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      3 <title>Android 6.0 Compatibility Definition</title>
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      8 
      9 <h6>Table of Contents</h6>
     10 
     11 <div id="toc">
     12 
     13 <div id="toc_left">
     14 
     15 <p class="toc_h1"><a href="#1_introduction">1. Introduction</a></p>
     16 
     17 <p class="toc_h1"><a href="#2_device_types">2. Device Types</a></p>
     18 
     19 <p class="toc_h2"><a href="#2_1_device_configurations">2.1 Device Configurations</a></p>
     20 
     21 <p class="toc_h1"><a href="#3_software">3. Software</a></p>
     22 
     23 <p class="toc_h2"><a href="#3_1_managed_api_compatibility">3.1. Managed API Compatibility</a></p>
     24 
     25 <p class="toc_h2"><a href="#3_2_soft_api_compatibility">3.2. Soft API Compatibility</a></p>
     26 
     27 <p class="toc_h3"><a href="#3_2_1_permissions">3.2.1. Permissions</a></p>
     28 
     29 <p class="toc_h3"><a href="#3_2_2_build_parameters">3.2.2. Build Parameters</a></p>
     30 
     31 <p class="toc_h3"><a href="#3_2_3_intent_compatibility">3.2.3. Intent Compatibility</a></p>
     32 
     33 <p class="toc_h4"><a href="#3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</a></p>
     34 
     35 <p class="toc_h4"><a href="#3_2_3_2_intent_resolution">3.2.3.2. Intent Resolution</a></p>
     36 
     37 <p class="toc_h4"><a href="#3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</a></p>
     38 
     39 <p class="toc_h4"><a href="#3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</a></p>
     40 
     41 <p class="toc_h4"><a href="#3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</a></p>
     42 
     43 <p class="toc_h2"><a href="#3_3_native_api_compatibility">3.3. Native API Compatibility</a></p>
     44 
     45 <p class="toc_h3"><a href="#3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</a></p>
     46 
     47 <p class="toc_h3"><a href="#3_3_2_32-bit_arm_native_code_compatibility">3.3.2. 32-bit ARM Native Code Compatibility</a></p>
     48 
     49 <p class="toc_h2"><a href="#3_4_web_compatibility">3.4. Web Compatibility</a></p>
     50 
     51 <p class="toc_h3"><a href="#3_4_1_webview_compatibility">3.4.1. WebView Compatibility</a></p>
     52 
     53 <p class="toc_h3"><a href="#3_4_2_browser_compatibility">3.4.2. Browser Compatibility</a></p>
     54 
     55 <p class="toc_h2"><a href="#3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</a></p>
     56 
     57 <p class="toc_h2"><a href="#3_6_api_namespaces">3.6. API Namespaces</a></p>
     58 
     59 <p class="toc_h2"><a href="#3_7_runtime_compatibility">3.7. Runtime Compatibility</a></p>
     60 
     61 <p class="toc_h2"><a href="#3_8_user_interface_compatibility">3.8. User Interface Compatibility</a></p>
     62 
     63 <p class="toc_h3"><a href="#3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</a></p>
     64 
     65 <p class="toc_h3"><a href="#3_8_2_widgets">3.8.2. Widgets</a></p>
     66 
     67 <p class="toc_h3"><a href="#3_8_3_notifications">3.8.3. Notifications</a></p>
     68 
     69 <p class="toc_h3"><a href="#3_8_4_search">3.8.4. Search</a></p>
     70 
     71 <p class="toc_h3"><a href="#3_8_5_toasts">3.8.5. Toasts</a></p>
     72 
     73 <p class="toc_h3"><a href="#3_8_6_themes">3.8.6. Themes</a></p>
     74 
     75 <p class="toc_h3"><a href="#3_8_7_live_wallpapers">3.8.7. Live Wallpapers</a></p>
     76 
     77 <p class="toc_h3"><a href="#3_8_8_activity_switching">3.8.8. Activity Switching</a></p>
     78 
     79 <p class="toc_h3"><a href="#3_8_9_input_management">3.8.9. Input Management</a></p>
     80 
     81 <p class="toc_h3"><a href="#3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</a></p>
     82 
     83 <p class="toc_h3"><a href="#3_8_11_dreams">3.8.11. Dreams</a></p>
     84 
     85 <p class="toc_h3"><a href="#3_8_12_location">3.8.12. Location</a></p>
     86 
     87 </div>
     88 
     89 <div id="toc_right">
     90 
     91 
     92 <p class="toc_h3"><a href="#3_8_13_unicode_and_font">3.8.13. Unicode and Font</a></p>
     93 
     94 <p class="toc_h2"><a href="#3_9_device_administration">3.9. Device Administration</a></p>
     95 
     96 <p class="toc_h3"><a href="#3_9_1_device_provisioning">3.9.1 Device Provisioning</a></p>
     97 
     98 <p class="toc_h4"><a href="#3_9_1_2_device_owner_provisioning">3.9.1.1 Device Owner provisioning</a></p>
     99 
    100 <p class="toc_h4"><a href="#3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile provisioning</a></p>
    101 
    102 <p class="toc_h3"><a href="#3_9_2_managed_profile_support">3.9.2. Managed Profile Support</a></p>
    103 
    104 
    105 <p class="toc_h2"><a href="#3_10_accessibility">3.10. Accessibility</a></p>
    106 
    107 <p class="toc_h2"><a href="#3_11_text-to-speech">3.11. Text-to-Speech</a></p>
    108 
    109 <p class="toc_h2"><a href="#3_12_tv_input_framework">3.12. TV Input Framework</a></p>
    110 
    111 <p class="toc_h3"><a href="#3_12_1_tv_app">3.12.1. TV App</a></p>
    112 
    113 <p class="toc_h4"><a href="#3_12_1_1_electronic_program_guide">3.12.1.1. Electronic Program Guide</a></p>
    114 
    115 <p class="toc_h4"><a href="#3_12_1_2_navigation">3.12.1.2. Navigation</a></p>
    116 
    117 <p class="toc_h4"><a href="#3_12_1_3_tv_input_app_linking">3.12.1.3. TV input app linking</a></p>
    118 
    119 <p class="toc_h1"><a href="#4_application_packaging_compatibility">4. Application Packaging Compatibility</a></p>
    120 
    121 <p class="toc_h1"><a href="#5_multimedia_compatibility">5. Multimedia Compatibility</a></p>
    122 
    123 <p class="toc_h2"><a href="#5_1_media_codecs">5.1. Media Codecs</a></p>
    124 
    125 <p class="toc_h3"><a href="#5_1_1_audio_codecs">5.1.1. Audio Codecs</a></p>
    126 
    127 <p class="toc_h3"><a href="#5_1_2_image_codecs">5.1.2. Image Codecs</a></p>
    128 
    129 <p class="toc_h3"><a href="#5_1_3_video_codecs">5.1.3. Video Codecs</a></p>
    130 
    131 <p class="toc_h2"><a href="#5_2_video_encoding">5.2. Video Encoding</a></p>
    132 
    133 <p class="toc_h2"><a href="#5_3_video_decoding">5.3. Video Decoding</a></p>
    134 
    135 <p class="toc_h2"><a href="#5_4_audio_recording">5.4. Audio Recording</a></p>
    136 
    137 <p class="toc_h3"><a href="#5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</a></p>
    138 
    139 <p class="toc_h3"><a href="#5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice Recognition</a></p>
    140 
    141 <p class="toc_h3"><a href="#5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of Playback</a></p>
    142 
    143 <p class="toc_h2"><a href="#5_5_audio_playback">5.5. Audio Playback</a></p>
    144 
    145 <p class="toc_h3"><a href="#5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</a></p>
    146 
    147 <p class="toc_h3"><a href="#5_5_2_audio_effects">5.5.2. Audio Effects</a></p>
    148 
    149 <p class="toc_h3"><a href="#5_5_3_audio_output_volume">5.5.3. Audio Output Volume</a></p>
    150 
    151 <p class="toc_h2"><a href="#5_6_audio_latency">5.6. Audio Latency</a></p>
    152 
    153 <p class="toc_h2"><a href="#5_7_network_protocols">5.7. Network Protocols</a></p>
    154 
    155 <p class="toc_h2"><a href="#5_8_secure_media">5.8. Secure Media</a></p>
    156 
    157 <p class="toc_h2"><a href="#5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</a></p>
    158 
    159 <p class="toc_h2"><a href="#5_10_pro_audio">5.10. Professional Audio</a></p>
    160 
    161 </div>
    162 
    163 <div style="clear: both; page-break-after:always; height:1px"></div>
    164 
    165 <div id="toc_left">
    166 
    167 <p class="toc_h1"><a href="#6_developer_tools_and_options_compatibility">6. Developer Tools and Options Compatibility</a></p>
    168 
    169 <p class="toc_h2"><a href="#6_1_developer_tools">6.1. Developer Tools</a></p>
    170 
    171 <p class="toc_h2"><a href="#6_2_developer_options">6.2. Developer Options</a></p>
    172 
    173 <p class="toc_h1"><a href="#7_hardware_compatibility">7. Hardware Compatibility</a></p>
    174 
    175 <p class="toc_h2"><a href="#7_1_display_and_graphics">7.1. Display and Graphics</a></p>
    176 
    177 <p class="toc_h3"><a href="#7_1_1_screen_configuration">7.1.1. Screen Configuration</a></p>
    178 
    179 <p class="toc_h4"><a href="#7_1_1_1_screen_size">7.1.1.1. Screen Size</a></p>
    180 
    181 <p class="toc_h4"><a href="#7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</a></p>
    182 
    183 <p class="toc_h4"><a href="#7_1_1_3_screen_density">7.1.1.3. Screen Density</a></p>
    184 
    185 <p class="toc_h3"><a href="#7_1_2_display_metrics">7.1.2. Display Metrics</a></p>
    186 
    187 <p class="toc_h3"><a href="#7_1_3_screen_orientation">7.1.3. Screen Orientation</a></p>
    188 
    189 <p class="toc_h3"><a href="#7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics Acceleration</a></p>
    190 
    191 <p class="toc_h3"><a href="#7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application Compatibility Mode</a></p>
    192 
    193 <p class="toc_h3"><a href="#7_1_6_screen_technology">7.1.6. Screen Technology</a></p>
    194 
    195 <p class="toc_h3"><a href="#7_1_7_external_displays">7.1.7. Secondary Displays</a></p>
    196 
    197 <p class="toc_h2"><a href="#7_2_input_devices">7.2. Input Devices</a></p>
    198 
    199 <p class="toc_h3"><a href="#7_2_1_keyboard">7.2.1. Keyboard</a></p>
    200 
    201 <p class="toc_h3"><a href="#7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</a></p>
    202 
    203 <p class="toc_h3"><a href="#7_2_3_navigation_keys">7.2.3. Navigation Keys</a></p>
    204 
    205 <p class="toc_h3"><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen Input</a></p>
    206 
    207 <p class="toc_h3"><a href="#7_2_5_fake_touch_input">7.2.5. Fake Touch Input</a></p>
    208 
    209 <p class="toc_h3"><a href="#7_2_6_game_controller_support">7.2.6. Game Controller Support</a></p>
    210 
    211 <p class="toc_h4"><a href="#7_2_6_1_button_mapping">7.2.6.1. Button Mappings</a></p>
    212 
    213 <p class="toc_h3"><a href="#7_2_7_remote_control">7.2.7. Remote Control</a></p>
    214 
    215 <p class="toc_h2"><a href="#7_3_sensors">7.3. Sensors</a></p>
    216 
    217 <p class="toc_h3"><a href="#7_3_1_accelerometer">7.3.1. Accelerometer</a></p>
    218 
    219 <p class="toc_h3"><a href="#7_3_2_magnetometer">7.3.2. Magnetometer</a></p>
    220 
    221 <p class="toc_h3"><a href="#7_3_3_gps">7.3.3. GPS</a></p>
    222 
    223 </div>
    224 
    225 <div id="toc_right">
    226 
    227 <p class="toc_h3"><a href="#7_3_4_gyroscope">7.3.4. Gyroscope</a></p>
    228 
    229 <p class="toc_h3"><a href="#7_3_5_barometer">7.3.5. Barometer</a></p>
    230 
    231 <p class="toc_h3"><a href="#7_3_6_thermometer">7.3.6. Thermometer</a></p>
    232 
    233 <p class="toc_h3"><a href="#7_3_7_photometer">7.3.7. Photometer</a></p>
    234 
    235 <p class="toc_h3"><a href="#7_3_8_proximity_sensor">7.3.8. Proximity Sensor</a></p>
    236 
    237 <p class="toc_h3"><a href="#7_3_9_hifi_sensors">7.3.9. High Fidelity Sensors</a></p>
    238 
    239 <p class="toc_h3"><a href="#7_3_10_fingerprint">7.3.10. Fingerprint Sensor</a></p>
    240 
    241 <p class="toc_h2"><a href="#7_4_data_connectivity">7.4. Data Connectivity</a></p>
    242 
    243 <p class="toc_h3"><a href="#7_4_1_telephony">7.4.1. Telephony</a></p>
    244 
    245 <p class="toc_h3"><a href="#7_4_2_ieee_80211_wi-fi">7.4.2. IEEE 802.11 (Wi-Fi)</a></p>
    246 
    247 <p class="toc_h4"><a href="#7_4_2_1_wi-fi_direct">7.4.2.1. Wi-Fi Direct</a></p>
    248 
    249 <p class="toc_h4"><a href="#7_4_2_2_wi-fi-tunneled-direct-link-setup">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</a></p>
    250 
    251 <p class="toc_h3"><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></p>
    252 
    253 <p class="toc_h3"><a href="#7_4_4_near-field_communications">7.4.4. Near-Field Communications</a></p>
    254 
    255 <p class="toc_h3"><a href="#7_4_5_minimum_network_capability">7.4.5. Minimum Network Capability</a></p>
    256 
    257 <p class="toc_h3"><a href="#7_4_6_sync_settings">7.4.6. Sync Settings</a></p>
    258 
    259 <p class="toc_h2"><a href="#7_5_cameras">7.5. Cameras</a></p>
    260 
    261 <p class="toc_h3"><a href="#7_5_1_rear-facing_camera">7.5.1. Rear-Facing Camera</a></p>
    262 
    263 <p class="toc_h3"><a href="#7_5_2_front-facing_camera">7.5.2. Front-Facing Camera</a></p>
    264 
    265 <p class="toc_h3"><a href="#7_5_3_external_camera">7.5.3. External Camera</a></p>
    266 
    267 <p class="toc_h3"><a href="#7_5_4_camera_api_behavior">7.5.4. Camera API Behavior</a></p>
    268 
    269 <p class="toc_h3"><a href="#7_5_5_camera_orientation">7.5.5. Camera Orientation</a></p>
    270 
    271 <p class="toc_h2"><a href="#7_6_memory_and_storage">7.6. Memory and Storage</a></p>
    272 
    273 <p class="toc_h3"><a href="#7_6_1_minimum_memory_and_storage">7.6.1. Minimum Memory and Storage</a></p>
    274 
    275 <p class="toc_h3"><a href="#7_6_2_application_shared_storage">7.6.2. Application Shared Storage</a></p>
    276 
    277 <p class="toc_h3"><a href="#7_6_3_adoptable_storage">7.6.3. Adoptable Storage</a></p>
    278 
    279 <p class="toc_h2"><a href="#7_7_usb">7.7. USB</a></p>
    280 
    281 <p class="toc_h2"><a href="#7_8_audio">7.8. Audio</a></p>
    282 
    283 <p class="toc_h3"><a href="#7_8_1_microphone">7.8.1. Microphone</a></p>
    284 
    285 <p class="toc_h3"><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></p>
    286 
    287 <p class="toc_h4"><a href="#7_8_2_1_analog_audio_ports">7.8.2.1. Analog Audio Ports</a></p>
    288 
    289 <p class="toc_h3"><a href="#7_8_3_near_ultrasound">7.8.3. Near-Ultrasound</a></p>
    290 
    291 <p class="toc_h1"><a href="#8_performance_power">8. Performance and Power</a></p>
    292 
    293 <p class="toc_h2"><a href="#8_1_user_experience_consistency">8.1. User Experience Consistency</a></p>
    294 
    295 <p class="toc_h2"><a href="#8_2_file_i_o_access_performance">8.2. File I/O Access Performance</a></p>
    296 
    297 <p class="toc_h2"><a href="#8_3_power_saving_modes">8.3. Power-Saving Modes</a></p>
    298 
    299 <p class="toc_h2"><a href="#8_4_power_consumption_accounting">8.4. Power Consumption Accounting</a></p>
    300 
    301 </div>
    302 
    303 <div style="clear: both; page-break-after:always; height:1px"></div>
    304 
    305 <div id="toc_left">
    306 
    307 <p class="toc_h1"><a href="#9_security_model_compatibility">9. Security Model Compatibility</a></p>
    308 
    309 <p class="toc_h2"><a href="#9_1_permissions">9.1. Permissions</a></p>
    310 
    311 <p class="toc_h2"><a href="#9_2_uid_and_process_isolation">9.2. UID and Process Isolation</a></p>
    312 
    313 <p class="toc_h2"><a href="#9_3_filesystem_permissions">9.3. Filesystem Permissions</a></p>
    314 
    315 <p class="toc_h2"><a href="#9_4_alternate_execution_environments">9.4. Alternate Execution Environments</a></p>
    316 
    317 <p class="toc_h2"><a href="#9_5_multi-user_support">9.5. Multi-User Support</a></p>
    318 
    319 <p class="toc_h2"><a href="#9_6_premium_sms_warning">9.6. Premium SMS Warning</a></p>
    320 
    321 <p class="toc_h2"><a href="#9_7_kernel_security_features">9.7. Kernel Security Features</a></p>
    322 
    323 <p class="toc_h2"><a href="#9_8_privacy">9.8. Privacy</a></p>
    324 
    325 <p class="toc_h2"><a href="#9_9_full-disk-encryption">9.9. Full-Disk Encryption</a></p>
    326 
    327 <p class="toc_h2"><a href="#9_10_verified_boot">9.10. Verified Boot</a></p>
    328 
    329 <p class="toc_h2"><a href="#9_11_keys_and_credentials">9.11. Keys and Credentials</a></p>
    330 
    331 <p class="toc_h2"><a href="#9_12_data_deletion">9.12. Data Deletion</a></p>
    332 
    333 <p class="toc_h1"><a href="#10_software_compatibility_testing">10. Software Compatibility Testing</a></p>
    334 
    335 <p class="toc_h2"><a href="#10_1_compatibility_test_suite">10.1. Compatibility Test Suite</a></p>
    336 
    337 <p class="toc_h2"><a href="#10_2_cts_verifier">10.2. CTS Verifier</a></p>
    338 
    339 <p class="toc_h1"><a href="#11_updatable_software">11. Updatable Software</a></p>
    340 
    341 <p class="toc_h1"><a href="#12_document_changelog">12. Document Changelog</a></p>
    342 
    343 <p class="toc_h1"><a href="#13_contact_us">13. Contact Us</a></p>
    344 
    345 <p class="toc_h1"><a href="#14_resources">14. Resources</a></p>
    346 
    347 </div>
    348 
    349 </div>
    350 
    351 <div style="clear: both"></div>
    352 
    353 <div id="main">
    354 
    355 <h1 id="1_introduction">1. Introduction</h1>
    356 
    357 
    358 <p>This document enumerates the requirements that must be met in order for devices
    359 to be compatible with Android 6.0.</p>
    360 
    361 <p>The use of &ldquo;MUST&rdquo;, &ldquo;MUST NOT&rdquo;, &ldquo;REQUIRED&rdquo;, &ldquo;SHALL&rdquo;, &ldquo;SHALL NOT&rdquo;, &ldquo;SHOULD&rdquo;, &ldquo;SHOULD NOT&rdquo;, &ldquo;RECOMMENDED&rdquo;, &ldquo;MAY&rdquo;, and &ldquo;OPTIONAL&rdquo; is per the IETF standard
    362 defined in RFC2119 [<a href="http://www.ietf.org/rfc/rfc2119.txt">Resources, 1</a>].</p>
    363 
    364 <p>As used in this document, a &ldquo;device implementer&rdquo; or &ldquo;implementer&rdquo; is a person
    365 or organization developing a hardware/software solution running Android 6.0. A
    366 &ldquo;device implementation&rdquo; or &ldquo;implementation is the hardware/software solution
    367 so developed.</p>
    368 
    369 <p>To be considered compatible with Android 6.0, device implementations MUST meet
    370 the requirements presented in this Compatibility Definition, including any
    371 documents incorporated via reference.</p>
    372 
    373 <p>Where this definition or the software tests described in <a href="#10_software_compatibility_testing">section 10</a> is silent, ambiguous, or incomplete, it is the responsibility of the device
    374 implementer to ensure compatibility with existing implementations.</p>
    375 
    376 <p>For this reason, the Android Open Source Project [<a href="http://source.android.com/">Resources, 2</a>] is both the reference and preferred implementation of Android. Device
    377 implementers are STRONGLY RECOMMENDED to base their implementations to the
    378 greatest extent possible on the &ldquo;upstream&rdquo; source code available from the
    379 Android Open Source Project. While some components can hypothetically be
    380 replaced with alternate implementations, it is STRONGLY RECOMMENDED to not follow this practice,
    381 as passing the software tests will become substantially more difficult. It is
    382 the implementer&rsquo;s responsibility to ensure full behavioral compatibility with
    383 the standard Android implementation, including and beyond the Compatibility
    384 Test Suite. Finally, note that certain component substitutions and
    385 modifications are explicitly forbidden by this document.</p>
    386 
    387 <p>Many of the resources listed in <a href="#14_resources">section 14</a> are derived directly or indirectly from the Android SDK, and will be
    388 functionally identical to the information in that SDK&rsquo;s documentation. For any
    389 case where this Compatibility Definition or the Compatibility Test Suite
    390 disagrees with the SDK documentation, the SDK documentation is considered
    391 authoritative. Any technical details provided in the references included in <a href="#14_resources">section 14</a> are considered by inclusion to be part of this Compatibility Definition. </p>
    392 
    393 <h1 id="2_device_types">2. Device Types</h1>
    394 
    395 
    396 <p>While the Android Open Source Project has been used in the implementation of a
    397 variety of device types and form factors, many aspects of the architecture and
    398 compatibility requirements were optimized for handheld devices. Starting from
    399 Android 5.0, the Android Open Source Project aims to embrace a wider variety of
    400 device types as described in this section.</p>
    401 
    402 <p><strong>Android Handheld device</strong> refers to an Android device implementation that is typically used by holding
    403 it in the hand, such as mp3 players, phones, and tablets. Android Handheld
    404 device implementations:</p>
    405 
    406 <ul>
    407   <li>MUST have a touchscreen embedded in the device.</li>
    408   <li>MUST have a power source that provides mobility, such as a battery.</li>
    409 </ul>
    410 
    411 <p><strong>Android Television device</strong> refers to an Android device implementation that is an entertainment interface
    412 for consuming digital media, movies, games, apps, and/or live TV for users
    413 sitting about ten feet away (a &ldquo;lean back&rdquo; or &ldquo;10-foot user interface&rdquo;).
    414 Android Television devices:</p>
    415 
    416 <ul>
    417   <li>MUST have an embedded screen OR include a video output port, such as VGA, HDMI,
    418 or a wireless port for display.</li>
    419   <li>MUST declare the features android.software.leanback and
    420 android.hardware.type.television [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK">Resources, 3</a>].</li>
    421 </ul>
    422 
    423 <p><strong>Android Watch device</strong> refers to an Android device implementation intended to be worn on the body,
    424 perhaps on the wrist, and:</p>
    425 
    426 <ul>
    427   <li>MUST have a screen with the physical diagonal length in the range from 1.1 to
    428 2.5 inches.</li>
    429   <li>MUST declare the feature android.hardware.type.watch.</li>
    430   <li>MUST support uiMode = UI_MODE_TYPE_WATCH [<a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH">Resources, 4</a>].</li>
    431 </ul>
    432 
    433 <p><strong>Android Automotive implementation</strong> refers to a vehicle head
    434 unit running Android as an operating system for part or all of the system and/or
    435 infotainment functionality. Android Automotive implementations:</p>
    436 
    437 <ul>
    438   <li>MUST declare the feature android.hardware.type.automotive.</li>
    439   <li>MUST support
    440 uiMode = UI_MODE_TYPE_CAR [<a
    441 href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR">Resources,
    442     5</a>].</li>
    443 </ul>
    444 
    445 <p>All Android device implementations that do not fit into any of the above device
    446 types still MUST meet all requirements in this document to be Android 6.0
    447 compatible, unless the requirement is explicitly described to be only
    448 applicable to a specific Android device type from above.</p>
    449 
    450 <h2 id="2_1_device_configurations">2.1 Device Configurations</h2>
    451 
    452 
    453 <p>This is a summary of major differences in hardware configuration by device
    454 type. (Empty cells denote a &ldquo;MAY&rdquo;). Not all configurations are covered in this
    455 table; see relevant hardware sections for more detail.</p>
    456 <table>
    457  <tr>
    458     <th>Category</th>
    459     <th>Feature</th>
    460     <th>Section</th>
    461     <th>Handheld</th>
    462     <th>Television</th>
    463     <th>Watch</th>
    464     <th>Automotive</th>
    465     <th>Other</th>
    466  </tr>
    467  <tr>
    468     <td rowspan="3">Input</td>
    469     <td>D-pad</td>
    470     <td><a href="#7_2_2_non-touch-navigation">7.2.2. Non-touch Navigation</a></td>
    471     <td></td>
    472     <td>MUST</td>
    473     <td></td>
    474     <td></td>
    475     <td></td>
    476  </tr>
    477  <tr>
    478     <td>Touchscreen </td>
    479     <td><a href="#7_2_4_touchscreen_input">7.2.4. Touchscreen input</a></td>
    480     <td>MUST</td>
    481     <td></td>
    482     <td>MUST</td>
    483     <td></td>
    484     <td>SHOULD</td>
    485  </tr>
    486  <tr>
    487     <td>Microphone </td>
    488     <td><a href="#7_8_1_microphone">7.8.1. Microphone</a></td>
    489     <td>MUST</td>
    490     <td>SHOULD </td>
    491     <td>MUST</td>
    492     <td>MUST</td>
    493     <td>SHOULD</td>
    494  </tr>
    495  <tr>
    496     <td rowspan="2">Sensors</td>
    497     <td>Accelerometer </td>
    498     <td><a href="#7_3_1_accelerometer">7.3.1 Accelerometer</a></td>
    499     <td>SHOULD</td>
    500     <td></td>
    501     <td>SHOULD</td>
    502     <td></td>
    503     <td>SHOULD</td>
    504  </tr>
    505  <tr>
    506     <td>GPS</td>
    507     <td><a href="#7_3_3_gps">7.3.3. GPS</a></td>
    508     <td>SHOULD</td>
    509     <td></td>
    510     <td></td>
    511     <td>SHOULD</td>
    512     <td></td>
    513  </tr>
    514  <tr>
    515     <td rowspan="5">Connectivity</td>
    516     <td>Wi-Fi</td>
    517     <td><a href="#7_4_2_ieee_802.11">7.4.2. IEEE 802.11</a></td>
    518     <td>SHOULD</td>
    519     <td> MUST</td>
    520     <td></td>
    521     <td>SHOULD</td>
    522     <td>SHOULD</td>
    523  </tr>
    524  <tr>
    525     <td>Wi-Fi Direct</td>
    526     <td><a href="#7_4_2_1_wi-fi-direct">7.4.2.1. Wi-Fi Direct</a></td>
    527     <td>SHOULD</td>
    528     <td>SHOULD</td>
    529     <td></td>
    530     <td></td>
    531     <td>SHOULD</td>
    532  </tr>
    533  <tr>
    534     <td>Bluetooth</td>
    535     <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td>
    536     <td>SHOULD</td>
    537     <td>MUST</td>
    538     <td>MUST</td>
    539     <td>MUST</td>
    540     <td>SHOULD</td>
    541  </tr>
    542  <tr>
    543     <td>Bluetooth Low Energy</td>
    544     <td><a href="#7_4_3_bluetooth">7.4.3. Bluetooth</a></td>
    545     <td>SHOULD</td>
    546     <td>MUST</td>
    547     <td>SHOULD</td>
    548     <td>SHOULD</td>
    549     <td>SHOULD</td>
    550  </tr>
    551  <tr>
    552     <td>USB peripheral/host mode</td>
    553     <td><a href="#7_7_usb">7.7. USB</a></td>
    554     <td>SHOULD</td>
    555     <td></td>
    556     <td></td>
    557     <td>SHOULD</td>
    558     <td>SHOULD</td>
    559  </tr>
    560  <tr>
    561     <td>Output</td>
    562     <td>Speaker and/or Audio output ports</td>
    563     <td><a href="#7_8_2_audio_output">7.8.2. Audio Output</a></td>
    564     <td>MUST</td>
    565     <td>MUST</td>
    566     <td></td>
    567     <td>MUST</td>
    568     <td>MUST</td>
    569  </tr>
    570 </table>
    571 
    572 
    573 <h1 id="3_software">3. Software</h1>
    574 
    575 
    576 <h2 id="3_1_managed_api_compatibility">3.1. Managed API Compatibility</h2>
    577 
    578 
    579 <p>The managed Dalvik bytecode execution environment is the primary vehicle for
    580 Android applications. The Android application programming interface (API) is
    581 the set of Android platform interfaces exposed to applications running in the
    582 managed runtime environment. Device implementations MUST provide complete
    583 implementations, including all documented behaviors, of any documented API
    584 exposed by the Android SDK [<a href="http://developer.android.com/reference/packages.html">Resources, 6</a>] or any API decorated with the &ldquo;@SystemApi&rdquo; marker in the upstream Android
    585 source code. </p>
    586 
    587 <p>Device implementations MUST NOT omit any managed APIs, alter API interfaces or
    588 signatures, deviate from the documented behavior, or include no-ops, except
    589 where specifically allowed by this Compatibility Definition.</p>
    590 
    591 <p>This Compatibility Definition permits some types of hardware for which Android
    592 includes APIs to be omitted by device implementations. In such cases, the APIs
    593 MUST still be present and behave in a reasonable way. See <a href="#7_hardware_compatibility">section 7</a> for specific requirements for this scenario.</p>
    594 
    595 <h2 id="3_2_soft_api_compatibility">3.2. Soft API Compatibility</h2>
    596 
    597 
    598 <p>In addition to the managed APIs from <a href="#3_1_managed_api_compatibility">section 3.1</a>, Android also includes a significant runtime-only &ldquo;soft&rdquo; API, in the form of
    599 such things as intents, permissions, and similar aspects of Android
    600 applications that cannot be enforced at application compile time.</p>
    601 
    602 <h3 id="3_2_1_permissions">3.2.1. Permissions</h3>
    603 
    604 
    605 <p>Device implementers MUST support and enforce all permission constants as
    606 documented by the Permission reference page [<a href="http://developer.android.com/reference/android/Manifest.permission.html">Resources, 7</a>]. Note that <a href="#9_security_model_compatibility">section 9</a> lists additional requirements related to the Android security model.</p>
    607 
    608 <h3 id="3_2_2_build_parameters">3.2.2. Build Parameters</h3>
    609 
    610 
    611 <p>The Android APIs include a number of constants on the android.os.Build class [<a href="http://developer.android.com/reference/android/os/Build.html">Resources, 8</a>] that are intended to describe the current device. To provide consistent,
    612 meaningful values across device implementations, the table below includes
    613 additional restrictions on the formats of these values to which device
    614 implementations MUST conform.</p>
    615 <table>
    616  <tr>
    617     <th>Parameter</th>
    618     <th>Details</th>
    619  </tr>
    620  <tr>
    621     <td>VERSION.RELEASE</td>
    622     <td>The version of the currently-executing Android system, in human-readable
    623 format. This field MUST have one of the string values defined in [<a href="http://source.android.com/compatibility/6.0/versions.html">Resources, 9</a>].</td>
    624  </tr>
    625  <tr>
    626     <td>VERSION.SDK</td>
    627     <td>The version of the currently-executing Android system, in a format accessible
    628 to third-party application code. For Android 6.0, this field MUST have the
    629 integer value 23.</td>
    630  </tr>
    631  <tr>
    632     <td>VERSION.SDK_INT</td>
    633     <td>The version of the currently-executing Android system, in a format accessible
    634 to third-party application code. For Android 6.0, this field MUST have the
    635 integer value 23.</td>
    636  </tr>
    637  <tr>
    638     <td>VERSION.INCREMENTAL</td>
    639     <td>A value chosen by the device implementer designating the specific build of the
    640 currently-executing Android system, in human-readable format. This value MUST
    641 NOT be reused for different builds made available to end users. A typical use
    642 of this field is to indicate which build number or source-control change
    643 identifier was used to generate the build. There are no requirements on the
    644 specific format of this field, except that it MUST NOT be null or the empty
    645 string ("").</td>
    646  </tr>
    647  <tr>
    648     <td>BOARD</td>
    649     <td>A value chosen by the device implementer identifying the specific internal
    650 hardware used by the device, in human-readable format. A possible use of this
    651 field is to indicate the specific revision of the board powering the device.
    652 The value of this field MUST be encodable as 7-bit ASCII and match the regular
    653 expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
    654  </tr>
    655  <tr>
    656     <td>BRAND</td>
    657     <td>A value reflecting the brand name associated with the device as known to the
    658 end users. MUST be in human-readable format and SHOULD represent the
    659 manufacturer of the device or the company brand under which the device is
    660 marketed. The value of this field MUST be encodable as 7-bit ASCII and match
    661 the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
    662  </tr>
    663  <tr>
    664     <td>SUPPORTED_ABIS</td>
    665     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
    666  </tr>
    667  <tr>
    668     <td>SUPPORTED_32_BIT_ABIS</td>
    669     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
    670  </tr>
    671  <tr>
    672     <td>SUPPORTED_64_BIT_ABIS</td>
    673     <td>The name of the second instruction set (CPU type + ABI convention) of native
    674 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
    675  </tr>
    676  <tr>
    677     <td>CPU_ABI</td>
    678     <td>The name of the instruction set (CPU type + ABI convention) of native code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
    679  </tr>
    680  <tr>
    681     <td>CPU_ABI2</td>
    682     <td>The name of the second instruction set (CPU type + ABI convention) of native
    683 code. See <a href="#3_3_native_api_compatibility">section 3.3. Native API Compatibility</a>.</td>
    684  </tr>
    685  <tr>
    686     <td>DEVICE</td>
    687     <td>A value chosen by the device implementer containing the development name or
    688 code name identifying the configuration of the hardware features and industrial
    689 design of the device. The value of this field MUST be encodable as 7-bit ASCII
    690 and match the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
    691  </tr>
    692  <tr>
    693     <td>FINGERPRINT</td>
    694     <td>A string that uniquely identifies this build. It SHOULD be reasonably
    695 human-readable. It MUST follow this template:
    696 <p class="small">$(BRAND)/$(PRODUCT)/<br>
    697 	&nbsp;&nbsp;&nbsp;&nbsp;$(DEVICE):$(VERSION.RELEASE)/$(ID)/$(VERSION.INCREMENTAL):$(TYPE)/$(TAGS)</p>
    698 <p>For example:</p>
    699 <p class="small">acme/myproduct/<br>
    700 	&nbsp;&nbsp;&nbsp;&nbsp;mydevice:6.0/LMYXX/3359:userdebug/test-keys</p>
    701 <p>The fingerprint MUST NOT include whitespace characters. If other fields
    702 included in the template above have whitespace characters, they MUST be
    703 replaced in the build fingerprint with another character, such as the
    704 underscore ("_") character. The value of this field MUST be encodable as 7-bit
    705 ASCII.</p></td>
    706  </tr>
    707  <tr>
    708     <td>HARDWARE</td>
    709     <td>The name of the hardware (from the kernel command line or /proc). It SHOULD be
    710 reasonably human-readable. The value of this field MUST be encodable as 7-bit
    711 ASCII and match the regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;. </td>
    712  </tr>
    713  <tr>
    714     <td>HOST</td>
    715     <td>A string that uniquely identifies the host the build was built on, in
    716 human-readable format. There are no requirements on the specific format of this
    717 field, except that it MUST NOT be null or the empty string ("").</td>
    718  </tr>
    719  <tr>
    720     <td>ID</td>
    721     <td>An identifier chosen by the device implementer to refer to a specific release,
    722 in human-readable format. This field can be the same as
    723 android.os.Build.VERSION.INCREMENTAL, but SHOULD be a value sufficiently
    724 meaningful for end users to distinguish between software builds. The value of
    725 this field MUST be encodable as 7-bit ASCII and match the regular expression &ldquo;^[a-zA-Z0-9._-]+$&rdquo;.</td>
    726  </tr>
    727  <tr>
    728     <td>MANUFACTURER</td>
    729     <td>The trade name of the Original Equipment Manufacturer (OEM) of the product.
    730 There are no requirements on the specific format of this field, except that it
    731 MUST NOT be null or the empty string ("").</td>
    732  </tr>
    733  <tr>
    734     <td>MODEL</td>
    735     <td>A value chosen by the device implementer containing the name of the device as
    736 known to the end user. This SHOULD be the same name under which the device is
    737 marketed and sold to end users. There are no requirements on the specific
    738 format of this field, except that it MUST NOT be null or the empty string ("").</td>
    739  </tr>
    740  <tr>
    741     <td>PRODUCT</td>
    742     <td>A value chosen by the device implementer containing the development name or
    743 code name of the specific product (SKU) that MUST be unique within the same
    744 brand. MUST be human-readable, but is not necessarily intended for view by end
    745 users. The value of this field MUST be encodable as 7-bit ASCII and match the
    746 regular expression &ldquo;^[a-zA-Z0-9_-]+$&rdquo;.</td>
    747  </tr>
    748  <tr>
    749     <td>SERIAL</td>
    750     <td>A hardware serial number, which MUST be available and unique across
    751 devices with the same MODEL and MANUFACTURER. The value of this field MUST
    752 be encodable as 7-bit ASCII and match the regular expression &ldquo;^([a-zA-Z0-9]{6,20})$&rdquo;.</td>
    753  </tr>
    754  <tr>
    755     <td>TAGS</td>
    756     <td>A comma-separated list of tags chosen by the device implementer that further
    757 distinguishes the build. This field MUST have one of the values corresponding
    758 to the three typical Android platform signing configurations: release-keys,
    759 dev-keys, test-keys. </td>
    760  </tr>
    761  <tr>
    762     <td>TIME</td>
    763     <td>A value representing the timestamp of when the build occurred.</td>
    764  </tr>
    765  <tr>
    766     <td>TYPE</td>
    767     <td>A value chosen by the device implementer specifying the runtime configuration
    768 of the build. This field MUST have one of the values corresponding to the three
    769 typical Android runtime configurations: user, userdebug, or eng.</td>
    770  </tr>
    771  <tr>
    772     <td>USER</td>
    773     <td>A name or user ID of the user (or automated user) that generated the build.
