and so on that is not under the 2288 kernel's control.</p> 2289 <p>Device implementations MUST have at least 350MB of non-volatile storage 2290 available for application private data. That is, the <code>/data</code> partition MUST be at 2291 least 350MB.</p> 2292 <p>The Android APIs include a Download Manager that applications may use to 2293 download data files [<a href="#resources56">Resources, 56</a>]. The device 2294 implementation of the Download Manager MUST be capable of downloading individual 2295 files of at least 100MB in size to the default "cache" location.</p> 2296 <a name="section-7.6.2"></a><h4>7.6.2. Application Shared Storage</h4> 2297 <p>Device implementations MUST offer shared storage for applications. The 2298 shared storage provided MUST be at least 1GB in size.</p> 2299 <p>Device implementations MUST be configured with shared storage mounted by 2300 default, "out of the box". If the shared storage is not mounted on the Linux 2301 path <code>/sdcard</code>, then the device MUST include a Linux symbolic link 2302 from <code>/sdcard</code> to the actual mount point.</p> 2303 <p>Device implementations MUST enforce as documented the 2304 <code>android.permission.WRITE_EXTERNAL_STORAGE</code> permission on this 2305 shared storage. Shared storage MUST otherwise be writable by any application 2306 that obtains that permission.</p> 2307 <p>Device implementations MAY have hardware for user-accessible removable 2308 storage, such as a Secure Digital card. Alternatively, device implementations 2309 MAY allocate internal (non-removable) storage as shared storage for apps.</p> 2310 <p>Regardless of the form of shared storage used, device implementations MUST 2311 provide some mechanism to access the contents of shared storage from a host 2312 computer, such as USB mass storage (UMS) or Media Transfer Protocol (MTP). Device 2313 implementations MAY use USB mass storage, but SHOULD use Media Transfer 2314 Protocol. If the device implementation supports Media Transfer Protocol:</p> 2315 <ul> 2316 <li>The device implementation SHOULD be compatible with the reference Android 2317 MTP host, Android File Transfer [<a href="#resources57">Resources, 57</a>].</li> 2318 <li>The device implementation SHOULD report a USB device class of <code>0x00</code>.</li> 2319 <li>The device implementation SHOULD report a USB interface name of 'MTP'.</li> 2320 </ul> 2321 <p>If the device implementation lacks USB ports, it MUST provide a host 2322 computer with access to the contents of shared storage by some other means, 2323 such as a network file system.</p> 2324 <p>It is illustrative to consider two common examples. If a device 2325 implementation includes an SD card slot to satisfy the shared storage 2326 requirement, a FAT-formatted SD card 1GB in size or larger MUST be included 2327 with the device as sold to users, and MUST be mounted by default. 2328 Alternatively, if a device implementation uses internal fixed storage to 2329 satisfy this requirement, that storage MUST be 1GB in size or larger 2330 and mounted on <code>/sdcard</code> (or <code>/sdcard</code> 2331 MUST be a symbolic link to the physical location if it is mounted elsewhere.)</p> 2332 <p>Device implementations that include multiple shared storage paths (such as 2333 both an SD card slot and shared internal storage) SHOULD modify the core 2334 applications such as the media scanner and ContentProvider to transparently 2335 support files placed in both locations.</p> 2336 2337 <a name="section-7.7"></a><h3>7.7. USB</h3> 2338 <p>Device implementations SHOULD include a USB client port, and SHOULD include 2339 a USB host port.</p> 2340 <p>If a device implementation includes a USB client port:</p> 2341 <ul> 2342 <li>the port MUST be connectable to a USB host with a standard USB-A port</li> 2343 <li>the port SHOULD use the micro USB form factor on the device side. Existing and 2344 new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements 2345 in Android 4.2</b> so they will be able to upgrade to the future platform releases</li> 2346 <li>the port SHOULD be centered in the middle of an edge. Device implementations SHOULD either 2347 locate the port on the bottom of the device (according to natural orientation) or enable software 2348 screen rotation for all apps (including home screen), so that the display draws correctly when the device 2349 is oriented with the port at bottom. Existing and new devices that run Android 4.2 are <b>very strongly 2350 encouraged to meet these requirements in Android 4.2</b> so they will be able to upgrade to future platform releases.