This sample shows how to implement an audio media app that provides media library metadata and playback controls through a standard service. It exposes a simple music library through the new MediaBrowserService and provides MediaSession callbacks. This allows it to be used in Android Auto, for example. When not connected to a car, the app has a very simple UI that browses the media library and provides simple playback controls. When connected to Android Auto, the same service provides data and callback to the Android Auto UI in the same manner as it provides them to the local UI.
To implement a MediaBrowserService, you need to:
Extend android.service.media.MediaBrowserService, implementing the media browsing related methods onGetRoot and onLoadChildren;
In onCreate, start a new MediaSession and call super.setSessionToken() with this MediaSession's token;
Set a MediaSession.Callback class on the MediaSession. The callback class 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)
Whenever it changes, update info about the playing item and the playing queue using MediaSession corresponding methods (setMetadata, setPlaybackState, setQueue, setQueueTitle, etc)
Handle AudioManager focus change events and react appropriately (e.g. pause when audio focus is lost)
To make it compatible with Android Auto, you also need to:
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/xml/automotive_app_desc.xml:
<?xml version="1.0" encoding="utf-8"?> <automotiveApp> <uses name="media"/> </automotiveApp>
<service android:name=".service.MusicService" android:exported="true"> <intent-filter> <action android:name="android.media.browse.MediaBrowserService" /> </intent-filter> </service>
This sample uses the Gradle build system. To build this project, use the “gradlew build” command or use “Import Project” in Android Studio.
If you've found an error in this sample, please file an issue: https://github.com/googlesamples/android-MediaBrowserService
Patches are encouraged, and may be submitted by forking this project and submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details.
Copyright 2014 The Android Open Source Project, Inc.
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