    774 There are no requirements on the specific format of this field, except that it
    775 MUST NOT be null or the empty string ("").</td>
    776  </tr>
    777  <tr>
    778     <td>SECURITY_PATCH</td>
    779     <td>An value indicating the security patch level of a build. It MUST signify that the
    780 build includes all security patches issued up through the designated Android Public
    781 Security Bulletin. It MUST be in the format, [YYYY-MM-DD], matching the Public Security
    782 Bulletin's broadcast date, for example [2015-10-01].</td>
    783  </tr>
    784  <tr>
    785     <td>BASE_OS</td>
    786     <td>An value representing the FINGERPRINT parameter of the build that is otherwise
    787       identical to this build except for the patches provided in the Android Public
    788       Security Bulletin. It MUST report the correct value and if such a build does not
    789       exist, report an emtpy string ("").</td>
    790  </tr>
    791 </table>
    792 
    793 
    794 <h3 id="3_2_3_intent_compatibility">3.2.3. Intent Compatibility</h3>
    795 
    796 
    797 <p>Device implementations MUST honor Android&rsquo;s loose-coupling intent system, as
    798 described in the sections below. By&ldquo;honored &rdquo; it is meant that the device
    799 implementer MUST provide an Android Activity or Service that specifies a
    800 matching intent filter that binds to and implements correct behavior for each
    801 specified intent pattern.</p>
    802 
    803 <h4 id="3_2_3_1_core_application_intents">3.2.3.1. Core Application Intents</h4>
    804 
    805 
    806 <p>Android intents allow application components to request functionality from
    807 other Android components. The Android upstream project includes a list of
    808 applications considered core Android applications, which implements several
    809 intent patterns to perform common actions. The core Android applications are:</p>
    810 
    811 <ul>
    812   <li>Desk Clock</li>
    813   <li>Browser</li>
    814   <li>Calendar</li>
    815   <li>Contacts</li>
    816   <li>Gallery</li>
    817   <li>GlobalSearch</li>
    818   <li>Launcher</li>
    819   <li>Music</li>
    820   <li>Settings</li>
    821 </ul>
    822 
    823 <p>Device implementations SHOULD include the core Android applications as
    824 appropriate but MUST include a component implementing the same intent patterns
    825 defined by all the &ldquo;public&rdquo; Activity or Service components of these core
    826 Android applications. Note that Activity or Service components are considered
    827 &ldquo;public&rdquo; when the attribute android:exported is absent or has the value true.</p>
    828 
    829 <h4 id="3_2_3_2_intent_resolution">3.2.3.2. Intent Resolution</h4>
    830 
    831 
    832 <p>As Android is an extensible platform, device implementations MUST allow each
    833 intent pattern referenced in <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>
    834 to be overridden by third-party applications. The upstream Android open source
    835 implementation allows this by default; device implementers MUST NOT attach
    836 special privileges to system applications' use of these intent patterns, or
    837 prevent third-party applications from binding to and assuming control of these
    838 patterns. This prohibition specifically includes but is not limited to
    839 disabling the&ldquo;Chooser&rdquo; user interface that allows the user to select between
    840 multiple applications that all handle the same intent pattern.</p>
    841 
    842 <p>Device implementations MUST provide a user interface for users to modify the default
    843 activity for intents.</p>
    844 
    845 <p>However, device implementations MAY provide default activities for specific URI
    846 patterns (eg. http://play.google.com) when the default activity provides a more
    847 specific attribute for the data URI. For example, an intent filter pattern specifying
    848 the data URI &ldquo;http://www.android.com&rdquo; is more specific than the browser's
    849 core intent pattern for &ldquo;http://&rdquo;.</p>
    850   
    851 <p>Android also includes a mechanism for third-party apps to declare an authoritative
    852 default app linking behavior for certain types of web URI intents [<a
    853 href="https://developer.android.com/training/app-links">Resources, 140</a>]. When such
    854 authoritative declarations are defined in an app's intent filter patterns, device
    855 implementations:</p>
    856 
    857 <ul>
    858 <li>MUST attempt to validate any intent filters by performing the validation steps 
    859 defined in the Digital Asset Links specification [<a
    860 href="https://developers.google.com/digital-asset-links">Resources, 141</a>] as implemented
    861 by the Package Manager in the upstream Android Open Source Project.</li>
    862 <li>MUST attempt validation of the intent filters during the installation of the
    863 application and set all successfully validated UIR intent filters as default app handlers
    864 for their UIRs.</li>
    865 <li>MAY set specific URI intent filters as default app handlers for their URIs, if they
    866 are successfully verified but other candidate URI filters fail verification. If a device
    867 implementation does this, it MUST provide the user appropriate per-URI pattern overrides
    868 in the settings menu.</li>
    869 <li>MUST provide the user with per-app App Links controls in Settings as follows:
    870   <ul>
    871   <li>The user MUST be able to override holistically the default app links behavior for
    872   an app to be: always open, always ask, or never open, which must apply to all candidate
    873   URI intent filters equally.</li>
    874   <li>The user MUST be able to see a list of the candidate URI intent filters.</li>
    875   <li>The device implementation MAY provide the user with the ability to override specific
    876   candidate URI intent filters that were successfully verified, on a per-intent filter basis.
    877   </li>
    878   <li>The device implementation MUST provide users with the ability to view and override
    879   specific candidate URI intent filters if the device implementation lets some candidate
    880   URI intent filters succeed verification while some others can fail.</li>
    881   </ul>
    882 </li>
    883 </ul>
    884 
    885 <h4 id="3_2_3_3_intent_namespaces">3.2.3.3. Intent Namespaces</h4>
    886 
    887 
    888 <p>Device implementations MUST NOT include any Android component that honors any
    889 new intent or broadcast intent patterns using an ACTION, CATEGORY, or other key
    890 string in the android.* or com.android.* namespace. Device implementers MUST
    891 NOT include any Android components that honor any new intent or broadcast
    892 intent patterns using an ACTION, CATEGORY, or other key string in a package
    893 space belonging to another organization. Device implementers MUST NOT alter or
    894 extend any of the intent patterns used by the core apps listed in <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. Device implementations MAY include intent patterns using namespaces clearly
    895 and obviously associated with their own organization. This prohibition is
    896 analogous to that specified for Java language classes in <a href="#3_6_api_namespaces">section 3.6</a>.</p>
    897 
    898 <h4 id="3_2_3_4_broadcast_intents">3.2.3.4. Broadcast Intents</h4>
    899 
    900 
    901 <p>Third-party applications rely on the platform to broadcast certain intents to
    902 notify them of changes in the hardware or software environment.
    903 Android-compatible devices MUST broadcast the public broadcast intents in
    904 response to appropriate system events. Broadcast intents are described in the
    905 SDK documentation.</p>
    906 
    907 <h4 id="3_2_3_5_default_app_settings">3.2.3.5. Default App Settings</h4>
    908 
    909 
    910 <p>Android includes settings that provide users an easy way to select their
    911 default applications, for example for Home screen or SMS. Where it makes sense,
    912 device implementations MUST provide a similar settings menu and be compatible
    913 with the intent filter pattern and API methods described in the SDK
    914 documentation as below.</p>
    915 
    916 <p>Device implementations:</p>
    917 
    918 <ul>
    919   <li>MUST honor the android.settings.HOME_SETTINGS intent to show a default app
    920 settings menu for Home Screen, if the device implementation reports
    921 android.software.home_screen [<a href="http://developer.android.com/reference/android/provider/Settings.html">Resources, 10</a>]</li>
    922   <li>MUST provide a settings menu that will call the
    923 android.provider.Telephony.ACTION_CHANGE_DEFAULT intent to show a dialog to
    924 change the default SMS application, if the device implementation reports
    925 android.hardware.telephony [<a href="http://developer.android.com/reference/android/provider/Telephony.Sms.Intents.html">Resources, 11</a>]</li>
    926   <li>MUST honor the android.settings.NFC_PAYMENT_SETTINGS intent to show a default
    927 app settings menu for Tap and Pay, if the device implementation reports
    928 android.hardware.nfc.hce [<a href="http://developer.android.com/reference/android/provider/Settings.html">Resources, 10</a>]</li>
    929 </ul>
    930 
    931 <h2 id="3_3_native_api_compatibility">3.3. Native API Compatibility</h2>
    932 
    933 
    934 <h3 id="3_3_1_application_binary_interfaces">3.3.1. Application Binary Interfaces</h3>
    935 
    936 
    937 <p>Managed Dalvik bytecode can call into native code provided in the application
    938 .apk file as an ELF .so file compiled for the appropriate device hardware
    939 architecture. As native code is highly dependent on the underlying processor
    940 technology, Android defines a number of Application Binary Interfaces (ABIs) in
    941 the Android NDK. Device implementations MUST be compatible with one or more
    942 defined ABIs, and MUST implement compatibility with the Android NDK, as below.</p>
    943 
    944 <p>If a device implementation includes support for an Android ABI, it:</p>
    945 
    946 <ul>
    947   <li>MUST include support for code running in the managed environment to call into
    948 native code, using the standard Java Native Interface (JNI) semantics</li>
    949   <li>MUST be source-compatible (i.e. header compatible) and binary-compatible (for
    950 the ABI) with each required library in the list below</li>
    951   <li>MUST support the equivalent 32-bit ABI if any 64-bit ABI is supported</li>
    952   <li>MUST accurately report the native Application Binary Interface (ABI) supported
    953 by the device, via the android.os.Build.SUPPORTED_ABIS,
    954 android.os.Build.SUPPORTED_32_BIT_ABIS, and
    955 android.os.Build.SUPPORTED_64_BIT_ABIS parameters, each a comma separated list
    956 of ABIs ordered from the most to the least preferred one</li>
    957   <li>MUST report, via the above parameters, only those ABIs documented and
    958 described in the latest version of the Android NDK ABI Management documentation
    959 [<a href="https://developer.android.com/ndk/guides/abis.html">Resources, 12</a>],
    960 and MUST include support for the Advanced SIMD (a.k.a. NEON)
    961 [<a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html">Resources, 13</a>]
    962 extension
    963   </li>
    964   <li>SHOULD be built using the source code and header files available in the
    965 upstream Android Open Source Project</li>
    966 </ul>
    967 
    968 <p>The following native code APIs MUST be available to apps that include native
    969 code:</p>
    970 
    971 <ul>
    972   <li>libc (C library)</li>
    973   <li>libm (math library)</li>
    974   <li>Minimal support for C++</li>
    975   <li>JNI interface</li>
    976   <li>liblog (Android logging)</li>
    977   <li>libz (Zlib compression)</li>
    978   <li>libdl (dynamic linker)</li>
    979   <li>libGLESv1_CM.so (OpenGL ES 1.x)</li>
    980   <li>libGLESv2.so (OpenGL ES 2.0)</li>
    981   <li>libGLESv3.so (OpenGL ES 3.x)</li>
    982   <li>libEGL.so (native OpenGL surface management)</li>
    983   <li>libjnigraphics.so</li>
    984   <li>libOpenSLES.so (OpenSL ES 1.0.1 audio support)</li>
    985   <li>libOpenMAXAL.so (OpenMAX AL 1.0.1 support)</li>
    986   <li>libandroid.so (native Android activity support)</li>
    987   <li>libmediandk.so (native media APIs support)</li>
    988   <li>Support for OpenGL, as described below</li>
    989 </ul>
    990 
    991 <p>Note that future releases of the Android NDK may introduce support for
    992 additional ABIs. If a device implementation is not compatible with an existing
    993 predefined ABI, it MUST NOT report support for any ABIs at all.</p>
    994 
    995 <p>Note that device implementations MUST include libGLESv3.so and it MUST symlink
    996 (symbolic link) to libGLESv2.so. in turn, MUST export all the OpenGL ES 3.1 and
    997 Android Extension Pack [<a href="http://developer.android.com/guide/topics/graphics/opengl.html#aep">Resources, 14</a>] function symbols as defined in the NDK release android-21. Although all the
    998 symbols must be present, only the corresponding functions for OpenGL ES
    999 versions and extensions actually supported by the device must be fully
   1000 implemented.</p>
   1001 
   1002 <p>Device implementations MUST NOT include a native library with the
   1003 name libvulkan.so.</p>
   1004 
   1005 <p>Native code compatibility is challenging. For this reason, device implementers
   1006 are <strong>STRONGLY RECOMMENDED</strong> to use the implementations of the libraries listed above from the upstream
   1007 Android Open Source Project. </p>
   1008 
   1009 <h3 id="3_3_2_32-bit_arm_native_code_compatibility">
   1010 3.3.2. 32-bit ARM Native Code Compatibility
   1011 </h3>
   1012 
   1013 <p>The ARMv8 architecture deprecates several CPU operations, including some
   1014 operations used in existing native code.  On 64-bit ARM devices, the following
   1015 deprecated operations MUST remain available to 32-bit native ARM code, either
   1016 through native CPU support or through software emulation:</p>
   1017 
   1018 <ul>
   1019 <li>SWP and SWPB instructions</li>
   1020 <li>SETEND instruction</li>
   1021 <li>CP15ISB, CP15DSB, and CP15DMB barrier operations</li>
   1022 </ul>
   1023 
   1024 <p>Legacy versions of the Android NDK used /proc/cpuinfo to discover CPU features
   1025 from 32-bit ARM native code. For compatibility with applications built using this
   1026 NDK, devices MUST include the following lines in /proc/cpuinfo when it is read
   1027 by 32-bit ARM applications:</p>
   1028 
   1029 <ul>
   1030 <li>&quot;Features: &quot;, followed by a list of any optional ARMv7 CPU features
   1031 supported by the device</li>
   1032 <li>&quot;CPU architecture: &quot;, followed by an integer describing the device's
   1033 highest supported ARM architecture (e.g., &quot;8&quot; for ARMv8 devices)</li>
   1034 </ul>
   1035 
   1036 <p>These requirements only apply when /proc/cpuinfo is read by 32-bit ARM
   1037 applications. Devices SHOULD not alter /proc/cpuinfo when read by 64-bit ARM or
   1038 non-ARM applications.</p>
   1039 
   1040 <h2 id="3_4_web_compatibility">3.4. Web Compatibility</h2>
   1041 
   1042 
   1043 <h3 id="3_4_1_webview_compatibility">3.4.1. WebView Compatibility</h3>
   1044 
   1045 <div class="note">
   1046 <p>Android Watch devices MAY, but all other device implementations MUST provide
   1047 a complete implementation of the android.webkit.Webview API.</p>
   1048 </div>
   1049 
   1050 
   1051 <p>The platform feature android.software.webview MUST be reported on any device
   1052 that provides a complete implementation of the android.webkit.WebView API, and
   1053 MUST NOT be reported on devices without a complete implementation of the API.
   1054 The Android Open Source implementation uses code from the Chromium Project to
   1055 implement the android.webkit.WebView [<a href="http://developer.android.com/reference/android/webkit/WebView.html">Resources, 15</a>]. Because it is not feasible to develop a comprehensive test suite for a web
   1056 rendering system, device implementers MUST use the specific upstream build of
   1057 Chromium in the WebView implementation. Specifically:</p>
   1058 
   1059 <ul>
   1060   <li>Device android.webkit.WebView implementations MUST be based on the Chromium
   1061 build from the upstream Android Open Source Project for Android 6.0. This build
   1062 includes a specific set of functionality and security fixes for the WebView [<a href="http://www.chromium.org/">Resources, 16</a>].</li>
   1063   <li>The user agent string reported by the WebView MUST be in this format:
   1064 <p>Mozilla/5.0 (Linux; Android $(VERSION); $(MODEL) Build/$(BUILD); wv)
   1065 AppleWebKit/537.36 (KHTML, like Gecko) Version/4.0 $(CHROMIUM_VER) Mobile
   1066 Safari/537.36</p>
   1067   <ul>
   1068     <li>The value of the $(VERSION) string MUST be the same as the value for
   1069 android.os.Build.VERSION.RELEASE.</li>
   1070     <li>The value of the $(MODEL) string MUST be the same as the value for
   1071 android.os.Build.MODEL.</li>
   1072     <li>The value of the $(BUILD) string MUST be the same as the value for
   1073 android.os.Build.ID.</li>
   1074     <li>The value of the $(CHROMIUM_VER) string MUST be the version of Chromium in the
   1075 upstream Android Open Source Project.</li>
   1076     <li>Device implementations MAY omit Mobile in the user agent string.</li>
   1077   </ul></li></ul>
   1078 
   1079 <p>The WebView component SHOULD include support for as many HTML5 features as
   1080 possible and if it supports the feature SHOULD conform to the HTML5
   1081 specification [<a href="http://html.spec.whatwg.org/multipage/">Resources, 17</a>].</p>
   1082 
   1083 <h3 id="3_4_2_browser_compatibility">3.4.2. Browser Compatibility</h3>
   1084 
   1085 <div class="note">
   1086 <p>Android Television, Watch, and Android Automotive implementations MAY omit a
   1087 browser application, but MUST support the public intent patterns as described in
   1088 <a href="#3_2_3_1_core_application_intents">section 3.2.3.1</a>. All other types
   1089 of device implementations MUST include a standalone Browser application for
   1090 general user web browsing.</p>
   1091 </div>
   1092 
   1093 <p>The standalone Browser MAY be based on a browser technology other than WebKit.
   1094 However, even if an alternate Browser application is used, the
   1095 android.webkit.WebView component provided to third-party applications MUST be
   1096 based on WebKit, as described in <a href="#3_4_1_webview_compatibility">section 3.4.1</a>.</p>
   1097 
   1098 <p>Implementations MAY ship a custom user agent string in the standalone Browser
   1099 application.</p>
   1100 
   1101 <p>The standalone Browser application (whether based on the upstream WebKit
   1102 Browser application or a third-party replacement) SHOULD include support for as
   1103 much of HTML5 [<a href="http://html.spec.whatwg.org/multipage/">Resources, 17</a>] as possible. Minimally, device implementations MUST support each of these
   1104 APIs associated with HTML5:</p>
   1105 
   1106 <ul>
   1107   <li>application cache/offline operation [<a href="http://www.w3.org/html/wg/drafts/html/master/browsers.html#offline">Resources, 18</a>]</li>
   1108   <li>the &#60;video&#62; tag [<a href="http://www.w3.org/html/wg/drafts/html/master/semantics.html#video">Resources, 19</a>]</li>
   1109   <li>geolocation [<a href="http://www.w3.org/TR/geolocation-API/">Resources, 20</a>]</li>
   1110 </ul>
   1111 
   1112 <p>Additionally, device implementations MUST support the HTML5/W3C webstorage API
   1113 [<a href="http://www.w3.org/TR/webstorage/">Resources, 21</a>], and SHOULD support the HTML5/W3C IndexedDB API [<a href="http://www.w3.org/TR/IndexedDB/">Resources, 22</a>]. Note that as the web development standards bodies are transitioning to favor
   1114 IndexedDB over webstorage, IndexedDB is expected to become a required component
   1115 in a future version of Android.</p>
   1116 
   1117 <h2 id="3_5_api_behavioral_compatibility">3.5. API Behavioral Compatibility</h2>
   1118 
   1119 
   1120 <p>The behaviors of each of the API types (managed, soft, native, and web) must be
   1121 consistent with the preferred implementation of the upstream Android Open
   1122 Source Project [<a href="http://source.android.com/">Resources, 2</a>]. Some specific areas of compatibility are:</p>
   1123 
   1124 <ul>
   1125   <li>Devices MUST NOT change the behavior or semantics of a standard intent.</li>
   1126   <li>Devices MUST NOT alter the lifecycle or lifecycle semantics of a particular
   1127 type of system component (such as Service, Activity, ContentProvider, etc.).</li>
   1128   <li>Devices MUST NOT change the semantics of a standard permission.</li>
   1129 </ul>
   1130 
   1131 <p>The above list is not comprehensive. The Compatibility Test Suite (CTS) tests
   1132 significant portions of the platform for behavioral compatibility, but not all.
   1133 It is the responsibility of the implementer to ensure behavioral compatibility
   1134 with the Android Open Source Project. For this reason, device implementers
   1135 SHOULD use the source code available via the Android Open Source Project where
   1136 possible, rather than re-implement significant parts of the system.</p>
   1137 
   1138 <h2 id="3_6_api_namespaces">3.6. API Namespaces</h2>
   1139 
   1140 
   1141 <p>Android follows the package and class namespace conventions defined by the Java
   1142 programming language. To ensure compatibility with third-party applications,
   1143 device implementers MUST NOT make any prohibited modifications (see below) to
   1144 these package namespaces:</p>
   1145 
   1146 <ul>
   1147   <li>java.*</li>
   1148   <li>javax.*</li>
   1149   <li>sun.*</li>
   1150   <li>android.*</li>
   1151   <li>com.android.*</li>
   1152 </ul>
   1153 
   1154 <p><strong>Prohibited modifications include</strong>:</p>
   1155 
   1156 <ul>
   1157   <li>Device implementations MUST NOT modify the publicly exposed APIs on the Android
   1158 platform by changing any method or class signatures, or by removing classes or
   1159 class fields.</li>
   1160   <li>Device implementers MAY modify the underlying implementation of the APIs, but
   1161 such modifications MUST NOT impact the stated behavior and Java-language
   1162 signature of any publicly exposed APIs.</li>
   1163   <li>Device implementers MUST NOT add any publicly exposed elements (such as classes
   1164 or interfaces, or fields or methods to existing classes or interfaces) to the
   1165 APIs above.</li>
   1166 </ul>
   1167 
   1168 <p>A &ldquo;publicly exposed element&rdquo; is any construct which is not decorated with the&ldquo;@hide&rdquo; marker as used in the upstream Android source code. In other words,
   1169 device implementers MUST NOT expose new APIs or alter existing APIs in the
   1170 namespaces noted above. Device implementers MAY make internal-only
   1171 modifications, but those modifications MUST NOT be advertised or otherwise
   1172 exposed to developers.</p>
   1173 
   1174 <p>Device implementers MAY add custom APIs, but any such APIs MUST NOT be in a
   1175 namespace owned by or referring to another organization. For instance, device
   1176 implementers MUST NOT add APIs to the com.google.* or similar namespace: only
   1177 Google may do so. Similarly, Google MUST NOT add APIs to other companies'
   1178 namespaces. Additionally, if a device implementation includes custom APIs
   1179 outside the standard Android namespace, those APIs MUST be packaged in an
   1180 Android shared library so that only apps that explicitly use them (via the
   1181 lt;uses-librarygt; mechanism) are affected by the increased memory usage of such
   1182 APIs.</p>
   1183 
   1184 <p>If a device implementer proposes to improve one of the package namespaces above
   1185 (such as by adding useful new functionality to an existing API, or adding a new
   1186 API), the implementer SHOULD visit <a href="http://source.android.com/">source.android.com</a> and begin the process for contributing changes and code, according to the
   1187 information on that site.</p>
   1188 
   1189 <p>Note that the restrictions above correspond to standard conventions for naming
   1190 APIs in the Java programming language; this section simply aims to reinforce
   1191 those conventions and make them binding through inclusion in this Compatibility
   1192 Definition.</p>
   1193 
   1194 <h2 id="3_7_runtime_compatibility">3.7. Runtime Compatibility</h2>
   1195 
   1196 
   1197 <p>Device implementations MUST support the full Dalvik Executable (DEX) format and
   1198 Dalvik bytecode specification and semantics [<a href="https://android.googlesource.com/platform/dalvik/">Resources, 23</a>]. Device implementers SHOULD use ART, the reference upstream implementation of
   1199 the Dalvik Executable Format, and the reference implementation&rsquo;s package
   1200 management system.</p>
   1201 
   1202 <p>Device implementations MUST configure Dalvik runtimes to allocate memory in
   1203 accordance with the upstream Android platform, and as specified by the
   1204 following table. (See <a href="#7_1_1_screen_configuration">section 7.1.1</a> for screen size and screen density definitions.)</p>
   1205 
   1206 <p>Note that memory values specified below are considered minimum values and
   1207 device implementations MAY allocate more memory per application.</p>
   1208 
   1209 <table>
   1210  <tr>
   1211     <th>Screen Layout</th>
   1212     <th>Screen Density</th>
   1213     <th>Minimum Application Memory</th>
   1214  </tr>
   1215  <tr>
   1216     <td rowspan="12">Android Watch</td>
   1217     <td>120 dpi (ldpi)</td>
   1218     <td rowspan="3">32MB</td>
   1219  </tr>
   1220  <tr>
   1221     <td>160 dpi (mdpi)</td>
   1222  </tr>
   1223  <tr>
   1224     <td>213 dpi (tvdpi)</td>
   1225  </tr>
   1226  <tr>
   1227     <td>240 dpi (hdpi)</td>
   1228     <td rowspan="2">36MB</td>
   1229  </tr>
   1230  <tr>
   1231     <td>280 dpi (280dpi)</td>
   1232  </tr>
   1233  <tr>
   1234     <td>320 dpi (xhdpi)</td>
   1235     <td rowspan="2">48MB</td>
   1236  </tr>
   1237  <tr>
   1238     <td>360 dpi (360dpi)</td>
   1239  </tr>
   1240  <tr>
   1241     <td>400 dpi (400dpi)</td>
   1242     <td>56MB</td>
   1243  </tr>
   1244  <tr>
   1245     <td>420 dpi (420dpi)</td>
   1246     <td>64MB</td>
   1247  </tr>
   1248  <tr>
   1249     <td>480 dpi (xxhdpi)</td>
   1250     <td>88MB</td>
   1251  </tr>
   1252  <tr>
   1253     <td>560 dpi (560dpi)</td>
   1254     <td>112MB</td>
   1255  </tr>
   1256  <tr>
   1257     <td>640 dpi (xxxhdpi)</td>
   1258     <td>154MB</td>
   1259  </tr>
   1260  <tr>
   1261     <td rowspan="12">small/normal</td>
   1262     <td>120 dpi (ldpi)</td>
   1263     <td rowspan="2">32MB</td>
   1264  </tr>
   1265  <tr>
   1266     <td>160 dpi (mdpi)</td>
   1267  </tr>
   1268  <tr>
   1269     <td>213 dpi (tvdpi)</td>
   1270     <td rowspan="3">48MB</td>
   1271  </tr>
   1272  <tr>
   1273     <td>240 dpi (hdpi)</td>
   1274  </tr>
   1275  <tr>
   1276     <td>280 dpi (280dpi)</td>
   1277  </tr>
   1278  <tr>
   1279     <td>320 dpi (xhdpi)</td>
   1280     <td rowspan="2">80MB</td>
   1281  </tr>
   1282  <tr>
   1283     <td>360 dpi (360dpi)</td>
   1284  </tr>
   1285  <tr>
   1286     <td>400 dpi (400dpi)</td>
   1287     <td>96MB</td>
   1288  </tr>
   1289  <tr>
   1290     <td>420 dpi (420dpi)</td>
   1291     <td>112MB</td>
   1292  </tr>
   1293  <tr>
   1294     <td>480 dpi (xxhdpi)</td>
   1295     <td>128MB</td>
   1296  </tr>
   1297  <tr>
   1298     <td>560 dpi (560dpi)</td>
   1299     <td>192MB</td>
   1300  </tr>
   1301  <tr>
   1302     <td>640 dpi (xxxhdpi)</td>
   1303     <td>256MB</td>
   1304  </tr>
   1305  <tr>
   1306     <td rowspan="12">large</td>
   1307     <td>120 dpi (ldpi)</td>
   1308     <td>32MB</td>
   1309  </tr>
   1310  <tr>
   1311     <td>160 dpi (mdpi)</td>
   1312     <td>48MB</td>
   1313  </tr>
   1314  <tr>
   1315     <td>213 dpi (tvdpi)</td>
   1316     <td rowspan="2">80MB</td>
   1317  </tr>
   1318  <tr>
   1319     <td>240 dpi (hdpi)</td>
   1320  </tr>
   1321  <tr>
   1322     <td>280 dpi (280dpi)</td>
   1323     <td>96MB</td>
   1324  </tr>
   1325  <tr>
   1326     <td>320 dpi (xhdpi)</td>
   1327     <td>128MB</td>
   1328  </tr>
   1329  <tr>
   1330     <td>360 dpi (360dpi)</td>
   1331     <td>160MB</td>
   1332  </tr>
   1333  <tr>
   1334     <td>400 dpi (400dpi)</td>
   1335     <td>192MB</td>
   1336  </tr>
   1337  <tr>
   1338     <td>420 dpi (420dpi)</td>
   1339     <td>228MB</td>
   1340  </tr>
   1341  <tr>
   1342     <td>480 dpi (xxhdpi)</td>
   1343     <td>256MB</td>
   1344  </tr>
   1345  <tr>
   1346     <td>560 dpi (560dpi)</td>
   1347     <td>384MB</td>
   1348  </tr>
   1349  <tr>
   1350     <td>640 dpi (xxxhdpi)</td>
   1351     <td>512MB</td>
   1352  </tr>
   1353  <tr>
   1354     <td rowspan="12">xlarge</td>
   1355     <td>120 dpi (ldpi)</td>
   1356     <td>48MB</td>
   1357  </tr>
   1358  <tr>
   1359     <td>160 dpi (mdpi)</td>
   1360     <td>80MB</td>
   1361  </tr>
   1362  <tr>
   1363     <td>213 dpi (tvdpi)</td>
   1364     <td rowspan="2">96MB</td>
   1365  </tr>
   1366  <tr>
   1367     <td>240 dpi (hdpi)</td>
   1368  </tr>
   1369  <tr>
   1370     <td>280 dpi (280dpi)</td>
   1371     <td>144MB</td>
   1372  </tr>
   1373  <tr>
   1374     <td>320 dpi (xhdpi)</td>
   1375     <td>192MB</td>
   1376  </tr>
   1377  <tr>
   1378     <td>360 dpi (360dpi)</td>
   1379     <td>240MB</td>
   1380  </tr>
   1381  <tr>
   1382     <td>400 dpi (400dpi)</td>
   1383     <td>288MB</td>
   1384  </tr>
   1385  <tr>
   1386     <td>420 dpi (420dpi)</td>
   1387     <td>336MB</td>
   1388  </tr>
   1389  <tr>
   1390     <td>480 dpi (xxhdpi)</td>
   1391     <td>384MB</td>
   1392  </tr>
   1393  <tr>
   1394     <td>560 dpi (560dpi)</td>
   1395     <td>576MB</td>
   1396  </tr>
   1397  <tr>
   1398     <td>640 dpi (xxxhdpi)</td>
   1399     <td>768MB</td>
   1400  </tr>
   1401 </table>
   1402 
   1403 
   1404 <h2 id="3_8_user_interface_compatibility">3.8. User Interface Compatibility</h2>
   1405 
   1406 
   1407 <h3 id="3_8_1_launcher_home_screen">3.8.1. Launcher (Home Screen)</h3>
   1408 
   1409 
   1410 <p>Android includes a launcher application (home screen) and support for
   1411 third-party applications to replace the device launcher (home screen). Device
   1412 implementations that allow third-party applications to replace the device home
   1413 screen MUST declare the platform feature android.software.home_screen.</p>
   1414 
   1415 <h3 id="3_8_2_widgets">3.8.2. Widgets</h3>
   1416 
   1417 <div class="note">
   1418 <p>Widgets are optional for all Android device implementations, but SHOULD be
   1419 supported on Android Handheld devices.</p>
   1420 </div>
   1421 
   1422 
   1423 <p>Android defines a component type and corresponding API and lifecycle that
   1424 allows applications to expose an &ldquo;AppWidget&rdquo; to the end user [<a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">Resources, 24</a>] a feature that is STRONGLY RECOMMENDED to be supported on Handheld Device
   1425 implementations. Device implementations that support embedding widgets on the
   1426 home screen MUST meet the following requirements and declare support for
   1427 platform feature android.software.app_widgets.</p>
   1428 
   1429 <ul>
   1430   <li>Device launchers MUST include built-in support for AppWidgets, and expose user
   1431 interface affordances to add, configure, view, and remove AppWidgets directly
   1432 within the Launcher.</li>
   1433   <li>Device implementations MUST be capable of rendering widgets that are 4 x 4 in
   1434 the standard grid size. See the App Widget Design Guidelines in the Android SDK
   1435 documentation [<a href="http://developer.android.com/guide/practices/ui_guidelines/widget_design.html">Resources, 24</a>] for details.</li>
   1436   <li>Device implementations that include support for lock screen MAY support
   1437 application widgets on the lock screen.</li>
   1438 </ul>
   1439 
   1440 <h3 id="3_8_3_notifications">3.8.3. Notifications</h3>
   1441 
   1442 
   1443 <p>Android includes APIs that allow developers to notify users of notable events [<a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">Resources, 25</a>], using hardware and software features of the device.</p>
   1444 
   1445 <p>Some APIs allow applications to perform notifications or attract attention
   1446 using hardware&#8212;specifically sound, vibration, and light. Device implementations
   1447 MUST support notifications that use hardware features, as described in the SDK
   1448 documentation, and to the extent possible with the device implementation
   1449 hardware. For instance, if a device implementation includes a vibrator, it MUST
   1450 correctly implement the vibration APIs. If a device implementation lacks
   1451 hardware, the corresponding APIs MUST be implemented as no-ops. This behavior
   1452 is further detailed in <a href="#7_hardware_compatibility">section 7</a>.</p>
   1453 
   1454 <p>Additionally, the implementation MUST correctly render all resources (icons, animation files
   1455 etc.) provided for in the APIs
   1456 [<a href="https://developer.android.com/guide/topics/resources/available-resources.html">Resources, 26</a>],
   1457 or in the Status/System Bar icon style guide
   1458 [<a href="http://developer.android.com/design/style/iconography.html">Resources, 27</a>],
   1459 which in the case of an Android Television device includes the possibility to not display the
   1460 notifications. Device implementers MAY provide an alternative user experience for
   1461 notifications than that provided by the reference Android Open Source
   1462 implementation; however, such alternative notification systems MUST support
   1463 existing notification resources, as above. </p>
   1464 
   1465 <p>Android includes support for various notifications, such as:</p>
   1466 
   1467 <ul>
   1468   <li><strong>Rich notifications</strong>. Interactive Views for ongoing notifications.</li>
   1469   <li><strong>Heads-up notifications</strong>. Interactive Views users can act on or dismiss without leaving the current app.</li>
   1470   <li><strong>Lockscreen notifications</strong>. Notifications shown over a lock screen with granular control on visibility.</li>
   1471 </ul>
   1472 
   1473 <p>Android device implementations, when such notifications are made visible, MUST properly execute
   1474 Rich and Heads-up notifications and include the title/name, icon, text as documented in the Android
   1475 APIs [<a href="https://developer.android.com/design/patterns/notifications.html">Resources, 28</a>].
   1476 </p>
   1477 
   1478 <p>Android includes Notification Listener Service APIs that allow apps (once
   1479 explicitly enabled by the user) to receive a copy of all notifications as they
   1480 are posted or updated. Device implementations MUST correctly and promptly send
   1481 notifications in their entirety to all such installed and user-enabled listener
   1482 services, including any and all metadata attached to the Notification object.</p>
   1483 
   1484 <h3 id="3_8_4_search">3.8.4. Search</h3>
   1485 
   1486 
   1487 <p>Android includes APIs [<a href="http://developer.android.com/reference/android/app/SearchManager.html">Resources, 29</a>] that allow developers to incorporate search into their applications, and
   1488 expose their application&rsquo;s data into the global system search. Generally
   1489 speaking, this functionality consists of a single, system-wide user interface
   1490 that allows users to enter queries, displays suggestions as users type, and
   1491 displays results. The Android APIs allow developers to reuse this interface to
   1492 provide search within their own apps, and allow developers to supply results to
   1493 the common global search user interface.</p>
   1494 
   1495 <p>Android device implementations SHOULD include global search, a single, shared,
   1496 system-wide search user interface capable of real-time suggestions in response
   1497 to user input. Device implementations SHOULD implement the APIs that allow
   1498 developers to reuse this user interface to provide search within their own
   1499 applications. Device implementations that implement the global search interface
   1500 MUST implement the APIs that allow third-party applications to add suggestions
   1501 to the search box when it is run in global search mode. If no third-party
   1502 applications are installed that make use of this functionality, the default
   1503 behavior SHOULD be to display web search engine results and suggestions.</p>
   1504 
   1505 <p>Android device implementations SHOULD implement an assistant on the device
   1506 to handle the Assist action [<a
   1507 href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">Resources,
   1508 30</a>].</p>
   1509 
   1510 <p>Android also includes the Assist APIs to allow applications to elect how much
   1511 information of the current context is shared with the assistant on the device [<a
   1512 href="https://developer.android.com/reference/android/app/assist/package-summary.html">Resources,
   1513 31</a>]. Device implementations supporting the Assist action MUST indicate clearly to
   1514 the end user when the the context is shared by displaying a white light around
   1515 the edges of the screen. To ensure clear visibility to the end user, the indication MUST
   1516 meet or exceed the duration and brightness of the Android Open Source Project
   1517 implementation.</p>
   1518 
   1519 <h3 id="3_8_5_toasts">3.8.5. Toasts</h3>
   1520 
   1521 
   1522 <p>Applications can use the &ldquo;Toast&rdquo; API to display short non-modal strings to the
   1523 end user, that disappear after a brief period of time [<a href="http://developer.android.com/reference/android/widget/Toast.html">Resources, 32</a>]. Device implementations MUST display Toasts from applications to end users in
   1524 some high-visibility manner.</p>
   1525 
   1526 <h3 id="3_8_6_themes">3.8.6. Themes</h3>
   1527 
   1528 
   1529 <p>Android provides &ldquo;themes&rdquo; as a mechanism for applications to apply styles
   1530 across an entire Activity or application.</p>
   1531 
   1532 <p>Android includes a &ldquo;Holo&rdquo; theme family as a set of defined styles for
   1533 application developers to use if they want to match the Holo theme look and
   1534 feel as defined by the Android SDK [<a href="http://developer.android.com/guide/topics/ui/themes.html">Resources, 33</a>]. Device implementations MUST NOT alter any of the Holo theme attributes
   1535 exposed to applications [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 34</a>].</p>
   1536 
   1537 <p>Android includes a &ldquo;Material&rdquo; theme family as a set of defined styles for
   1538 application developers to use if they want to match the design theme&rsquo;s look and
   1539 feel across the wide variety of different Android device types. Device
   1540 implementations MUST support the &ldquo;Material&rdquo; theme family and MUST NOT alter any
   1541 of the Material theme attributes or their assets exposed to applications [<a href="http://developer.android.com/reference/android/R.style.html#Theme_Material">Resources, 35</a>].</p>
   1542 
   1543 <p>Android also includes a &ldquo;Device Default&rdquo; theme family as a set of defined
   1544 styles for application developers to use if they want to match the look and
   1545 feel of the device theme as defined by the device implementer. Device
   1546 implementations MAY modify the Device Default theme attributes exposed to
   1547 applications [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 34</a>].</p>
   1548 
   1549 <p>Android supports a variant theme with translucent system bars, which allows
   1550 application developers to fill the area behind the status and navigation bar
   1551 with their app content. To enable a consistent developer experience in this
   1552 configuration, it is important the status bar icon style is maintained across
   1553 different device implementations. Therefore, Android device implementations
   1554 MUST use white for system status icons (such as signal strength and battery
   1555 level) and notifications issued by the system, unless the icon is indicating a
   1556 problematic status or an app requests a light status bar using the
   1557 SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag. When an app requests a light status bar,
   1558 Android device implementations MUST change the color of the system status icons
   1559 to black [<a href="http://developer.android.com/reference/android/R.style.html">Resources, 34</a>].</p>
   1560 
   1561 <h3 id="3_8_7_live_wallpapers">3.8.7. Live Wallpapers</h3>
   1562 
   1563 
   1564 <p>Android defines a component type and corresponding API and lifecycle that
   1565 allows applications to expose one or more &ldquo;Live Wallpapers&rdquo; to the end user [<a href="http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html">Resources, 36</a>]. Live wallpapers are animations, patterns, or similar images with limited
   1566 input capabilities that display as a wallpaper, behind other applications.</p>
   1567 
   1568 <p>Hardware is considered capable of reliably running live wallpapers if it can
   1569 run all live wallpapers, with no limitations on functionality, at a reasonable
   1570 frame rate with no adverse effects on other applications. If limitations in the
   1571 hardware cause wallpapers and/or applications to crash, malfunction, consume
   1572 excessive CPU or battery power, or run at unacceptably low frame rates, the
   1573 hardware is considered incapable of running live wallpaper. As an example, some
   1574 live wallpapers may use an OpenGL 2.0 or 3.x context to render their content.