</li> 2351 <li>if the device has other ports (such as a non-USB charging port) it SHOULD be on the same edge as the 2352 micro-USB port</li> 2353 <li>it MUST allow a host connected to the device to access the contents of the 2354 shared storage volume using either USB mass storage or Media Transfer 2355 Protocol</li> 2356 <li>it MUST implement the Android Open Accessory API and specification as documented 2357 in the Android SDK documentation, and MUST declare support for the hardware 2358 feature <code>android.hardware.usb.accessory</code> [<a href="#resources52">Resources, 2359 52</a>]</li> 2360 <li>it MUST implement the USB audio class as documented in the Android SDK documentation [<a href="#resources66">Resources, 66</a>]</li> 2361 <li>it SHOULD implement support for USB battery charging specification [<a href="#resources64">Resources, 64</a>] 2362 Existing and new devices that run Android 4.2 are <b>very strongly encouraged to meet these requirements in Android 4.2</b> 2363 so they will be able to upgrade to the future platform releases</li> 2364 2365 </ul> 2366 <p>If a device implementation includes a USB host port:</p> 2367 <ul> 2368 <li>it MAY use a non-standard port form factor, but if so MUST ship with a 2369 cable or cables adapting the port to standard USB-A</li> 2370 <li>it MUST implement the Android USB host API as documented in the Android 2371 SDK, and MUST declare support for the hardware feature 2372 <code>android.hardware.usb.host</code> [<a href="#resources53">Resources, 53</a>]</li> 2373 </ul> 2374 <p>Device implementations MUST implement the Android Debug Bridge. If a device 2375 implementation omits a USB client port, it MUST implement the Android Debug 2376 Bridge via local-area network (such as Ethernet or 802.11)</p> 2377 2378 <a name="section-8"></a><h2>8. Performance Compatibility</h2> 2379 <p>Device implementations MUST meet the key performance metrics of an Android 2380 4.2 compatible device defined in the table below:</p> 2381 <table><tbody><tr> 2382 <td><b>Metric</b></td> 2383 <td><b>Performance Threshold</b></td> 2384 <td><b>Comments</b></td> 2385 </tr> 2386 <tr> 2387 <td>Application Launch Time</td> 2388 <td>The following applications should launch within the specified time.<ul> 2389 <li>Browser: less than 1300ms</li> 2390 <li>Contacts: less than 700ms</li> 2391 <li>Settings: less than 700ms</li> 2392 </ul></td> 2393 <td>The launch time is measured as the total time to 2394 complete loading the default activity for the application, including the time 2395 it takes to start the Linux process, load the Android package into the Dalvik 2396 VM, and call onCreate.</td> 2397 </tr> 2398 <tr> 2399 <td>Simultaneous Applications</td> 2400 <td>When multiple applications have been launched, re-launching an 2401 already-running application after it has been launched must take less than the 2402 original launch time.</td> 2403 <td> </td> 2404 </tr> 2405 </tbody> 2406 </table> 2407 2408 <a name="section-9"></a><h2>9. Security Model Compatibility</h2> 2409 <p>Device implementations MUST implement a security model consistent with the 2410 Android platform security model as defined in Security and Permissions 2411 reference document in the APIs [<a href="#resources54">Resources, 54</a>] in the 2412 Android developer documentation. Device implementations MUST support 2413 installation of self-signed applications without requiring any additional 2414 permissions/certificates from any third parties/authorities. Specifically, 2415 compatible devices MUST support the security mechanisms described in the 2416 follow sub-sections.</p> 2417 <a name="section-9.1"></a><h3>9.1. Permissions</h3> 2418 <p>Device implementations MUST support the Android permissions model as 2419 defined in the Android developer documentation [<a 2420 href="#resources54">Resources, 54</a>]. Specifically, 2421 implementations MUST enforce each permission defined as described in the SDK 2422 documentation; no permissions may be omitted, altered, or ignored. 2423 Implementations MAY add additional permissions, provided the new permission ID 2424 strings are not in the android.* namespace.</p> 2425 <a name="section-9.2"></a><h3>9.2. UID and Process Isolation</h3> 2426 <p>Device implementations MUST support the Android application sandbox model, 2427 in which each application runs as a unique Unix-style UID and in a separate 2428 process. Device implementations MUST support running multiple applications as 2429 the same Linux user ID, provided that the applications are properly signed and 2430 constructed, as defined in the Security and Permissions reference [<a 2431 href="#resources54">Resources, 54</a>].</p> 2432 <a name="section-9.3"></a><h3>9.3. Filesystem Permissions</h3> 2433 <p>Device implementations MUST support the Android file access permissions 2434 model as defined in as defined in the Security and Permissions reference [<a 2435 href="#resources54">Resources, 54</a>].