State of Media Playback

Talk from Android Dev Summit 2015 on taking your app beyond just playing audio. Learn how the Android Support Library makes it easy to integrate your app with bluetooth controls, lockscreens, notifications, Android Wear, and more with this talk focused on best practices for making the best user experience.

1. +AndroidDevelopers State of Media Playback Ian Lake @AndroidDev Media playback the right way
2. ~5 years of Android Development experience Previously at Phunware, Facebook Developer Advocate at Google • Advanced Android Udacity Course • Android Development Patterns About me
3. Specifically audio Video: github.com/googlecast/CastCompanionLibrary-android Media playback
4. User expectations
5. Background playback = Service
6. Important events in media playback Created Playing Paused Stopped Destroyed
7. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Playing audio Media Player* Mission Accomplished! *Or ExoPlayer: github.com/google/ExoPlayer
8. Media playback the right way What do we still need?
9. // Request audio focus AudioManager audioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE); int result = audioManager.requestAudioFocus( mOnAudioFocusChangeListener, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN); if (result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED) { // Proceed with the playing of glorious music } // On stop audioManager.abandonAudioFocus( mOnAudioFocusChangeListener); Audio Focus Ensure apps don’t talk over one another Hold audio focus until we’ve stopped playback
10. OnAudioFocusChangeListener ➔ AUDIOFOCUS_LOSS ◆ Stop Playback ➔ AUDIOFOCUS_LOSS_TRANSIENT ◆ Pause ➔ AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK ◆ Lower volume (keep playing) ➔ AUDIOFOCUS_GAIN ◆ Play at full volume (if previously paused)
11. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus Lifecycle of media playback Done! Not quite...
12. private BroadcastReceiver mNoisyReceiver = new BroadcastReceiver() { @Override public void onReceive(Context context, Intent intent) { // Pause the music } }; // On Play IntentFilter filter = new IntentFilter( AudioManager.ACTION_AUDIO_BECOMING_NOISY)); registerReceiver(mNoisyReceiver, filter); // On Pause unregisterReceiver(mNoisyReceiver); ACTION_AUDIO_BECOMING_NOISY
13. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus NOISY register unregister Lifecycle of media playback Minimum viable product?
14. Controls everywhere
15. Headphones and bluetooth controls ‘Media buttons’ android.intent.action.MEDIA_BUTTON broadcasts sent by the system Use Support Library provided MediaButtonReceiver
16. <service android:name="com.example.android.MediaPlaybackService" android:exported="false" > <intent-filter> <action android:name="android.intent.action.MEDIA_BUTTON" /> </intent-filter> </service> <!-- Intents received by MediaButtonReceiver will now be available in MediaPlaybackService’s onStartCommand() --> <!-- AndroidManifest.xml --> <receiver android:name="android.support.v4.media.session.MediaButtonReceiver" > <intent-filter> <action android:name="android.intent.action.MEDIA_BUTTON" /> </intent-filter> </receiver> But… not working?
17. Preferred media button receiver Becoming the chosen one
18. Your app <--> media APIs Callbacks // In onCreate() mMediaSession = new MediaSessionCompat(context, LOG_TAG); mMediaSession.setFlags( MediaSessionCompat.FLAG_HANDLES_MEDIA_BUTTONS | MediaSessionCompat.FLAG_HANDLES_TRANSPORT_CONTROLS); mMediaSession.setCallback(new ExampleCallbacks()); MediaSessionCompat
19. // In onStartCommand() MediaButtonReceiver.handleIntent( mMediaSession, intent); setActive(boolean) MediaSessionCompat handleIntent() links media buttons to Callback methods // Right after audio focus mMediaSession.setActive(true); // On stop mMediaSession.setActive(false);
20. PlaybackStateCompat MediaSessionCompat PlaybackStateCompat setState() setActions() setState()
21. Lock screen controls & Metadata Requires an image Set via setMetadata(MediaMetadataCompat) Metadata isn’t just for the lock screen - Android Wear also uses it!
22. Important Metadata Fields Text ➔ METADATA_KEY_TITLE ➔ METADATA_KEY_ARTIST ➔ METADATA_KEY_ALBUM ➔ METADATA_KEY_ALBUM_ARTIST Long ➔ METADATA_KEY_DURATION Bitmap ➔ METADATA_KEY_ART ➔ METADATA_KEY_ALBUM_ART Uri ➔ METADATA_KEY_ART_URI ➔ METADATA_KEY_ALBUM_ART_URI Also consider METADATA_KEY_USER_RATING
23. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus NOISY register unregister MediaSession Compat new set flags set callback setActive(true) set metadata set state set state setActive(false) release Lifecycle of media playback Lock screen on 5.0+?
