Add external media controls

Add the ability to listen to external media controls, such as through a bluetooth headset.

app/build.gradle

@@ -69,6 +69,9 @@ dependencies {
     implementation "androidx.navigation:navigation-fragment-ktx:$navigation_version"
     implementation "androidx.navigation:navigation-ui-ktx:$navigation_version"
 
+    // Media
+    implementation 'androidx.media:media:1.2.0'
+
     // --- THIRD PARTY ---
 
     // Image loading
@@ -81,7 +84,9 @@ dependencies {
     ktlint "com.pinterest:ktlint:0.37.2"
 
     // ExoPlayer
-    implementation 'com.google.android.exoplayer:exoplayer-core:2.12.1'
+    def exoplayer_version = "2.12.1"
+    implementation "com.google.android.exoplayer:exoplayer-core:$exoplayer_version"
+    implementation "com.google.android.exoplayer:extension-mediasession:$exoplayer_version"
 
     // Memory Leak checking
     debugImplementation 'com.squareup.leakcanary:leakcanary-android:2.4'

app/src/main/java/org/oxycblt/auxio/playback/CompactPlaybackFragment.kt

@@ -25,6 +25,8 @@ class CompactPlaybackFragment : Fragment() {
     ): View? {
         val binding = FragmentCompactPlaybackBinding.inflate(inflater)
 
+        // FIXME: Prevent the play/pause icon from animating on startup
+        //  [requires new callback from PlaybackStateManager]
         val iconPauseToPlay = ContextCompat.getDrawable(
             requireContext(), R.drawable.ic_pause_to_play
         ) as AnimatedVectorDrawable
@@ -60,7 +62,7 @@ class CompactPlaybackFragment : Fragment() {
         }
 
         playbackModel.isPlaying.observe(viewLifecycleOwner) {
-            if (playbackModel.canAnimate) {
+            if (true) {
                 if (it) {
                     // Animate the icon transition when the playing status switches
                     binding.playbackControls.setImageDrawable(iconPauseToPlay)
@@ -90,6 +92,6 @@ class CompactPlaybackFragment : Fragment() {
     override fun onPause() {
         super.onPause()
 
-        playbackModel.resetAnimStatus()
+        // playbackModel.resetAnimStatus()
     }
 }

app/src/main/java/org/oxycblt/auxio/playback/PlaybackService.kt

@@ -8,14 +8,19 @@ import android.content.Context
 import android.content.Intent
 import android.os.Build
 import android.os.IBinder
+import android.os.Parcelable
+import android.support.v4.media.session.MediaSessionCompat
 import android.util.Log
+import android.view.KeyEvent
 import androidx.core.app.NotificationCompat
 import com.google.android.exoplayer2.MediaItem
 import com.google.android.exoplayer2.Player
 import com.google.android.exoplayer2.SimpleExoPlayer
+import com.google.android.exoplayer2.ext.mediasession.MediaSessionConnector
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.Job
+import kotlinx.coroutines.cancel
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.collect
 import kotlinx.coroutines.flow.conflate
@@ -44,6 +49,14 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateCallback {
     }
 
     private val playbackManager = PlaybackStateManager.getInstance()
+    private lateinit var mediaSession: MediaSessionCompat
+    private val buttonMediaCallback = object : MediaSessionCompat.Callback() {
+        override fun onMediaButtonEvent(mediaButtonEvent: Intent): Boolean {
+            Log.d(this::class.simpleName, "Hello?")
+
+            return true
+        }
+    }
 
     private val serviceJob = Job()
     private val serviceScope = CoroutineScope(
@@ -67,6 +80,39 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateCallback {
     override fun onCreate() {
         super.onCreate()
 
+        mediaSession = MediaSessionCompat(this, packageName).apply {
+            isActive = true
+        }
+
+        val connector = MediaSessionConnector(mediaSession)
+        connector.setPlayer(player)
+        connector.setMediaButtonEventHandler { _, _, mediaButtonEvent ->
+            val item = mediaButtonEvent
+                .getParcelableExtra<Parcelable>(Intent.EXTRA_KEY_EVENT) as KeyEvent
+
+            if (item.action == KeyEvent.ACTION_DOWN) {
+                when (item.keyCode) {
+                    KeyEvent.KEYCODE_MEDIA_PAUSE, KeyEvent.KEYCODE_MEDIA_PLAY,
+                    KeyEvent.KEYCODE_MEDIA_PLAY_PAUSE, KeyEvent.KEYCODE_HEADSETHOOK -> {
+                        playbackManager.setPlayingStatus(!playbackManager.isPlaying)
+                    }
+
+                    KeyEvent.KEYCODE_MEDIA_NEXT -> {
+                        playbackManager.next()
+                    }
+
+                    KeyEvent.KEYCODE_MEDIA_PREVIOUS -> {
+                        playbackManager.prev()
+                    }
+
+                    // TODO: Implement the other callbacks for
+                    //  CLOSE/STOP & REWIND
+                }
+            }
+
+            true
+        }
+
         notification = createNotification()
 
         playbackManager.addCallback(this)
@@ -76,6 +122,7 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateCallback {
         super.onDestroy()
 
         player.release()
+        mediaSession.release()
         serviceJob.cancel()
         playbackManager.removeCallback(this)
 

app/src/main/java/org/oxycblt/auxio/playback/PlaybackViewModel.kt

@@ -56,9 +56,6 @@ class PlaybackViewModel() : ViewModel(), PlaybackStateCallback {
         it.slice((mIndex.value!! + 1) until it.size)
     }
 
-    private var mCanAnimate = false
-    val canAnimate: Boolean get() = mCanAnimate
-
     // Service setup
     private val playbackManager = PlaybackStateManager.getInstance()
 
@@ -168,8 +165,6 @@ class PlaybackViewModel() : ViewModel(), PlaybackStateCallback {
 
     // Flip the playing status.
     fun invertPlayingStatus() {
-        mCanAnimate = true
-
         playbackManager.setPlayingStatus(!playbackManager.isPlaying)
     }
 
@@ -180,10 +175,6 @@ class PlaybackViewModel() : ViewModel(), PlaybackStateCallback {
 
     // --- OTHER FUNCTIONS ---
 
-    fun resetAnimStatus() {
-        mCanAnimate = false
-    }
-
     fun setSeekingStatus(value: Boolean) {
         mIsSeeking.value = value
     }