</p> 2436 <a name="section-9.4"></a><h3>9.4. Alternate Execution Environments</h3> 2437 <p>Device implementations MAY include runtime environments that execute 2438 applications using some other software or technology than the Dalvik virtual 2439 machine or native code. However, such alternate execution environments MUST 2440 NOT compromise the Android security model or the security of installed Android 2441 applications, as described in this section.</p> 2442 <p>Alternate runtimes MUST themselves be Android applications, and abide by 2443 the standard Android security model, as described elsewhere in Section 9.</p> 2444 <p>Alternate runtimes MUST NOT be granted access to resources protected by 2445 permissions not requested in the runtime's AndroidManifest.xml file via the 2446 <code><uses-permission></code> mechanism.</p> 2447 <p>Alternate runtimes MUST NOT permit applications to make use of features 2448 protected by Android permissions restricted to system applications.</p> 2449 <p>Alternate runtimes MUST abide by the Android sandbox model. Specifically:</p> 2450 <ul> 2451 <li>Alternate runtimes SHOULD install apps via the PackageManager into 2452 separate Android sandboxes (that is, Linux user IDs, etc.)</li> 2453 <li>Alternate runtimes MAY provide a single Android sandbox shared by all 2454 applications using the alternate runtime</li> 2455 <li>Alternate runtimes and installed applications using an alternate runtime 2456 MUST NOT reuse the sandbox of any other app installed on the device, except 2457 through the standard Android mechanisms of shared user ID and signing 2458 certificate</li> 2459 <li>Alternate runtimes MUST NOT launch with, grant, or be granted access to 2460 the sandboxes corresponding to other Android applications</li> 2461 </ul> 2462 <p>Alternate runtimes MUST NOT be launched with, be granted, or grant to other 2463 applications any privileges of the superuser (root), or of any other user ID.</p> 2464 <p>The .apk files of alternate runtimes MAY be included in the system image of 2465 a device implementation, but MUST be signed with a key distinct 2466 from the key used to sign other applications included with the device 2467 implementation.</p> 2468 <p>When installing applications, alternate runtimes MUST obtain user consent 2469 for the Android permissions used by the application. That is, if an 2470 application needs to make use of a device resource for which there is a 2471 corresponding Android permission (such as Camera, GPS, etc.), the alternate 2472 runtime MUST inform the user that the application will be able to access 2473 that resource. If the runtime environment does not record application 2474 capabilities in this manner, the runtime environment MUST list all 2475 permissions held by the runtime itself when installing any application 2476 using that runtime.</p> 2477 2478 <a name="section-9.5"></a><h3>9.5. Multi-User Support </h3> 2479 <p>Android 4.2 includes support for multiple users and provides support for full user isolation 2480 [<a href="#resources70">Resources, 70</a>].</p> 2481 <p>Device implementations MUST meet these requirements related to multi-user support[<a href="#resources71">Resources, 71</a>]:</p> 2482 <ul> 2483 <li>As the behavior of the telephony APIs on devices with multiple users is currently undefined, device implementations that 2484 declare android.hardware.telephony MUST NOT enable multi-user support. </li> 2485 <li>Device implementations MUST, for each user, implement a security model consistent with the Android platform security model 2486 as defined in Security and Permissions reference document in the APIs [Resources, 54]</li> 2487 </ul> 2488 </p> 2489 2490 <p>Each user instance on an Android device MUST have separate and isolated external storage directories. Device implementations MAY store multiple users' data on the same volume or filesystem. 2491 However, the device implementation MUST ensure that applications owned by and running on behalf a given user cannot list, read, or write to data owned by any other user. 2492 Note that removable media, such as SD card slots, can allow one user to access another's data by means of a host PC. For this reason, device implementations that use removable media for the 2493 external storage APIs MUST encrypt the contents of the SD card if multi-user is enabled using a key stored only on non-removable media accessible only to the system. As this will make the 2494 media unreadable by a host PC, device implementations will be required to switch to MTP or a similar system to provide host PCs with access to the current user's data. Accordingly, device 2495 implementations MAY but SHOULD NOT enable multi-user if they use removable media [<a href="#resources72">Resources, 72</a>] for primary external storage. The upstream Android open-source 2496 project includes an implementation that uses internal device storage for application external storage APIs; device implementations SHOULD use this configuration and software implementation. 