Rewrite Audio Focus

Switch from the built-in exoplayer AudioFocus to a custom AudioFocus setup that supports ducking and auto-resumes after a short interuption.

app/src/main/java/org/oxycblt/auxio/database/PlaybackStateDatabase.kt

@@ -13,7 +13,6 @@ import org.oxycblt.auxio.logD
  * A SQLite database for managing the persistent playback state and queue.
  * Yes, I know androidx has Room which supposedly makes database creation easier, but it also
  * has a crippling bug where it will endlessly allocate rows even if you clear the entire db, so...
- * TODO: Turn queue loading info flow
  * @author OxygenCobalt
  */
 class PlaybackStateDatabase(context: Context) :

app/src/main/java/org/oxycblt/auxio/detail/ArtistDetailFragment.kt

@@ -19,6 +19,7 @@ import org.oxycblt.auxio.ui.setupAlbumActions
 
 /**
  * The [DetailFragment] for an artist.
+ * TODO: Show a list of songs?
  * @author OxygenCobalt
  */
 class ArtistDetailFragment : DetailFragment() {

app/src/main/java/org/oxycblt/auxio/detail/DetailFragment.kt

@@ -19,7 +19,6 @@ import org.oxycblt.auxio.ui.memberBinding
 /**
  * A Base [Fragment] implementing the base features shared across all detail fragments.
  * TODO: Add custom artist images
- * TODO: Add playing item highlighting
  * @author OxygenCobalt
  */
 abstract class DetailFragment : Fragment() {

app/src/main/java/org/oxycblt/auxio/detail/adapters/AlbumDetailAdapter.kt

@@ -13,8 +13,8 @@ import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.BaseModel
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.recycler.DiffCallback
-import org.oxycblt.auxio.recycler.Highlightable
 import org.oxycblt.auxio.recycler.viewholders.BaseViewHolder
+import org.oxycblt.auxio.recycler.viewholders.Highlightable
 import org.oxycblt.auxio.ui.accent
 import org.oxycblt.auxio.ui.disable
 import org.oxycblt.auxio.ui.setTextColorResource

app/src/main/java/org/oxycblt/auxio/detail/adapters/ArtistDetailAdapter.kt

@@ -13,8 +13,8 @@ import org.oxycblt.auxio.music.Album
 import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.BaseModel
 import org.oxycblt.auxio.recycler.DiffCallback
-import org.oxycblt.auxio.recycler.Highlightable
 import org.oxycblt.auxio.recycler.viewholders.BaseViewHolder
+import org.oxycblt.auxio.recycler.viewholders.Highlightable
 import org.oxycblt.auxio.ui.accent
 import org.oxycblt.auxio.ui.disable
 import org.oxycblt.auxio.ui.setTextColorResource

app/src/main/java/org/oxycblt/auxio/detail/adapters/GenreDetailAdapter.kt

@@ -13,8 +13,8 @@ import org.oxycblt.auxio.music.BaseModel
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Song
 import org.oxycblt.auxio.recycler.DiffCallback
-import org.oxycblt.auxio.recycler.Highlightable
 import org.oxycblt.auxio.recycler.viewholders.BaseViewHolder
+import org.oxycblt.auxio.recycler.viewholders.Highlightable
 import org.oxycblt.auxio.ui.accent
 import org.oxycblt.auxio.ui.disable
 import org.oxycblt.auxio.ui.setTextColorResource

app/src/main/java/org/oxycblt/auxio/library/LibraryFragment.kt

@@ -42,7 +42,7 @@ import org.oxycblt.auxio.ui.setupSongActions
  * A [Fragment] that shows a custom list of [Genre], [Artist], or [Album] data. Also allows for
  * search functionality.
  * FIXME: Heisenleak when navving from search
- * FIXME: Heisen on older versions
+ * FIXME: Heisenleak on older versions
  */
 class LibraryFragment : Fragment(), SearchView.OnQueryTextListener {
 

app/src/main/java/org/oxycblt/auxio/music/coil/CoilUtils.kt

@@ -14,6 +14,8 @@ import org.oxycblt.auxio.music.Artist
 import org.oxycblt.auxio.music.Genre
 import org.oxycblt.auxio.music.Song
 
+// TODO: Add option to ignore MediaStore
+
 /**
  * Get a bitmap for a song. onDone will be called when the bitmap is loaded.
  * **Do not use this on the UI elements, instead use the Binding Adapters.**