   1575 Live wallpaper will not run reliably on hardware that does not support multiple
   1576 OpenGL contexts because the live wallpaper use of an OpenGL context may
   1577 conflict with other applications that also use an OpenGL context.</p>
   1578 
   1579 <p>Device implementations capable of running live wallpapers reliably as described
   1580 above SHOULD implement live wallpapers, and when implemented MUST report the
   1581 platform feature flag android.software.live_wallpaper.</p>
   1582 
   1583 <h3 id="3_8_8_activity_switching">3.8.8. Activity Switching</h3>
   1584 
   1585 <div class="note">
   1586 <p>As the Recent function navigation key is OPTIONAL, the requirements to
   1587 implement the overview screen is OPTIONAL for Android Television devices and
   1588 Android Watch devices.</p>
   1589 </div>
   1590 
   1591 
   1592 <p>The upstream Android source code includes the overview screen [<a href="http://developer.android.com/guide/components/recents.html">Resources, 37</a>], a system-level user interface for task switching and displaying recently
   1593 accessed activities and tasks using a thumbnail image of the application&rsquo;s
   1594 graphical state at the moment the user last left the application. Device
   1595 implementations including the recents function navigation key as detailed in <a href="#7_2_3_navigation_keys">section 7.2.3</a>, MAY alter the interface but MUST meet the following requirements:</p>
   1596 
   1597 <ul>
   1598   <li>MUST display affiliated recents as a group that moves together.</li>
   1599   <li>MUST support at least up to 20 displayed activities.</li>
   1600   <li>MUST at least display the title of 4 activities at a time.</li>
   1601   <li>SHOULD display highlight color, icon, screen title in recents.</li>
   1602   <li>MUST implement the screen pinning behavior [<a href="http://developer.android.com/about/versions/android-5.0.html#ScreenPinning">Resources, 38</a>] and provide the user with a settings menu to toggle the feature.</li>
   1603   <li>SHOULD display a closing affordance ("x") but MAY delay this until user
   1604 interacts with screens.</li>
   1605 </ul>
   1606 
   1607 <p>Device implementations are STRONGLY RECOMMENDED to use the upstream Android user
   1608 interface (or a similar thumbnail-based interface) for the overview screen.</p>
   1609 
   1610 <h3 id="3_8_9_input_management">3.8.9. Input Management</h3>
   1611 
   1612 
   1613 <p>Android includes support for Input Management and support for third-party input
   1614 method editors [<a href="http://developer.android.com/guide/topics/text/creating-input-method.html">Resources, 39</a>]. Device implementations that allow users to use third-party input methods on
   1615 the device MUST declare the platform feature android.software.input_methods and
   1616 support IME APIs as defined in the Android SDK documentation.</p>
   1617 
   1618 <p>Device implementations that declare the android.software.input_methods feature
   1619 MUST provide a user-accessible mechanism to add and configure third-party input
   1620 methods. Device implementations MUST display the settings interface in response
   1621 to the android.settings.INPUT_METHOD_SETTINGS intent.</p>
   1622 
   1623 <h3 id="3_8_10_lock_screen_media_control">3.8.10. Lock Screen Media Control</h3>
   1624 
   1625 
   1626 <p>The Remote Control Client API is deprecated from Android 5.0 in favor of the
   1627 Media Notification Template that allows media applications to integrate with
   1628 playback controls that are displayed on the lock screen [<a href="http://developer.android.com/reference/android/app/Notification.MediaStyle.html">Resources, 40</a>].
   1629 Device implementations that support a lock screen, unless an Android Automotive or Watch
   1630 implementation, MUST display the Lockscreen Notifications including the Media Notification
   1631 Template.</p>
   1632 
   1633 <h3 id="3_8_11_dreams">3.8.11. Dreams</h3>
   1634 
   1635 
   1636 <p>Android includes support for interactive screensavers called Dreams [<a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">Resources, 41</a>]. Dreams allows users to interact with applications when a device connected to
   1637 a power source is idle or docked in a desk dock. Android Watch devices MAY
   1638 implement Dreams, but other types of device implementations SHOULD include
   1639 support for Dreams and provide a settings option for users to configure Dreams
   1640 in response to the android.settings.DREAM_SETTINGS intent.</p>
   1641 
   1642 <h3 id="3_8_12_location">3.8.12. Location</h3>
   1643 
   1644 
   1645 <p>When a device has a hardware sensor (e.g. GPS) that is capable of providing the
   1646 location coordinates, location modes MUST be displayed in the Location menu
   1647 within Settings [<a href="http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE">Resources, 42</a>].</p>
   1648 
   1649 <h3 id="3_8_13_unicode_and_font">3.8.13. Unicode and Font</h3>
   1650 
   1651 
   1652 <p>Android includes support for color emoji characters. When Android device
   1653 implementations include an IME, devices SHOULD provide an input method to the
   1654 user for the Emoji characters defined in Unicode 6.1 [<a href="http://www.unicode.org/versions/Unicode6.1.0/">Resources, 43</a>]. All devices MUST be capable of rendering these emoji characters in color glyph.</p>
   1655 
   1656 <p>Android includes support for Roboto 2 font with different
   1657 weights&mdash;sans-serif-thin, sans-serif-light, sans-serif-medium, sans-serif-black,
   1658 sans-serif-condensed, sans-serif-condensed-light&mdash;which MUST all be included for
   1659 the languages available on the device and full Unicode 7.0 coverage of Latin,
   1660 Greek, and Cyrillic, including the Latin Extended A, B, C, and D ranges, and
   1661 all glyphs in the currency symbols block of Unicode 7.0.</p>
   1662 
   1663 <h2 id="3_9_device_administration">3.9. Device Administration</h2>
   1664 
   1665 <p>Android includes features that allow security-aware applications to perform
   1666 device administration functions at the system level, such as enforcing password
   1667 policies or performing remote wipe, through the Android Device Administration
   1668 API [<a href="http://developer.android.com/guide/topics/admin/device-admin.html">Resources, 44</a>].
   1669 Device implementations MUST provide an implementation of the DevicePolicyManager class
   1670 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html">Resources, 45</a>].
   1671 Device implementations that include support for PIN (numeric) or PASSWORD
   1672 (alphanumeric) based lock screens MUST support the full range of device
   1673 administration policies defined in the Android SDK documentation
   1674 [<a href="http://developer.android.com/guide/topics/admin/device-admin.html">Resources, 44</a>]
   1675 and report the platform feature android.software.device_admin.</p>
   1676 
   1677 <h3 id="3_9_1_device_provisioning">3.9.1 Device Provisioning</h3>
   1678 <h4 id="3_9_1_1_device_owner_provisioning">3.9.1.1 Device owner provisioning</h4>
   1679 <p>If a device implementation declares the android.software.device_admin feature,
   1680 the out of box setup flow MUST make it possible to enroll a Device Policy
   1681 Controller (DPC) application as the Device Owner app
   1682 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)">
   1683 Resources, 46</a>]. Device implementations MAY have a preinstalled application
   1684 performing device administration functions but this application MUST NOT be set
   1685 as the Device Owner app without explicit consent or action from the user or the
   1686 administrator of the device.</p>
   1687 
   1688 <p>The device owner provisioning process (the flow initiated by
   1689 android.app.action.PROVISION_MANAGED_DEVICE
   1690 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE">
   1691 Resources, 47</a>]) user experience MUST align with the AOSP implementation</p>
   1692 
   1693 <p>If the device implementation reports android.hardware.nfc, it MUST have NFC
   1694 enabled, even during the out-of-box setup flow, in order to allow for NFC
   1695 provisioning of Device owners
   1696 [<a href="https://source.android.com/devices/tech/admin/provision.html#device_owner_provisioning_via_nfc">Resources, 48</a>].
   1697 </p>
   1698 
   1699 <h4 id="3_9_1_2_managed_profile_provisioning">3.9.1.2 Managed profile provisioning</h4>
   1700 <p>If a device implementation declares the android.software.managed_users,
   1701 it MUST be possible to enroll a Device Policy Controller (DPC) application
   1702 as the owner of a new Managed Profile
   1703 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)">
   1704 Resources, 49</a>]</p>
   1705 
   1706 <p>The managed profile provisioning process (the flow initiated by
   1707 android.app.action.PROVISION_MANAGED_PROFILE
   1708 [<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">
   1709 Resources, 50</a>]) user experience MUST align with the AOSP implementation
   1710 </p>
   1711 
   1712 
   1713 <h2 id="3_9_2_managed_profile_support">3.9.2 Managed Profile Support</h2>
   1714 
   1715 <p>Managed profile capable devices are those devices that:</p>
   1716 <ul>
   1717   <li>Declare android.software.device_admin (see <a href="#3_9_device_administration">section 3.9 Device Administration)</a></li>
   1718   <li>Are not low RAM devices (see <a href="#7_6_1_minimum_memory_and_storage">section 7.6.1</a></li>
   1719   <li>Allocate internal (non-removable) storage as shared storage (see
   1720     <a href="#7_6_2_application_shared_storage">section 7.6.2</a>)</li>
   1721 </ul>
   1722 <p>Managed profile capable devices MUST:</p>
   1723 <ul>
   1724   <li>Declare the platform feature flag android.software.managed_users.</li>
   1725   <li>Support managed profiles via the android.app.admin.DevicePolicyManager APIs</li>
   1726   <li>Allow one and only one managed profile to be created [<a
   1727 href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">Resources,
   1728 50</a>]</li>
   1729   <li>Use an icon badge (similar to the AOSP upstream work badge) to represent
   1730 the managed applications and widgets and other badged UI elements like Recents
   1731 &amp; Notifications</li>
   1732   <li>Display a notification icon (similar to the AOSP upstream work badge) to
   1733 indicate when user is within a managed profile application</li>
   1734   <li>Display a toast indicating that the user is in the managed profile if and when the
   1735 device wakes up (ACTION_USER_PRESENT) and the foreground application is within
   1736 the managed profile</li>
   1737   <li>Where a managed profile exists, show a visual affordance in the Intent
   1738 'Chooser' to allow the user to forward the intent from the managed profile to
   1739 the primary user or vice versa, if enabled by the Device Policy Controller</li>
   1740   <li>Where a managed profile exists, expose the following user affordances for both
   1741 the primary user and the managed profile:
   1742     <ul>
   1743       <li>Separate accounting for battery, location, mobile data and storage usage
   1744       for the primary user and managed profile.</li>
   1745       <li>Independent management of VPN Applications installed within the primary
   1746       user or managed profile.</li>
   1747       <li>Independent management of applications installed within the primary user
   1748       user or managed profile.</li>
   1749       <li>Independent management of accounts within the primary user or managed
   1750       profile.</li>
   1751     </ul>
   1752   </li>
   1753   <li>Ensure the default dialer can look up caller information from the managed
   1754 profile (if one exists) alongside those from the primary profile, if the Device
   1755 Policy Controller permits it.</li>
   1756   <li>MUST ensure that it satisfies all the security requirements applicable for a device
   1757     with multiple users enabled (see <a href="#9_5_multi-user_support">section 9.5</a>),
   1758     even though the managed profile is not counted as another user in addition to the
   1759     primary user.</li>
   1760 </ul>
   1761 
   1762 <h2 id="3_10_accessibility">3.10. Accessibility</h2>
   1763 
   1764 
   1765 <p>Android provides an accessibility layer that helps users with disabilities to
   1766 navigate their devices more easily. In addition, Android provides platform APIs
   1767 that enable accessibility service implementations to receive callbacks for user
   1768 and system events and generate alternate feedback mechanisms, such as
   1769 text-to-speech, haptic feedback, and trackball/d-pad navigation [<a href="http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html">Resources, 51</a>].</p>
   1770 
   1771 <p>Device implementations include the following requirements:</p>
   1772 
   1773 <ul>
   1774 <li>Android Automotive implementations SHOULD provide an implementation of the
   1775 Android accessibility framework consistent with the default Android
   1776 implementation.</li>
   1777 <li>Device implementations (Android Automotive excluded) MUST provide an
   1778 implementation of the Android accessibility framework consistent with the
   1779 default Android implementation.</li>
   1780 <li>Device implementations (Android Automotive excluded) MUST support
   1781 third-party accessibility service implementations through the
   1782 android.accessibilityservice APIs
   1783 [<a href="http://developer.android.com/reference/android/view/accessibility/package-summary.html">Resources, 52</a>]</li>
   1784 <li>Device implementations (Android Automotive excluded) MUST generate
   1785 AccessibilityEvents and deliver these events to all registered
   1786 AccessibilityService implementations in a manner consistent with the default
   1787 Android implementation</li>
   1788 <li> Device implementations (Android Automotive and Android Watch devices with
   1789 no audio output excluded), MUST provide a user-accessible mechanism to enable
   1790 and disable accessibility services, and MUST display this interface in response
   1791 to the android.provider.Settings.ACTION_ACCESSIBILITY_SETTINGS intent.</li>
   1792 </ul>
   1793 
   1794 <p>Additionally, device implementations SHOULD provide an implementation of an
   1795 accessibility service on the device, and SHOULD provide a mechanism for users
   1796 to enable the accessibility service during device setup. An open source
   1797 implementation of an accessibility service is available from the Eyes Free
   1798 project [<a href="http://code.google.com/p/eyes-free/">Resources, 53</a>].</p>
   1799 
   1800 <h2 id="3_11_text-to-speech">3.11. Text-to-Speech</h2>
   1801 
   1802 
   1803 <p>Android includes APIs that allow applications to make use of text-to-speech
   1804 (TTS) services and allows service providers to provide implementations of TTS
   1805 services [<a href="http://developer.android.com/reference/android/speech/tts/package-summary.html">Resources, 54</a>]. Device implementations reporting the feature android.hardware.audio.output
   1806 MUST meet these requirements related to the Android TTS framework. </p>
   1807 
   1808 <p>Android Automotive implementations:</p>
   1809 <ul>
   1810 <li>MUST support the Android TTS framework APIs.</li>
   1811 <li>MAY support installation of third-party TTS engines. If supported, partners
   1812 MUST provide a user-accessible interface that allows the user to select a TTS
   1813 engine for use at system level.</li>
   1814 </ul>
   1815 
   1816 <p>All other device implementations:</p>
   1817 
   1818 <ul>
   1819   <li> MUST support the Android TTS framework APIs and SHOULD include a TTS engine
   1820 supporting the languages available on the device. Note that the upstream
   1821 Android open source software includes a full-featured TTS engine
   1822 implementation.
   1823   <li> MUST support installation of third-party TTS engines
   1824   <li> MUST provide a user-accessible interface that allows users to select a TTS
   1825 engine for use at the system level
   1826 </ul>
   1827 
   1828 <h2 id="3_12_tv_input_framework">3.12. TV Input Framework</h2>
   1829 
   1830 
   1831 <p>The Android Television Input Framework (TIF) simplifies the delivery of live
   1832 content to Android Television devices. TIF provides a standard API to create
   1833 input modules that control Android Television devices. Android Television
   1834 device implementations MUST support TV Input Framework
   1835 [<a href="http://source.android.com/devices/tv/index.html">Resources, 55</a>].</p>
   1836 
   1837 <p>Device implementations that support TIF MUST declare the platform feature
   1838 android.software.live_tv.</p>
   1839 
   1840 <h3 id="3_12_1_tv_app">3.12.1. TV App</h3>
   1841 
   1842 <p>Any device implementation that declares support for Live TV MUST have an
   1843 installed TV application (TV App). The Android Open Source Project provides an implementation of the TV
   1844 App.</p>
   1845 
   1846 <p>The TV App MUST provide facilities to install and use TV Channels
   1847 [<a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html">Resources, 56</a>]
   1848  and meet the following requirements:</p>
   1849 
   1850 <ul>
   1851   <li>Device implementations MUST allow third-party TIF-based inputs (third-party inputs)
   1852 [<a href="https://source.android.com/devices/tv/index.html#third-party_input_example">Resources, 57</a>]
   1853  to be installed and managed.
   1854   <li>Device implementations MAY provide visual separation between pre-installed
   1855  TIF-based inputs (installed inputs)
   1856 [<a href="https://source.android.com/devices/tv/index.html#tv_inputs">Resources, 58</a>]
   1857  and third-party inputs.
   1858   <li>The device implementations MUST NOT display the third-party inputs more than a
   1859 single navigation action away from the TV App (i.e. expanding a list of
   1860 third-party inputs from the TV App).
   1861 </ul>
   1862 
   1863 <h4 id="3_12_1_1_electronic_program_guide">3.12.1.1. Electronic Program Guide</h4>
   1864 
   1865 <p>Android Television device implementations MUST show an informational and
   1866 interactive overlay, which MUST include an electronic program guide (EPG)
   1867 generated from the values in the TvContract.Programs fields
   1868 [<a href="https://developer.android.com/reference/android/media/tv/TvContract.Programs.html">Resources, 59</a>].
   1869  The EPG MUST meet the following requirements:</p>
   1870 
   1871 <ul>
   1872   <li>The EPG MUST display information from all installed inputs and third-party
   1873 inputs.
   1874   <li>The EPG MAY provide visual separation between the installed inputs and
   1875 third-party inputs.
   1876   <li>The EPG is STRONGLY RECOMMENDED to display installed inputs and third-party
   1877 inputs with equal prominence. The EPG MUST NOT display the third-party inputs
   1878 more than a single navigation action away from the installed inputs on the EPG.
   1879   <li>On channel change, device implementations MUST display EPG data for the
   1880 currently playing program.
   1881 </ul>
   1882 
   1883 <h4 id="3_12_1_2_navigation">3.12.1.2. Navigation</h4>
   1884 
   1885 <p>Android Television device input devices (i.e. remote control, remote control
   1886 application, or game controller) MUST allow navigation to all actionable
   1887 sections of the screen via the D-pad. D-pad up and down MUST be used to change
   1888 live TV channels when there is no actionable section on the screen.</p>
   1889 
   1890 <p>The TV App SHOULD pass key events to HDMI inputs through CEC.</p>
   1891 
   1892 <h4 id="3_12_1_3_tv_input_app_linking">3.12.1.3. TV input app linking</h4>
   1893 
   1894 <p>Android Television device implementations MUST support TV input app linking,
   1895 which allows all inputs to provide activity links from the current activity to
   1896 another activity (i.e. a link from live programming to related content)
   1897 [<a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI">Resources, 60</a>].
   1898  The TV App MUST show TV input app linking when it is provided.</p>
   1899 
   1900 <h1 id="4_application_packaging_compatibility">4. Application Packaging Compatibility</h1>
   1901 
   1902 
   1903 <p>Device implementations MUST install and run Android &ldquo;.apk&rdquo; files as generated
   1904 by the &ldquo;aapt&rdquo; tool included in the official Android SDK [<a href="http://developer.android.com/tools/help/index.html">Resources, 61</a>].</p>
   1905 
   1906 <p>Devices implementations MUST NOT extend either the .apk [<a href="http://developer.android.com/guide/components/fundamentals.html">Resources, 62</a>], Android Manifest [<a href="http://developer.android.com/guide/topics/manifest/manifest-intro.html">Resources, 49</a>], Dalvik bytecode [<a href="https://android.googlesource.com/platform/dalvik/">Resources, 23</a>], or RenderScript bytecode formats in such a way that would prevent those
   1907 files from installing and running correctly on other compatible devices.</p>
   1908 
   1909 <h1 id="5_multimedia_compatibility">5. Multimedia Compatibility</h1>
   1910 
   1911 
   1912 <h2 id="5_1_media_codecs">5.1. Media Codecs</h2>
   1913 
   1914 
   1915 <p>Device implementations MUST support the core media formats specified in the
   1916 Android SDK documentation [<a href="http://developer.android.com/guide/appendix/media-formats.html">Resources, 64</a>]
   1917 except where explicitly permitted in this document. Specifically, device
   1918 implementations MUST support the media formats, encoders, decoders, file types,
   1919 and container formats defined in the tables below and reported via MediaCodecList
   1920 [<a href="http://developer.android.com/reference/android/media/MediaCodecList.html">Resources, 65</a>].
   1921 Device implementations MUST also be able to decode all profiles reported in its CamcorderProfile
   1922 [<a href="http://developer.android.com/reference/android/media/CamcorderProfile.html">Resources,
   1923 66</a>] and MUST be able to decode all formats it can encode.
   1924 
   1925 All of these codecs are
   1926 provided as software implementations in the preferred Android implementation
   1927 from the Android Open Source Project.</p>
   1928 
   1929 <p>Please note that neither Google nor the Open Handset Alliance make any
   1930 representation that these codecs are free from third-party patents. Those
   1931 intending to use this source code in hardware or software products are advised
   1932 that implementations of this code, including in open source software or
   1933 shareware, may require patent licenses from the relevant patent holders.</p>
   1934 
   1935 <h3 id="5_1_1_audio_codecs">5.1.1. Audio Codecs</h3>
   1936 
   1937 <table>
   1938  <tr>
   1939     <th>Format/Codec</th>
   1940     <th>Encoder</th>
   1941     <th>Decoder</th>
   1942     <th>Details</th>
   1943     <th>Supported File Types/Container Formats</th>
   1944  </tr>
   1945  <tr>
   1946     <td>MPEG-4 AAC Profile<br />
   1947 
   1948 (AAC LC)</td>
   1949     <td>REQUIRED<sup>1</sup></td>
   1950     <td>REQUIRED</td>
   1951     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 8 to
   1952 48 kHz.</td>
   1953     <td>
   1954     <ul>
   1955     <li class="table_list">3GPP (.3gp)</li>
   1956     <li class="table_list">MPEG-4 (.mp4, .m4a)</li>
   1957     <li class="table_list">ADTS raw AAC (.aac, decode in Android 3.1+, encode in Android 4.0+, ADIF not
   1958 supported)</li>
   1959     <li class="table_list">MPEG-TS (.ts, not seekable, Android 3.0+)</li></ul></td>
   1960  </tr>
   1961  <tr>
   1962     <td>MPEG-4 HE AAC Profile (AAC+)</td>
   1963     <td>REQUIRED<sup>1</sup><br>(Android 4.1+)</td>
   1964     <td>REQUIRED</td>
   1965     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 16
   1966 to 48 kHz.</td>
   1967     <td></td>
   1968  </tr>
   1969  <tr>
   1970     <td>MPEG-4 HE AACv2<br />
   1971 
   1972 Profile (enhanced AAC+)</td>
   1973     <td> </td>
   1974     <td>REQUIRED</td>
   1975     <td>Support for mono/stereo/5.0/5.1<sup>2</sup> content with standard sampling rates from 16
   1976 to 48 kHz.</td>
   1977     <td></td>
   1978  </tr>
   1979  <tr>
   1980     <td>AAC ELD (enhanced low delay AAC)</td>
   1981     <td>REQUIRED<sup>1</sup> <br />
   1982 
   1983 (Android 4.1+)</td>
   1984     <td>REQUIRED<br />
   1985 
   1986 (Android 4.1+)</td>
   1987     <td>Support for mono/stereo content with standard sampling rates from 16 to 48 kHz.</td>
   1988     <td></td>
   1989  </tr>
   1990  <tr>
   1991     <td>AMR-NB</td>
   1992     <td>REQUIRED<sup>3</sup></td>
   1993     <td>REQUIRED<sup>3</sup></td>
   1994     <td>4.75 to 12.2 kbps sampled @ 8 kHz</td>
   1995     <td>3GPP (.3gp)</td>
   1996  </tr>
   1997  <tr>
   1998     <td>AMR-WB</td>
   1999     <td>REQUIRED<sup>3</sup></td>
   2000     <td>REQUIRED<sup>3</sup></td>
   2001     <td>9 rates from 6.60 kbit/s to 23.85 kbit/s sampled @ 16 kHz</td>
   2002     <td></td>
   2003  </tr>
   2004  <tr>
   2005     <td>FLAC</td>
   2006     <td></td>
   2007     <td>REQUIRED <br>(Android 3.1+)</td>
   2008     <td>Mono/Stereo (no multichannel). Sample rates up to 48 kHz (but up to 44.1 kHz is
   2009 RECOMMENDED on devices with 44.1 kHz output, as the 48 to 44.1 kHz downsampler
   2010 does not include a low-pass filter). 16-bit RECOMMENDED; no dither applied for
   2011 24-bit.</td>
   2012     <td>FLAC (.flac) only</td>
   2013  </tr>
   2014  <tr>
   2015     <td>MP3</td>
   2016     <td></td>
   2017     <td>REQUIRED</td>
   2018     <td>Mono/Stereo 8-320Kbps constant (CBR) or variable bitrate (VBR)</td>
   2019     <td>MP3 (.mp3)</td>
   2020  </tr>
   2021  <tr>
   2022     <td>MIDI</td>
   2023     <td></td>
   2024     <td>REQUIRED</td>
   2025     <td>MIDI Type 0 and 1. DLS Version 1 and 2. XMF and Mobile XMF. Support for
   2026 ringtone formats RTTTL/RTX, OTA, and iMelody</td>
   2027     <td><ul>
   2028     <li class="table_list">Type 0 and 1 (.mid, .xmf, .mxmf)</li>
   2029     <li class="table_list">RTTTL/RTX (.rtttl, .rtx)</li>
   2030     <li class="table_list">OTA (.ota)</li>
   2031     <li class="table_list">iMelody (.imy)</li></ul></td>
   2032  </tr>
   2033  <tr>
   2034     <td>Vorbis</td>
   2035     <td></td>
   2036     <td>REQUIRED</td>
   2037     <td></td>
   2038     <td><ul>
   2039     <li class="table_list">Ogg (.ogg)</li>
   2040     <li class="table_list">Matroska (.mkv, Android 4.0+)</li></ul></td>
   2041  </tr>
   2042  <tr>
   2043     <td>PCM/WAVE</td>
   2044     <td>REQUIRED<sup>4</sup><br> (Android 4.1+)</td>
   2045     <td>REQUIRED</td>
   2046     <td>16-bit linear PCM (rates up to limit of hardware). Devices MUST support
   2047 sampling rates for raw PCM recording at 8000, 11025, 16000, and 44100 Hz
   2048 frequencies.</td>
   2049     <td>WAVE (.wav)</td>
   2050  </tr>
   2051  <tr>
   2052     <td>Opus</td>
   2053     <td></td>
   2054     <td>REQUIRED<br> (Android 5.0+)</td>
   2055     <td></td>
   2056     <td>Matroska (.mkv)</td>
   2057  </tr>
   2058 </table>
   2059 
   2060 
   2061 <p class="table_footnote"> 1 Required for device implementations that define android.hardware.microphone
   2062 but optional for Android Watch device implementations.</p>
   2063 
   2064 <p class="table_footnote">2 Only downmix of 5.0/5.1 content is required; recording or rendering more than
   2065 2 channels is optional.</p>
   2066 
   2067 <p class="table_footnote">3 Required for Android Handheld device implementations. </p>
   2068 
   2069 <p class="table_footnote">4 Required for device implementations that define android.hardware.microphone,
   2070 including Android Watch device implementations.</p>
   2071 
   2072 <h3 id="5_1_2_image_codecs">5.1.2. Image Codecs</h3>
   2073 
   2074 <table>
   2075  <tr>
   2076     <th>Format/Codec</th>
   2077     <th>Encoder</th>
   2078     <th>Decoder</th>
   2079     <th>Details</th>
   2080     <th>Supported File Types/Container Formats</th>
   2081  </tr>
   2082  <tr>
   2083     <td>JPEG</td>
   2084     <td>REQUIRED</td>
   2085     <td>REQUIRED</td>
   2086     <td>Base+progressive</td>
   2087     <td>JPEG (.jpg)</td>
   2088  </tr>
   2089  <tr>
   2090     <td>GIF</td>
   2091     <td></td>
   2092     <td>REQUIRED</td>
   2093     <td></td>
   2094     <td>GIF (.gif)</td>
   2095  </tr>
   2096  <tr>
   2097     <td>PNG</td>
   2098     <td>REQUIRED</td>
   2099     <td>REQUIRED</td>
   2100     <td></td>
   2101     <td>PNG (.png)</td>
   2102  </tr>
   2103  <tr>
   2104     <td>BMP</td>
   2105     <td></td>
   2106     <td>REQUIRED</td>
   2107     <td></td>
   2108     <td>BMP (.bmp)</td>
   2109  </tr>
   2110  <tr>
   2111     <td>WebP</td>
   2112     <td>REQUIRED</td>
   2113     <td>REQUIRED</td>
   2114     <td></td>
   2115     <td>WebP (.webp)</td>
   2116  </tr>
   2117 </table>
   2118 
   2119 
   2120 <h3 id="5_1_3_video_codecs">5.1.3. Video Codecs</h3>
   2121 
   2122 <table>
   2123  <tr>
   2124     <th>Format/Codec</th>
   2125     <th>Encoder</th>
   2126     <th>Decoder</th>
   2127     <th>Details</th>
   2128     <th>Supported File Types/<br>Container Formats</th>
   2129  </tr>
   2130  <tr>
   2131     <td>H.263</td>
   2132     <td>REQUIRED<sup>1</sup></td>
   2133     <td>REQUIRED<sup>2</sup></td>
   2134     <td></td>
   2135     <td><ul>
   2136     <li class="table_list">3GPP (.3gp)</li>
   2137     <li class="table_list">MPEG-4 (.mp4)</li></ul></td>
   2138  </tr>
   2139  <tr>
   2140     <td>H.264 AVC</td>
   2141     <td>REQUIRED<sup>2</sup></td>
   2142     <td>REQUIRED<sup>2</sup></td>
   2143     <td>See <a href="#5_2_video_encoding">section 5.2 </a>and <a href="#5_3_video_decoding">5.3</a> for details</td>
   2144     <td><ul>
   2145     <li class="table_list">3GPP (.3gp)</li>
   2146     <li class="table_list">MPEG-4 (.mp4)</li>
   2147     <li class="table_list">MPEG-2 TS (.ts, AAC audio only, not seekable, Android 3.0+)</li></ul></td>
   2148  </tr>
   2149  <tr>
   2150     <td>H.265 HEVC</td>
   2151     <td></td>
   2152     <td>REQUIRED<sup>5</sup></td>
   2153     <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td>
   2154     <td>MPEG-4 (.mp4)</td>
   2155  </tr>
   2156 <tr>
   2157   <td>MPEG-2</td>
   2158   <td></td>  
   2159   <td>STRONGLY RECOMMENDED<sup>6</sup></td>
   2160   <td>Main Profile</td>
   2161   <td>MPEG2-TS</td>
   2162 </tr>
   2163  <tr>
   2164     <td>MPEG-4 SP</td>
   2165     <td></td>
   2166     <td>REQUIRED<sup>2</sup></td>
   2167     <td></td>
   2168     <td>3GPP (.3gp)</td>
   2169  </tr>
   2170  <tr>
   2171     <td>VP8<sup>3</sup></td>
   2172     <td>REQUIRED<sup>2</sup><br />
   2173 
   2174 (Android 4.3+)</td>
   2175     <td>REQUIRED<sup>2</sup><br />
   2176 
   2177 (Android 2.3.3+)</td>
   2178     <td>See <a href="#5_2_video_encoding">section 5.2</a> and <a href="#5_3_video_decoding">5.3</a> for details</td>
   2179     <td><ul>
   2180     <li class="table_list">WebM (.webm) [<a href="http://www.webmproject.org/">Resources, 67</a></li>
   2181     <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul></td>
   2182  </tr>
   2183  <tr>
   2184     <td>VP9</td>
   2185     <td></td>
   2186     <td>REQUIRED<sup>2</sup><br> (Android 4.4+)</td>
   2187     <td>See <a href="#5_3_video_decoding">section 5.3</a> for details</td>
   2188     <td><ul>
   2189     <li class="table_list">WebM (.webm) [<a href="http://www.webmproject.org/">Resources, 67</a>]</li>
   2190     <li class="table_list">Matroska (.mkv, Android 4.0+)<sup>4</sup></li></ul></td>
   2191  </tr>
   2192 </table>
   2193 
   2194 
   2195 <p class="table_footnote">1 Required for device implementations that include camera hardware and define
   2196 android.hardware.camera or android.hardware.camera.front.</p>
   2197 
   2198 <p class="table_footnote">2 Required for device implementations except Android Watch devices. </p>
   2199 
   2200 <p class="table_footnote">3 For acceptable quality of web video streaming and video-conference services,
   2201 device implementations SHOULD use a hardware VP8 codec that meets the
   2202 requirements in [<a href="http://www.webmproject.org/hardware/rtc-coding-requirements/">Resources, 68</a>].</p>
   2203 
   2204 <p class="table_footnote">4 Device implementations SHOULD support writing Matroska WebM files.</p>
   2205 
   2206 <p class="table_footnote">5 STRONGLY RECOMMENDED for Android Automotive, optional for Android Watch, and required for all other device types.</p>
   2207 
   2208 <p class="table_footnote">6 Applies only to Android Television device implementations.</p>
   2209 
   2210 <h2 id="5_2_video_encoding">5.2. Video Encoding</h2>
   2211 
   2212 <div class="note">
   2213 <p>Video codecs are optional for Android Watch device implementations.</p>
   2214 </div>
   2215 
   2216 <p>Android device implementations with H.263 encoders, MUST support Baseline Profile Level 45.</p>
   2217 
   2218 <p>Android device implementations with H.264 codec support, MUST support Baseline
   2219 Profile Level 3 and the following SD (Standard Definition) video encoding
   2220 profiles and SHOULD support Main Profile Level 4 and the following HD (High
   2221 Definition) video encoding profiles. Android Television devices are STRONGLY RECOMMENDED
   2222 to encode HD 1080p video at 30 fps.</p>
   2223 <table>
   2224  <tr>
   2225     <th></th>
   2226     <th>SD (Low quality)</th>
   2227     <th>SD (High quality)</th>
   2228     <th>HD 720p<sup>1</sup></th>
   2229     <th>HD 1080p<sup>1</sup></th>
   2230  </tr>
   2231  <tr>
   2232     <th>Video resolution</th>
   2233     <td>320 x 240 px</td>
   2234     <td>720 x 480 px</td>
   2235     <td>1280 x 720 px</td>
   2236     <td>1920 x 1080 px</td>
   2237  </tr>
   2238  <tr>
   2239     <th>Video frame rate</th>
   2240     <td>20 fps</td>
   2241     <td>30 fps</td>
   2242     <td>30 fps</td>
   2243     <td>30 fps</td>
   2244  </tr>
   2245  <tr>
   2246     <th>Video bitrate</th>
   2247     <td>384 Kbps</td>
   2248     <td>2 Mbps</td>
   2249     <td>4 Mbps</td>
   2250     <td>10 Mbps</td>
   2251  </tr>
   2252 </table>
   2253 
   2254 
   2255 <p class="table_footnote">1 When supported by hardware, but STRONGLY RECOMMENDED for Android Television
   2256 devices.</p>
   2257 
   2258 <p>Android device implementations with VP8 codec support MUST support the SD video
   2259 encoding profiles and SHOULD support the following HD (High Definition) video
   2260 encoding profiles.</p>
   2261 <table>
   2262  <tr>
   2263     <th></th>
   2264     <th>SD (Low quality)</th>
   2265     <th>SD (High quality)</th>
   2266     <th>HD 720p<sup>1</sup></th>
   2267     <th>HD 1080p<sup>1</sup></th>
   2268  </tr>
   2269  <tr>
   2270     <th>Video resolution</th>
   2271     <td>320 x 180 px</td>
   2272     <td>640 x 360 px</td>
   2273     <td>1280 x 720 px</td>
   2274     <td>1920 x 1080 px</td>
   2275  </tr>
   2276  <tr>
   2277     <th>Video frame rate</th>
   2278     <td>30 fps</td>
   2279     <td>30 fps</td>
   2280     <td>30 fps</td>
   2281     <td>30 fps</td>
   2282  </tr>
   2283  <tr>
   2284     <th>Video bitrate</th>
   2285     <td>800 Kbps </td>
   2286     <td>2 Mbps</td>
   2287     <td>4 Mbps</td>
   2288     <td>10 Mbps</td>
   2289  </tr>
   2290 </table>
   2291 
   2292 <p class="table_footnote">1 When supported by hardware.</p>
   2293 
   2294 <h2 id="5_3_video_decoding">5.3. Video Decoding</h2>
   2295 
   2296 <div class="note">
   2297 <p>Video codecs are optional for Android Watch device implementations.</p>
   2298 </div>
   2299 
   2300 <p>Device implementations MUST support dynamic video resolution and frame rate
   2301 switching through the standard Android APIs within the same stream for all VP8,
   2302 VP9, H.264, and H.265 codecs in real time and up to the maximum resolution
   2303 supported on the device.</p>
   2304 
   2305 <p>Android device implementations with H.263 decoders, MUST support Baseline
   2306 Profile Level 30.</p>
   2307 
   2308 <p>Android device implementations with MPEG-4 decoders, MUST support Simple
   2309 Profile Level 3.</p>
   2310 
   2311 <p>Android device implementations with H.264 decoders, MUST support Main Profile
   2312 Level 3.1 and the following SD video decoding profiles and SHOULD support the
   2313 HD decoding profiles. Android Television devices MUST support High Profile
   2314 Level 4.2 and the HD 1080p decoding profile.</p>
   2315 <table>
   2316  <tr>
   2317     <th></th>
   2318     <th>SD (Low quality)</th>
   2319     <th>SD (High quality)</th>
   2320     <th>HD 720p<sup>1</sup></th>
   2321     <th>HD 1080p<sup>1</sup></th>
   2322  </tr>
   2323  <tr>
   2324     <th>Video resolution</th>
   2325     <td>320 x 240 px</td>
   2326     <td>720 x 480 px</td>
   2327     <td>1280 x 720 px</td>
   2328     <td>1920 x 1080 px</td>
   2329  </tr>
   2330  <tr>
   2331     <th>Video frame rate</th>
   2332     <td>30 fps</td>
   2333     <td>30 fps</td>
   2334     <td>60 fps</td>
   2335     <td>30 fps / 60 fps<sup>2</sup></td>
   2336  </tr>
   2337  <tr>
   2338     <th>Video bitrate</th>
   2339     <td>800 Kbps </td>
   2340     <td>2 Mbps</td>
   2341     <td>8 Mbps</td>
   2342     <td>20 Mbps</td>
   2343  </tr>
   2344 </table>
   2345 
   2346 
   2347 <p class="table_footnote">1 REQUIRED for when the height as reported by the
   2348 Display.getSupportedModes() method is not smaller than the video resolution.</p>
   2349 
   2350 <p class="table_footnote">2 REQUIRED for Android Television device implementations.</p>
   2351 
   2352 <p>Android device implementations when supporting VP8 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD decoding profiles and SHOULD support the HD
   2353 decoding profiles. Android Television devices MUST support the HD 1080p
   2354 decoding profile.  </p>
   2355 <table>
   2356  <tr>
   2357     <th></th>
   2358     <th>SD (Low quality)</th>
   2359     <th>SD (High quality)</th>
   2360     <th>HD 720p<sup>1</sup></th>
   2361     <th>HD 1080p<sup>1</sup></th>
   2362  </tr>
   2363  <tr>
   2364     <th>Video resolution</th>
   2365     <td>320 x 180 px</td>
   2366     <td>640 x 360 px</td>
   2367     <td>1280 x 720 px</td>
   2368     <td>1920 x 1080 px</td>
   2369  </tr>
   2370  <tr>
   2371     <th>Video frame rate</th>
   2372     <td>30 fps</td>
   2373     <td>30 fps</td>
   2374     <td>30 fps / 60 fps<sup>2</sup></td>
   2375     <td>30 / 60 fps<sup>2</sup></td>
   2376  </tr>
   2377  <tr>
   2378     <th>Video bitrate</th>
   2379     <td>800 Kbps </td>
   2380     <td>2 Mbps</td>
   2381     <td>8 Mbps</td>
   2382     <td>20 Mbps</td>
   2383  </tr>
   2384 </table>
   2385 
   2386 <p class="table_footnote">1 REQUIRED for when the height as reported by the
   2387 Display.getSupportedModes() method is not smaller than the video resolution.</p>
   2388 
   2389 <p class="table_footnote">2 REQUIRED for Android Television device implementations.</p>
   2390 
   2391 <p>Android device implementations, when supporting VP9 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the following SD video decoding profiles and SHOULD support the
   2392 HD decoding profiles. Android Television devices are STRONGLY RECOMMENDED to
   2393 support the HD 1080p decoding profile and SHOULD support the UHD decoding
   2394 profile. When the UHD video decoding profile is supported, it MUST support 8-bit
   2395 color depth and SHOULD support VP9 Profile 2 (10-bit).</p>
   2396 <table>
   2397  <tr>
   2398     <th></th>
   2399     <th>SD (Low quality)</th>
   2400     <th>SD (High quality)</th>
   2401     <th>HD 720p<sup>1</sup></th>
   2402     <th>HD 1080p<sup>2</sup></th>
   2403     <th>UHD<sup>2</sup></th>
   2404  </tr>
   2405  <tr>
   2406     <th>Video resolution</th>
   2407     <td>320 x 180 px</td>
   2408     <td>640 x 360 px</td>
   2409     <td>1280 x 720 px</td>
   2410     <td>1920 x 1080 px</td>
   2411     <td>3840 x 2160 px</td>
   2412  </tr>
   2413  <tr>
   2414     <th>Video frame rate</th>
   2415     <td>30 fps</td>
   2416     <td>30 fps</td>
   2417     <td>30 fps</td>
   2418     <td>60 fps</td>
   2419     <td>60 fps</td>
   2420  </tr>
   2421  <tr>
   2422     <th>Video bitrate</th>
   2423     <td>600 Kbps</td>
   2424     <td>1.6 Mbps</td>
   2425     <td>4 Mbps</td>
   2426     <td>10 Mbps</td>
   2427     <td>20 Mbps</td>
   2428  </tr>
   2429 </table>
   2430 
   2431 
   2432 <p class="table_footnote">1 Required for Android Television device implementations, but for other type of
   2433 devices only when supported by hardware.</p>
   2434 
   2435 <p class="table_footnote">2 STRONGLY RECOMMENDED for existing Android Television device implementations when
   2436 supported by hardware.</p>
   2437 
   2438 <p>Android device implementations, when supporting H.265 codec as described in <a href="#5_1_3_video_codecs">section 5.1.3</a>, MUST support the Main Profile Level 3 Main tier and the following SD video
   2439 decoding profiles and SHOULD support the HD decoding profiles. Android
   2440 Television devices MUST support the Main Profile Level 4.1 Main tier and the HD
   2441 1080p decoding profile and SHOULD support Main10 Level 5 Main Tier profile and
   2442 the UHD decoding profile.</p>
   2443 <table>
   2444  <tr>
   2445     <th></th>
   2446     <th>SD (Low quality)</th>
   2447     <th>SD (High quality)</th>
   2448     <th>HD 720p<sup>1</sup></th>
   2449     <th>HD 1080p<sup>1</sup></th>
   2450     <th>UHD<sup>2</sup></th>
   2451  </tr>
   2452  <tr>
   2453     <th>Video resolution</th>
   2454     <td>352 x 288 px</td>
   2455     <td>640 x 360 px</td>
   2456     <td>1280 x 720 px</td>
   2457     <td>1920 x 1080 px</td>
   2458     <td>3840 x 2160 px</td>
   2459  </tr>
   2460  <tr>
   2461     <th>Video frame rate</th>
   2462     <td>30 fps</td>
   2463     <td>30 fps</td>
   2464     <td>30 fps</td>
   2465     <td>60 fps<sup>2</sup></td>
   2466     <td>60 fps</td>
   2467  </tr>
   2468  <tr>
   2469     <th>Video bitrate</th>
   2470     <td>600 Kbps </td>
   2471     <td>1.6 Mbps</td>
   2472     <td>4 Mbps</td>
   2473     <td>10 Mbps</td>
   2474     <td>20 Mbps</td>
   2475  </tr>
   2476 </table>
   2477 
   2478 
   2479 <p class="table_footnote">1 Required for Android Television device implementations, but for other type of
   2480 devices only when supported by hardware.</p>
   2481 
   2482 <p class="table_footnote">2 STRONGLY RECOMMENDED
   2483 for existing Android Television device implementations when supported by hardware.</p>
   2484 
   2485 <h2 id="5_4_audio_recording">5.4. Audio Recording</h2>
   2486 
   2487 
   2488 <p>While some of the requirements outlined in this section are stated as SHOULD
   2489 since Android 4.3, the Compatibility Definition for a future version is planned
   2490 to change these to MUST. Existing and new Android devices are <strong>STRONGLY RECOMMENDED</strong>
   2491 to meet these requirements, or they will not be able to attain Android compatibility when upgraded
   2492 to the future version.</p>
   2493 
   2494 <h3 id="5_4_1_raw_audio_capture">5.4.1. Raw Audio Capture</h3>
   2495 
   2496 
   2497 <p>Device implementations that declare android.hardware.microphone MUST allow
   2498 capture of raw audio content with the following characteristics:</p>
   2499 
   2500 <ul>
   2501   <li><strong>Format</strong>: Linear PCM, 16-bit
   2502   <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 44100
   2503   <li><strong>Channels</strong>: Mono
   2504 </ul>
   2505 
   2506 <p>The capture for the above sample rates MUST be done without up-sampling, and
   2507 any down-sampling MUST include an appropriate anti-aliasing filter.</p>
   2508 
   2509 <p>Device implementations that declare android.hardware.microphone SHOULD allow
   2510 capture of raw audio content with the following characteristics:</p>
   2511 
   2512 <ul>
   2513   <li><strong>Format</strong>: Linear PCM, 16-bit
   2514   <li><strong>Sampling rates</strong>: 22050, 48000
   2515   <li><strong>Channels</strong>: Stereo
   2516 </ul>
   2517 
   2518 <p>If capture for the above sample rates is supported,
   2519 then the capture MUST be done without up-sampling at any ratio higher than 16000:22050
   2520 or 44100:48000.