24. Notifications and media controls NotificationCompat.MediaStyle • <API 14: basic notification • API 14+: up to 3 actions in collapsed notification • API 16+: up to 5 actions in expanded notification • API 21+: uses framework MediaStyle Note: MediaStyle is part of v7.app.NotificationCompat (which extends v4)
25. NotificationCompat.Builder builder = new NotificationCompat.Builder(context); builder .setContentTitle(description.getTitle()) .setContentText(description.getSubtitle()) .setSubText(description.getDescription()) .setLargeIcon(description.getIconBitmap()) .setContentIntent(controller.getSessionActivity()) .setVisibility(NotificationCompat.VISIBILITY_PUBLIC) .setDeleteIntent(getActionIntent(context, KeyEvent.KEYCODE_MEDIA_STOP)); return builder; } MediaControllerCompat controller = mediaSession.getController(); MediaMetadataCompat mediaMetadata = controller.getMetadata(); MediaDescriptionCompat description = mediaMetadata.getDescription(); public static NotificationCompat.Builder from( Context context, MediaSessionCompat mediaSession) {
26. public static PendingIntent getActionIntent( Context context, int mediaKeyEvent) { Intent intent = new Intent(Intent.ACTION_MEDIA_BUTTON); intent.setPackage(context.getPackageName()); intent.putExtra(Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_DOWN, mediaKeyEvent)); return PendingIntent.getBroadcast(context, mediaKeyEvent, intent, 0); } Full code at gist.github.com/ianhanniballake/47617ec3488e0257325c
27. NotificationCompat.Builder builder = MediaStyleHelper.from(this, mediaSession); builder .setSmallIcon(R.drawable.notification_icon) .setColor(ContextCompat.getColor(this, R.color.primaryDark)); builder .addAction(new NotificationCompat.Action( R.drawable.pause, getString(R.string.pause), MediaStyleHelper.getActionIntent(this, KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE))); builder.setStyle(new NotificationCompat.MediaStyle() .setShowActionsInCompactView(0) .setMediaSession(mediaSession.getSessionToken()));
28. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus NOISY register unregister MediaSession Compat new set flags set callback setActive(true) set metadata set state set state setActive(false) release Notification show notification update notification clear notification Lifecycle of media playback
29. Foreground Services Caveat: always ongoing pre-Lollipop
30. builder.setStyle(new NotificationCompat.MediaStyle() .setShowActionsInCompactView(0) .setMediaSession(mediaSession.getSessionToken()) .setShowCancelButton(true) .setCancelButtonIntent(MediaStyleHelper.getActionIntent( context, KeyEvent.KEYCODE_MEDIA_STOP)); Handling ongoing pre-Lollipop
31. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus NOISY register unregister MediaSession Compat new set flags set callback setActive(true) set metadata set state set state setActive(false) release Notification start FG stopFG(false) stopFG(true) Lifecycle of media playback
32. Service <-> UI
33. MediaControllerCompat getMetadata() -> MediaMetadataCompat getPlaybackState() -> PlaybackStateCompat getTransportControls() -> 1:1 with Callback MediaControllerCompat.Callback
34. MediaControllerCompat requires a Token
35. MediaBrowserService / MediaBrowser API to connect and retrieve a Token New APIs for browsing available media items Required for Android Auto integration Adds browse option on Android Wear notification
36. Implementing MediaBrowserService Call setSessionToken() in onCreate() New methods: ➔ onGetRoot() ➔ onLoadChildren() ➔ onLoadItem() See example Universal Android Music Player (UAMP) github.com/googlesamples/android-UniversalMusicPlayer
37. Using MediaControllerCompat Static getSessionToken() method in Service, send a local broadcast on change • Pros: simple • Cons: no multi-process, still need to start the Service Bind to Service, build API to retrieve Token ➔ Pros: ensures Service will be alive and ready while UI is up ➔ Cons: complicated
38. Created Playing Paused Stopped Destroyed MediaPlayer new prepare -> play pause stop release Audio Focus request focus abandon focus NOISY register unregister MediaSession Compat new set flags set callback setActive(true) set metadata set state set state setActive(false) release Notification start FG stopFG(false) stopFG(true) MediaBrowser Service set session token Lifecycle of media playback
39. SECTION TITLE +IanLake @ianhlake