2497 Device implementations that include multiple external storage paths MUST NOT allow Android applications to write to the secondary external storage</p> 2498 2499 <a name="section-9.6"></a><h3>9.6. Premium SMS Warning</h3> 2500 <p>Android 4.2 includes support for warning users for any outgoing premium SMS message. Premium SMS messages are text messages sent to a service registered with a carrier that may incur a charge to the user. 2501 Device implementations that declare support for <code>android.hardware.telephony</code> MUST warn users before sending a SMS message to numbers identified by regular expressions defined in <code>/data/misc/sms/codes.xml</code> file in the device. 2502 The upstream Android open-source project provides an implementation that satisfies this requirement. 2503 </p> 2504 2505 <a name="section-10"></a><h2>10. Software Compatibility Testing</h2> 2506 <p>Device implementations MUST pass all tests described in this section.</p> 2507 <p>However, note that no software test package is fully comprehensive. For 2508 this reason, device implementers are very strongly encouraged to make the 2509 minimum number of changes as possible to the reference and preferred 2510 implementation of Android 4.2 available from the Android Open Source Project. 2511 This will minimize the risk of introducing bugs that create incompatibilities 2512 requiring rework and potential device updates.</p> 2513 <a name="section-10.1"></a><h3>10.1. Compatibility Test Suite</h3> 2514 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) 2515 [<a href="#resources02">Resources, 2</a>] available from the Android Open Source 2516 Project, using the final shipping software on the device. Additionally, device 2517 implementers SHOULD use the reference implementation in the Android Open 2518 Source tree as much as possible, and MUST ensure compatibility in cases of 2519 ambiguity in CTS and for any reimplementations of parts of the reference 2520 source code.</p> 2521 <p>The CTS is designed to be run on an actual device. Like any software, the 2522 CTS may itself contain bugs. The CTS will be versioned independently of this 2523 Compatibility Definition, and multiple revisions of the CTS may be released 2524 for Android 4.2. Device implementations MUST pass the latest CTS version 2525 available at the time the device software is completed.</p> 2526 <a name="section-10.2"></a><h3>10.2. CTS Verifier</h3> 2527 <p>Device implementations MUST correctly execute all applicable cases in the 2528 CTS Verifier. The CTS Verifier is included with the Compatibility Test Suite, 2529 and is intended to be run by a human operator to test functionality that 2530 cannot be tested by an automated system, such as correct functioning of a 2531 camera and sensors.</p> 2532 <p>The CTS Verifier has tests for many kinds of hardware, including some 2533 hardware that is optional. Device implementations MUST pass all tests for 2534 hardware which they possess; for instance, if a device possesses an 2535 accelerometer, it MUST correctly execute the Accelerometer test case in the 2536 CTS Verifier. Test cases for features noted as optional by this Compatibility 2537 Definition Document MAY be skipped or omitted.</p> 2538 <p>Every device and every build MUST correctly run the CTS Verifier, as noted 2539 above. However, since many builds are very similar, device implementers are 2540 not expected to explicitly run the CTS Verifier on builds that differ only in 2541 trivial ways. Specifically, device implementations that differ from an 2542 implementation that has passed the CTS Verfier only by the set of included 2543 locales, branding, etc. MAY omit the CTS Verifier test.</p> 2544 <a name="section-10.3"></a><h3>10.3. Reference Applications</h3> 2545 <p>Device implementers MUST test implementation compatibility using the 2546 following open source applications:</p> 2547 <ul> 2548 <li>The "Apps for Android" applications [<a href="#resources55">Resources, 55</a>]</li> 2549 <li>Replica Island (available in Android Market)</li> 2550 </ul> 2551 <p>Each app above MUST launch and behave correctly on the implementation, for 2552 the implementation to be considered compatible.</p> 2553 2554 2555 <a name="section-11"></a><h2>11. Updatable Software</h2> 2556 <p>Device implementations MUST include a mechanism to replace the entirety of 2557 the system software. The mechanism need not perform "live" upgrades - that 2558 is, a device restart MAY be required.