   2521 Any up-sampling or down-sampling MUST include an appropriate anti-aliasing filter.</p>
   2522 
   2523 <h3 id="5_4_2_capture_for_voice_recognition">5.4.2. Capture for Voice Recognition</h3>
   2524 
   2525 
   2526 <p>In addition to the above recording specifications, when an application has
   2527 started recording an audio stream using the
   2528 android.media.MediaRecorder.AudioSource.VOICE_RECOGNITION audio source:</p>
   2529 
   2530 <ul>
   2531   <li>The device SHOULD exhibit approximately flat amplitude versus frequency
   2532 characteristics: specifically, &plusmn;3 dB, from 100 Hz to 4000 Hz.
   2533   <li>Audio input sensitivity SHOULD be set such that a 90 dB sound power level (SPL)
   2534 source at 1000 Hz yields RMS of 2500 for 16-bit samples.
   2535   <li>PCM amplitude levels SHOULD linearly track input SPL changes over at least a 30
   2536 dB range from -18 dB to +12 dB re 90 dB SPL at the microphone.
   2537   <li>Total harmonic distortion SHOULD be less than 1% for 1 kHz at 90 dB SPL input
   2538 level at the microphone.
   2539   <li>Noise reduction processing, if present, MUST be disabled.
   2540   <li>Automatic gain control, if present, MUST be disabled
   2541 </ul>
   2542 
   2543 <p>If the platform supports noise suppression technologies tuned for speech
   2544 recognition, the effect MUST be controllable from the
   2545 android.media.audiofx.NoiseSuppressor API. Moreover, the UUID field for the
   2546 noise suppressor&rsquo;s effect descriptor MUST uniquely identify each implementation
   2547 of the noise suppression technology.</p>
   2548 
   2549 <h3 id="5_4_3_capture_for_rerouting_of_playback">5.4.3. Capture for Rerouting of Playback</h3>
   2550 
   2551 
   2552 <p>The android.media.MediaRecorder.AudioSource class includes the REMOTE_SUBMIX
   2553 audio source. Devices that declare android.hardware.audio.output MUST properly
   2554 implement the REMOTE_SUBMIX audio source so that when an application uses the
   2555 android.media.AudioRecord API to record from this audio source, it can capture
   2556 a mix of all audio streams except for the following:</p>
   2557 
   2558 <ul>
   2559   <li>STREAM_RING
   2560   <li>STREAM_ALARM
   2561   <li>STREAM_NOTIFICATION
   2562 </ul>
   2563 
   2564 <h2 id="5_5_audio_playback">5.5. Audio Playback</h2>
   2565 
   2566 
   2567 <p>Device implementations that declare android.hardware.audio.output MUST conform
   2568 to the requirements in this section.</p>
   2569 
   2570 <h3 id="5_5_1_raw_audio_playback">5.5.1. Raw Audio Playback</h3>
   2571 
   2572 
   2573 <p>The device MUST allow playback of raw audio content with the following
   2574 characteristics:</p>
   2575 
   2576 <ul>
   2577   <li><strong>Format</strong>: Linear PCM, 16-bit</li>
   2578   <li><strong>Sampling rates</strong>: 8000, 11025, 16000, 22050, 32000, 44100</li>
   2579   <li><strong>Channels</strong>: Mono, Stereo</li>
   2580 </ul>
   2581 
   2582 <p>The device SHOULD allow playback of raw audio content with the following
   2583 characteristics:</p>
   2584 
   2585 <ul>
   2586   <li><strong>Sampling rates</strong>: 24000, 48000</li>
   2587 </ul>
   2588 
   2589 <h3 id="5_5_2_audio_effects">5.5.2. Audio Effects</h3>
   2590 
   2591 
   2592 <p>Android provides an API for audio effects for device implementations [<a href="http://developer.android.com/reference/android/media/audiofx/AudioEffect.html">Resources, 69</a>]. Device implementations that declare the feature
   2593 android.hardware.audio.output:</p>
   2594 
   2595 <ul>
   2596   <li>MUST support the EFFECT_TYPE_EQUALIZER and EFFECT_TYPE_LOUDNESS_ENHANCER
   2597 implementations controllable through the AudioEffect subclasses Equalizer,
   2598 LoudnessEnhancer.</li>
   2599   <li>MUST support the visualizer API implementation, controllable through the
   2600 Visualizer class.</li>
   2601   <li>SHOULD support the EFFECT_TYPE_BASS_BOOST, EFFECT_TYPE_ENV_REVERB,
   2602 EFFECT_TYPE_PRESET_REVERB, and EFFECT_TYPE_VIRTUALIZER implementations
   2603 controllable through the AudioEffect sub-classes BassBoost,
   2604 EnvironmentalReverb, PresetReverb, and Virtualizer.</li>
   2605 </ul>
   2606 
   2607 <h3 id="5_5_3_audio_output_volume">5.5.3. Audio Output Volume</h3>
   2608 
   2609 
   2610 <p>Android Television device implementations MUST include support for system
   2611 Master Volume and digital audio output volume attenuation on supported outputs,
   2612 except for compressed audio passthrough output (where no audio decoding is done
   2613 on the device).</p>
   2614 
   2615 <h2 id="5_6_audio_latency">5.6. Audio Latency</h2>
   2616 
   2617 
   2618 <p>Audio latency is the time delay as an audio signal passes through a system.
   2619 Many classes of applications rely on short latencies, to achieve real-time
   2620 sound effects.</p>
   2621 
   2622 <p>For the purposes of this section, use the following definitions:</p>
   2623 
   2624 <ul>
   2625   <li><strong>output latency</strong>. The interval between when an application writes a frame of PCM-coded data and
   2626 when the corresponding sound can be heard by an external listener or observed
   2627 by a transducer.</li>
   2628   <li><strong>cold output latency</strong>. The output latency for the first frame, when the audio output system has been
   2629 idle and powered down prior to the request.</li>
   2630   <li><strong>continuous output latency</strong>. The output latency for subsequent frames, after the device is playing audio.</li>
   2631   <li><strong>input latency</strong>. The interval between when an external sound is presented to the device and
   2632 when an application reads the corresponding frame of PCM-coded data.</li>
   2633   <li><strong>cold input latency</strong>. The sum of lost input time and the input latency for the first frame, when the
   2634 audio input system has been idle and powered down prior to the request.</li>
   2635   <li><strong>continuous input latency</strong>. The input latency for subsequent frames, while the device is capturing audio.</li>
   2636   <li><strong>cold output jitter</strong>. The variance among separate measurements of cold output latency values.</li>
   2637   <li><strong>cold input jitter</strong>. The variance among separate measurements of cold input latency values.</li>
   2638   <li><strong>continuous round-trip latency</strong>. The sum of continuous input latency plus continuous output latency plus
   2639   one buffer period.
   2640   The buffer period term allows processing time for the app and for the app to
   2641   mitigate phase difference between input and output streams.
   2642   </li>
   2643   <li><strong>OpenSL ES PCM buffer queue API</strong>. The set of PCM-related OpenSL ES APIs within Android NDK; see
   2644 NDK_root/docs/opensles/index.html.</li>
   2645 </ul>
   2646 
   2647 <p>Device implementations that declare android.hardware.audio.output are STRONGLY RECOMMENDED to meet
   2648 or exceed these audio output requirements:</p>
   2649 
   2650 <ul>
   2651   <li>cold output latency of 100 milliseconds or less</li>
   2652   <li>continuous output latency of 45 milliseconds or less</li>
   2653   <li>minimize the cold output jitter</li>
   2654 </ul>
   2655 
   2656 <p>If a device implementation meets the requirements of this section after any
   2657 initial calibration when using the OpenSL ES PCM buffer queue API, for
   2658 continuous output latency and cold output latency over at least one supported
   2659 audio output device, it is STRONGLY RECOMMENDED to report support for low-latency audio, by reporting
   2660 the feature android.hardware.audio.low_latency via the
   2661 android.content.pm.PackageManager class [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>]. Conversely, if the device implementation does not meet these requirements it
   2662 MUST NOT report support for low-latency audio.</p>
   2663 
   2664 <p>Device implementations that include android.hardware.microphone are STRONGLY RECOMMENDED to meet
   2665 these input audio requirements:</p>
   2666 
   2667 <ul>
   2668   <li>cold input latency of 100 milliseconds or less</li>
   2669   <li>continuous input latency of 30 milliseconds or less</li>
   2670   <li>continuous round-trip latency of 50 milliseconds or less</li>
   2671   <li>minimize the cold input jitter</li>
   2672 </ul>
   2673 
   2674 <h2 id="5_7_network_protocols">5.7. Network Protocols</h2>
   2675 
   2676 
   2677 <p>Devices MUST support the media network protocols for audio and video playback
   2678 as specified in the Android SDK documentation [<a href="http://developer.android.com/guide/appendix/media-formats.html">Resources, 64</a>]. Specifically, devices MUST support the following media network protocols:</p>
   2679 
   2680 <ul>
   2681   <li>RTSP (RTP, SDP)</li>
   2682   <li>HTTP(S) progressive streaming</li>
   2683   <li>HTTP(S) Live Streaming draft protocol, Version 3 [<a href="http://tools.ietf.org/html/draft-pantos-http-live-streaming-03">Resources, 71</a>]</li>
   2684 </ul>
   2685 
   2686 <h2 id="5_8_secure_media">5.8. Secure Media</h2>
   2687 
   2688 
   2689 <p>Device implementations that support secure video output and are capable of
   2690 supporting secure surfaces MUST declare support for Display.FLAG_SECURE. Device
   2691 implementations that declare support for Display.FLAG_SECURE, if they support a
   2692 wireless display protocol, MUST secure the link with a cryptographically strong
   2693 mechanism such as HDCP 2.x or higher for Miracast wireless displays. Similarly
   2694 if they support a wired external display, the device implementations MUST
   2695 support HDCP 1.2 or higher. Android Television device implementations MUST
   2696 support HDCP 2.2 for devices supporting 4K resolution and HDCP 1.4 or above for
   2697 lower resolutions. The upstream Android open source implementation includes
   2698 support for wireless (Miracast) and wired (HDMI) displays that satisfies this
   2699 requirement.</p>
   2700 
   2701 <h2 id="5_9_midi">5.9. Musical Instrument Digital Interface (MIDI)</h2>
   2702 
   2703 <p>
   2704 If a device implementation supports the inter-app MIDI software transport
   2705 (virtual MIDI devices), and it supports MIDI over
   2706 <em>all</em> of the following MIDI-capable hardware transports
   2707 for which it provides generic non-MIDI connectivity, it is STRONGLY RECOMMENDED to report
   2708 support for feature android.software.midi via the
   2709 android.content.pm.PackageManager class
   2710 [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>].
   2711 </p>
   2712 
   2713 <p>The MIDI-capable hardware transports are:</p>
   2714 <ul>
   2715   <li>USB host mode (section 7.7 USB)</li>
   2716   <li>USB peripheral mode (section 7.7 USB)</li>
   2717 </ul>
   2718 
   2719 <p>
   2720 Conversely, if the device implementation provides generic non-MIDI connectivity over a particular
   2721 MIDI-capable hardware transport listed above, but does not support MIDI over that hardware transport,
   2722 it MUST NOT report support for feature android.software.midi.
   2723 </p>
   2724 
   2725 <p>
   2726 MIDI over Bluetooth LE acting in central role (section 7.4.3 Bluetooth)
   2727 is in trial use status.  A device implementation that reports
   2728 feature android.software.midi, and which provides generic non-MIDI connectivity
   2729 over Bluetooth LE, SHOULD support MIDI over Bluetooth LE.
   2730 </p>
   2731 
   2732 <h2 id="5_10_pro_audio">5.10. Professional Audio</h2>
   2733 
   2734 <p>
   2735 If a device implementation meets <em>all</em> of the following requirements,
   2736 it is STRONGLY RECOMMENDED to report support for feature android.hardware.audio.pro via the
   2737 android.content.pm.PackageManager class
   2738 [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>].
   2739 </p>
   2740 
   2741 <ul>
   2742 
   2743 <li>
   2744 The device implementation MUST report support for feature android.hardware.audio.low_latency.
   2745 </li>
   2746 
   2747 <li> The continuous round-trip audio latency, as defined in section 5.6 Audio Latency,
   2748 MUST be 20 milliseconds or less and SHOULD be 10 milliseconds or less over at least one
   2749 supported path.
   2750 </li>
   2751 
   2752 <li>
   2753 If the device includes a 4 conductor 3.5mm audio jack,
   2754 the continuous round-trip audio latency MUST be 20 milliseconds or less over the audio jack path,
   2755 and SHOULD be 10 milliseconds or less over at the audio jack path.
   2756 </li>
   2757 
   2758 <li>
   2759 The device implementation MUST include a USB port(s) supporting USB host mode and
   2760 USB peripheral mode.
   2761 </li>
   2762 
   2763 <li>
   2764 The USB host mode MUST implement the USB audio class.
   2765 </li>
   2766 
   2767 <li>
   2768 If the device includes an HDMI port, the device implementation
   2769 MUST support output in stereo and eight channels
   2770 at 20-bit or 24-bit depth and 192 kHz without bit-depth loss or resampling.
   2771 </li>
   2772 
   2773 <li>
   2774 The device implementation MUST report support for feature android.software.midi.
   2775 </li>
   2776 
   2777 <li>
   2778 If the device includes a 4 conductor 3.5mm audio jack,
   2779 the device implementation is STRONGLY RECOMMENDED to comply with section
   2780 <a href="https://source.android.com/accessories/headset/specification.html#mobile_device_jack_specifications">Mobile device (jack) specifications</a>
   2781 of the
   2782 <a href="https://source.android.com/accessories/headset/specification.html">Wired Audio Headset Specification (v1.1)</a>.
   2783 </li>
   2784 
   2785 </ul>
   2786 
   2787 <h1 id="6_developer_tools_and_options_compatibility">6. Developer Tools and Options Compatibility</h1>
   2788 
   2789 <h2 id="6_1_developer_tools">6.1. Developer Tools</h2>
   2790 
   2791 <p>Device implementations MUST support the Android Developer Tools provided in the
   2792 Android SDK. Android compatible devices MUST be compatible with:</p>
   2793 
   2794 <ul>
   2795   <li><strong>Android Debug Bridge (adb)</strong> [<a href="http://developer.android.com/tools/help/adb.html">Resources, 72</a>]</li>
   2796 </ul>
   2797 
   2798 <p>Device implementations MUST support all adb functions as documented in the
   2799 Android SDK including dumpsys [<a href="https://source.android.com/devices/input/diagnostics.html">Resources, 73</a>]. The device-side adb daemon MUST be inactive by default and there MUST be a
   2800 user-accessible mechanism to turn on the Android Debug Bridge. If a device
   2801 implementation omits USB peripheral mode, it MUST implement the Android Debug
   2802 Bridge via local-area network (such as Ethernet or 802.11). </p>
   2803 
   2804 <p>Android includes support for secure adb. Secure adb enables adb on known
   2805 authenticated hosts. Device implementations MUST support secure adb.</p>
   2806 
   2807 <ul>
   2808   <li><strong>Dalvik Debug Monitor Service (ddms)</strong> [<a href="http://developer.android.com/tools/debugging/ddms.html">Resources, 74</a>]</li>
   2809 </ul>
   2810 
   2811 <p>Device implementations MUST support all ddms features as documented in the
   2812 Android SDK. As ddms uses adb, support for ddms SHOULD be inactive by default,
   2813 but MUST be supported whenever the user has activated the Android Debug Bridge,
   2814 as above.</p>
   2815 
   2816 <ul>
   2817   <li><strong>Monkey</strong> [<a href="http://developer.android.com/tools/help/monkey.html">Resources, 75</a>]</li>
   2818 </ul>
   2819 
   2820 <p>Device implementations MUST include the Monkey framework, and make it available
   2821 for applications to use.</p>
   2822 
   2823 <ul>
   2824   <li><strong>SysTrace</strong> [<a href="http://developer.android.com/tools/help/systrace.html">Resources, 76</a>]</li>
   2825 </ul>
   2826 
   2827 <p>Device implementations MUST support systrace tool as documented in the Android
   2828 SDK. Systrace must be inactive by default, and there MUST be a user-accessible
   2829 mechanism to turn on Systrace.</p>
   2830 
   2831 <p>Most Linux-based systems and Apple Macintosh systems recognize Android devices
   2832 using the standard Android SDK tools, without additional support; however
   2833 Microsoft Windows systems typically require a driver for new Android devices.
   2834 (For instance, new vendor IDs and sometimes new device IDs require custom USB
   2835 drivers for Windows systems.) If a device implementation is unrecognized by the
   2836 adb tool as provided in the standard Android SDK, device implementers MUST
   2837 provide Windows drivers allowing developers to connect to the device using the
   2838 adb protocol. These drivers MUST be provided for Windows XP, Windows Vista,
   2839 Windows 7, Windows 8 and Windows 10 in both 32-bit and 64-bit versions.
   2840 </p>
   2841 
   2842 <h2 id="6_2_developer_options">6.2. Developer Options</h2>
   2843 
   2844 
   2845 <p>Android includes support for developers to configure application
   2846 development-related settings. Device implementations MUST honor the
   2847 android.settings.APPLICATION_DEVELOPMENT_SETTINGS intent to show application
   2848 development-related settings [<a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_APPLICATION_DEVELOPMENT_SETTINGS">Resources, 77</a>]. The upstream Android implementation hides the Developer Options menu by
   2849 default and enables users to launch Developer Options after pressing seven (7)
   2850 times on the <strong>Settings</strong> > <strong>About Device</strong> > <strong>Build Number</strong> menu item. Device implementations MUST provide a consistent experience for
   2851 Developer Options. Specifically, device implementations MUST hide Developer
   2852 Options by default and MUST provide a mechanism to enable Developer Options
   2853 that is consistent with the upstream Android implementation.</p>
   2854 
   2855 <h1 id="7_hardware_compatibility">7. Hardware Compatibility</h1>
   2856 
   2857 
   2858 <p>If a device includes a particular hardware component that has a corresponding
   2859 API for third-party developers, the device implementation MUST implement that
   2860 API as described in the Android SDK documentation. If an API in the SDK
   2861 interacts with a hardware component that is stated to be optional and the
   2862 device implementation does not possess that component:</p>
   2863 
   2864 <ul>
   2865   <li>Complete class definitions (as documented by the SDK) for the component APIs
   2866 MUST still be presented.
   2867   <li>The API&rsquo;s behaviors MUST be implemented as no-ops in some reasonable fashion.
   2868   <li>API methods MUST return null values where permitted by the SDK documentation.
   2869   <li>API methods MUST return no-op implementations of classes where null values are
   2870 not permitted by the SDK documentation.
   2871   <li>API methods MUST NOT throw exceptions not documented by the SDK documentation.
   2872 </ul>
   2873 
   2874 <p>A typical example of a scenario where these requirements apply is the telephony
   2875 API: even on non-phone devices, these APIs must be implemented as reasonable
   2876 no-ops.</p>
   2877 
   2878 <p>Device implementations MUST consistently report accurate hardware configuration
   2879 information via the getSystemAvailableFeatures() and hasSystemFeature(String)
   2880 methods on the android.content.pm.PackageManager class for the same build
   2881 fingerprint. [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>]</p>
   2882 
   2883 <h2 id="7_1_display_and_graphics">7.1. Display and Graphics</h2>
   2884 
   2885 
   2886 <p>Android includes facilities that automatically adjust application assets and UI
   2887 layouts appropriately for the device, to ensure that third-party applications
   2888 run well on a variety of hardware configurations [<a href="http://developer.android.com/guide/practices/screens_support.html">Resources, 78</a>]. Devices MUST properly implement these APIs and behaviors, as detailed in
   2889 this section.</p>
   2890 
   2891 <p>The units referenced by the requirements in this section are defined as
   2892 follows:</p>
   2893 
   2894 <ul>
   2895   <li><strong>physical diagonal size</strong>. The distance in inches between two opposing corners of the illuminated portion
   2896 of the display.</li>
   2897   <li><strong>dots per inch (dpi)</strong>. The number of pixels encompassed by a linear horizontal or vertical span of
   2898 1&rdquo;. Where dpi values are listed, both horizontal and vertical dpi must fall
   2899 within the range.</li>
   2900   <li><strong>aspect ratio</strong>. The ratio of the pixels of the longer dimension
   2901   to the shorter dimension of the screen. For example, a display of 480x854 pixels
   2902   would be 854/480 = 1.779, or roughly &ldquo;16:9&rdquo;.</li>
   2903   <li><strong>density-independent pixel (dp)</strong> The virtual pixel unit normalized to a 160 dpi screen, calculated as: pixels =
   2904 dps * (density/160).</li>
   2905 </ul>
   2906 
   2907 <h3 id="7_1_1_screen_configuration">7.1.1. Screen Configuration</h3>
   2908 
   2909 
   2910 <h4 id="7_1_1_1_screen_size">7.1.1.1. Screen Size</h4>
   2911 
   2912 <div class="note">
   2913 <p>Android Watch devices (detailed in <a href="#2_device_types">section 2</a>) MAY have smaller screen sizes as described in this section.</p>
   2914 </div>
   2915 
   2916 <p>The Android UI framework supports a variety of different screen sizes, and
   2917 allows applications to query the device screen size (aka &ldquo;screen layout") via
   2918 android.content.res.Configuration.screenLayout with the SCREENLAYOUT_SIZE_MASK.
   2919 Device implementations MUST report the correct screen size as defined in the
   2920 Android SDK documentation [<a href="http://developer.android.com/guide/practices/screens_support.html">Resources, 78</a>] and determined by the upstream Android platform. Specifically, device
   2921 implementations MUST report the correct screen size according to the following
   2922 logical density-independent pixel (dp) screen dimensions.</p>
   2923 
   2924 <ul>
   2925   <li>Devices MUST have screen sizes of at least 426 dp x 320 dp (&lsquo;small&rsquo;), unless it
   2926 is an Android Watch device.</li>
   2927   <li>Devices that report screen size &lsquo;normal&rsquo; MUST have screen sizes of at least 480
   2928 dp x 320 dp.</li>
   2929   <li>Devices that report screen size &lsquo;large&rsquo; MUST have screen sizes of at least 640
   2930 dp x 480 dp.</li>
   2931   <li>Devices that report screen size &lsquo;xlarge&rsquo; MUST have screen sizes of at least 960
   2932 dp x 720 dp.</li>
   2933 </ul>
   2934 
   2935 <p>In addition, </p>
   2936 
   2937 <ul>
   2938   <li>Android Watch devices MUST have a screen with the physical diagonal size in the
   2939 range from 1.1 to 2.5 inches.</li>
   2940   <li>Other types of Android device implementations, with a physically integrated
   2941 screen, MUST have a screen at least 2.5 inches in physical diagonal size.</li>
   2942 </ul>
   2943 
   2944 <p>Devices MUST NOT change their reported screen size at any time.</p>
   2945 
   2946 <p>Applications optionally indicate which screen sizes they support via the
   2947 &lt;supports-screens&gt; attribute in the AndroidManifest.xml file. Device
   2948 implementations MUST correctly honor applications' stated support for small,
   2949 normal, large, and xlarge screens, as described in the Android SDK
   2950 documentation.</p>
   2951 
   2952 <h4 id="7_1_1_2_screen_aspect_ratio">7.1.1.2. Screen Aspect Ratio</h4>
   2953 
   2954 <div class="note">
   2955 <p>Android Watch devices MAY have an aspect ratio of 1.0 (1:1).</p>
   2956 </div>
   2957 
   2958 
   2959 <p>The screen aspect ratio MUST be a value from 1.3333 (4:3) to 1.86 (roughly
   2960 16:9), but Android Watch devices MAY have an aspect ratio of 1.0 (1:1) because
   2961 such a device implementation will use a UI_MODE_TYPE_WATCH as the
   2962 android.content.res.Configuration.uiMode.</p>
   2963 
   2964 <h4 id="7_1_1_3_screen_density">7.1.1.3. Screen Density</h4>
   2965 
   2966 
   2967 <p>The Android UI framework defines a set of standard logical densities to help
   2968 application developers target application resources. Device implementations
   2969 MUST report only one of the following logical Android framework densities
   2970 through the android.util.DisplayMetrics APIs, and MUST execute applications at
   2971 this standard density and MUST NOT change the value at at any time for the
   2972 default display.</p>
   2973 
   2974 <ul>
   2975   <li>120 dpi (ldpi)</li>
   2976   <li>160 dpi (mdpi)</li>
   2977   <li>213 dpi (tvdpi)</li>
   2978   <li>240 dpi (hdpi)</li>
   2979   <li>280 dpi (280dpi)</li>
   2980   <li>320 dpi (xhdpi)</li>
   2981   <li>360 dpi (360dpi)</li>
   2982   <li>400 dpi (400dpi)</li>
   2983   <li>420 dpi (420dpi)</li>
   2984   <li>480 dpi (xxhdpi)</li>
   2985   <li>560 dpi (560dpi)</li>
   2986   <li>640 dpi (xxxhdpi)</li>
   2987 </ul>
   2988 
   2989 <p>Device implementations SHOULD define the standard Android framework density
   2990 that is numerically closest to the physical density of the screen, unless that
   2991 logical density pushes the reported screen size below the minimum supported. If
   2992 the standard Android framework density that is numerically closest to the
   2993 physical density results in a screen size that is smaller than the smallest
   2994 supported compatible screen size (320 dp width), device implementations SHOULD
   2995 report the next lowest standard Android framework density.</p>
   2996 
   2997 <h3 id="7_1_2_display_metrics">7.1.2. Display Metrics</h3>
   2998 
   2999 
   3000 <p>Device implementations MUST report correct values for all display metrics
   3001 defined in android.util.DisplayMetrics [<a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">Resources, 79</a>] and MUST report the same values regardless of whether the embedded or
   3002 external screen is used as the default display.</p>
   3003 
   3004 <h3 id="7_1_3_screen_orientation">7.1.3. Screen Orientation</h3>
   3005 
   3006 
   3007 <p>Devices MUST report which screen orientations they support
   3008 (android.hardware.screen.portrait and/or android.hardware.screen.landscape) and
   3009 MUST report at least one supported orientation. For example, a device with a
   3010 fixed orientation landscape screen, such as a television or laptop, SHOULD only
   3011 report android.hardware.screen.landscape.</p>
   3012 
   3013 <p>Devices that report both screen orientations MUST support dynamic orientation
   3014 by applications to either portrait or landscape screen orientation. That is,
   3015 the device must respect the application&rsquo;s request for a specific screen
   3016 orientation. Device implementations MAY select either portrait or landscape
   3017 orientation as the default.</p>
   3018 
   3019 <p>Devices MUST report the correct value for the device&rsquo;s current orientation,
   3020 whenever queried via the android.content.res.Configuration.orientation,
   3021 android.view.Display.getOrientation(), or other APIs.</p>
   3022 
   3023 <p>Devices MUST NOT change the reported screen size or density when changing
   3024 orientation.</p>
   3025 
   3026 <h3 id="7_1_4_2d_and_3d_graphics_acceleration">7.1.4. 2D and 3D Graphics Acceleration</h3>
   3027 
   3028 
   3029 <p>Device implementations MUST support both OpenGL ES 1.0 and 2.0, as embodied and
   3030 detailed in the Android SDK documentations. Device implementations SHOULD
   3031 support OpenGL ES 3.0 or 3.1 on devices capable of supporting it. Device
   3032 implementations MUST also support Android RenderScript, as detailed in the
   3033 Android SDK documentation [<a href="http://developer.android.com/guide/topics/renderscript/">Resources, 80</a>].</p>
   3034 
   3035 <p>Device implementations MUST also correctly identify themselves as supporting
   3036 OpenGL ES 1.0, OpenGL ES 2.0, OpenGL ES 3.0 or OpenGL 3.1. That is:</p>
   3037 
   3038 <ul>
   3039   <li>The managed APIs (such as via the GLES10.getString() method) MUST report support
   3040 for OpenGL ES 1.0 and OpenGL ES 2.0.</li>
   3041   <li>The native C/C++ OpenGL APIs (APIs available to apps via libGLES_v1CM.so,
   3042 libGLES_v2.so, or libEGL.so) MUST report support for OpenGL ES 1.0 and OpenGL
   3043 ES 2.0.</li>
   3044   <li>Device implementations that declare support for OpenGL ES 3.0 or 3.1 MUST
   3045 support the corresponding managed APIs and include support for native C/C++
   3046 APIs. On device implementations that declare support for OpenGL ES 3.0 or 3.1,
   3047 libGLESv2.so MUST export the corresponding function symbols in addition to the
   3048 OpenGL ES 2.0 function symbols.</li>
   3049 </ul>
   3050 
   3051 <p>In addition to OpenGL ES 3.1, Android provides an extension pack with Java
   3052 interfaces [<a href="https://developer.android.com/reference/android/opengl/GLES31Ext.html">Resources, 81</a>] and native support for advanced graphics functionality such as tessellation
   3053 and the ASTC texture compression format. Android device implementations MAY
   3054 support this extension pack, and&mdash;only if fully implemented&mdash;MUST identify the
   3055 support through the android.hardware.opengles.aep feature flag.</p>
   3056 
   3057 <p>Also, device implementations MAY implement any desired OpenGL ES extensions.
