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Android Automobile sample
=========================
Integration points
------------------
MusicService.java is the main entry point to the integration. It needs to:
- extend android.service.media.MediaBrowserService, implementing the media browsing related methods onGetRoot and onLoadChildren;
- start a new MediaSession and notify it's parent of the session's token (super.setSessionToken());
- set a callback on the MediaSession. The callback will receive all the user's actions, like play, pause, etc;
- handle all the actual music playing using any method your app prefers (for example, the Android MediaPlayer class)
- update info about the playing item and the playing queue using MediaSession (setMetadata, setPlaybackState, setQueue, setQueueTitle, etc)
- handle AudioManager focus change events and react appropriately (eg, pause when audio focus is lost)
- declare a meta-data tag in AndroidManifest.xml linking to a xml resource
with a <automotiveApp> root element. For a media app, this must include
an <uses name="media"/> element as a child.
For example, in AndroidManifest.xml:
<meta-data android:name="com.google.android.gms.car.application"
android:resource="@xml/automotive_app_desc"/>
And in res/values/automotive_app_desc.xml:
<?xml version="1.0" encoding="utf-8"?>
<automotiveApp>
<uses name="media"/>
</automotiveApp>
- be declared in AndroidManifest as an intent receiver for the action android.media.browse.MediaBrowserService:
<!-- Implement a service -->
<service
android:name=".service.MusicService"
android:exported="true"
>
<intent-filter>
<action android:name="android.media.browse.MediaBrowserService" />
</intent-filter>
</service>
Optionally, you can listen to special intents that notify your app when a car is connected/disconnected. This may be useful if your app has special requirements when running on a car - for example, different media or ads. See CarPlugReceiver for more information.
Customization
-------------
The car media app has only a few customization opportunities. You may:
- Set the background color by using Android L primary color:
<style name="AppTheme" parent="android:Theme.Material">
<item name="android:colorPrimary">#ff0000</item>
</style>
- Add custom actions in the state passed to setPlaybackState(state)
- Handle custom actions in the MediaSession.Callback.onCustomAction
Known issues:
-------------
- Sample: Resuming after pause makes the "Skip to previous" button disappear
- Sample: playFromSearch creates a queue with search results, but then skip to next/previous don't work correctly because the queue is recreated without the search criteria
- Emulator: running menu->search twice throws an exception.
- Emulator: Under some circumstances, stop or onDestroy may never get called on MusicService and the MediaPlayer keeps locking some resources. Then, mediaPlayer.setDataSource on a new MediaPlayer object halts (probably) due to a deadlock. The workaround is to reboot the device.
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