</p> 2559 <p>Any method can be used, provided that it can replace the entirety of the 2560 software preinstalled on the device. For instance, any of the following 2561 approaches will satisfy this requirement:</p> 2562 <ul> 2563 <li>Over-the-air (OTA) downloads with offline update via reboot</li> 2564 <li>"Tethered" updates over USB from a host PC</li> 2565 <li>"Offline" updates via a reboot and update from a file on removable 2566 storage</li> 2567 </ul> 2568 <p>The update mechanism used MUST support updates without wiping user data. 2569 That is, the update mechanism MUST preserve application private data 2570 and application shared data. Note that the upstream Android software includes 2571 an update mechanism that satisfies this requirement.</p> 2572 <p>If an error is found in a device implementation after it has been released 2573 but within its reasonable product lifetime that is determined in consultation 2574 with the Android Compatibility Team to affect the compatibility of third-party 2575 applications, the device implementer MUST correct the error via a software 2576 update available that can be applied per the mechanism just described.</p> 2577 2578 <a name="section-12"></a><h2>12. Contact Us</h2> 2579 <p>You can contact the document authors at <a 2580 href="mailto:compatibility (a] android.com">compatibility (a] android.com</a> for 2581 clarifications and to bring up any issues that you think the document does not 2582 cover.</p> 2583 2584 <div style="page-break-before: always;"></div> 2585 2586 <a name="appendix-A"></a><h2>Appendix A - Bluetooth Test Procedure</h2> 2587 <p>The Compatibility Test Suite includes cases that cover basic operation of 2588 the Android RFCOMM Bluetooth API. However, since Bluetooth is a communications 2589 protocol between devices, it cannot be fully tested by unit tests running on a 2590 single device. Consequently, device implementations MUST also pass the 2591 human-operated Bluetooth test procedure described below.</p> 2592 <p>The test procedure is based on the BluetoothChat sample app included in the 2593 Android open source project tree. The procedure requires two devices:</p> 2594 <ul> 2595 <li>a candidate device implementation running the software build to be tested</li> 2596 <li>a separate device implementation already known to be compatible, and of a 2597 model from the device implementation being tested - that is, a "known 2598 good" device implementation</li> 2599 </ul> 2600 <p>The test procedure below refers to these devices as the "candidate" and "known 2601 good" devices, respectively.</p> 2602 <h3>Setup and Installation</h3> 2603 <ol> 2604 <li>Build BluetoothChat.apk via 'make samples' from an Android source code tree</li> 2605 <li>Install BluetoothChat.apk on the known-good device</li> 2606 <li>Install BluetoothChat.apk on the candidate device</li> 2607 </ol> 2608 <h3>Test Bluetooth Control by Apps</h3> 2609 <ol> 2610 <li>Launch BluetoothChat on the candidate device, while Bluetooth is disabled</li> 2611 <li>Verify that the candidate device either turns on Bluetooth, or prompts the user with a dialog to turn on Bluetooth</li> 2612 </ol> 2613 <h3>Test Pairing and Communication</h3> 2614 <ol> 2615 <li>Launch the Bluetooth Chat app on both devices</li> 2616 <li>Make the known-good device discoverable from within BluetoothChat (using the Menu)</li> 2617 <li>On the candidate device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the known-good device</li> 2618 <li>Send 10 or more messages from each device, and verify that the other device receives them correctly</li> 2619 <li>Close the BluetoothChat app on both devices by pressing <b>Home</b></li> 2620 <li>Unpair each device from the other, using the device Settings app</li> 2621 </ol> 2622 <h3>Test Pairing and Communication in the Reverse Direction</h3> 2623 <ol> 2624 <li>Launch the Bluetooth Chat app on both devices.</li> 2625 <li>Make the candidate device discoverable from within BluetoothChat (using the Menu).</li> 2626 <li>On the known-good device, scan for Bluetooth devices from within BluetoothChat (using the Menu) and pair with the candidate device.</li> 2627 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 2628 <li>Close the Bluetooth Chat app on both devices by pressing Back repeatedly to get to the Launcher.</li> 2629 </ol> 2630 <h3>Test Re-Launches</h3> 2631 <ol> 2632 <li>Re-launch the Bluetooth Chat app on both devices.</li> 2633 <li>Send 10 or messages from each device, and verify that the other device receives them correctly.</li> 2634 </ol> 2635 <p>Note: the above tests have some cases which end a test section by using 2636 Home, and some using Back. These tests are not redundant and are not optional: 2637 the objective is to verify that the Bluetooth API and stack works correctly 2638 both when Activities are explicitly terminated (via the user pressing Back, 2639 which calls finish()), and implicitly sent to background (via the user 2640 pressing Home.) Each test sequence MUST be performed as described.</p> 2641 <div id="footerContent" xmlns:pdf="http://whatever"> 2642 <pdf:pagenumber/> 2643 </div> 2644 </body> 2645 </html> 2646