   3058 However, device implementations MUST report via the OpenGL ES managed and
   3059 native APIs all extension strings that they do support, and conversely MUST NOT
   3060 report extension strings that they do not support.</p>
   3061 
   3062 <p>Note that Android includes support for applications to optionally specify that
   3063 they require specific OpenGL texture compression formats. These formats are
   3064 typically vendor-specific. Device implementations are not required by Android
   3065 to implement any specific texture compression format. However, they SHOULD
   3066 accurately report any texture compression formats that they do support, via the
   3067 getString() method in the OpenGL API.</p>
   3068 
   3069 <p>Android includes a mechanism for applications to declare that they want to
   3070 enable hardware acceleration for 2D graphics at the Application, Activity,
   3071 Window, or View level through the use of a manifest tag
   3072 android:hardwareAccelerated or direct API calls [<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">Resources, 82</a>].</p>
   3073 
   3074 <p>Device implementations MUST enable hardware acceleration by default, and MUST
   3075 disable hardware acceleration if the developer so requests by setting
   3076 android:hardwareAccelerated="false&rdquo; or disabling hardware acceleration directly
   3077 through the Android View APIs.</p>
   3078 
   3079 <p>In addition, device implementations MUST exhibit behavior consistent with the
   3080 Android SDK documentation on hardware acceleration [<a href="http://developer.android.com/guide/topics/graphics/hardware-accel.html">Resources, 82</a>].</p>
   3081 
   3082 <p>Android includes a TextureView object that lets developers directly integrate
   3083 hardware-accelerated OpenGL ES textures as rendering targets in a UI hierarchy.
   3084 Device implementations MUST support the TextureView API, and MUST exhibit
   3085 consistent behavior with the upstream Android implementation.</p>
   3086 
   3087 <p>Android includes support for EGL_ANDROID_RECORDABLE, an EGLConfig attribute
   3088 that indicates whether the EGLConfig supports rendering to an ANativeWindow
   3089 that records images to a video. Device implementations MUST support
   3090 EGL_ANDROID_RECORDABLE extension [<a href="https://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">Resources, 83</a>].</p>
   3091 
   3092 <h3 id="7_1_5_legacy_application_compatibility_mode">7.1.5. Legacy Application Compatibility Mode</h3>
   3093 
   3094 
   3095 <p>Android specifies a &ldquo;compatibility mode&rdquo; in which the framework operates in a
   3096 'normal' screen size equivalent (320dp width) mode for the benefit of legacy
   3097 applications not developed for old versions of Android that pre-date
   3098 screen-size independence.</p>
   3099 
   3100 <ul>
   3101 <li>Android Automotive does not support legacy compatibility mode.</li>
   3102 <li>All other device implementations MUST include support for legacy application
   3103 compatibility mode as implemented by the upstream Android open source code. That
   3104 is, device implementations MUST NOT alter the triggers or thresholds at which
   3105 compatibility mode is activated, and MUST NOT alter the behavior of the
   3106 compatibility mode itself.</li>
   3107 </ul>
   3108 
   3109 <h3 id="7_1_6_screen_technology">7.1.6. Screen Technology</h3>
   3110 
   3111 
   3112 <p>The Android platform includes APIs that allow applications to render rich
   3113 graphics to the display. Devices MUST support all of these APIs as defined by
   3114 the Android SDK unless specifically allowed in this document. </p>
   3115 
   3116 <ul>
   3117   <li>Devices MUST support displays capable of rendering 16-bit color graphics and
   3118 SHOULD support displays capable of 24-bit color graphics.</li>
   3119   <li>Devices MUST support displays capable of rendering animations.</li>
   3120   <li>The display technology used MUST have a pixel aspect ratio (PAR) between 0.9
   3121 and 1.15. That is, the pixel aspect ratio MUST be near square (1.0) with a 10 ~
   3122 15% tolerance.</li>
   3123 </ul>
   3124 
   3125 <h3 id="7_1_7_external_displays">7.1.7. Secondary Displays</h3>
   3126 
   3127 
   3128 <p>Android includes support for secondary display to enable media sharing
   3129 capabilities and developer APIs for accessing external displays. If a device
   3130 supports an external display either via a wired, wireless, or an embedded
   3131 additional display connection then the device implementation MUST implement the
   3132 display manager API as described in the Android SDK documentation [<a href="http://developer.android.com/reference/android/hardware/display/DisplayManager.html">Resources, 84</a>].</p>
   3133 
   3134 <h2 id="7_2_input_devices">7.2. Input Devices</h2>
   3135 
   3136 <p>Devices MUST support a touchscreen or meet the requirements listed in 7.2.2
   3137 for non-touch navigation.</p>
   3138 
   3139 <h3 id="7_2_1_keyboard">7.2.1. Keyboard</h3>
   3140 
   3141 <div class="note">
   3142 <p>Android Watch and Android Automotive implementations MAY implement a soft
   3143 keyboard. All other device implementations MUST implement a soft keyboard and:</p>
   3144 </div>
   3145 
   3146 
   3147 <p>Device implementations:</p>
   3148 
   3149 <ul>
   3150   <li>MUST include support for the Input Management Framework (which allows
   3151 third-party developers to create Input Method Editors&mdash;i.e. soft keyboard) as
   3152 detailed at <a href="http://developer.android.com">http://developer.android.com</a>.</li>
   3153   <li>MUST provide at least one soft keyboard implementation (regardless of whether a
   3154 hard keyboard is present) except for Android Watch devices where the screen
   3155 size makes it less reasonable to have a soft keyboard.</li>
   3156   <li>MAY include additional soft keyboard implementations.</li>
   3157   <li>MAY include a hardware keyboard.</li>
   3158   <li>MUST NOT include a hardware keyboard that does not match one of the formats
   3159 specified in android.content.res.Configuration.keyboard [<a href="http://developer.android.com/reference/android/content/res/Configuration.html">Resources, 85</a>] (QWERTY or 12-key).</li>
   3160 </ul>
   3161 
   3162 <h3 id="7_2_2_non-touch_navigation">7.2.2. Non-touch Navigation</h3>
   3163 
   3164 <div class="note">
   3165 <p>Android Television devices MUST support D-pad.</p>
   3166 </div>
   3167 
   3168 <p>Device implementations:</p>
   3169 
   3170 <ul>
   3171   <li>MAY omit a non-touch navigation option (trackball, d-pad, or wheel) if the
   3172 device implementation is not an Android Television device.</li>
   3173   <li>MUST report the correct value for android.content.res.Configuration.navigation
   3174 [<a href="http://developer.android.com/reference/android/content/res/Configuration.html">Resources, 85</a>].</li>
   3175   <li>MUST provide a reasonable alternative user interface mechanism for the
   3176 selection and editing of text, compatible with Input Management Engines. The
   3177 upstream Android open source implementation includes a selection mechanism
   3178 suitable for use with devices that lack non-touch navigation inputs.</li>
   3179 </ul>
   3180 
   3181 <h3 id="7_2_3_navigation_keys">7.2.3. Navigation Keys</h3>
   3182 
   3183 <div class="note">
   3184 <p>The availability and visibility requirement of the Home, Recents, and Back
   3185 functions differ between device types as described in this section.</p>
   3186 </div>
   3187 
   3188 <p>The Home, Recents, and Back functions (mapped to the key events KEYCODE_HOME,
   3189 KEYCODE_APP_SWITCH, KEYCODE_BACK, respectively) are essential to the Android
   3190 navigation paradigm and therefore:</p>
   3191 
   3192 <ul>
   3193   <li>Android Handheld device implementations MUST provide the Home, Recents, and
   3194 Back functions.</li>
   3195   <li>Android Television device implementations MUST provide the Home and Back
   3196 functions.</li>
   3197   <li>Android Watch device implementations MUST have the Home function available to
   3198 the user, and the Back function except for when it is in UI_MODE_TYPE_WATCH.</li>
   3199   <li>Android Automotive implementations MUST provide the Home function and MAY
   3200 provide Back and Recent functions.</li>
   3201   <li>All other types of device implementations MUST provide the Home and Back
   3202 functions.</li>
   3203 </ul>
   3204 
   3205 <p>These functions MAY be implemented via dedicated physical buttons (such as
   3206 mechanical or capacitive touch buttons), or MAY be implemented using dedicated
   3207 software keys on a distinct portion of the screen, gestures, touch panel, etc.
   3208 Android supports both implementations. All of these functions MUST be
   3209 accessible with a single action (e.g. tap, double-click or gesture) when
   3210 visible.</p>
   3211 
   3212 <p>Recents function, if provided, MUST have a visible button or icon unless hidden
   3213 together with other navigation functions in full-screen mode. This does not
   3214 apply to devices upgrading from earlier Android versions that have physical
   3215 buttons for navigation and no recents key.</p>
   3216 
   3217 <p> The Home and Back functions, if provided, MUST each have a visible button or
   3218 icon unless hidden together with other navigation functions in full-screen mode
   3219 or when the uiMode UI_MODE_TYPE_MASK is set to UI_MODE_TYPE_WATCH.</p>
   3220 
   3221 <p>The Menu function is deprecated in favor of action bar since Android 4.0.
   3222 Therefore the new device implementations shipping with Android 6.0 and later MUST NOT
   3223 implement a dedicated physical button for the Menu function. Older device
   3224 implementations SHOULD NOT implement a dedicated physical button for the Menu
   3225 function, but if the physical Menu button is implemented and the device is
   3226 running applications with targetSdkVersion > 10, the device implementation:</p>
   3227 
   3228 <ul>
   3229   <li>MUST display the action overflow button on the action bar when it is visible
   3230 and the resulting action overflow menu popup is not empty. For a device
   3231 implementation launched before Android 4.4 but upgrading to Android 6.0, this
   3232 is RECOMMENDED.</li>
   3233   <li>MUST NOT modify the position of the action overflow popup displayed by
   3234 selecting the overflow button in the action bar.</li>
   3235   <li>MAY render the action overflow popup at a modified position on the screen when
   3236 it is displayed by selecting the physical menu button.</li>
   3237 </ul>
   3238 
   3239 <p>For backwards compatibility, device implementations MUST make the Menu function
   3240 available to applications when targetSdkVersion is less than 10, either by a physical
   3241 button, a software key, or gestures. This Menu function should be presented
   3242 unless hidden together with other navigation functions.</p>
   3243 
   3244 <p>Android device implementations with the support of the Assist action [<a
   3245 href="http://developer.android.com/reference/android/content/Intent.html#ACTION_ASSIST">Resources,
   3246 30</a>] MUST make this accessisble with a single action (e.g. tap, double-click,
   3247 or gesture) when other navigation keys are visible, and are STRONGLY RECOMMENDED to
   3248 use the long-press on the Home button or software key as the single action.</p>
   3249 
   3250 <p>Device implementations MAY use a distinct portion of the screen to display the
   3251 navigation keys, but if so, MUST meet these requirements:</p>
   3252 
   3253 <ul>
   3254   <li>Device implementation navigation keys MUST use a distinct portion of the
   3255 screen, not available to applications, and MUST NOT obscure or otherwise
   3256 interfere with the portion of the screen available to applications.</li>
   3257   <li>Device implementations MUST make available a portion of the display to
   3258 applications that meets the requirements defined in <a href="#7_1_1_screen_configuration">section 7.1.1</a>.</li>
   3259   <li>Device implementations MUST display the navigation keys when applications do
   3260 not specify a system UI mode, or specify SYSTEM_UI_FLAG_VISIBLE.</li>
   3261   <li>Device implementations MUST present the navigation keys in an unobtrusive &ldquo;low
   3262 profile&rdquo; (eg. dimmed) mode when applications specify
   3263 SYSTEM_UI_FLAG_LOW_PROFILE.</li>
   3264   <li>Device implementations MUST hide the navigation keys when applications specify
   3265 SYSTEM_UI_FLAG_HIDE_NAVIGATION.</li>
   3266 </ul>
   3267 
   3268 <h3 id="7_2_4_touchscreen_input">7.2.4. Touchscreen Input</h3>
   3269 
   3270 <div class="note">
   3271 <p>Android Handhelds and Watch Devices MUST support touchscreen input.</p>
   3272 </div>
   3273 
   3274 
   3275 <p>Device implementations SHOULD have a pointer input system of some kind (either
   3276 mouse-like or touch). However, if a device implementation does not support a
   3277 pointer input system, it MUST NOT report the android.hardware.touchscreen or
   3278 android.hardware.faketouch feature constant. Device implementations that do
   3279 include a pointer input system:</p>
   3280 
   3281 <ul>
   3282   <li>SHOULD support fully independently tracked pointers, if the device input system
   3283 supports multiple pointers.</li>
   3284   <li>MUST report the value of android.content.res.Configuration.touchscreen [<a href="http://developer.android.com/reference/android/content/res/Configuration.html">Resources, 85</a>] corresponding to the type of the specific touchscreen on the device.</li>
   3285 </ul>
   3286 
   3287 <p>Android includes support for a variety of touchscreens, touch pads, and fake
   3288 touch input devices. Touchscreen based device implementations are associated
   3289 with a display [<a href="http://source.android.com/devices/tech/input/touch-devices.html">Resources, 86</a>] such that the user has the impression of directly manipulating items on
   3290 screen. Since the user is directly touching the screen, the system does not
   3291 require any additional affordances to indicate the objects being manipulated.
   3292 In contrast, a fake touch interface provides a user input system that
   3293 approximates a subset of touchscreen capabilities. For example, a mouse or
   3294 remote control that drives an on-screen cursor approximates touch, but requires
   3295 the user to first point or focus then click. Numerous input devices like the
   3296 mouse, trackpad, gyro-based air mouse, gyro-pointer, joystick, and multi-touch
   3297 trackpad can support fake touch interactions. Android includes the feature
   3298 constant android.hardware.faketouch, which corresponds to a high-fidelity
   3299 non-touch (pointer-based) input device such as a mouse or trackpad that can
   3300 adequately emulate touch-based input (including basic gesture support), and
   3301 indicates that the device supports an emulated subset of touchscreen
   3302 functionality. Device implementations that declare the fake touch feature MUST
   3303 meet the fake touch requirements in <a href="#7_2_5_fake_touch_input">section 7.2.5</a>.</p>
   3304 
   3305 <p>Device implementations MUST report the correct feature corresponding to the
   3306 type of input used. Device implementations that include a touchscreen
   3307 (single-touch or better) MUST report the platform feature constant
   3308 android.hardware.touchscreen. Device implementations that report the platform
   3309 feature constant android.hardware.touchscreen MUST also report the platform
   3310 feature constant android.hardware.faketouch. Device implementations that do not
   3311 include a touchscreen (and rely on a pointer device only) MUST NOT report any
   3312 touchscreen feature, and MUST report only android.hardware.faketouch if they
   3313 meet the fake touch requirements in <a href="#7_2_5_fake_touch_input">section 7.2.5</a>.</p>
   3314 
   3315 <h3 id="7_2_5_fake_touch_input">7.2.5. Fake Touch Input</h3>
   3316 
   3317 
   3318 <p>Device implementations that declare support for android.hardware.faketouch:</p>
   3319 
   3320 <ul>
   3321   <li>MUST report the absolute X and Y screen positions of the pointer location and
   3322 display a visual pointer on the screen [<a href="http://developer.android.com/reference/android/view/MotionEvent.html">Resources, 87</a>].</li>
   3323   <li>MUST report touch event with the action code that specifies the state change
   3324 that occurs on the pointer going down or up on the screen [<a href="http://developer.android.com/reference/android/view/MotionEvent.html">Resources, 87</a>].</li>
   3325   <li>MUST support pointer down and up on an object on the screen, which allows users
   3326 to emulate tap on an object on the screen.</li>
   3327   <li>MUST support pointer down, pointer up, pointer down then pointer up in the same
   3328 place on an object on the screen within a time threshold, which allows users to
   3329 emulate double tap on an object on the screen [<a href="http://developer.android.com/reference/android/view/MotionEvent.html">Resources, 87</a>].</li>
   3330   <li>MUST support pointer down on an arbitrary point on the screen, pointer move to
   3331 any other arbitrary point on the screen, followed by a pointer up, which allows
   3332 users to emulate a touch drag.</li>
   3333   <li>MUST support pointer down then allow users to quickly move the object to a
   3334 different position on the screen and then pointer up on the screen, which
   3335 allows users to fling an object on the screen.</li>
   3336 </ul>
   3337 
   3338 <p>Devices that declare support for android.hardware.faketouch.multitouch.distinct
   3339 MUST meet the requirements for faketouch above, and MUST also support distinct
   3340 tracking of two or more independent pointer inputs.</p>
   3341 
   3342 <h3 id="7_2_6_game_controller_support">7.2.6. Game Controller Support</h3>
   3343 
   3344 
   3345 <p>Android Television device implementations MUST support button mappings for game
   3346 controllers as listed below. The upstream Android implementation includes
   3347 implementation for game controllers that satisfies this requirement. </p>
   3348 
   3349 <h4 id="7_2_6_1_button_mappings">7.2.6.1. Button Mappings</h4>
   3350 
   3351 
   3352 <p>Android Television device implementations MUST support the following key
   3353 mappings:</p>
   3354 <table>
   3355  <tr>
   3356     <th>Button</th>
   3357     <th>HID Usage<sup>2</sup></th>
   3358     <th>Android Button</th>
   3359  </tr>
   3360  <tr>
   3361     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_A">A</a><sup>1</sup></td>
   3362     <td>0x09 0x0001</td>
   3363     <td>KEYCODE_BUTTON_A (96)</td>
   3364  </tr>
   3365  <tr>
   3366     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_B">B</a><sup>1</sup></td>
   3367     <td>0x09 0x0002</td>
   3368     <td>KEYCODE_BUTTON_B (97)</td>
   3369  </tr>
   3370  <tr>
   3371     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_X">X</a><sup>1</sup></td>
   3372     <td>0x09 0x0004</td>
   3373     <td>KEYCODE_BUTTON_X (99)</td>
   3374  </tr>
   3375  <tr>
   3376     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_Y">Y</a><sup>1</sup></td>
   3377     <td>0x09 0x0005</td>
   3378     <td>KEYCODE_BUTTON_Y (100)</td>
   3379  </tr>
   3380  <tr>
   3381     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_UP">D-pad up</a><sup>1</sup><br />
   3382 
   3383 <a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_DOWN">D-pad down</a><sup>1</sup></td>
   3384     <td>0x01 0x0039<sup>3</sup></td>
   3385     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_HAT_Y">AXIS_HAT_Y</a><sup>4</sup></td>
   3386  </tr>
   3387  <tr>
   3388     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_LEFT">D-pad left</a>1<br />
   3389 
   3390 <a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_DPAD_RIGHT">D-pad right</a><sup>1</sup></td>
   3391     <td>0x01 0x0039<sup>3</sup></td>
   3392     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_HAT_X">AXIS_HAT_X</a><sup>4</sup></td>
   3393  </tr>
   3394  <tr>
   3395     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_L1">Left shoulder button</a><sup>1</sup></td>
   3396     <td>0x09 0x0007</td>
   3397     <td>KEYCODE_BUTTON_L1 (102)</td>
   3398  </tr>
   3399  <tr>
   3400     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_R1">Right shoulder button</a><sup>1</sup></td>
   3401     <td>0x09 0x0008</td>
   3402     <td>KEYCODE_BUTTON_R1 (103)</td>
   3403  </tr>
   3404  <tr>
   3405     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_THUMBL">Left stick click</a><sup>1</sup></td>
   3406     <td>0x09 0x000E</td>
   3407     <td>KEYCODE_BUTTON_THUMBL (106)</td>
   3408  </tr>
   3409  <tr>
   3410     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BUTTON_THUMBR">Right stick click</a><sup>1</sup></td>
   3411     <td>0x09 0x000F</td>
   3412     <td>KEYCODE_BUTTON_THUMBR (107)</td>
   3413  </tr>
   3414  <tr>
   3415     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_HOME">Home</a><sup>1</sup></td>
   3416     <td>0x0c 0x0223</td>
   3417     <td>KEYCODE_HOME (3)</td>
   3418  </tr>
   3419  <tr>
   3420     <td><a href="http://developer.android.com/reference/android/view/KeyEvent.html#KEYCODE_BACK">Back</a><sup>1</sup></td>
   3421     <td>0x0c 0x0224</td>
   3422     <td>KEYCODE_BACK (4)</td>
   3423  </tr>
   3424 </table>
   3425 
   3426 
   3427 <p class="table_footnote">1 [<a href="http://developer.android.com/reference/android/view/KeyEvent.html">Resources, 88</a>]</p>
   3428 
   3429 <p class="table_footnote">2 The above HID usages must be declared within a Game pad CA (0x01 0x0005).</p>
   3430 
   3431 <p class="table_footnote">3 This usage must have a Logical Minimum of 0, a Logical Maximum of 7, a
   3432 Physical Minimum of 0, a Physical Maximum of 315, Units in Degrees, and a
   3433 Report Size of 4. The logical value is defined to be the clockwise rotation
   3434 away from the vertical axis; for example, a logical value of 0 represents no
   3435 rotation and the up button being pressed, while a logical value of 1 represents
   3436 a rotation of 45 degrees and both the up and left keys being pressed.</p>
   3437 
   3438 <p class="table_footnote">4 [<a href="http://developer.android.com/reference/android/view/MotionEvent.html">Resources, 87</a>]</p>
   3439 
   3440 <table>
   3441  <tr>
   3442     <th>Analog Controls<sup>1</sup></th>
   3443     <th>HID Usage</th>
   3444     <th>Android Button</th>
   3445  </tr>
   3446  <tr>
   3447     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_LTRIGGER">Left Trigger</a></td>
   3448     <td>0x02 0x00C5</td>
   3449     <td>AXIS_LTRIGGER </td>
   3450  </tr>
   3451  <tr>
   3452     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_THROTTLE">Right Trigger</a></td>
   3453     <td>0x02 0x00C4</td>
   3454     <td>AXIS_RTRIGGER </td>
   3455  </tr>
   3456  <tr>
   3457     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_Y">Left Joystick</a></td>
   3458     <td>0x01 0x0030<br />
   3459 
   3460 0x01 0x0031</td>
   3461     <td>AXIS_X<br />
   3462 
   3463 AXIS_Y</td>
   3464  </tr>
   3465  <tr>
   3466     <td><a href="http://developer.android.com/reference/android/view/MotionEvent.html#AXIS_Z">Right Joystick</a></td>
   3467     <td>0x01 0x0032<br />
   3468 
   3469 0x01 0x0035</td>
   3470     <td>AXIS_Z<br />
   3471 
   3472 AXIS_RZ</td>
   3473  </tr>
   3474 </table>
   3475 
   3476 
   3477 <p class="table_footnote">1 [<a href="http://developer.android.com/reference/android/view/MotionEvent.html">Resources, 87</a>]</p>
   3478 
   3479 <h3 id="7_2_7_remote_control">7.2.7. Remote Control</h3>
   3480 
   3481 
   3482 <p>Android Television device implementations SHOULD provide a remote control to
   3483 allow users to access the TV interface. The remote control MAY be a physical
   3484 remote or can be a software-based remote that is accessible from a mobile phone
   3485 or tablet. The remote control MUST meet the requirements defined below.</p>
   3486 
   3487 <ul>
   3488   <li><strong>Search affordance</strong>. Device implementations MUST fire KEYCODE_SEARCH when the user invokes voice search either on the physical or software-based remote.</li>
   3489   <li><strong>Navigation</strong>. All Android Television remotes MUST include Back, Home, and Select buttons and
   3490 support for D-pad events [<a href="http://developer.android.com/reference/android/view/KeyEvent.html">Resources, 88</a>].</li>
   3491 </ul>
   3492 
   3493 <h2 id="7_3_sensors">7.3. Sensors</h2>
   3494 
   3495 
   3496 <p>Android includes APIs for accessing a variety of sensor types. Devices
   3497 implementations generally MAY omit these sensors, as provided for in the
   3498 following subsections. If a device includes a particular sensor type that has a
   3499 corresponding API for third-party developers, the device implementation MUST
   3500 implement that API as described in the Android SDK documentation and the
   3501 Android Open Source documentation on sensors [<a href="http://source.android.com/devices/sensors/">Resources, 89</a>]. For example, device implementations:</p>
   3502 
   3503 <ul>
   3504   <li>MUST accurately report the presence or absence of sensors per the
   3505 android.content.pm.PackageManager class [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70]</a>.</li>
   3506   <li>MUST return an accurate list of supported sensors via the
   3507 SensorManager.getSensorList() and similar methods.</li>
   3508   <li>MUST behave reasonably for all other sensor APIs (for example, by returning
   3509 true or false as appropriate when applications attempt to register listeners,
   3510 not calling sensor listeners when the corresponding sensors are not present;
   3511 etc.).</li>
   3512   <li>MUST report all sensor measurements using the relevant International System of
   3513 Units (metric) values for each sensor type as defined in the Android SDK
   3514 documentation [<a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">Resources, 90</a>].</li>
   3515   <li>SHOULD report the event time in nanoseconds as defined in the Android SDK
   3516 documentation, representing the time the event happened and synchronized with
   3517 the SystemClock.elapsedRealtimeNano() clock. Existing and new Android devices
   3518 are <strong>STRONGLY RECOMMENDED</strong> to meet these requirement so they will be able to upgrade to the future
   3519 platform releases where this might become a REQUIRED component. The
   3520 synchronization error SHOULD be below 100 milliseconds [<a href="http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp">Resources, 91</a>].</li>
   3521   <li>MUST report sensor data with a maximum latency of 100 milliseconds + 2 * sample_time for the case of a sensor streamed
   3522     with a minimum required latency of 5 ms + 2 * sample_time when the application processor is active. This delay does not include any filtering delays.</li>
   3523   <li>MUST report the first sensor sample within 400 milliseconds + 2 * sample_time of the sensor being activated. It is acceptable for this sample to have an accuracy of 0.</li>
   3524 </ul>
   3525 
   3526 <p>The list above is not comprehensive; the documented behavior of the Android SDK
   3527 and the Android Open Source Documentations on Sensors [<a href="http://source.android.com/devices/sensors/">Resources, 89</a>] is to be considered authoritative.</p>
   3528 
   3529 <p>Some sensor types are composite, meaning they can be derived from data provided
   3530 by one or more other sensors. (Examples include the orientation sensor, and the
   3531 linear acceleration sensor.) Device implementations SHOULD implement these
   3532 sensor types, when they include the prerequisite physical sensors as described
   3533 in [<a href="https://source.android.com/devices/sensors/sensor-types.html">Resources, 92</a>].
   3534 If a device implementation includes a composite sensor it MUST implement the
   3535 sensor as described in the Android Open Source documentation on composite
   3536 sensors [<a href="https://source.android.com/devices/sensors/sensor-types.html#composite_sensor_type_summary">Resources, 92</a>].</p>
   3537 
   3538 <p>Some Android sensors support a &ldquo;continuous&rdquo; trigger mode, which returns data
   3539 continuously [<a href="https://source.android.com/devices/sensors/report-modes.html#continuous">Resources, 93</a>]. For any API indicated by the Android SDK documentation to be a continuous
   3540 sensor, device implementations MUST continuously provide periodic data samples
   3541 that SHOULD have a jitter below 3%, where jitter is defined as the standard
   3542 deviation of the difference of the reported timestamp values between
   3543 consecutive events.</p>
   3544 
   3545 <p>Note that the device implementations MUST ensure that the sensor event stream
   3546 MUST NOT prevent the device CPU from entering a suspend state or waking up from
   3547 a suspend state.</p>
   3548 
   3549 <p>Finally, when several sensors are activated, the power consumption SHOULD NOT
   3550 exceed the sum of the individual sensor&rsquo;s reported power consumption.</p>
   3551 
   3552 <h3 id="7_3_1_accelerometer">7.3.1. Accelerometer</h3>
   3553 
   3554 
   3555 <p>Device implementations SHOULD include a 3-axis accelerometer. Android Handheld
   3556 devices and Android Watch devices are STRONGLY RECOMMENDED to include this
   3557 sensor. If a device implementation does include a 3-axis accelerometer, it:</p>
   3558 
   3559 <ul>
   3560   <li>MUST implement and report TYPE_ACCELEROMETER sensor [<a href="http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER">Resources, 94</a>].</li>
   3561   <li>MUST be able to report events up to a frequency of at least 50 Hz for
   3562   Android Watch devices as such devices have a stricter power constraint and
   3563   100 Hz for all other device types.</li>
   3564   <li>SHOULD report events up to at least 200 Hz.</li>
   3565   <li>MUST comply with the Android sensor coordinate system as detailed in the
   3566 Android APIs [<a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">Resources, 90</a>].</li>
   3567   <li>MUST be capable of measuring from freefall up to four times the gravity (4g) or
   3568 more on any axis.</li>
   3569   <li>MUST have a resolution of at least 12-bits and SHOULD have a resolution of at
   3570 least 16-bits.</li>
   3571   <li>SHOULD be calibrated while in use if the characteristics changes over the life
   3572 cycle and compensated, and preserve the compensation parameters between device
   3573 reboots.</li>
   3574   <li>SHOULD be temperature compensated.</li>
   3575   <li>MUST have a standard deviation no greater than 0.05 m/s^, where the standard
   3576 deviation should be calculated on a per axis basis on samples collected over a
   3577 period of at least 3 seconds at the fastest sampling rate.</li>
   3578   <li>SHOULD implement the TYPE_SIGNIFICANT_MOTION, TYPE_TILT_DETECTOR,
   3579 TYPE_STEP_DETECTOR, TYPE_STEP_COUNTER composite sensors as described in the
   3580 Android SDK document. Existing and new Android devices are <strong>STRONGLY RECOMMENDED</strong> to implement the TYPE_SIGNIFICANT_MOTION composite sensor. If any of these
   3581 sensors are implemented, the sum of their power consumption MUST always be less
   3582 than 4 mW and SHOULD each be below 2 mW and 0.5 mW for when the device is in a
   3583 dynamic or static condition.</li>
   3584   <li>If a gyroscope sensor is included, MUST implement the TYPE_GRAVITY and
   3585 TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the
   3586 TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices
   3587 are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.</li>
   3588   <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if a gyroscope sensor
   3589 and a magnetometer sensor is also included.</li>
   3590 </ul>
   3591 
   3592 <h3 id="7_3_2_magnetometer">7.3.2. Magnetometer</h3>
   3593 
   3594 
   3595 <p>Device implementations SHOULD include a 3-axis magnetometer (compass). If a
   3596 device does include a 3-axis magnetometer, it:</p>
   3597 
   3598 <ul>
   3599   <li>MUST implement the TYPE_MAGNETIC_FIELD sensor and SHOULD also implement
   3600 TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor. Existing and new Android devices are
   3601 STRONGLY RECOMMENDED to implement the TYPE_MAGNETIC_FIELD_UNCALIBRATED sensor.</li>
   3602   <li>MUST be able to report events up to a frequency of at least 10 Hz and SHOULD
   3603 report events up to at least 50 Hz.</li>
   3604   <li>MUST comply with the Android sensor coordinate system as detailed in the
   3605 Android APIs [<a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">Resources, 90</a>].</li>
   3606   <li>MUST be capable of measuring between -900 &micro;T and +900 &micro;T on each axis before
   3607 saturating.</li>
   3608   <li>MUST have a hard iron offset value less than 700 &micro;T and SHOULD have a value
   3609 below 200 &micro;T, by placing the magnetometer far from dynamic (current-induced)
   3610 and static (magnet-induced) magnetic fields.</li>
   3611   <li>MUST have a resolution equal or denser than 0.6 &micro;T and SHOULD have a resolution
   3612 equal or denser than 0.2 &micro;.</li>
   3613   <li>SHOULD be temperature compensated.</li>
   3614   <li>MUST support online calibration and compensation of the hard iron bias, and
   3615 preserve the compensation parameters between device reboots.</li>
   3616   <li>MUST have the soft iron compensation applied&mdash;the calibration can be done either
   3617 while in use or during the production of the device.</li>
   3618   <li>SHOULD have a standard deviation, calculated on a per axis basis on samples
   3619 collected over a period of at least 3 seconds at the fastest sampling rate, no
   3620 greater than 0.5 &micro;T.</li>
   3621   <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer
   3622 sensor and a gyroscope sensor is also included.</li>
   3623   <li>MAY implement the TYPE_GEOMAGNETIC_ROTATION_VECTOR sensor if an accelerometer
   3624 sensor is also implemented. However if implemented, it MUST consume less than
   3625 10 mW and SHOULD consume less than 3 mW when the sensor is registered for batch
   3626 mode at 10 Hz.</li>
   3627 </ul>
   3628 
   3629 <h3 id="7_3_3_gps">7.3.3. GPS</h3>
   3630 
   3631 
   3632 <p>Device implementations SHOULD include a GPS receiver. If a device
   3633 implementation does include a GPS receiver, it SHOULD include some form of&ldquo;assisted GPS&rdquo; technique to minimize GPS lock-on time.</p>
   3634 
   3635 <h3 id="7_3_4_gyroscope">7.3.4. Gyroscope</h3>
   3636 
   3637 
   3638 <p>Device implementations SHOULD include a gyroscope (angular change sensor).
   3639 Devices SHOULD NOT include a gyroscope sensor unless a 3-axis accelerometer is
   3640 also included. If a device implementation includes a gyroscope, it:</p>
   3641 
   3642 <ul>
   3643   <li>MUST implement the TYPE_GYROSCOPE sensor and SHOULD also implement
   3644 TYPE_GYROSCOPE_UNCALIBRATED sensor. Existing and new Android devices are
   3645 STRONGLY RECOMMENDED to implement the SENSOR_TYPE_GYROSCOPE_UNCALIBRATED sensor.</li>
   3646   <li>MUST be capable of measuring orientation changes up to 1,000 degrees per second.</li>
   3647   <li>MUST be able to report events up to a frequency of at least 50 Hz for
   3648   Android Watch devices as such devices have a stricter power constraint and 
   3649   100 Hz for all other device types.</li>
   3650   <li>SHOULD report events up to at least 200 Hz.</li>
   3651   <li>MUST have a resolution of 12-bits or more and SHOULD have a resolution of
   3652 16-bits or more.</li>
   3653   <li>MUST be temperature compensated.</li>
   3654   <li>MUST be calibrated and compensated while in use, and preserve the compensation
   3655 parameters between device reboots.</li>
   3656   <li>MUST have a variance no greater than 1e-7 rad^2 / s^2 per Hz (variance per Hz,
   3657 or rad^2 / s). The variance is allowed to vary with the sampling rate, but must
   3658 be constrained by this value. In other words, if you measure the variance of
   3659 the gyro at 1 Hz sampling rate it should be no greater than 1e-7 rad^2/s^2.</li>
   3660   <li>MUST implement a TYPE_ROTATION_VECTOR composite sensor, if an accelerometer
   3661 sensor and a magnetometer sensor is also included.</li>
   3662   <li>If an accelerometer sensor is included, MUST implement the TYPE_GRAVITY and
   3663 TYPE_LINEAR_ACCELERATION composite sensors and SHOULD implement the
   3664 TYPE_GAME_ROTATION_VECTOR composite sensor. Existing and new Android devices
   3665 are STRONGLY RECOMMENDED to implement the TYPE_GAME_ROTATION_VECTOR sensor.</li>
   3666 </ul>
   3667 
   3668 <h3 id="7_3_5_barometer">7.3.5. Barometer</h3>
   3669 
   3670 
   3671 <p>Device implementations SHOULD include a barometer (ambient air pressure
   3672 sensor). If a device implementation includes a barometer, it:</p>
   3673 
   3674 <ul>
   3675   <li>MUST implement and report TYPE_PRESSURE sensor.</li>
   3676   <li>MUST be able to deliver events at 5 Hz or greater.</li>
   3677   <li>MUST have adequate precision to enable estimating altitude.</li>
   3678   <li>MUST be temperature compensated.</li>
   3679 </ul>
   3680 
   3681 <h3 id="7_3_6_thermometer">7.3.6. Thermometer</h3>
   3682 
   3683 
   3684 <p>Device implementations MAY include an ambient thermometer (temperature sensor).
   3685 If present, it MUST be defined as SENSOR_TYPE_AMBIENT_TEMPERATURE and it MUST
   3686 measure the ambient (room) temperature in degrees Celsius.</p>
   3687 
   3688 <p>Device implementations MAY but SHOULD NOT include a CPU temperature sensor. If
   3689 present, it MUST be defined as SENSOR_TYPE_TEMPERATURE, it MUST measure the
   3690 temperature of the device CPU, and it MUST NOT measure any other temperature.
   3691 Note the SENSOR_TYPE_TEMPERATURE sensor type was deprecated in Android 4.0.</p>
   3692 
   3693 <h3 id="7_3_7_photometer">7.3.7. Photometer</h3>
   3694 
   3695 
   3696 <p>Device implementations MAY include a photometer (ambient light sensor).</p>
   3697 
   3698 <h3 id="7_3_8_proximity_sensor">7.3.8. Proximity Sensor</h3>
   3699 
   3700 
   3701 <p>Device implementations MAY include a proximity sensor. Devices that can make a
   3702 voice call and indicate any value other than PHONE_TYPE_NONE in getPhoneType
   3703 SHOULD include a proximity sensor. If a device implementation does include a
   3704 proximity sensor, it:</p>
   3705 
   3706 <ul>
   3707   <li>MUST measure the proximity of an object in the same direction as the screen.
   3708 That is, the proximity sensor MUST be oriented to detect objects close to the
   3709 screen, as the primary intent of this sensor type is to detect a phone in use
   3710 by the user. If a device implementation includes a proximity sensor with any
   3711 other orientation, it MUST NOT be accessible through this API.</li>
   3712   <li>MUST have 1-bit of accuracy or more.</li>
   3713 </ul>
   3714 
   3715 
   3716 <h3 id="7_3_9_hifi_sensors">7.3.9. High Fidelity Sensors</h3>
   3717 
   3718 <p>Device implementations supporting a set of higher quality sensors that can meet all
   3719 the requirements listed in this section MUST identify the support through the
   3720 <code>android.hardware.sensor.hifi_sensors</code> feature flag.</p>
   3721 
   3722 <p>A device declaring android.hardware.sensor.hifi_sensors MUST support all of the following
   3723 sensor types meeting the quality requirements as below:</p>
   3724 
   3725 <ul>
   3726   <li>SENSOR_TYPE_ACCELEROMETER
   3727   <ul>
   3728     <li>MUST have a measurement range between at least -8g and +8g</li>
   3729     <li>MUST have a measurement resolution of at least 1024 LSB/G</li>
   3730     <li>MUST have a minimum measurement frequency of 12.5 Hz or lower</li>
   3731     <li>MUST have a maxmium measurement frequency of 200 Hz or higher</li>
   3732     <li>MUST have a measurement noise not above 400uG/&radic;Hz</li>
   3733     <li>MUST implement a non-wake-up form of this sensor with a buffering capability of at least 3000 sensor events</li>
   3734     <li>MUST have a batching power consumption not worse than 3 mW</li>
   3735   </ul>
   3736   </li>
   3737   <li>SENSOR_TYPE_GYROSCOPE
   3738   <ul>
   3739     <li>MUST have a measurement range between at least -1000 and +1000 dps</li>
   3740     <li>MUST have a measurement resolution of at least 16 LSB/dps</li>
   3741     <li>MUST have a minimum measurement frequency of 12.5 Hz or lower</li>
   3742     <li>MUST have a maxmium measurement frequency of 200 Hz or higher</li>
   3743     <li>MUST have a measurement noise not above 0.014&deg;/s/&radic;Hz</li>
   3744   </ul>
   3745   </li>
   3746   <li>SENSOR_TYPE_GYROSCOPE_UNCALIBRATED with the same quality requirements as
   3747     SENSOR_TYPE_GYROSCOPE</li>
   3748   <li>SENSOR_TYPE_GEOMAGNETIC_FIELD
   3749   <ul>
   3750     <li>MUST have a measurement range between at least -900 and +900 uT</li>
   3751     <li>MUST have a measurement resolution of at least 5 LSB/uT</li>
   3752     <li>MUST have a minimum measurement frequency of 5 Hz or lower</li>
   3753     <li>MUST have a maxmium measurement frequency of 50 Hz or higher</li>
   3754     <li>MUST have a measurement noise not above 0.5 uT</li>
   3755   </ul>
   3756   </li>
   3757   <li>SENSOR_TYPE_MAGNETIC_FIELD_UNCALIBRATED with the same quality requirements as
   3758     SENSOR_TYPE_GEOMAGNETIC_FIELD and in addition:
   3759   <ul>
   3760     <li>MUST implement a non-wake-up form of this sensor with a buffering capability of at least 600 sensor events</li>
   3761   </ul>
   3762   </li>
   3763   <li>SENSOR_TYPE_PRESSURE
   3764   <ul>
   3765     <li>MUST have a measurement range between at least 300 and 1100 hPa</li>
   3766     <li>MUST have a measurement resolution of at least 80 LSB/hPa</li>
   3767     <li>MUST have a minimum measurement frequency of 1 Hz or lower</li>
   3768     <li>MUST have a maximum measurement frequency of 10 Hz or higher</li>
   3769     <li>MUST have a measurement noise not above 2 Pa/&radic;Hz</li>
   3770     <li>MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events</li>
   3771     <li>MUST have a batching power consumption not worse than 2 mW</li>
   3772   </ul>
   3773   </li>
   3774   <li>SENSOR_TYPE_ROTATION_VECTOR
   3775   <ul>
   3776     <li>MUST have a batching power consumption not worse than 4 mW</li>
   3777   </ul>
   3778   </li>
   3779   <li>SENSOR_TYPE_GAME_ROTATION_VECTOR MUST implement a non-wake-up form of this sensor with a buffering capability of at least 300 sensor events</li>
   3780   <li>SENSOR_TYPE_SIGNIFICANT_MOTION
   3781   <ul>
   3782     <li>MUST have a power consumption not worse than 0.5 mW when device is static
   3783       and 1.5 mW when device is moving</li>
   3784   </ul>
   3785   </li>
   3786   <li>SENSOR_TYPE_STEP_DETECTOR
   3787   <ul>
   3788     <li>MUST implement a non-wake-up form of this sensor with a buffering capability of at least 100 sensor events</li>
   3789     <li>MUST have a power consumption not worse than 0.5 mW when device is static
   3790       and 1.5 mW when device is moving</li>
   3791     <li>MUST have a batching power consumption not worse than 4 mW</li>
   3792   </ul>
   3793   </li>
   3794   <li>SENSOR_TYPE_STEP_COUNTER
   3795   <ul>
   3796     <li>MUST have a power consumption not worse than 0.5 mW when device is static
   3797       and 1.5 mW when device is moving</li>
   3798   </ul>
   3799   </li>
   3800   <li>SENSOR_TILT_DETECTOR
   3801   <ul>
   3802     <li>MUST have a power consumption not worse than 0.5 mW when device is static
   3803       and 1.5 mW when device is moving</li>
   3804   </ul>
   3805   </li>
   3806 </ul>
   3807 
   3808 <p>Also such a device MUST meet the following sensor subsystem requirements:</p>
   3809 
   3810 <ul>
   3811   <li>The event timestamp of the same physical event reported by the Accelerometer, Gyroscope
   3812     sensor and Magnetometer MUST be within 2.5 milliseconds of each other.</li>
   3813   <li>The Gyroscope sensor event timestamps MUST be on the same time base as the camera
   3814     subsystem and within 1 millisconds of error.</li>
   3815   <li>The latency of delivery of samples to the HAL SHOULD be below 5 milliseconds from
   3816     the instant the data is available on the physical sensor hardware.</li>
   3817   <li>The power consumption MUST not be higher than 0.5 mW when device is static and 2.0 mW
   3818     when device is moving when any combination of the following sensors are enabled:
   3819   <ul>
   3820     <li>SENSOR_TYPE_SIGNIFICANT_MOTION</li>
   3821     <li>SENSOR_TYPE_STEP_DETECTOR</li>
   3822     <li>SENSOR_TYPE_STEP_COUNTER</li>
   3823     <li>SENSOR_TILT_DETECTORS</li>
   3824   </ul>
   3825   </li>
   3826 </ul>
   3827 
   3828 <p>Note that all power consumption requirements in this section do not include the power
   3829   consumption of the Application Processor. It is inclusive of the power drawn by the entire
   3830   sensor chain - the sensor, any supporting circuitry, any dedicated sensor processing system,
   3831   etc.</p>
   3832 
   3833 <p>The following sensor types MAY also be supported on a device implementation declaring
   3834   android.hardware.sensor.hifi_sensors, but if these sensor types are present they MUST meet the
   3835   following minimum buffering capability requirement:</p>
   3836 
   3837 <ul>
   3838   <li>SENSOR_TYPE_PROXIMITY: 100 sensor events</li>
   3839 </ul>
   3840 
   3841 <h3 id="7_3_10_fingeprint">7.3.10. Fingerprint Sensor</h3>
   3842 
   3843 <p>Device implementations with a secure lock screen SHOULD include a fingerprint sensor.
   3844 If a device implementation includes a fingerprint sensor and has a corresponding API for
   3845 third-party developers, it:</p>
   3846 
   3847 <ul>
   3848   <li>MUST declare support for the android.hardware.fingerprint feature.</li>
   3849   <li>MUST fully implement the corresponding API as described in the Android SDK documentation
   3850 [<a href="https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html">Resources, 95</a>].
   3851   </li>
   3852   <li>MUST have a false acceptance rate not higher than 0.002%.</li>
   3853   <li>Is STRONGLY RECOMMENDED to have a false rejection rate not higher than 10%, and a
   3854     latency from when the fingerprint sensor is touched until the screen is unlocked below
   3855     1 second, for 1 enrolled finger.</li>
   3856   <li>MUST rate limit attempts for at least 30 seconds after 5 false trials for fingerprint
   3857     verification.</li>
   3858   <li>MUST have a hardware-backed keystore implementation, and perform the fingerprint matching
   3859     in a Trusted Execution Environment (TEE) or on a chip with a secure channel to the TEE.
   3860   </li>
   3861   <li>MUST have all identifiable fingerprint data encrypted and cryptographically
   3862     authenticated such that they cannot be acquired, read or altered outside of the
   3863     Trusted Execution Environment (TEE) as documented in the implementation guidelines
   3864     on the Android Open Source Project site
   3865     [<a href="https://source.android.com/devices/tech/security/authentication/fingerprint-hal.html">Resources, 96</a>].
   3866   </li>
   3867   <li>MUST prevent adding a fingerprint without first establishing a chain of trust by
   3868     having the user confirm existing or add a new device credential (PIN/pattern/password)
   3869     using the TEE as implemented in the Android Open Source project.</li>
   3870   <li>MUST NOT enable 3rd-party applications to distinguish between individual fingerprints.
   3871   </li>
   3872   <li>MUST honor the DevicePolicyManager.KEYGUARD_DISABLE_FINGERPRINT flag.</li>
   3873   <li>MUST, when upgraded from a version earlier than Android 6.0, have the fingerprint
   3874     data securely migrated to meet the above requirements or removed.</li>
   3875   <li>SHOULD use the Android Fingerprint icon provided in the Android Open Source Project.</li>
   3876 </ul>
   3877 
   3878 <h2 id="7_4_data_connectivity">7.4. Data Connectivity</h2>
   3879 
   3880 
   3881 <h3 id="7_4_1_telephony">7.4.1. Telephony</h3>
   3882 
   3883 
   3884 <p>&ldquo;Telephony&rdquo; as used by the Android APIs and this document refers specifically
   3885 to hardware related to placing voice calls and sending SMS messages via a GSM
   3886 or CDMA network. While these voice calls may or may not be packet-switched,
   3887 they are for the purposes of Android considered independent of any data
   3888 connectivity that may be implemented using the same network. In other words,
   3889 the Android &ldquo;telephony&rdquo; functionality and APIs refer specifically to voice
   3890 calls and SMS. For instance, device implementations that cannot place calls or
   3891 send/receive SMS messages MUST NOT report the android.hardware.telephony
   3892 feature or any subfeatures, regardless of whether they use a cellular network
   3893 for data connectivity.</p>
   3894 
   3895 <p>Android MAY be used on devices that do not include telephony hardware. That is,
   3896 Android is compatible with devices that are not phones. However, if a device
   3897 implementation does include GSM or CDMA telephony, it MUST implement full
   3898 support for the API for that technology. Device implementations that do not
   3899 include telephony hardware MUST implement the full APIs as no-ops.</p>
   3900 
   3901 <h3 id="7_4_2_ieee_802_11_wi-fi">7.4.2. IEEE 802.11 (Wi-Fi)</h3>
   3902 
   3903 <div class="note">
   3904 <p>Android Television device implementations MUST include Wi-Fi support.</p>
   3905 </div>
   3906 
   3907 
   3908 <p>Android Television device implementations MUST include support for one or more
   3909 forms of 802.11 (b/g/a/n, etc.) and other types of Android device
   3910 implementation SHOULD include support for one or more forms of 802.11. If a
   3911 device implementation does include support for 802.11 and exposes the
   3912 functionality to a third-party application, it MUST implement the corresponding
   3913 Android API and:</p>
   3914 
   3915 <ul>
   3916   <li>MUST report the hardware feature flag android.hardware.wifi.</li>
   3917   <li>MUST implement the multicast API as described in the SDK documentation [<a href="http://developer.android.com/reference/android/net/wifi/WifiManager.MulticastLock.html">Resources, 97</a>].</li>
   3918   <li>MUST support multicast DNS (mDNS) and MUST NOT filter mDNS packets
   3919 (224.0.0.251) at any time of operation including:
   3920     <ul>
   3921       <li>Even when the screen is not in an active state.</li>
   3922       <li>For Android Television device implementations, even when in standby power states.</li>
   3923     </ul>
   3924 </ul>
   3925 
   3926 <h4 id="7_4_2_1_wi-fi_direct">7.4.2.1. Wi-Fi Direct</h4>
   3927 
   3928 
   3929 <p>Device implementations SHOULD include support for Wi-Fi Direct (Wi-Fi
   3930 peer-to-peer). If a device implementation does include support for Wi-Fi
   3931 Direct, it MUST implement the corresponding Android API as described in the SDK
   3932 documentation [<a href="http://developer.android.com/reference/android/net/wifi/p2p/WifiP2pManager.html">Resources, 98</a>]. If a device implementation includes support for Wi-Fi Direct, then it:</p>
   3933 
   3934 <ul>
   3935   <li>MUST report the hardware feature android.hardware.wifi.direct.</li>
   3936   <li>MUST support regular Wi-Fi operation.</li>
   3937   <li>SHOULD support concurrent Wi-Fi and Wi-Fi Direct operation.</li>
   3938 </ul>
   3939 
   3940 <h4 id="7_4_2_2_wi-fi_tunneled_direct_link_setup">7.4.2.2. Wi-Fi Tunneled Direct Link Setup</h4>
   3941 
   3942 <div class="note">
   3943 <p>Android Television device implementations MUST include support for Wi-Fi
   3944 Tunneled Direct Link Setup (TDLS).</p>
   3945 </div>
   3946 
   3947 
   3948 <p>Android Television device implementations MUST include support for Wi-Fi
   3949 Tunneled Direct Link Setup (TDLS) and other types of Android device
   3950 implementations SHOULD include support for Wi-Fi TDLS as described in the
   3951 Android SDK Documentation [<a href="http://developer.android.com/reference/android/net/wifi/WifiManager.html">Resources, 99</a>]. If a device implementation does include support for TDLS and TDLS is enabled
   3952 by the WiFiManager API, the device:</p>
   3953 
   3954 <ul>
   3955   <li>SHOULD use TDLS only when it is possible AND beneficial.</li>
   3956   <li>SHOULD have some heuristic and NOT use TDLS when its performance might be worse
   3957 than going through the Wi-Fi access point.</li>
   3958 </ul>
   3959 
   3960 <h3 id="7_4_3_bluetooth">7.4.3. Bluetooth</h3>
   3961 
   3962 <div class="note">
   3963 <p>Android Watch and Automotive implementations MUST support Bluetooth. Android
   3964 Television implementations MUST support Bluetooth and Bluetooth LE.</p>
   3965 </div>
   3966 
   3967 
   3968 <p>Android includes support for Bluetooth and Bluetooth Low Energy [<a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">Resources, 100</a>]. Device implementations that include support for Bluetooth and Bluetooth Low
   3969 Energy MUST declare the relevant platform features (android.hardware.bluetooth
   3970 and android.hardware.bluetooth_le respectively) and implement the platform
   3971 APIs. Device implementations SHOULD implement relevant Bluetooth profiles such
   3972 as A2DP, AVCP, OBEX, etc. as appropriate for the device. Android Television
   3973 device implementations MUST support Bluetooth and Bluetooth LE. </p>
   3974 
   3975 <p>Device implementations including support for Bluetooth Low Energy:</p>
   3976 
   3977 <ul>
   3978   <li>MUST declare the hardware feature android.hardware.bluetooth_le.</li>
   3979   <li>MUST enable the GATT (generic attribute profile) based Bluetooth APIs as
   3980 described in the SDK documentation and [<a href="http://developer.android.com/reference/android/bluetooth/package-summary.html">Resources, 100</a>].</li>
   3981   <li>MUST implement a Resolvable Private Address (RPA) timeout no longer than
   3982 15 minutes, and rotate the address at timeout to protect user privacy.</li>
   3983   <li>SHOULD support offloading of the filtering logic to the bluetooth chipset when
   3984 implementing the ScanFilter API [<a href="https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html">Resources, 101</a>], and MUST report the correct value of where the filtering logic is implemented whenever queried via the
   3985 android.bluetooth.BluetoothAdapter.isOffloadedFilteringSupported() method.</li>
   3986   <li>SHOULD support offloading of the batched scanning to the bluetooth chipset, but
   3987 if not supported, MUST report &lsquo;false&rsquo; whenever queried via the
   3988 android.bluetooth.BluetoothAdapater.isOffloadedScanBatchingSupported() method.</li>
   3989   <li>SHOULD support multi advertisement with at least 4 slots, but if not supported,
   3990 MUST report &lsquo;false&rsquo; whenever queried via the
   3991 android.bluetooth.BluetoothAdapter.isMultipleAdvertisementSupported() method.</li>
   3992 </ul>
   3993 
   3994 <h3 id="7_4_4_near-field_communications">7.4.4. Near-Field Communications</h3>
   3995 
   3996 
   3997 <p>Device implementations SHOULD include a transceiver and related hardware for
   3998 Near-Field Communications (NFC). If a device implementation does include NFC
   3999 hardware and plans to make it available to third-party apps, then it:</p>
   4000 
   4001 <ul>
   4002   <li>MUST report the android.hardware.nfc feature from the
   4003 android.content.pm.PackageManager.hasSystemFeature() method [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>].</li>
   4004   <li>MUST be capable of reading and writing NDEF messages via the following NFC
   4005 standards:
   4006   <ul>
   4007     <li>MUST be capable of acting as an NFC Forum reader/writer (as defined by the NFC
   4008 Forum technical specification NFCForum-TS-DigitalProtocol-1.0) via the
   4009 following NFC standards:
   4010     <ul>
   4011       <li>NfcA (ISO14443-3A)</li>
   4012       <li>NfcB (ISO14443-3B)</li>
   4013       <li>NfcF (JIS X 6319-4)</li>
   4014       <li>IsoDep (ISO 14443-4)</li>
   4015       <li>NFC Forum Tag Types 1, 2, 3, 4 (defined by the NFC Forum)</li>
   4016     </ul>
   4017   <li>STRONGLY RECOMMENDED to be capable of reading and writing NDEF messages as well
   4018       as raw data via the following NFC standards. Note that while the NFC standards
   4019       below are stated as STRONGLY RECOMMENDED, the Compatibility Definition for a
   4020       future version is planned to change these to MUST. These standards are optional
   4021       in this version but will be required in future versions. Existing and new devices
   4022       that run this version of Android are very strongly encouraged to meet these
   4023       requirements now so they will be able to upgrade to the future platform releases.
   4024   <ul>
   4025     <li>NfcV (ISO 15693)</li>
   4026   </ul></li>
   4027   <li>SHOULD be capable of reading the barcode and URL (if encoded) of
   4028       Thinfilm NFC Barcode
   4029       [<a href="http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html">Resources, 102</a>] products.
   4030   </li>
   4031   <li>MUST be capable of transmitting and receiving data via the following
   4032 peer-to-peer standards and protocols:
   4033   <ul>
   4034     <li>ISO 18092</li>
   4035     <li>LLCP 1.2 (defined by the NFC Forum)</li>
   4036     <li>SDP 1.0 (defined by the NFC Forum)</li>
   4037     <li>NDEF Push Protocol [<a href="http://static.googleusercontent.com/media/source.android.com/en/us/compatibility/ndef-push-protocol.pdf">Resources, 103</a>]</li>
   4038     <li>SNEP 1.0 (defined by the NFC Forum)</li>
   4039   </ul></li>
   4040   <li>MUST include support for Android Beam [<a href="http://developer.android.com/guide/topics/connectivity/nfc/nfc.html">Resources, 104</a>]:
   4041   <ul>
   4042     <li>MUST implement the SNEP default server. Valid NDEF messages received by the
   4043 default SNEP server MUST be dispatched to applications using the
   4044 android.nfc.ACTION_NDEF_DISCOVERED intent. Disabling Android Beam in settings
   4045 MUST NOT disable dispatch of incoming NDEF message.</li>
   4046     <li>MUST honor the android.settings.NFCSHARING_SETTINGS intent to show NFC sharing
   4047 settings [<a href="http://developer.android.com/reference/android/provider/Settings.html#ACTION_NFCSHARING_SETTINGS">Resources, 105</a>].</li>
   4048     <li>MUST implement the NPP server. Messages received by the NPP server MUST be
   4049 processed the same way as the SNEP default server.</li>
   4050     <li>MUST implement a SNEP client and attempt to send outbound P2P NDEF to the
   4051 default SNEP server when Android Beam is enabled. If no default SNEP server is
   4052 found then the client MUST attempt to send to an NPP server.</li>
   4053     <li>MUST allow foreground activities to set the outbound P2P NDEF message using
   4054 android.nfc.NfcAdapter.setNdefPushMessage, and
   4055 android.nfc.NfcAdapter.setNdefPushMessageCallback, and
   4056 android.nfc.NfcAdapter.enableForegroundNdefPush.</li>
   4057     <li>SHOULD use a gesture or on-screen confirmation, such as 'Touch to Beam', before
   4058 sending outbound P2P NDEF messages.</li>
   4059     <li>SHOULD enable Android Beam by default and MUST be able to send and receive
   4060 using Android Beam, even when another proprietary NFC P2p mode is turned on.</li>
   4061     <li>MUST support NFC Connection handover to Bluetooth when the device supports
   4062 Bluetooth Object Push Profile. Device implementations MUST support connection
   4063 handover to Bluetooth when using android.nfc.NfcAdapter.setBeamPushUris, by
   4064 implementing the &ldquo;Connection Handover version 1.2&rdquo; [<a href="http://members.nfc-forum.org/specs/spec_list/#conn_handover">Resources, 106</a>] and &ldquo;Bluetooth Secure Simple Pairing Using NFC version 1.0&rdquo; [<a href="http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf">Resources, 107</a>] specs from the NFC Forum. Such an implementation MUST implement the handover
   4065 LLCP service with service name &ldquo;urn:nfc:sn:handover&rdquo; for exchanging the
   4066 handover request/select records over NFC, and it MUST use the Bluetooth Object
   4067 Push Profile for the actual Bluetooth data transfer. For legacy reasons (to
   4068 remain compatible with Android 4.1 devices), the implementation SHOULD still
   4069 accept SNEP GET requests for exchanging the handover request/select records
   4070 over NFC. However an implementation itself SHOULD NOT send SNEP GET requests
   4071 for performing connection handover.</li>
   4072   </ul></li>
   4073   <li>MUST poll for all supported technologies while in NFC discovery mode.</li>
   4074   <li>SHOULD be in NFC discovery mode while the device is awake with the screen
   4075 active and the lock-screen unlocked.</li>
   4076 </ul>
   4077 </ul>
   4078 
   4079 <p>(Note that publicly available links are not available for the JIS, ISO, and NFC
   4080 Forum specifications cited above.)</p>
   4081 
   4082 <p>Android includes support for NFC Host Card Emulation (HCE) mode. If a
   4083 device implementation does include an NFC controller chipset capable of HCE and
   4084 Application ID (AID) routing, then it:</p>
   4085 
   4086 <ul>
   4087   <li>MUST report the android.hardware.nfc.hce feature constant.</li>
   4088   <li>MUST support NFC HCE APIs as defined in the Android SDK [<a href="http://developer.android.com/guide/topics/connectivity/nfc/hce.html">Resources, 108</a>].</li>
   4089 </ul>
   4090 
   4091 <p>Additionally, device implementations MAY include reader/writer support for the
   4092 following MIFARE technologies.</p>
   4093 
   4094 <ul>
   4095   <li>MIFARE Classic</li>
   4096   <li>MIFARE Ultralight</li>
   4097   <li>NDEF on MIFARE Classic</li>
   4098 </ul>
   4099 
   4100 <p>Note that Android includes APIs for these MIFARE types. If a device
   4101 implementation supports MIFARE in the reader/writer role, it:</p>
   4102 
   4103 <ul>
   4104   <li>MUST implement the corresponding Android APIs as documented by the Android SDK.</li>
   4105   <li>MUST report the feature com.nxp.mifare from the
   4106 android.content.pm.PackageManager.hasSystemFeature() method [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>]. Note that this is not a standard Android feature and as such does not appear
   4107 as a constant in the android.content.pm.PackageManager class.</li>
   4108   <li>MUST NOT implement the corresponding Android APIs nor report the com.nxp.mifare
   4109 feature unless it also implements general NFC support as described in this
   4110 section.</li>
   4111 </ul>
   4112 
   4113 <p>If a device implementation does not include NFC hardware, it MUST NOT declare
   4114 the android.hardware.nfc feature from the
   4115 android.content.pm.PackageManager.hasSystemFeature() method [<a href="http://developer.android.com/reference/android/content/pm/PackageManager.html">Resources, 70</a>], and MUST implement the Android NFC API as a no-op.</p>
   4116 
   4117 <p>As the classes android.nfc.NdefMessage and android.nfc.NdefRecord represent a
   4118 protocol-independent data representation format, device implementations MUST
   4119 implement these APIs even if they do not include support for NFC or declare the
   4120 android.hardware.nfc feature.</p>
   4121 
   4122 <h3 id="7_4_5_minimum_network_capability">7.4.5. Minimum Network Capability</h3>
   4123 
   4124 
   4125 <p>Device implementations MUST include support for one or more forms of data
   4126 networking. Specifically, device implementations MUST include support for at
   4127 least one data standard capable of 200Kbit/sec or greater. Examples of
   4128 technologies that satisfy this requirement include EDGE, HSPA, EV-DO, 802.11g,
   4129 Ethernet, Bluetooth PAN, etc.</p>
   4130 
   4131 <p>Device implementations where a physical networking standard (such as Ethernet)
   4132 is the primary data connection SHOULD also include support for at least one
   4133 common wireless data standard, such as 802.11 (Wi-Fi).</p>
   4134 
   4135 <p>Devices MAY implement more than one form of data connectivity.</p>
   4136 
   4137 <p>Devices MUST include an IPv6 networking stack and support IPv6 communication
   4138 using the managed APIs, such as <code>java.net.Socket</code> and
   4139 <code>java.net.URLConnection</code>, as well as the native APIs, such as
   4140 <code>AF_INET6</code> sockets. The required level of IPv6 support depends on
   4141 the network type, as follows:</p>
   4142 <ul>
   4143   <li>Devices that support Wi-Fi networks MUST support dual-stack and IPv6-only
   4144   operation on Wi-Fi.</li>
   4145   <li>Devices that support Ethernet networks MUST support dual-stack operation
   4146   on Ethernet.</li>
   4147   <li>Devices that support cellular data SHOULD support IPv6 operation
   4148   (IPv6-only and possibly dual-stack) on cellular data.</li>
   4149   <li>When a device is simultaneously connected to more than one network (e.g.,
   4150   Wi-Fi and cellular data), it MUST simultaneously meet these requirements on
   4151   each network to which it is connected.</li>
   4152 </ul>
   4153 
   4154 <p>IPv6 MUST be enabled by default.</p>
   4155 
   4156 <p>In order to ensure that IPv6 communication is as reliable as IPv4, unicast
   4157 IPv6 packets sent to the device MUST NOT be dropped, even when the screen is
   4158 not in an active state. Redundant multicast IPv6 packets, such as repeated
   4159 identical Router Advertisements, MAY be rate-limited in hardware or firmware
   4160 if doing so is necessary to save power. In such cases, rate-limiting MUST NOT
   4161 cause the device to lose IPv6 connectivity on any IPv6-compliant network that
   4162 uses RA lifetimes of at least 180 seconds.</p>
   4163 
   4164 <p>IPv6 connectivity MUST be maintained in doze mode.</p>
   4165 
   4166 <h3 id="7_4_6_sync_settings">7.4.6. Sync Settings</h3>
   4167 
   4168 
   4169 <p>Device implementations MUST have the master auto-sync setting on by default so
   4170 that the method getMasterSyncAutomatically() returns &ldquo;true&rdquo; [<a href="http://developer.android.com/reference/android/content/ContentResolver.html">Resources, 109</a>].</p>
   4171 
   4172 <h2 id="7_5_cameras">7.5. Cameras</h2>
   4173 
   4174 
   4175 <p>Device implementations SHOULD include a rear-facing camera and MAY include a
   4176 front-facing camera. A rear-facing camera is a camera located on the side of
   4177 the device opposite the display; that is, it images scenes on the far side of
   4178 the device, like a traditional camera. A front-facing camera is a camera
   4179 located on the same side of the device as the display; that is, a camera
   4180 typically used to image the user, such as for video conferencing and similar
   4181 applications.</p>
   4182 
   4183 <p>If a device implementation includes at least one camera, it SHOULD be possible
   4184 for an application to simultaneously allocate 3 bitmaps equal to the size of
   4185 the images produced by the largest-resolution camera sensor on the device.</p>
   4186 
   4187 <h3 id="7_5_1_rear-facing_camera">7.5.1. Rear-Facing Camera</h3>
   4188 
   4189 
   4190 <p>Device implementations SHOULD include a rear-facing camera. If a device
   4191 implementation includes at least one rear-facing camera, it:</p>
   4192 
   4193 <ul>
   4194   <li>MUST report the feature flag android.hardware.camera and
   4195 android.hardware.camera.any.</li>
   4196   <li>MUST have a resolution of at least 2 megapixels.</li>
   4197   <li>SHOULD have either hardware auto-focus or software auto-focus implemented in
   4198 the camera driver (transparent to application software).</li>
   4199   <li>MAY have fixed-focus or EDOF (extended depth of field) hardware.</li>
   4200   <li>MAY include a flash. If the Camera includes a flash, the flash lamp MUST NOT be
   4201 lit while an android.hardware.Camera.PreviewCallback instance has been
   4202 registered on a Camera preview surface, unless the application has explicitly
   4203 enabled the flash by enabling the FLASH_MODE_AUTO or FLASH_MODE_ON attributes
   4204 of a Camera.Parameters object. Note that this constraint does not apply to the
   4205 device&rsquo;s built-in system camera application, but only to third-party
   4206 applications using Camera.PreviewCallback.</li>
   4207 </ul>
   4208 
   4209 <h3 id="7_5_2_front-facing_camera">7.5.2. Front-Facing Camera</h3>
   4210 
   4211 
   4212 <p>Device implementations MAY include a front-facing camera. If a device
   4213 implementation includes at least one front-facing camera, it:</p>
   4214 
   4215 <ul>
   4216   <li>MUST report the feature flag android.hardware.camera.any and
   4217 android.hardware.camera.front.</li>
   4218   <li>MUST have a resolution of at least VGA (640x480 pixels).</li>
   4219   <li>MUST NOT use a front-facing camera as the default for the Camera API. The
   4220 camera API in Android has specific support for front-facing cameras and device
   4221 implementations MUST NOT configure the API to to treat a front-facing camera as
   4222 the default rear-facing camera, even if it is the only camera on the device.</li>
   4223   <li>MAY include features (such as auto-focus, flash, etc.) available to rear-facing
   4224 cameras as described in <a href="#7_5_1_rear-facing_camera">section 7.5.1</a>.</li>
   4225   <li>MUST horizontally reflect (i.e. mirror) the stream displayed by an app in a
   4226 CameraPreview, as follows:
   4227   <ul>
   4228     <li>If the device implementation is capable of being rotated by user (such as
   4229 automatically via an accelerometer or manually via user input), the camera
   4230 preview MUST be mirrored horizontally relative to the device&rsquo;s current
   4231 orientation.</li>
   4232     <li>If the current application has explicitly requested that the Camera display be
   4233 rotated via a call to the android.hardware.Camera.setDisplayOrientation()[<a href="http://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)">Resources, 110</a>] method, the camera preview MUST be mirrored horizontally relative to the
   4234 orientation specified by the application.</li>
   4235     <li>Otherwise, the preview MUST be mirrored along the device&rsquo;s default horizontal
   4236 axis.</li>
   4237   </ul></li>
   4238   <li>MUST mirror the image displayed by the postview in the same manner as the
   4239 camera preview image stream. If the device implementation does not support
   4240 postview, this requirement obviously does not apply.</li>
   4241   <li>MUST NOT mirror the final captured still image or video streams returned to
   4242 application callbacks or committed to media storage.</li>
   4243 </ul>
   4244 
   4245 <h3 id="7_5_3_external_camera">7.5.3. External Camera</h3>
   4246 
   4247 
   4248 <p>Device implementations with USB host mode MAY include support for an external
   4249 camera that connects to the USB port. If a device includes support for an
   4250 external camera, it:</p>
   4251 
   4252 <ul>
   4253   <li>MUST declare the platform feature android.hardware.camera.external and
   4254 android.hardware camera.any.</li>
   4255   <li>MUST support USB Video Class (UVC 1.0 or higher).</li>
   4256   <li>MAY support multiple cameras.</li>
   4257 </ul>
   4258 
   4259 <p>Video compression (such as MJPEG) support is RECOMMENDED to enable transfer of
   4260 high-quality unencoded streams (i.e. raw or independently compressed picture
   4261 streams). Camera-based video encoding MAY be supported. If so, a simultaneous
   4262 unencoded/ MJPEG stream (QVGA or greater resolution) MUST be accessible to the
   4263 device implementation.</p>
   4264 
   4265 <h3 id="7_5_4_camera_api_behavior">7.5.4. Camera API Behavior</h3>
   4266 
   4267 
   4268 <p>Android includes two API packages to access the camera, the newer
   4269 android.hardware.camera2 API expose lower-level camera control to the app,
   4270 including efficient zero-copy burst/streaming flows and per-frame controls of
   4271 exposure, gain, white balance gains, color conversion, denoising, sharpening,
   4272 and more.</p>
   4273 
   4274 <p>The older API package, android.hardware.Camera, is marked as deprecated in
   4275 Android 5.0 but as it should still be available for apps to use Android device
   4276 implementations MUST ensure the continued support of the API as described in
   4277 this section and in the Android SDK.</p>
   4278 
   4279 <p>Device implementations MUST implement the following behaviors for the
   4280 camera-related APIs, for all available cameras:</p>
   4281 
   4282 <ul>
   4283   <li>If an application has never called
   4284 android.hardware.Camera.Parameters.setPreviewFormat(int), then the device MUST
   4285 use android.hardware.PixelFormat.YCbCr_420_SP for preview data provided to
   4286 application callbacks.</li>
   4287   <li>If an application registers an android.hardware.Camera.PreviewCallback instance
   4288 and the system calls the onPreviewFrame() method when the preview format is
   4289 YCbCr_420_SP, the data in the byte[] passed into onPreviewFrame() must further
   4290 be in the NV21 encoding format. That is, NV21 MUST be the default.</li>
   4291   <li>For android.hardware.Camera, device implementations MUST support the YV12
   4292 format (as denoted by the android.graphics.ImageFormat.YV12 constant) for
   4293 camera previews for both front- and rear-facing cameras. (The hardware video
   4294 encoder and camera may use any native pixel format, but the device
   4295 implementation MUST support conversion to YV12.)</li>
   4296   <li>For android.hardware.camera2, device implementations must support the
   4297 android.hardware.ImageFormat.YUV_420_888 and android.hardware.ImageFormat.JPEG
   4298 formats as outputs through the android.media.ImageReader API.</li>
   4299 </ul>
   4300 
   4301 <p>Device implementations MUST still implement the full Camera API included in the
   4302 Android SDK documentation [<a href="http://developer.android.com/reference/android/hardware/Camera.html">Resources, 111</a>],
   4303 regardless of whether the device includes hardware autofocus or other
   4304 capabilities. For instance, cameras that lack autofocus MUST still call any
   4305 registered android.hardware.Camera.AutoFocusCallback instances (even though
   4306 this has no relevance to a non-autofocus camera.) Note that this does apply to
   4307 front-facing cameras; for instance, even though most front-facing cameras do
   4308 not support autofocus, the API callbacks must still be &ldquo;faked&rdquo; as described.</p>
   4309 
   4310 <p>Device implementations MUST recognize and honor each parameter name defined as
   4311 a constant on the android.hardware.Camera.Parameters class, if the underlying
   4312 hardware supports the feature. If the device hardware does not support a
   4313 feature, the API must behave as documented. Conversely, device implementations
   4314 MUST NOT honor or recognize string constants passed to the
   4315 android.hardware.Camera.setParameters() method other than those documented as
   4316 constants on the android.hardware.Camera.Parameters. That is, device
   4317 implementations MUST support all standard Camera parameters if the hardware
   4318 allows, and MUST NOT support custom Camera parameter types. For instance,
   4319 device implementations that support image capture using high dynamic range
   4320 (HDR) imaging techniques MUST support camera parameter Camera.SCENE_MODE_HDR [<a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">Resources, 112</a>].</p>
   4321 
   4322 <p>Because not all device implementations can fully support all the features of
   4323 the android.hardware.camera2 API, device implementations MUST report the proper
   4324 level of support with the android.info.supportedHardwareLevel property as
   4325 described in the Android SDK [<a href="https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL">Resources, 113</a>] and report the appropriate framework feature flags [<a href="http://source.android.com/devices/camera/versioning.html">Resources, 114</a>].</p>
   4326 
   4327 <p>Device implementations MUST also declare its Individual camera capabilities of
   4328 android.hardware.camera2 via the android.request.availableCapabilities property
   4329 and declare the appropriate feature flags [<a href="http://source.android.com/devices/camera/versioning.html">Resources, 114</a>]; a device must define the feature flag if any of its attached camera devices supports the feature.</p>
   4330 
   4331 <p>Device implementations MUST broadcast the Camera.ACTION_NEW_PICTURE intent
   4332 whenever a new picture is taken by the camera and the entry of the picture has
   4333 been added to the media store.</p>
   4334 
   4335 <p>Device implementations MUST broadcast the Camera.ACTION_NEW_VIDEO intent
   4336 whenever a new video is recorded by the camera and the entry of the picture has
   4337 been added to the media store.</p>
   4338 
   4339 <h3 id="7_5_5_camera_orientation">7.5.5. Camera Orientation</h3>
   4340 
   4341 
   4342 <p>Both front- and rear-facing cameras, if present, MUST be oriented so that the
   4343 long dimension of the camera aligns with the screen&rsquo;s long dimension. That is,
   4344 when the device is held in the landscape orientation, cameras MUST capture
   4345 images in the landscape orientation. This applies regardless of the device&rsquo;s
   4346 natural orientation; that is, it applies to landscape-primary devices as well
   4347 as portrait-primary devices.</p>
   4348 
   4349 <h2 id="7_6_memory_and_storage">7.6. Memory and Storage</h2>
   4350 
   4351 
   4352 <h3 id="7_6_1_minimum_memory_and_storage">7.6.1. Minimum Memory and Storage</h3>
   4353 
   4354 <div class="note">
   4355 <p>Android Television devices MUST have at least 5GB of non-volatile storage
   4356 available for application private data.</p>
   4357 </div>
   4358 
   4359 
   4360 <p>The memory available to the kernel and userspace on device implementations MUST
   4361 be at least equal or larger than the minimum values specified by the following
   4362 table. (See <a href="#7_1_1_screen_configuration">section 7.1.1</a> for screen size and density definitions.)</p>
   4363 <table>
   4364  <tr>
   4365     <th>Density and screen size</th>
   4366     <th>32-bit device</th>
   4367     <th>64-bit device</th>
   4368  </tr>
   4369  <tr>
   4370     <td>Android Watch devices (due to smaller screens)</td>
   4371     <td>416MB</td>
   4372     <td>Not applicable</td>
   4373  </tr>
   4374  <tr>
   4375     <td><ul>
   4376     <li class="table_list">280dpi or lower on small/normal screens</li>
   4377     <li class="table_list">mdpi or lower on large screens</li>
   4378     <li class="table_list">ldpi or lower on extra large screens</li>
   4379     </ul></td>
   4380     <td>424MB</td>
   4381     <td>704MB</td>
   4382  </tr>
   4383  <tr>
   4384     <td><ul>
   4385     <li class="table_list">xhdpi or higher on small/normal screens</li>
   4386     <li class="table_list">hdpi or higher on large screens</li>
   4387     <li class="table_list">mdpi or higher on extra large screens</li></ul></td>
   4388     <td>512MB</td>
   4389     <td>832MB</td>
   4390  </tr>
   4391  <tr>
   4392     <td><ul>
   4393     <li class="table_list">400dpi or higher on small/normal screens</li>
   4394     <li class="table_list">xhdpi or higher on large screens</li>
   4395      <li class="table_list">tvdpi or higher on extra large screens</li></ul></td>
   4396     <td>896MB</td>
   4397     <td>1280MB</td>
   4398  </tr>
   4399  <tr>
   4400     <td><ul>
   4401     <li class="table_list">560dpi or higher on small/normal screens</li>
   4402     <li class="table_list">400dpi or higher on large screens</li>
   4403     <li class="table_list">xhdpi or higher on extra large screens</li></ul></td>
   4404     <td>1344MB</td>
   4405     <td>1824MB</td>
   4406  </tr>
   4407 </table>
   4408 
   4409 
   4410 <p>The minimum memory values MUST be in addition to any memory space already
   4411 dedicated to hardware components such as radio, video, and so on that is not
   4412 under the kernel&rsquo;s control.</p>
   4413 
   4414 <p>Device implementations with less than 512MB of memory available to the kernel
   4415 and userspace, unless an Android Watch, MUST return the value "true" for
   4416 ActivityManager.isLowRamDevice().</p>
   4417 
   4418 <p>Android Television devices MUST have at least 5GB and other device
   4419 implementations MUST have at least 1.5GB of non-volatile storage available for
   4420 application private data. That is, the /data partition MUST be at least 5GB for
   4421 Android Television devices and at least 1.5GB for other device implementations.
   4422 Device implementations that run Android are <strong>STRONGLY RECOMMENDED</strong> to have at least 3GB of non-volatile storage for application private data so
   4423 they will be able to upgrade to the future platform releases.</p>
   4424 
   4425 <p>The Android APIs include a Download Manager that applications MAY use to
   4426 download data files [<a href="http://developer.android.com/reference/android/app/DownloadManager.html">Resources, 115</a>]. The device implementation of the Download Manager MUST be capable of
   4427 downloading individual files of at least 100MB in size to the default &ldquo;cache"
   4428 location.</p>
   4429 
   4430 <h3 id="7_6_2_application_shared_storage">7.6.2. Application Shared Storage</h3>
   4431 
   4432 
   4433 <p>Device implementations MUST offer shared storage for applications also often
   4434 referred as &ldquo;shared external storage&rdquo;. </p>
   4435 
   4436 <p>Device implementations MUST be configured with shared storage mounted by
   4437 default, &ldquo;out of the box&rdquo;. If the shared storage is not mounted on the Linux
   4438 path /sdcard, then the device MUST include a Linux symbolic link from /sdcard
   4439 to the actual mount point.</p>
   4440 
   4441 <p>Device implementations MAY have hardware for user-accessible removable storage,
   4442 such as a Secure Digital (SD) card slot. If this slot is used to satisfy the
   4443 shared storage requirement, the device implementation:</p>
   4444 
   4445 <ul>
   4446   <li>MUST implement a toast or pop-up user interface warning the user when there is
   4447 no SD card.</li>
   4448   <li>MUST include a FAT-formatted SD card 1GB in size or larger OR show on the box
   4449 and other material available at time of purchase that the SD card has to be
   4450 separately purchased.</li>
   4451   <li>MUST mount the SD card by default.</li>
   4452 </ul>
   4453 
   4454 <p>Alternatively, device implementations MAY allocate internal (non-removable)
   4455 storage as shared storage for apps as included in the upstream Android Open
   4456 Source Project; device implementations SHOULD use this configuration and
   4457 software implementation. If a device implementation uses internal
   4458 (non-removable) storage to satisfy the shared storage requirement, that storage
   4459 MUST be 1GB in size or larger and mounted on /sdcard (or /sdcard MUST be a
   4460 symbolic link to the physical location if it is mounted elsewhere).</p>
   4461 
   4462 <p>Device implementations MUST enforce as documented the
   4463 android.permission.WRITE_EXTERNAL_STORAGE permission on this shared storage.
   4464 Shared storage MUST otherwise be writable by any application that obtains that
   4465 permission.</p>
   4466 
   4467 <p>Device implementations that include multiple shared storage paths (such as both
   4468 an SD card slot and shared internal storage) MUST NOT allow Android
   4469 applications to write to the secondary external storage, except for their
   4470 package-specific directories on the secondary external storage, but SHOULD
   4471 expose content from both storage paths transparently through Android&rsquo;s media
   4472 scanner service and android.provider.MediaStore.</p>
   4473 
   4474 <p>Regardless of the form of shared storage used, if the device implementation
   4475 has a USB port with USB peripheral mode support, it MUST provide some mechanism
   4476 to access the contents of shared storage from a host computer. Device
   4477 implementations MAY use USB mass storage, but SHOULD use Media Transfer Protocol
   4478 to satisfy this requirement. If the device implementation supports Media
   4479 Transfer Protocol, it:</p>
   4480 
   4481 <ul>
   4482   <li>SHOULD be compatible with the reference Android MTP host, Android File Transfer
   4483 [<a href="http://www.android.com/filetransfer">Resources, 116</a>].</li>
   4484   <li>SHOULD report a USB device class of 0x00.</li>
   4485   <li>SHOULD report a USB interface name of 'MTP'.</li>
   4486 </ul>
   4487 
   4488 <h3 id="7_6_3_adoptable_storage">7.6.3. Adoptable Storage</h3>
   4489 
   4490 <p>Device implementations are STRONGLY RECOMMENDED to implement adoptable
   4491 storage if the removable storage device port is in a long-term stable location,
   4492 such as within the battery compartment or other protective cover
   4493 [<a
   4494 href="http://source.android.com/devices/storage/adoptable.html">Resources,
   4495 117</a>].</p>
   4496 
   4497 <p>Device implementations such as a television, MAY enable adoption through USB
   4498 ports as the device is expected to be static and not mobile. But for other
   4499 device implementations that are mobile in nature, it is STRONGLY RECOMMENDED to
   4500 implement the adoptable storage in a long-term stable location, since accidentally
   4501 disconnecting them can cause data loss/corruption.</p>
   4502 
   4503 <h2 id="7_7_usb">7.7. USB</h2>
   4504 
   4505 
   4506 <p>Device implementations SHOULD support USB peripheral mode and SHOULD support
   4507 USB host mode.</p>
   4508 
   4509 <p>If a device implementation includes a USB port supporting peripheral mode:</p>
   4510 
   4511 <ul>
   4512   <li>The port MUST be connectable to a USB host that has a standard type-A or type
   4513 -C USB port.</li>
   4514   <li>The port SHOULD use micro-A, micro-AB or type-C USB form factor. Existing and
   4515 new Android devices are <strong>STRONGLY RECOMMENDED to meet these requirements</strong> so they will be able to upgrade to the future platform releases.</li>
   4516   <li>The port SHOULD be centered in the middle of an edge. Device implementations
   4517 SHOULD either locate the port on the bottom of the device (according to natural
   4518 orientation) or enable software screen rotation for all apps (including home
   4519 screen), so that the display draws correctly when the device is oriented with
   4520 the port at bottom. Existing and new Android devices are <strong>STRONGLY RECOMMENDED to meet these requirements</strong> so they will be able to upgrade to future platform releases.</li>
   4521   <li>It MUST allow a USB host connected with the Android device to access the
   4522 contents of the shared storage volume using either USB mass storage or Media
   4523 Transfer Protocol.</li>
   4524   <li>It SHOULD implement the Android Open Accessory (AOA) API and specification as
   4525 documented in the Android SDK documentation, and if it is an Android Handheld
   4526 device it MUST implement the AOA API. Device implementations implementing the
   4527 AOA specification:
   4528   <ul>
   4529     <li>MUST declare support for the hardware feature android.hardware.usb.accessory [<a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html">Resources, 118</a>].</li>
   4530     <li>MUST implement the USB audio class as documented in the Android SDK
   4531 documentation [<a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">Resources, 119</a>].</li>
   4532     <li>And also the USB mass storage class, MUST include the string "android"
   4533 at the end of the interface description <code>iInterface</code> string of the
   4534 USB mass storage</li>
   4535   </ul>
   4536   </li>
   4537   <li>It SHOULD implement support to draw 1.5 A current during HS chirp and traffic
   4538 as specified in the USB battery charging specification [<a href="http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf">Resources, 120</a>]. Existing and new Android devices are <strong>STRONGLY RECOMMENDED to meet these requirements</strong> so they will be able to upgrade to the future platform releases.</li>
   4539   <li>The value of iSerialNumber in USB standard device descriptor MUST be equal to
   4540 the value of android.os.Build.SERIAL.</li>
   4541 </ul>
   4542 
   4543 <p>If a device implementation includes a USB port supporting host mode, it:</p>
   4544 
   4545 <ul>
   4546   <li>SHOULD use a type-C USB port, if the device implementation supports USB 3.1.</li>
   4547   <li>MAY use a non-standard port form factor, but if so MUST ship with a cable or
   4548 cables adapting the port to a standard type-A or type-C USB port.</li>
   4549   <li>MAY use a micro-AB USB port, but if so SHOULD ship with a cable or cables
   4550 adapting the port to a standard type-A or type-C USB port.</li>
   4551   <li>is <strong>STRONGLY RECOMMENDED</strong> to implement the USB audio class as documented in the Android SDK
   4552 documentation [<a href="http://developer.android.com/reference/android/hardware/usb/UsbConstants.html#USB_CLASS_AUDIO">Resources, 119</a>].</li>
   4553   <li>MUST implement the Android USB host API as documented in the Android SDK, and
   4554 MUST declare support for the hardware feature android.hardware.usb.host [<a href="http://developer.android.com/guide/topics/connectivity/usb/host.html">Resources, 121</a>].</li>
   4555   <li>SHOULD support the Charging Downstream Port output current range of 1.5 A ~ 5 A
   4556 as specified in the USB Battery Charging Specifications [<a href="http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf">Resources, 120</a>].</li>
   4557 </ul>
   4558 
   4559 <h2 id="7_8_audio">7.8. Audio</h2>
   4560 
   4561 
   4562 <h3 id="7_8_1_microphone">7.8.1. Microphone</h3>
   4563 
   4564 <div class="note">
   4565 <p>Android Handheld, Watch, and Automotive implementations MUST include a
   4566 microphone.</p>
   4567 </div>
   4568 
   4569 
   4570 <p>Device implementations MAY omit a microphone. However, if a device
   4571 implementation omits a microphone, it MUST NOT report the
   4572 android.hardware.microphone feature constant, and MUST implement the audio
   4573 recording API at least as no-ops, per <a href="#7_hardware_compatibility">section 7</a>.
   4574 Conversely, device implementations that do possess a microphone:</p>
   4575 
   4576 <ul>
   4577   <li>MUST report the android.hardware.microphone feature constant</li>
   4578   <li>MUST meet the audio recording requirements in <a href="#5_4_audio_recording">section 5.4</a></li>
   4579   <li>MUST meet the audio latency requirements in <a href="#5_6_audio_latency">section 5.6</a></li>
   4580   <li>STRONGLY RECOMMENDED to support near-ultrasound recording as described in
   4581     <a href="#7_8_3_near_ultrasound">section 7.8.3</a></li>
   4582 </ul>
   4583 
   4584 <h3 id="7_8_2_audio_output">7.8.2. Audio Output</h3>
   4585 
   4586 <div class="note">
   4587 <p>Android Watch devices MAY include an audio output.</p>
   4588 </div>
   4589 
   4590 <p>Device implementations including a speaker or with an audio/multimedia output
   4591 port for an audio output peripheral as a headset or an external speaker:</p>
   4592 
   4593 <ul>
   4594   <li>MUST report the android.hardware.audio.output feature constant.</li>
   4595   <li>MUST meet the audio playback requirements in <a href="#5_5_audio_playback">section 5.5</a>.</li>
   4596   <li>MUST meet the audio latency requirements in <a href="#5_6_audio_latency">section 5.6</a>.</li>
   4597   <li>STRONGLY RECOMMENDED to support near-ultrasound playback as described in
   4598     <a href="#7_8_3_near_ultrasound">section 7.8.3</a></li>
   4599 </ul>
   4600 
   4601 <p>Conversely, if a device implementation does not include a speaker or audio
   4602 output port, it MUST NOT report the android.hardware.audio output feature, and
   4603 MUST implement the Audio Output related APIs as no-ops at least. </p>
   4604 
   4605 <p>Android Watch device implementation MAY but SHOULD NOT have audio output, but
   4606 other types of Android device implementations MUST have an audio output and
   4607 declare android.hardware.audio.output.</p>
   4608 
   4609 <h4 id="7_8_2_1_analog_audio_ports">7.8.2.1. Analog Audio Ports</h4>
   4610 
   4611 
   4612 <p>In order to be compatible with the headsets and other audio accessories using
   4613 the 3.5mm audio plug across the Android ecosystem [<a href="http://source.android.com/accessories/headset-spec.html">Resources, 122</a>], if a device implementation includes one or more analog audio ports, at least
   4614 one of the audio port(s) SHOULD be a 4 conductor 3.5mm audio jack. If a device
   4615 implementation has a 4 conductor 3.5mm audio jack, it:</p>
   4616 
   4617 <ul>
   4618   <li>MUST support audio playback to stereo headphones and stereo headsets with a
   4619 microphone, and SHOULD support audio recording from stereo headsets with a
   4620 microphone.</li>
   4621   <li>MUST support TRRS audio plugs with the CTIA pin-out order, and SHOULD support
   4622 audio plugs with the OMTP pin-out order.</li>
   4623   <li>MUST support the detection of microphone on the plugged in audio accessory, if
   4624 the device implementation supports a microphone, and broadcast the
   4625 android.intent.action.HEADSET_PLUG with the extra value microphone set as 1.</li>
   4626   <li>SHOULD support the detection and mapping to the keycodes for the following 3
   4627 ranges of equivalent impedance between the microphone and ground conductors on
   4628 the audio plug:
   4629   <ul>
   4630     <li><strong>70 ohm or less</strong>: KEYCODE_HEADSETHOOK</li>
   4631     <li><strong>210&#45;290 Ohm</strong>: KEYCODE_VOLUME_UP</li>
   4632     <li><strong>360&#45;680 Ohm</strong>: KEYCODE_VOLUME_DOWN</li>
   4633   </ul></li>
   4634   <li>SHOULD support the detection and mapping to the keycode for the following range
   4635 of equivalent impedance between the microphone and ground conductors on the
   4636 audio plug:
   4637   <ul>
   4638     <li><strong>110&#45;180 Ohm: </strong>KEYCODE_VOICE_ASSIST</li>
   4639   </ul></li>
   4640   <li>MUST trigger ACTION_HEADSET_PLUG upon a plug insert, but only after all
   4641 contacts on plug are touching their relevant segments on the jack.</li>
   4642   <li>MUST be capable of driving at least 150mV &plusmn; 10% of output voltage on a 32 Ohm
   4643 speaker impedance.</li>
   4644   <li>MUST have a microphone bias voltage between 1.8V ~ 2.9V.</li>
   4645 </ul>
   4646 
   4647 <h3 id="7_8_3_near_ultrasound">7.8.3. Near-Ultrasound </h3>
   4648 
   4649 <p>Near-Ultrasound audio is the 18.5 kHz to 20 kHz band.
   4650 Device implementations MUST correctly report the support
   4651 of near-ultrasound audio capability via the
   4652 <a href="http://developer.android.com/reference/android/media/AudioManager.html#getProperty(java.lang.String)">AudioManager.getProperty</a>
   4653 API as follows:
   4654 </p>
   4655 
   4656 <ul>
   4657   <li>If
   4658   <a href="http://developer.android.com/reference/android/media/AudioManager.html#PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND">PROPERTY_SUPPORT_MIC_NEAR_ULTRASOUND</a>
   4659   is "true", then
   4660   <ul>
   4661     <li>The microphone's mean power response in the 18.5 kHz to 20 kHz band MUST be no more than
   4662     15 dB below the response at 2 kHz.</li>
   4663     <li>The signal to noise ratio of the microphone MUST be no lower than 80 dB.</li>
   4664   </ul>
   4665   </li>
   4666   <li>If
   4667   <a href="http://developer.android.com/reference/android/media/AudioManager.html#PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND">PROPERTY_SUPPORT_SPEAKER_NEAR_ULTRASOUND</a>
   4668   is "true", then the speaker's mean response in 18.5 kHz - 20 kHz MUST be no lower than 40 dB
   4669   below the response at 2 kHz.
   4670   </li>
   4671 </ul>
   4672 
   4673 <h1 id="8_performance_power">8. Performance and Power</h1>
   4674 
   4675 
   4676 <p>Some minimum performance and power criteria are critical to the user experience
   4677 and impact the baseline assumptions developers would have when developing an app.
   4678 Android Watch devices SHOULD and other type of device implementations MUST meet
   4679 the following criteria:</p>
   4680 
   4681 <h2 id="8_1_user_experience_consistency">8.1. User Experience Consistency</h2>
   4682 
   4683 
   4684 <p>Device implementations MUST provide a smooth user interface by ensuring a
   4685 consistent frame rate and response times for applications and games. Device
   4686 implementations MUST meet the following requirements: </p>
   4687 
   4688 <ul>
   4689   <li><strong>Consistent frame latency</strong>. Inconsistent frame latency or a delay to render frames MUST NOT happen more
   4690 often than 5 frames in a second, and SHOULD be below 1 frames in a second.</li>
   4691   <li><strong>User interface latency</strong>. Device implementations MUST ensure low latency user experience by scrolling a
   4692 list of 10K list entries as defined by the Android Compatibility Test Suite
   4693 (CTS) in less than 36 secs.</li>
   4694   <li><strong>Task switching</strong>. When multiple applications have been launched, re-launching an already-running
   4695 application after it has been launched MUST take less than 1 second.</li>
   4696 </ul>
   4697 
   4698 <h2 id="8_2_file_i_o_access_performance">8.2. File I/O Access Performance</h2>
   4699 
   4700 
   4701 <p>Device implementations MUST ensure internal storage file access performance consistency for read
   4702 and write operations. </p>
   4703 
   4704 <ul>
   4705   <li><strong>Sequential write</strong>. Device implementations MUST ensure a sequential write performance of at least 5MB/s
   4706 for a 256MB file using 10MB write buffer.</li>
   4707   <li><strong>Random write</strong>. Device implementations MUST ensure a random write performance of at least 0.5MB/s for a
   4708 256MB file using 4KB write buffer.</li>
   4709   <li><strong>Sequential read</strong>. Device implementations MUST ensure a sequential read performance of at least 15MB/s for
   4710 a 256MB file using 10MB write buffer.</li>
   4711   <li><strong>Random read</strong>. Device implementations MUST ensure a random read performance of at least 3.5MB/s for a
   4712 256MB file using 4KB write buffer.</li>
   4713 </ul>
   4714 
   4715 <h2 id="8_3_power_saving_modes">8.3. Power-Saving Modes</h2>
   4716 
   4717 <p>All apps exempted from App Standby and/or Doze mode MUST be made visible to
   4718 the end user. Further, the triggering, maintenance, wakeup algorithms and
   4719 the use of Global system settings of these power-saving modes MUST not deviate
   4720 from the Android Open Source Project.</p>
   4721 
   4722 <h2 id="8_4_power_consumption_accounting">8.4. Power Consumption Accounting</h2>
   4723 
   4724 <p>A more accurate accounting and reporting of the power consumption provides the
   4725 app developer both the incentives and the tools to optimize the power usage pattern
   4726 of the application. Therefore, device implementations:</p>
   4727 
   4728 <ul>
   4729   <li>MUST be able to track hardware component power usage and attribute that power
   4730     usage to specific applications. Specifically, implementations:
   4731     <ul>
   4732       <li>MUST provide a per-component power profile that defines the current consumption
   4733         value for each hardware component and the approximate battery drain caused by the
   4734         components over time as documented in the Android Open Source Project site [<a
   4735 href="http://source.android.com/devices/tech/power/values.html">Resources, 123</a>].</li>
   4736       <li>MUST report all power consumption values in milliampere hours (mAh)</li>
   4737       <li>SHOULD be attributed to the hardware component itself if unable to
   4738         attribute hardware component power usage to an application.</li>
   4739       <li>MUST report CPU power consumption per each process's UID. The Android Open
   4740         Source Project meets the requirement through the <code>uid_cputime</code>
   4741         kernel module implementation.</li>
   4742     </ul>
   4743   </li>
   4744   <li>MUST make this power usage available via the <code>adb shell dumpsys
   4745     batterystats</code> shell command to the app developer [<a
   4746 href="http://source.android.com/devices/tech/power/batterystats.html">Resources, 124</a>].</li>
   4747   <li>MUST honor the android.intent.action.POWER_USAGE_SUMMARY intent and display
   4748     a settings menu that shows this power usage [<a
   4749 href="http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY">Resources,
   4750 125</a>].</li>
   4751 </ul>
   4752 
   4753 <h1 id="9_security_model_compatibility">9. Security Model Compatibility</h1>
   4754 
   4755 
   4756 <p>Device implementations MUST implement a security model consistent with the
   4757 Android platform security model as defined in Security and Permissions
   4758 reference document in the APIs [<a href="http://developer.android.com/guide/topics/security/permissions.html">Resources, 126</a>] in the Android developer documentation. Device implementations MUST support
   4759 installation of self-signed applications without requiring any additional
   4760 permissions/certificates from any third parties/authorities. Specifically,
   4761 compatible devices MUST support the security mechanisms described in the follow
   4762 subsections.</p>
   4763 
   4764 <h2 id="9_1_permissions">9.1. Permissions</h2>
   4765 
   4766 
   4767 <p>Device implementations MUST support the Android permissions model as defined in
   4768 the Android developer documentation [<a href="http://developer.android.com/guide/topics/security/permissions.html">Resources, 126</a>]. Specifically, implementations MUST enforce each permission defined as
   4769 described in the SDK documentation; no permissions may be omitted, altered, or
   4770 ignored. Implementations MAY add additional permissions, provided the new
   4771 permission ID strings are not in the android.* namespace.</p>
   4772 
   4773 <p>Permissions with a protection level of dangerous are runtime permissions. Applications
   4774 with targetSdkVersion > 22 request them at runtime. Device implementations:</p>
   4775 
   4776 <ul>
   4777 <li>MUST show a dedicated interface for the user to decide whether to grant the
   4778 requested runtime permissions and also provide an interface for the user to manage
   4779 runtime permissions.</li>
   4780 <li>MUST have one and only one implementation of both user interfaces.</li>
   4781 <li>MUST NOT grant any runtime permissions to preinstalled apps unless:
   4782   <ul>
   4783     <li>the user's consent can be obtained before the application uses it</li>
   4784     <li>the runtime permissions are associated with an intent pattern for which the preinstalled
   4785     application is set as the default handler</li>
   4786   </ul>
   4787 </li>
   4788 </ul>
   4789 
   4790 <h2 id="9_2_uid_and_process_isolation">9.2. UID and Process Isolation</h2>
   4791 
   4792 
   4793 <p>Device implementations MUST support the Android application sandbox model, in
   4794 which each application runs as a unique Unixstyle UID and in a separate
   4795 process. Device implementations MUST support running multiple applications as
   4796 the same Linux user ID, provided that the applications are properly signed and
   4797 constructed, as defined in the Security and Permissions reference [<a href="http://developer.android.com/guide/topics/security/permissions.html">Resources, 126</a>].</p>
   4798 
   4799 <h2 id="9_3_filesystem_permissions">9.3. Filesystem Permissions</h2>
   4800 
   4801 
   4802 <p>Device implementations MUST support the Android file access permissions model
   4803 as defined in the Security and Permissions reference [<a href="http://developer.android.com/guide/topics/security/permissions.html">Resources, 126</a>].</p>
   4804 
   4805 <h2 id="9_4_alternate_execution_environments">9.4. Alternate Execution Environments</h2>
   4806 
   4807 
   4808 <p>Device implementations MAY include runtime environments that execute
   4809 applications using some other software or technology than the Dalvik Executable
   4810 Format or native code. However, such alternate execution environments MUST NOT
   4811 compromise the Android security model or the security of installed Android
   4812 applications, as described in this section.</p>
   4813 
   4814 <p>Alternate runtimes MUST themselves be Android applications, and abide by the
   4815 standard Android security model, as described elsewhere in <a href="#9_security_model_compatibility">section 9</a>.</p>
   4816 
   4817 <p>Alternate runtimes MUST NOT be granted access to resources protected by
   4818 permissions not requested in the runtime&rsquo;s AndroidManifest.xml file via the
   4819 &lt;uses-permission&gt; mechanism.</p>
   4820 
   4821 <p>Alternate runtimes MUST NOT permit applications to make use of features
   4822 protected by Android permissions restricted to system applications.</p>
   4823 
   4824 <p>Alternate runtimes MUST abide by the Android sandbox model. Specifically,
   4825 alternate runtimes:</p>
   4826 
   4827 <ul>
   4828   <li>SHOULD install apps via the PackageManager into separate Android sandboxes (
   4829 Linux user IDs, etc.).</li>
   4830   <li>MAY provide a single Android sandbox shared by all applications using the
   4831 alternate runtime.</li>
   4832   <li>and installed applications using an alternate runtime, MUST NOT reuse the
   4833 sandbox of any other app installed on the device, except through the standard
   4834 Android mechanisms of shared user ID and signing certificate.</li>
   4835   <li>MUST NOT launch with, grant, or be granted access to the sandboxes
   4836 corresponding to other Android applications.</li>
   4837   <li>MUST NOT be launched with, be granted, or grant to other applications any
   4838 privileges of the superuser (root), or of any other user ID.</li>
   4839 </ul>
   4840 
   4841 <p>The .apk files of alternate runtimes MAY be included in the system image of a
   4842 device implementation, but MUST be signed with a key distinct from the key used
   4843 to sign other applications included with the device implementation.</p>
   4844 
   4845 <p>When installing applications, alternate runtimes MUST obtain user consent for
   4846 the Android permissions used by the application. If an application needs to
   4847 make use of a device resource for which there is a corresponding Android
   4848 permission (such as Camera, GPS, etc.), the alternate runtime MUST inform the
   4849 user that the application will be able to access that resource. If the runtime
   4850 environment does not record application capabilities in this manner, the
   4851 runtime environment MUST list all permissions held by the runtime itself when
   4852 installing any application using that runtime.</p>
   4853 
   4854 <h2 id="9_5_multi-user_support">9.5. Multi-User Support</h2>
   4855 
   4856 <div class="note">
   4857 <p>This feature is optional for all device types.</p>
   4858 </div>
   4859 
   4860 
   4861 <p>Android includes support for multiple users and provides support for full user
   4862 isolation [<a href="http://developer.android.com/reference/android/os/UserManager.html">Resources, 127</a>]. Device implementations MAY enable multiple users, but when enabled MUST meet
   4863 the following requirements related to multi-user support [<a href="http://source.android.com/devices/storage/traditional.html">Resources, 128</a>]:</p>
   4864 
   4865 <ul>
   4866   <li>Device implementations that do not declare the android.hardware.telephony
   4867 feature flag MUST support restricted profiles, a feature that allows device
   4868 owners to manage additional users and their capabilities on the device. With
   4869 restricted profiles, device owners can quickly set up separate environments for
   4870 additional users to work in, with the ability to manage finer-grained
   4871 restrictions in the apps that are available in those environments.</li>
   4872   <li>Conversely device implementations that declare the android.hardware.telephony
   4873 feature flag MUST NOT support restricted profiles but MUST align with the AOSP
   4874 implementation of controls to enable /disable other users from accessing the
   4875 voice calls and SMS.</li>
   4876   <li>Device implementations MUST, for each user, implement a security model
   4877 consistent with the Android platform security model as defined in Security and
   4878 Permissions reference document in the APIs [<a href="http://developer.android.com/guide/topics/security/permissions.html">Resources, 126</a>].</li>
   4879   <li>Each user instance on an Android device MUST have separate and isolated
   4880 external storage directories. Device implementations MAY store multiple users'
   4881 data on the same volume or filesystem. However, the device implementation MUST
   4882 ensure that applications owned by and running on behalf a given user cannot
   4883 list, read, or write to data owned by any other user. Note that removable
   4884 media, such as SD card slots, can allow one user to access another&rsquo;s data by
   4885 means of a host PC. For this reason, device implementations that use removable
   4886 media for the external storage APIs MUST encrypt the contents of the SD card if
   4887 multiuser is enabled using a key stored only on non-removable media accessible
   4888 only to the system. As this will make the media unreadable by a host PC, device
   4889 implementations will be required to switch to MTP or a similar system to
   4890 provide host PCs with access to the current user&rsquo;s data. Accordingly, device
   4891 implementations MAY but SHOULD NOT enable multi-user if they use removable
   4892 media [<a href="http://developer.android.com/reference/android/os/Environment.html">Resources, 129</a>] for primary external storage.</li>
   4893 </ul>
   4894 
   4895 <h2 id="9_6_premium_sms_warning">9.6. Premium SMS Warning</h2>
   4896 
   4897 
   4898 <p>Android includes support for warning users of any outgoing premium SMS message
   4899 [<a href="http://en.wikipedia.org/wiki/Short_code">Resources, 130</a>]. Premium SMS messages are text messages sent to a service registered with a
   4900 carrier that may incur a charge to the user. Device implementations that
   4901 declare support for android.hardware.telephony MUST warn users before sending a
   4902 SMS message to numbers identified by regular expressions defined in
   4903 /data/misc/sms/codes.xml file in the device. The upstream Android Open Source
   4904 Project provides an implementation that satisfies this requirement.</p>
   4905 
   4906 <h2 id="9_7_kernel_security_features">9.7. Kernel Security Features</h2>
   4907 
   4908 
   4909 <p>The Android Sandbox includes features that use the Security-Enhanced Linux
   4910 (SELinux) mandatory access control (MAC) system and other security features in
   4911 the Linux kernel. SELinux or any other security features implemented below
   4912 the Android framework:</p>
   4913 
   4914 <ul>
   4915   <li>MUST maintain compatibility with existing applications.</li>
   4916   <li>MUST NOT have a visible user interface when a security violation is detected
   4917 and successfully blocked, but MAY have a visible user interface when an
   4918 unblocked security violation occurs resulting in a successful exploit.</li>
   4919   <li>SHOULD NOT be user or developer configurable.</li>
   4920 </ul>
   4921 
   4922 <p>If any API for configuration of policy is exposed to an application that can
   4923 affect another application (such as a Device Administration API), the API MUST
   4924 NOT allow configurations that break compatibility.</p>
   4925 
   4926 <p>Devices MUST implement SELinux or, if using a kernel other than Linux, an
   4927 equivalent mandatory access control system. Devices MUST also meet the
   4928 following requirements, which are satisfied by the reference implementation
   4929 in the upstream Android Open Source Project.</p>
   4930 
   4931 <p>Device implementations:</p>
   4932 
   4933 <ul>
   4934   <li>MUST set SELinux to global enforcing mode.</li>
   4935   <li>MUST configure all domains in enforcing mode. No permissive mode domains
   4936 are allowed, including domains specific to a device/vendor.</li>
   4937   <li>MUST NOT modify, omit, or replace the neverallow rules present within the
   4938 external/sepolicy folder provided in the upstream Android Open Source Project (AOSP) and
   4939 the policy MUST compile with all neverallow rules present, for both AOSP SELinux
   4940 domains as well as device/vendor specific domains.</li>
   4941 </ul>
   4942 
   4943 <p>Device implementations SHOULD retain the default SELinux policy provided in the
   4944 external/sepolicy folder of the upstream Android Open Source Project and only
   4945 further add to this policy for their own device-specific configuration. Device
   4946 implementations MUST be compatible with the upstream Android Open Source Project.
   4947 </p>
   4948 
   4949 <h2 id="9_8_privacy">9.8. Privacy</h2>
   4950 
   4951 <p>If the device implements functionality in the system that captures the contents
   4952 displayed on the screen and/or records the audio stream played on the device,
   4953 it MUST continuously notify the user whenever this functionality is enabled and
   4954 actively capturing/recording.</p>
   4955 
   4956 <p>If a device implementation has a mechanism that routes network data traffic
   4957 through a proxy server or VPN gateway by default (for example, preloading a VPN
   4958 service with android.permission.CONTROL_VPN granted), the device implementation
   4959 MUST ask for the user's consent before enabling that mechanism.</p>
   4960 
   4961 <p>If a device implementation has a USB port with USB peripheral mode support,
   4962 it MUST present a user interface asking for the user's consent before allowing
   4963 access to the contents of the shared storage over the USB port.</p>
   4964 
   4965 <h2 id="9_9_full-disk_encryption">9.9. Full-Disk Encryption</h2>
   4966 
   4967 <div class="note">
   4968 <p>Optional for Android device implementations without a lock screen.</p>
   4969 </div>
   4970 
   4971 <p>If the device implementation supports a secure lock screen reporting "<code>true</code>"
   4972 for KeyguardManager.isDeviceSecure()
   4973 [<a href="http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()">Resources, 131</a>],
   4974 and is not a device with restricted memory as reported through the
   4975 ActivityManager.isLowRamDevice() method, then the device MUST support full-disk encryption
   4976 [<a href="http://source.android.com/devices/tech/security/encryption/index.html">Resources, 132</a>]
   4977 of the application private data (/data partition), as well as the application
   4978 shared storage partition (/sdcard partition) if it is a permanent, non-removable
   4979 part of the device.</p>
   4980 
   4981 <p>For device implementations supporting full-disk encryption and with Advanced
   4982 Encryption Standard (AES) crypto performance above 50MiB/sec, the full-disk
   4983 encryption MUST be enabled by default at the time the user has completed the out-of-box
   4984 setup experience. If a device implementation is already launched on an earlier Android
   4985 version with full-disk encryption disabled by default, such a device cannot
   4986 meet the requirement through a system software update and thus MAY be exempted.</p>
   4987 
   4988 <p>Encryption MUST use AES with a key of 128-bits (or greater) and a mode designed
   4989 for storage (for example, AES-XTS, AES-CBC-ESSIV). The encryption key MUST NOT
   4990 be written to storage at any time without being encrypted. Other than when in
   4991 active use, the encryption key SHOULD be AES encrypted with the lockscreen
   4992 passcode stretched using a slow stretching algorithm (e.g. PBKDF2 or scrypt).
   4993 If the user has not specified a lockscreen passcode or has disabled use of the
   4994 passcode for encryption, the system SHOULD use a default passcode to wrap the
   4995 encryption key. If the device provides a hardware-backed keystore, the password
   4996 stretching algorithm MUST be cryptographically bound to that keystore. The
   4997 encryption key MUST NOT be sent off the device (even when wrapped with the user
   4998 passcode and/or hardware bound key). The upstream Android Open Source project
   4999 provides a preferred implementation of this feature based on the Linux kernel
   5000 feature dm-crypt.</p>
   5001 
   5002 <h2 id="9_10_verified_boot">9.10. Verified Boot</h2>
   5003 
   5004 <p>
   5005 Verified boot is a feature that guarantees the integrity of the device software.
   5006 If a device implementation supports the feature, it MUST:
   5007 </p>
   5008 <ul>
   5009 <li>Declare the platform feature flag android.software.verified_boot</li>
   5010 <li>Perform verification on every boot sequence</li>
   5011 <li>Start verification from an immutable hardware key that is the root of trust, 
   5012 and go all the way up to the system partition</li>
   5013 <li>Implement each stage of verification to check the integrity and authenticity
   5014 of all the bytes in the next stage before executing the code in the next stage</li>
   5015 <li>Use verification algorithms as strong as current recommendations
   5016 from NIST for hashing algorithms (SHA-256) and public key sizes (RSA-2048)</li>
   5017 </ul>
   5018 
   5019 <p>The upstream Android Open Source Project provides a preferred implementation of this 
   5020 feature based on the Linux kernel feature dm-verity.</p>
   5021 
   5022 <p>Starting from Android 6.0, device implementations with Advanced Encryption Standard (AES)
   5023 crypto perfomance above 50MiB/seconds MUST support verified boot for device integrity.
   5024 If a device implementation is already launched without supporting verified boot on an earlier
   5025 version of Android, such a device can not add support for this feature with a system software
   5026 update and thus are exempted from the requirement.</p>
   5027 
   5028 <h2 id="9_11_keys_and_credentials">9.11. Keys and Credentials</h2>
   5029 
   5030 <p>The Android Keystore System
   5031 [<a href="https://developer.android.com/training/articles/keystore.html">Resources, 133</a>]
   5032 allows app developers to store cryptographic keys in a container and use them in cryptographic
   5033 operations through the KeyChain API
   5034 [<a href="https://developer.android.com/reference/android/security/KeyChain.html">Resources, 134</a>]
   5035 or the Keystore API
   5036   [<a href="https://developer.android.com/reference/java/security/KeyStore.html">Resources, 135</a>].
   5037 </p>
   5038 
   5039 <p>All Android device implementations MUST meet the following requirements:</p>
   5040 
   5041 <ul>
   5042 <li>SHOULD not limit the number of keys that can be generated, and MUST at least allow more
   5043 than 8,192 keys to be imported.</li>
   5044 <li>The lock screen authentication MUST rate limit attempts and SHOULD have an exponential
   5045   backoff algorithm as implemented in the Android Open Source Project.</li>
   5046 <li>When the device implementation supports a secure lock screen and has a secure hardware
   5047   such as a Secure Element (SE) where a Trusted Execution Environment (TEE) can be implemented,
   5048   then it:
   5049   <ul>
   5050   <li>Is STRONGLY RECOMMENDED to back up the keystore implementation with the secure hardware.
   5051     The upstream Android Open Source Project provides the Keymaster Hardware Abstraction Layer
   5052     (HAL) implementation that can be used to satisfy this requirement.</li>
   5053   <li>MUST perform the lock screen authentication in the secure hardware if the device has a
   5054     hardware-backed keystore implementation and only when successful allow the authentication-bound
   5055     keys to be used. The upstream Android Open Source Project provides the Gatekeeper Hardware
   5056     Abstraction Layer (HAL) that can be used to satisfy this requirement
   5057     [<a href="http://source.android.com/devices/tech/security/authentication/gatekeeper.html">Resources, 136</a>].</li>
   5058   </ul>
   5059 </li>
   5060 </ul>
   5061 
   5062 <p>Note that while the above TEE-related requirements are stated as STRONGLY RECOMMENDED, the
   5063   Compatibility Definition for the next API version is planned to changed these to REQIUIRED. If a
   5064   device implementation is already launched on an earlier Android version and has not implemented a
   5065   trusted operating system on the secure hardware, such a device might not be able to meet the
   5066   requirements through a system software update and thus is STRONGLY RECOMMENDED to implement a
   5067   TEE.</p>
   5068 
   5069 <h2 id="9_12_data_deletion">9.12. Data Deletion</h2>
   5070 
   5071 <p>Devices MUST provide users with a mechanism to perform a "Factory Data Reset"
   5072 that allows logical and physical deletion of all data. This MUST satisfy relevant
   5073 industry standards for data deletion such as NIST SP800-88. This MUST be used for
   5074 the implementation of the wipeData() API (part of the Android Device Administration API)
   5075 described in <a href="#3_9_device_administration">section 3.9 Device Administration</a>.</p>
   5076 
   5077 <p>Devices MAY provide a fast data wipe that conducts a logical data erase.</p>
   5078 
   5079 <h1 id="10_software_compatibility_testing">10. Software Compatibility Testing</h1>
   5080 
   5081 
   5082 <p>Device implementations MUST pass all tests described in this section.</p>
   5083 
   5084 <p>However, note that no software test package is fully comprehensive. For this
   5085 reason, device implementers are <strong>STRONGLY RECOMMENDED</strong> to make the minimum number of changes as possible to the reference and
   5086 preferred implementation of Android available from the Android Open Source
   5087 Project. This will minimize the risk of introducing bugs that create
   5088 incompatibilities requiring rework and potential device updates.</p>
   5089 
   5090 <h2 id="10_1_compatibility_test_suite">10.1. Compatibility Test Suite</h2>
   5091 
   5092 
   5093 <p>Device implementations MUST pass the Android Compatibility Test Suite (CTS) [<a href="http://source.android.com/compatibility/index.html">Resources, 137</a>] available from the Android Open Source Project, using the final shipping
   5094 software on the device. Additionally, device implementers SHOULD use the
   5095 reference implementation in the Android Open Source tree as much as possible,
   5096 and MUST ensure compatibility in cases of ambiguity in CTS and for any
   5097 reimplementations of parts of the reference source code.</p>
   5098 
   5099 <p>The CTS is designed to be run on an actual device. Like any software, the CTS
   5100 may itself contain bugs. The CTS will be versioned independently of this
   5101 Compatibility Definition, and multiple revisions of the CTS may be released for
   5102 Android 6.0. Device implementations MUST pass the latest CTS version available
   5103 at the time the device software is completed.</p>
   5104 
   5105 <h2 id="10_2_cts_verifier">10.2. CTS Verifier</h2>
   5106 
   5107 
   5108 <p>Device implementations MUST correctly execute all applicable cases in the CTS
   5109 Verifier. The CTS Verifier is included with the Compatibility Test Suite, and
   5110 is intended to be run by a human operator to test functionality that cannot be
   5111 tested by an automated system, such as correct functioning of a camera and
   5112 sensors.</p>
   5113 
   5114 <p>The CTS Verifier has tests for many kinds of hardware, including some hardware
   5115 that is optional. Device implementations MUST pass all tests for hardware that
   5116 they possess; for instance, if a device possesses an accelerometer, it MUST
   5117 correctly execute the Accelerometer test case in the CTS Verifier. Test cases
   5118 for features noted as optional by this Compatibility Definition Document MAY be
   5119 skipped or omitted.</p>
   5120 
   5121 <p>Every device and every build MUST correctly run the CTS Verifier, as noted
   5122 above. However, since many builds are very similar, device implementers are not
   5123 expected to explicitly run the CTS Verifier on builds that differ only in
   5124 trivial ways. Specifically, device implementations that differ from an
   5125 implementation that has passed the CTS Verifier only by the set of included
   5126 locales, branding, etc. MAY omit the CTS Verifier test.</p>
   5127 
   5128 <h1 id="11_updatable_software">11. Updatable Software</h1>
   5129 
   5130 
   5131 <p>Device implementations MUST include a mechanism to replace the entirety of the
   5132 system software. The mechanism need not perform &ldquo;live&rdquo; upgrades&mdash;that is, a
   5133 device restart MAY be required.</p>
   5134 
   5135 <p>Any method can be used, provided that it can replace the entirety of the
   5136 software preinstalled on the device. For instance, any of the following
   5137 approaches will satisfy this requirement:</p>
   5138 
   5139 <ul>
   5140   <li>&ldquo;Over-the-air (OTA)&rdquo; downloads with offline update via reboot</li>
   5141   <li>&ldquo;Tethered&rdquo; updates over USB from a host PC</li>
   5142   <li>&ldquo;Offline&rdquo; updates via a reboot and update from a file on removable storage</li>
   5143 </ul>
   5144 
   5145 <p>However, if the device implementation includes support for an unmetered data
   5146 connection such as 802.11 or Bluetooth PAN (Personal Area Network) profile:</p>
   5147 
   5148 <ul>
   5149 <li>Android Automotive implementations SHOULD support OTA downloads with offline
   5150 update via reboot.</li>
   5151 <li>All other device implementations MUST support OTA downloads with offline
   5152 update via reboot.</li>
   5153 </ul>
   5154 
   5155 <p>The update mechanism used MUST support updates without wiping user data. That
   5156 is, the update mechanism MUST preserve application private data and application
   5157 shared data. Note that the upstream Android software includes an update
   5158 mechanism that satisfies this requirement.</p>
   5159 
   5160 <p>For device implementations that are launching with Android 6.0 and later, the
   5161 update mechanism SHOULD support verifying that the system image is binary
   5162 identical to expected result following an OTA. The block-based OTA
   5163 implementation in the upstream Android Open Source Project, added since Android
   5164 5.1, satisfies this requirement.</p>
   5165 
   5166 <p>If an error is found in a device implementation after it has been released but
   5167 within its reasonable product lifetime that is determined in consultation with
   5168 the Android Compatibility Team to affect the compatibility of third-party
   5169 applications, the device implementer MUST correct the error via a software
   5170 update available that can be applied per the mechanism just described.</p>
   5171 
   5172 <p>Android includes features that allow the Device Owner app (if present) to control the
   5173 installation of system updates. To facilitate this, the system update subsystem
   5174 for devices that report android.software.device_admin MUST implement the behavior
   5175 described in the SystemUpdatePolicy class
   5176 [<a href="http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html">
   5177 Resources, 138</a>].</p>
   5178 
   5179 <h1 id="12_document_changelog">12. Document Changelog</h1>
   5180 
   5181 <p>The following table contains a summary of the changes to the Compatibility
   5182 Definition in this release.</p>
   5183 <table>
   5184  <tr>
   5185     <th>Section</th>
   5186     <th>Summary of changes</th>
   5187  </tr>
   5188  <tr>
   5189     <td>Various</td>
   5190     <td>Replaced instances of the "encouraged" term with "RECOMMENDED"</td>
   5191  </tr>
   5192  <tr>
   5193     <td>2. Device Types</td>
   5194     <td>Update for Android Automotive implementations</td>
   5195  </tr>
   5196  <tr>
   5197     <td>3.2.2. Build Parameters</td>
   5198     <td>Additions for the hardware serial number and for the security patch level of a build</td>
   5199  </tr>
   5200  <tr>
   5201     <td>3.2.3.2. Intent Resolution</td>
   5202     <td>Section renamed from "Intent Overrides" to "Intent Resolution," with new requirements related to authoritative default app linking</td>
   5203  </tr>
   5204  <tr>
   5205     <td>3.3.1. Application Binary Interfaces</td>
   5206     <td>Additions for Android ABI support; change related to Vulkan library name</td>
   5207  </tr>
   5208  <tr>
   5209     <td>3.4.1. WebView Compatibility</td>
   5210     <td>Change for the user agent string reported by the WebView</td>
   5211  </tr>
   5212  <tr>
   5213     <td>3.7. Runtime Compatibility</td>
   5214     <td>Updates to memory allocation table</td>
   5215  </tr>
   5216  <tr>
   5217     <td>3.8.4. Search</td>
   5218     <td>Updates regarding Assistant requirements</td>
   5219  </tr>
   5220  <tr>
   5221     <td>3.8.6. Themes</td>
   5222     <td>Added requirement to support black system icons when requested by the SYSTEM_UI_FLAG_LIGHT_STATUS_BAR flag</td>
   5223  </tr>
   5224  <tr>
   5225     <td>3.9.1. Device Provisioning</td>
   5226     <td>Contains new sections for device owner provisioning and managed profile provisioning</td>
   5227  </tr>
   5228  <tr>
   5229     <td>3.9.2. Managed Profile Support</td>
   5230     <td>New section with requirements for device support of managed profile functionality</td>
   5231  </tr>
   5232 <tr>
   5233     <td>3.12.1. TV App</td>
   5234     <td>Added section to clarify TV App requirements for Android Television devices</td>
   5235  </tr>
   5236  <tr>
   5237     <td>3.12.1.1. Electronic Program Guide</td>
   5238     <td>Added section to clarify EPG requirements for Android Television devices</td>
   5239  </tr>
   5240  <tr>
   5241     <td>3.12.1.2. Navigation</td>
   5242     <td>Added section to clarify TV App navigation requirements for Android Television devices</td>
   5243  </tr>
   5244     <td>3.12.1.3. TV input app linking</td>
   5245     <td>Added section to clarify TV input app linking support requirements for Android Television devices</td>
   5246  </tr>
   5247  <tr>
   5248     <td>5.1. Media Codecs</td>
   5249     <td>Updates regarding support for core media formats and decoding.</td>
   5250  </tr>
   5251  <tr>
   5252     <td>5.1.3. Video Codecs</td>
   5253     <td>Changes and additions related to Android Televisions</td>
   5254  </tr>
   5255  <tr>
   5256     <td>5.2. Video Encoding</td>
   5257     <td>Changes for encoders</td>
   5258  </tr>
   5259  <tr>
   5260     <td>5.3. Video Decoding</td>
   5261     <td>Changes for decoders, including regarding support for dynamic video resolution, frame rate
   5262 switching, and more</td>
   5263  </tr>
   5264  <tr>
   5265     <td>5.4. Audio Recording</td>
   5266     <td>Additions related to audio capture</td>
   5267  </tr>
   5268  <tr>
   5269     <td>5.6. Audio Latency</td>
   5270     <td>Update regarding reporting of support for low-latency audio</td>
   5271  </tr>
   5272  <tr>
   5273     <td>5.10. Professional Audio</td>
   5274     <td>General updates for professional audio support; updates for mobile device (jack) specifications, USB audio host mode, and other updates</td>
   5275  </tr>
   5276  <tr>
   5277     <td>5.9. Musical Instrument Digital Interface (MIDI)</td>
   5278     <td>Added new section on optional Musical Instrument Digital Interface (MIDI) support</td>
   5279  </tr>
   5280 <tr>
   5281     <td>6.1. Developer Tools</td>
   5282     <td>Update for drivers supporting Windows 10</td>
   5283  </tr>
   5284  <tr>
   5285     <td>7.1.1.3. Screen Density</td>
   5286     <td>Updates for screen density, for example related to an Android watch</td>
   5287  </tr>
   5288  <tr>
   5289     <td>7.2.3. Navigation Keys</td>
   5290     <td>Updated requirements for device implementations that include the Assist action</td>
   5291  </tr>
   5292  <tr>
   5293     <td>7.3. Sensors (and subsections)</td>
   5294     <td>New requirements for some sensor types</td>
   5295  </tr>
   5296  <tr>
   5297     <td>7.3.9. High Fidelity Sensors</td>
   5298     <td>New section with requirements for devices supporting high fidelity sensors</td>
   5299  </tr>
   5300  <tr>
   5301     <td>7.3.10. Fingerprint Sensor</td>
   5302     <td>New section on requirements related to fingerprint sensors</td>
   5303  </tr>
   5304  <tr>
   5305     <td>7.4.2. IEEE 802.11 (Wi-Fi)</td>
   5306     <td>Updates regarding support for multicast DNS (mDNS)</td>
   5307  </tr>
   5308  <tr>
   5309     <td>7.4.3. Bluetooth</td>
   5310     <td>Addition related to Resolvable Private Address (RPA) for Bluetooth Low Energy (BLE)</td>
   5311  </tr>
   5312  <tr>
   5313     <td>7.4.4. Near-Field Communications</td>
   5314     <td>Additions to requirements for Near-Field Communications (NFC)</td>
   5315  </tr>
   5316  <tr>
   5317     <td>7.4.5. Minimum Network Capability</td>
   5318     <td>Added requirements for IPv6 support</td>
   5319  </tr>
   5320  <tr>
   5321     <td>7.6.3. Adoptable Storage</td>
   5322     <td>New section for implementation of adoptable storage</td>
   5323  </tr>
   5324  <tr>
   5325     <td>7.7. USB</td>
   5326     <td>Requirement related to implementing the AOA specification</td>
   5327  </tr>
   5328  <tr>
   5329     <td>7.8.3. Near-Ultrasound</td>
   5330     <td>Additions related to near-ultrasound recording, playback, and audio</td>
   5331  </tr>
   5332  <tr>
   5333     <td>8.3. Power-Saving Modes</td>
   5334     <td>New section with requirements regarding the App Standby and Doze modes</td>
   5335  </tr>
   5336 <tr>
   5337     <td>8.4. Power Consumption Accounting</td>
   5338     <td>New section with requirements for tracking hardware component power usage and attributing that power usage to specific applications</td>
   5339  </tr>
   5340  <tr>
   5341     <td>9.1. Permissions</td>
   5342     <td>Addition to Permissions requirements</td>
   5343  </tr>
   5344 <tr>
   5345     <td>9.7. Kernel Security Features</td>
   5346     <td>SE Linux updates</td>
   5347  </tr>
   5348 <tr>
   5349     <td>9.8. Privacy</td>
   5350     <td>Addition regarding user's consent for access to shared storage over a USB port</td>
   5351  </tr>
   5352  <tr>
   5353     <td>9.9. Full-Disk Encryption</td>
   5354     <td>Requirements related to full disk encryption</td>
   5355  </tr>
   5356  <tr>
   5357     <td>9.10. Verified Boot</td>
   5358     <td>Additional requirement for verified boot</td>
   5359  </tr>
   5360  <tr>
   5361     <td>9.11. Keys and Credentials</td>
   5362     <td>New section of requirements related to keys and credentials</td>
   5363  </tr>
   5364  <tr>
   5365     <td>9.12. Data Deletion</td>
   5366     <td>New section for "Factory Data Reset"</td>
   5367  </tr>
   5368  <tr>
   5369     <td>11. Updatable Software</td>
   5370     <td>Requirement related to the system update policy set by the device owner</td>
   5371  </tr>
   5372  </table>
   5373 
   5374 
   5375 <h1 id="13_contact_us">13. Contact Us</h1>
   5376 
   5377 
   5378 <p>You can join the android-compatibility forum <a href="https://groups.google.com/forum/#!forum/android-compatibility">[Resources, 139</a>] and ask for clarifications or bring up any issues that you think the document
   5379 does not cover.</p>
   5380 
   5381 <h1 id="14_resources">14. Resources</h1>
   5382 
   5383 <p>1. IETF RFC2119 Requirement Levels: <a href="http://www.ietf.org/rfc/rfc2119.txt">http://www.ietf.org/rfc/rfc2119.txt</a></p>
   5384 
   5385 <p>2. Android Open Source Project: <a href="http://source.android.com/">http://source.android.com/</a></p>
   5386 
   5387 <p>3. Android Television features: <a href="http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK">http://developer.android.com/reference/android/content/pm/PackageManager.html#FEATURE_LEANBACK</a></p>
   5388 
   5389 <p>4. Android Watch feature: <a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH">http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_WATCH</a></p>
   5390 
   5391 <p>5. Android UI_MODE_TYPE_CAR API: <a href="http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR">http://developer.android.com/reference/android/content/res/Configuration.html#UI_MODE_TYPE_CAR</a></p>
   5392 
   5393 <p>6. API definitions and documentation: <a href="http://developer.android.com/reference/packages.html">http://developer.android.com/reference/packages.html</a></p>
   5394 
   5395 <p>7. Android Permissions reference: <a href="http://developer.android.com/reference/android/Manifest.permission.html">http://developer.android.com/reference/android/Manifest.permission.html</a></p>
   5396 
   5397 <p>8. 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></p>
   5398 
   5399 <p>9. Android 6.0 allowed version strings: <a href="http://source.android.com/compatibility/6.0/versions.html">http://source.android.com/compatibility/6.0/versions.html</a></p>
   5400 
   5401 <p>10. Android Developer Settings: <a href="http://developer.android.com/reference/android/provider/Settings.html">http://developer.android.com/reference/android/provider/Settings.html</a></p>
   5402 
   5403 <p>11. Telephony Provider: <a href="http://developer.android.com/reference/android/provider/Telephony.html">http://developer.android.com/reference/android/provider/Telephony.html</a></p>
   5404 
   5405 <p>12. Android NDK ABI Management: <a href="https://developer.android.com/ndk/guides/abis.html">https://developer.android.com/ndk/guides/abis.html</a></p>
   5406 
   5407 <p>13. Advanced SIMD architecture: <a href="http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html">http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0388f/Beijfcja.html</a></p>
   5408 
   5409 <p>14. Android Extension Pack: <a href="http://developer.android.com/guide/topics/graphics/opengl.html#aep">http://developer.android.com/guide/topics/graphics/opengl.html#aep</a></p>
   5410 
   5411 <p>15. 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></p>
   5412 
   5413 <p>16. WebView compatibility: <a href="http://www.chromium.org/">http://www.chromium.org/</a></p>
   5414 
   5415 <p>17. HTML5: <a href="http://html.spec.whatwg.org/multipage/">http://html.spec.whatwg.org/multipage/</a></p>
   5416 
   5417 <p>18. HTML5 offline capabilities:<a href="http://dev.w3.org/html5/spec/Overview.html#offline"> http://dev.w3.org/html5/spec/Overview.html#offline</a></p>
   5418 
   5419 <p>19. HTML5 video tag: <a href="http://dev.w3.org/html5/spec/Overview.html#video">http://dev.w3.org/html5/spec/Overview.html#video</a></p>
   5420 
   5421 <p>20. HTML5/W3C geolocation API: <a href="http://www.w3.org/TR/geolocation-API/">http://www.w3.org/TR/geolocation-API/</a></p>
   5422 
   5423 <p>21. HTML5/W3C webstorage API: <a href="http://www.w3.org/TR/webstorage/">http://www.w3.org/TR/webstorage/</a></p>
   5424 
   5425 <p>22. HTML5/W3C IndexedDB API: <a href="http://www.w3.org/TR/IndexedDB/">http://www.w3.org/TR/IndexedDB/</a></p>
   5426 
   5427 <p>23. Dalvik Executable Format and bytecode specification: available in the
   5428 Android source code, at dalvik/docs</p>
   5429 
   5430 <p>24. 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></p>
   5431 
   5432 <p>25. Notifications: <a href="http://developer.android.com/guide/topics/ui/notifiers/notifications.html">http://developer.android.com/guide/topics/ui/notifiers/notifications.html</a></p>
   5433 
   5434 <p>26. Application Resources: <a href="https://developer.android.com/guide/topics/resources/available-resources.html">https://developer.android.com/guide/topics/resources/available-resources.html</a></p>
   5435 
   5436 <p>27. Status Bar icon style guide: <a href="http://developer.android.com/design/style/iconography.html">http://developer.android.com/design/style/iconography.html</a></p>
   5437 
   5438 <p>28. Notifications Resources: <a href="https://developer.android.com/design/patterns/notifications.html">https://developer.android.com/design/patterns/notifications.html</a></p>
   5439 
   5440 <p>29. Search Manager: <a href="http://developer.android.com/reference/android/app/SearchManager.html">http://developer.android.com/reference/android/app/SearchManager.html</a></p>
   5441 
   5442 <p>30. 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></p>
   5443 
   5444 <p>31. Android Assist APIs: <a href="https://developer.android.com/reference/android/app/assist/package-summary.html">https://developer.android.com/reference/android/app/assist/package-summary.html</a></p>
   5445 
   5446 <p>32. Toasts: <a href="http://developer.android.com/reference/android/widget/Toast.html">http://developer.android.com/reference/android/widget/Toast.html</a></p>
   5447 
   5448 <p>33. Themes: <a href="http://developer.android.com/guide/topics/ui/themes.html">http://developer.android.com/guide/topics/ui/themes.html</a></p>
   5449 
   5450 <p>34. R.style class: <a href="http://developer.android.com/reference/android/R.style.html">http://developer.android.com/reference/android/R.style.html</a></p>
   5451 
   5452 <p>35. Material design: <a href="http://developer.android.com/reference/android/R.style.html#Theme_Material">http://developer.android.com/reference/android/R.style.html#Theme_Material</a></p>
   5453 
   5454 <p>36. Live Wallpapers: <a href="http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html">http://developer.android.com/reference/android/service/wallpaper/WallpaperService.html</a></p>
   5455 
   5456 <p>37. Overview screen resources: <a href="http://developer.android.com/guide/components/recents.html">http://developer.android.com/guide/components/recents.html</a></p>
   5457 
   5458 <p>38. Screen pinning: <a href="https://developer.android.com/about/versions/android-5.0.html#ScreenPinning">https://developer.android.com/about/versions/android-5.0.html#ScreenPinning</a></p>
   5459 
   5460 <p>39. Input methods: <a href="http://developer.android.com/guide/topics/text/creating-input-method.html">http://developer.android.com/guide/topics/text/creating-input-method.html</a></p>
   5461 
   5462 <p>40. Media Notification: <a href="https://developer.android.com/reference/android/app/Notification.MediaStyle.html">https://developer.android.com/reference/android/app/Notification.MediaStyle.html</a></p>
   5463 
   5464 <p>41. Dreams: <a href="http://developer.android.com/reference/android/service/dreams/DreamService.html">http://developer.android.com/reference/android/service/dreams/DreamService.html</a></p>
   5465 
   5466 <p>42. Settings.Secure LOCATION_MODE: <a href="http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE">http://developer.android.com/reference/android/provider/Settings.Secure.html#LOCATION_MODE</a></p>
   5467 
   5468 <p>43. Unicode 6.1.0: <a href="http://www.unicode.org/versions/Unicode6.1.0/">http://www.unicode.org/versions/Unicode6.1.0/</a></p>
   5469 
   5470 <p>44. 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></p>
   5471 
   5472 <p>45. 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></p>
   5473 
   5474 <p>46. Device Owner App: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isDeviceOwnerApp(java.lang.String)</a></p>
   5475 
   5476 
   5477 <p>47. Android Device Owner Provisioning Flow: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_DEVICE</a></p>
   5478 
   5479 <p>48. Device Owner Provisioning via NFC: <a href="https://source.android.com/devices/tech/admin/provision.html#device_owner_provisioning_via_nfc">https://source.android.com/devices/tech/admin/provision.html#device_owner_provisioning_via_nfc</a></p>
   5480 
   5481 <p>49. Android Profile Owner App:<a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#isProfileOwnerApp(java.lang.String)</a></p>
   5482 
   5483 <p>50. Android Managed Profile Provisioning flow: <a href="http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE">http://developer.android.com/reference/android/app/admin/DevicePolicyManager.html#ACTION_PROVISION_MANAGED_PROFILE</a></p>
   5484 
   5485 <p>51. Android Accessibility Service APIs: <a href="http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html">http://developer.android.com/reference/android/accessibilityservice/AccessibilityService.html</a></p>
   5486 
   5487 <p>52. 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></p>
   5488 
   5489 <p>53. Eyes Free project: <a href="http://code.google.com/p/eyes-free/">http://code.google.com/p/eyes-free</a></p>
   5490 
   5491 <p>54. 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></p>
   5492 
   5493 <p>55. Television Input Framework: <a href="https://source.android.com/devices/tv/index.html">https://source.android.com/devices/tv/index.html</a></p>
   5494 
   5495 <p>56. TV App channels: <a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html">http://developer.android.com/reference/android/media/tv/TvContract.Channels.html</a></p>
   5496 
   5497 <p>57. Third-party TV inputs: <a href="https://source.android.com/devices/tv/index.html#third-party_input_example">https://source.android.com/devices/tv/index.html#third-party_input_example</a></p>
   5498 
   5499 <p>58. TV inputs: <a href="https://source.android.com/devices/tv/index.html#tv_inputs">https://source.android.com/devices/tv/index.html#tv_inputs</a></p>
   5500 
   5501 <p>59. TV channel EPG fields: <a href="https://developer.android.com/reference/android/media/tv/TvContract.Programs.html">https://developer.android.com/reference/android/media/tv/TvContract.Programs.html</a></p>
   5502 
   5503 <p>60. TV input app linking: <a href="http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI">http://developer.android.com/reference/android/media/tv/TvContract.Channels.html#COLUMN_APP_LINK_INTENT_URI</a></p>
   5504 
   5505 <p>61. Reference tool documentation (for adb, aapt, ddms, systrace): <a href="http://developer.android.com/tools/help/index.html">http://developer.android.com/tools/help/index.html</a></p>
   5506 
   5507 <p>62. Android apk file description: <a href="http://developer.android.com/guide/components/fundamentals.html">http://developer.android.com/guide/components/fundamentals.html</a></p>
   5508 
   5509 <p>63. 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></p>
   5510 
   5511 <p>64. Android Media Formats: <a href="http://developer.android.com/guide/appendix/media-formats.html">http://developer.android.com/guide/appendix/media-formats.html</a></p>
   5512 
   5513 <p>65. Android MediaCodecList API: <a href="http://developer.android.com/reference/android/media/MediaCodecList.html">http://developer.android.com/reference/android/media/MediaCodecList.html</a></p>
   5514 
   5515 <p>66. Android CamcorderProfile API: <a href="http://developer.android.com/reference/android/media/CamcorderProfile.html">http://developer.android.com/reference/android/media/CamcorderProfile.html</a></p>
   5516 
   5517 <p>67. WebM project: <a href="http://www.webmproject.org/">http://www.webmproject.org/</a></p>
   5518 
   5519 <p>68. RTC Hardware Coding Requirements: <a href="http://www.webmproject.org/hardware/rtc-coding-requirements/">http://www.webmproject.org/hardware/rtc-coding-requirements/</a></p>
   5520 
   5521 <p>69. AudioEffect API: <a href="http://developer.android.com/reference/android/media/audiofx/AudioEffect.html">http://developer.android.com/reference/android/media/audiofx/AudioEffect.html</a></p>
   5522 
   5523 <p>70. 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></p>
   5524 
   5525 <p>71. 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></p>
   5526 
   5527 <p>72. ADB: <a href="http://developer.android.com/tools/help/adb.html">http://developer.android.com/tools/help/adb.html</a></p>
   5528 
   5529 <p>73. Dumpsys: <a href="https://source.android.com/devices/input/diagnostics.html">https://source.android.com/devices/input/diagnostics.html</a></p>
   5530 
   5531 <p>74. DDMS: <a href="http://developer.android.com/tools/debugging/ddms.html">http://developer.android.com/tools/debugging/ddms.html</a></p>
   5532 
   5533 <p>75. Monkey testing tool: <a href="http://developer.android.com/tools/help/monkey.html">http://developer.android.com/tools/help/monkey.html</a></p>
   5534 
   5535 <p>76. SysyTrace tool: <a href="http://developer.android.com/tools/help/systrace.html">http://developer.android.com/tools/help/systrace.html</a></p>
   5536 
   5537 <p>77. 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></p>
   5538 
   5539 <p>78. Supporting Multiple Screens: <a href="http://developer.android.com/guide/practices/screens_support.html">http://developer.android.com/guide/practices/screens_support.html</a></p>
   5540 
   5541 <p>79. android.util.DisplayMetrics: <a href="http://developer.android.com/reference/android/util/DisplayMetrics.html">http://developer.android.com/reference/android/util/DisplayMetrics.html</a></p>
   5542 
   5543 <p>80. RenderScript: <a href="http://developer.android.com/guide/topics/renderscript/">http://developer.android.com/guide/topics/renderscript/</a></p>
   5544 
   5545 <p>81. Android extension pack for OpenGL ES: <a href="https://developer.android.com/reference/android/opengl/GLES31Ext.html">https://developer.android.com/reference/android/opengl/GLES31Ext.html</a></p>
   5546 
   5547 <p>82. 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></p>
   5548 
   5549 <p>83. EGL Extension-EGL_ANDROID_RECORDABLE: <a href="http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt">http://www.khronos.org/registry/egl/extensions/ANDROID/EGL_ANDROID_recordable.txt</a></p>
   5550 
   5551 <p>84. 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></p>
   5552 
   5553 <p>85. 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></p>
   5554 
   5555 <p>86. Touch Input Configuration: <a href="http://source.android.com/devices/tech/input/touch-devices.html">http://source.android.com/devices/tech/input/touch-devices.html</a></p>
   5556 
   5557 <p>87. Motion Event API: <a href="http://developer.android.com/reference/android/view/MotionEvent.html">http://developer.android.com/reference/android/view/MotionEvent.html</a></p>
   5558 
   5559 <p>88. Key Event API: <a href="http://developer.android.com/reference/android/view/KeyEvent.html">http://developer.android.com/reference/android/view/KeyEvent.html</a></p>
   5560 
   5561 <p>89. Android Open Source sensors: <a href="http://source.android.com/devices/sensors/">http://source.android.com/devices/sensors</a></p>
   5562 
   5563 <p>90. android.hardware.SensorEvent: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html">http://developer.android.com/reference/android/hardware/SensorEvent.html</a></p>
   5564 
   5565 <p>91. Timestamp sensor event: <a href="http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp">http://developer.android.com/reference/android/hardware/SensorEvent.html#timestamp</a></p>
   5566 
   5567 <p>92. Android Open Source composite sensors: <a href="http://source.android.com/devices/sensors/sensor-types.html#composite_sensor_type_summary">https://source.android.com/devices/sensors/sensor-types.html#composite_sensor_type_summary</a></p>
   5568 
   5569 <p>93. Continuous trigger mode: <a href="http://source.android.com/devices/sensors/report-modes.html#continuous">https://source.android.com/devices/sensors/report-modes.html#continuous</a></p>
   5570 
   5571 <p>94. Accelerometer sensor: <a href="http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER">http://developer.android.com/reference/android/hardware/Sensor.html#TYPE_ACCELEROMETER</a></p>
   5572 
   5573 <p>95. Android Fingerprint API: <a href="https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html">https://developer.android.com/reference/android/hardware/fingerprint/package-summary.html</a></p>
   5574 
   5575 <p>96. Android Fingerprint HAL: <a href="https://source.android.com/devices/tech/security/authentication/fingerprint-hal.html">https://source.android.com/devices/tech/security/authentication/fingerprint-hal.html</a></p>
   5576 
   5577 <p>97. Wi-Fi 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></p>
   5578 
   5579 <p>98. Wi-Fi Direct (Wi-Fi 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></p>
   5580 
   5581 <p>99. WifiManager API: <a href="http://developer.android.com/reference/android/net/wifi/WifiManager.html">http://developer.android.com/reference/android/net/wifi/WifiManager.html</a></p>
   5582 
   5583 <p>100. 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></p>
   5584 
   5585 <p>101. Bluetooth ScanFilter API: <a href="https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html">https://developer.android.com/reference/android/bluetooth/le/ScanFilter.html</a></p>
   5586 
   5587 <p>102. NFC Barcode: <a href="http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html">http://developer.android.com/reference/android/nfc/tech/NfcBarcode.html</a></p>
   5588 
   5589 <p>103. NDEF Push Protocol: <a href="http://source.android.com/compatibility/ndef-push-protocol.pdf">http://source.android.com/compatibility/ndef-push-protocol.pdf</a></p>
   5590 
   5591 <p>104. Android Beam: <a href="http://developer.android.com/guide/topics/connectivity/nfc/nfc.html">http://developer.android.com/guide/topics/connectivity/nfc/nfc.html</a></p>
   5592 
   5593 <p>105. 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></p>
   5594 
   5595 <p>106. NFC Connection Handover: <a href="http://members.nfc-forum.org/specs/spec_list/#conn_handover">http://members.nfc-forum.org/specs/spec_list/#conn_handover</a></p>
   5596 
   5597 <p>107. Bluetooth Secure Simple Pairing Using NFC: <a href="http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf">http://members.nfc-forum.org/apps/group_public/download.php/18688/NFCForum-AD-BTSSP_1_1.pdf</a></p>
   5598 
   5599 <p>108. Host-based Card Emulation: <a href="http://developer.android.com/guide/topics/connectivity/nfc/hce.html">http://developer.android.com/guide/topics/connectivity/nfc/hce.html</a></p>
   5600 
   5601 <p>109. Content Resolver: <a href="http://developer.android.com/reference/android/content/ContentResolver.html">http://developer.android.com/reference/android/content/ContentResolver.html</a></p>
   5602 
   5603 <p>110. 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></p>
   5604 
   5605 <p>111. Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.html">http://developer.android.com/reference/android/hardware/Camera.html</a></p>
   5606 
   5607 <p>112. Camera: <a href="http://developer.android.com/reference/android/hardware/Camera.Parameters.html">http://developer.android.com/reference/android/hardware/Camera.Parameters.html</a></p>
   5608 
   5609 <p>113. Camera hardware level: <a href="https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL">https://developer.android.com/reference/android/hardware/camera2/CameraCharacteristics.html#INFO_SUPPORTED_HARDWARE_LEVEL</a></p>
   5610 
   5611 <p>114. Camera version support: <a href="http://source.android.com/devices/camera/versioning.html">http://source.android.com/devices/camera/versioning.html</a></p>
   5612 
   5613 <p>115. Android DownloadManager: <a href="http://developer.android.com/reference/android/app/DownloadManager.html">http://developer.android.com/reference/android/app/DownloadManager.html</a></p>
   5614 
   5615 <p>116. Android File Transfer: <a href="http://www.android.com/filetransfer">http://www.android.com/filetransfer</a></p>
   5616 
   5617 <p>117. Adoptable storage: <a href="http://source.android.com/devices/storage/adoptable.html">http://source.android.com/devices/storage/adoptable.html</a></p>
   5618 
   5619 <p>118. Android Open Accessories: <a href="http://developer.android.com/guide/topics/connectivity/usb/accessory.html">http://developer.android.com/guide/topics/connectivity/usb/accessory.html</a></p>
   5620 
   5621 <p>119. 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></p>
   5622 
   5623 <p>120. USB Charging Specification: <a href="http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf">http://www.usb.org/developers/docs/devclass_docs/USB_Battery_Charging_1.2.pdf</a></p>
   5624 
   5625 <p>121. USB Host API:<a href="http://developer.android.com/guide/topics/connectivity/usb/host.html"> http://developer.android.com/guide/topics/connectivity/usb/host.html</a></p>
   5626 
   5627 <p>122. Wired audio headset: <a href="http://source.android.com/accessories/headset-spec.html">http://source.android.com/accessories/headset-spec.html</a></p>
   5628 
   5629 <p>123. Power profile components: <a href="http://source.android.com/devices/tech/power/values.html">http://source.android.com/devices/tech/power/values.html</a></p>
   5630 
   5631 <p>124. Batterystats: <a href="http://source.android.com/devices/tech/power/batterystats.html">http://source.android.com/devices/tech/power/batterystats.html</a></p>
   5632 
   5633 <p>125. Power usage summary: <a href="http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY">http://developer.android.com/reference/android/content/Intent.html#ACTION_POWER_USAGE_SUMMARY</a></p>
   5634 
   5635 <p>126. Android Security and Permissions reference: <a href="http://developer.android.com/guide/topics/security/permissions.html">http://developer.android.com/guide/topics/security/permissions.html</a></p>
   5636 
   5637 <p>127. UserManager reference: <a href="http://developer.android.com/reference/android/os/UserManager.html">http://developer.android.com/reference/android/os/UserManager.html</a></p>
   5638 
   5639 <p>128. External Storage reference: <a href="http://source.android.com/devices/storage/traditional.html">http://source.android.com/devices/storage</a></p>
   5640 
   5641 <p>129. External Storage APIs: <a href="http://developer.android.com/reference/android/os/Environment.html">http://developer.android.com/reference/android/os/Environment.html</a></p>
   5642 
   5643 <p>130. SMS Short Code: <a href="http://en.wikipedia.org/wiki/Short_code">http://en.wikipedia.org/wiki/Short_code</a></p>
   5644 
   5645 <p>131. Secure lock screen reporting: <a href="http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()">http://developer.android.com/reference/android/app/KeyguardManager.html#isDeviceSecure()</a></p>
   5646 
   5647 <p>132. Android Open Source Encryption: <a href="http://source.android.com/devices/tech/security/encryption/index.html">http://source.android.com/devices/tech/security/encryption/index.html</a></p>
   5648 
   5649 <p>133. Android Keystore System: <a href="https://developer.android.com/training/articles/keystore.html">https://developer.android.com/training/articles/keystore.html</a></p>
   5650 
   5651 <p>134. KeyChain API: <a href="https://developer.android.com/reference/android/security/KeyChain.html">https://developer.android.com/reference/android/security/KeyChain.html</a></p>
   5652 
   5653 <p>135. Keystore API: <a href="https://developer.android.com/reference/java/security/KeyStore.html">https://developer.android.com/reference/java/security/KeyStore.html</a></p>
   5654 
   5655 <p>136. Gatekeeper HAL: <a href="http://source.android.com/devices/tech/security/authentication/gatekeeper.html">http://source.android.com/devices/tech/security/authentication/gatekeeper.html</a></p>
   5656 
   5657 <p>137. Android Compatibility Program Overview: <a href="http://source.android.com/compatibility/index.html">http://source.android.com/compatibility/index.html</a></p>
   5658 
   5659 <p>138. SystemUpdatePolicy class: <a href="http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html">http://developer.android.com/reference/android/app/admin/SystemUpdatePolicy.html</a></p>
   5660 
   5661 <p>139. Android Compatibility forum: <a href="https://groups.google.com/forum/#!forum/android-compatibility">https://groups.google.com/forum/#!forum/android-compatibility</a></p>
   5662 
   5663 <p>140. Handling app links: <a href="https://developer.android.com/training/app-links">https://developer.android.com/training/app-links/index.html</a></p>
   5664 
   5665 <p>141. Google Digital Asset Links: <a href="https://developers.google.com/digital-asset-links">https://developers.google.com/digital-asset-links</a></p>
   5666 
   5667 <p>Many of these resources are derived directly or indirectly from the Android
   5668 SDK, and will be functionally identical to the information in that SDK&rsquo;s
   5669 documentation. In any cases where this Compatibility Definition or the
   5670 Compatibility Test Suite disagrees with the SDK documentation, the SDK
   5671 documentation is considered authoritative. Any technical details provided in
   5672 the references included above are considered by inclusion to be part of this
   5673 Compatibility Definition.</p>
   5674 
   5675 </div>
   5676 </body>
   5677 </html>
   5678