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

@@ -1,5 +1,6 @@
 package org.oxycblt.auxio.playback
 
+import android.animation.ValueAnimator
 import android.app.NotificationManager
 import android.app.Service
 import android.bluetooth.BluetoothDevice
@@ -15,7 +16,11 @@ import android.os.Parcelable
 import android.support.v4.media.MediaMetadataCompat
 import android.support.v4.media.session.MediaSessionCompat
 import android.view.KeyEvent
+import androidx.core.animation.addListener
 import androidx.core.app.NotificationCompat
+import androidx.core.content.ContextCompat
+import androidx.media.AudioFocusRequestCompat
+import androidx.media.AudioManagerCompat
 import com.google.android.exoplayer2.C
 import com.google.android.exoplayer2.ExoPlaybackException
 import com.google.android.exoplayer2.MediaItem
@@ -75,7 +80,7 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     private lateinit var notificationManager: NotificationManager
     private lateinit var notification: NotificationCompat.Builder
 
-    private var changeIsFromAudioFocus = true
+    private lateinit var audioFocusManager: AudioFocusManager
     private var isForeground = false
 
     private val serviceJob = Job()
@@ -103,13 +108,15 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
 
         // Set up AudioFocus/AudioAttributes
         player.setAudioAttributes(
-            audioAttributes, settingsManager.doAudioFocus
+            audioAttributes, false
         )
 
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.Q) {
             player.experimentalSetOffloadSchedulingEnabled(true)
         }
 
+        audioFocusManager = AudioFocusManager()
+
         // --- SYSTEM RECEIVER SETUP ---
 
         // Set up the media button callbacks
@@ -173,9 +180,11 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
         // Release everything that could cause a memory leak if left around
         player.release()
         mediaSession.release()
+        audioFocusManager.destroy()
         playbackManager.removeCallback(this)
         settingsManager.removeCallback(this)
 
+        // The service coroutines last job is to save the state to the DB, before terminating itself.
         serviceScope.launch {
             playbackManager.saveStateToDatabase(this@PlaybackService)
             serviceJob.cancel()
@@ -187,8 +196,6 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     // --- PLAYER EVENT LISTENER OVERRIDES ---
 
     override fun onPlaybackStateChanged(state: Int) {
-        changeIsFromAudioFocus = false
-
         if (state == Player.STATE_ENDED) {
             playbackManager.next()
         } else if (state == Player.STATE_READY) {
@@ -196,16 +203,6 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
         }
     }
 
-    override fun onIsPlayingChanged(isPlaying: Boolean) {
-        // Only sync the playing status with PlaybackStateManager if the change occurred
-        // from an Audio Focus change. Nowhere else.
-        if (isPlaying != playbackManager.isPlaying && changeIsFromAudioFocus) {
-            playbackManager.setPlayingStatus(isPlaying)
-        }
-
-        changeIsFromAudioFocus = true
-    }
-
     override fun onMediaItemTransition(mediaItem: MediaItem?, reason: Int) {
         // If the song loops while in the LOOP_ONCE mode, then stop looping after that.
         if (reason == Player.MEDIA_ITEM_TRANSITION_REASON_REPEAT &&
@@ -260,11 +257,10 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     }
 
     override fun onPlayingUpdate(isPlaying: Boolean) {
-        changeIsFromAudioFocus = false
-
         if (isPlaying && !player.isPlaying) {
             player.play()
             notification.updatePlaying(this)
+            audioFocusManager.requestFocus()
             startForegroundOrNotify("Play")
 
             startPollingPosition()
@@ -276,8 +272,6 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     }
 
     override fun onLoopUpdate(mode: LoopMode) {
-        changeIsFromAudioFocus = false
-
         when (mode) {
             LoopMode.NONE -> {
                 player.repeatMode = Player.REPEAT_MODE_OFF
@@ -300,8 +294,6 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     }
 
     override fun onSeekConfirm(position: Long) {
-        changeIsFromAudioFocus = false
-
         player.seekTo(position)
     }
 
@@ -327,13 +319,6 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
         startForegroundOrNotify("Notif action update")
     }
 
-    override fun onAudioFocusUpdate(doAudioFocus: Boolean) {
-        player.setAudioAttributes(
-            audioAttributes,
-            doAudioFocus
-        )
-    }
-
     // --- OTHER FUNCTIONS ---
 
     /**
@@ -517,6 +502,76 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
         return false
     }
 
+    /**
+     * Object that manages the AudioFocus state.
+     * Adapted from NewPipe (https://github.com/TeamNewPipe/NewPipe)
+     */
+    inner class AudioFocusManager : AudioManager.OnAudioFocusChangeListener {
+        private val audioManager = ContextCompat.getSystemService(
+            this@PlaybackService, AudioManager::class.java
+        ) ?: error("Cannot obtain AudioManager.")
+
+        private val request = AudioFocusRequestCompat.Builder(AudioManagerCompat.AUDIOFOCUS_GAIN)
+            .setWillPauseWhenDucked(true)
+            .setOnAudioFocusChangeListener(this)
+            .build()
+
+        fun requestFocus() {
+            AudioManagerCompat.requestAudioFocus(audioManager, request)
+        }
+
+        fun destroy() {
+            AudioManagerCompat.abandonAudioFocusRequest(audioManager, request)
+        }
+
+        override fun onAudioFocusChange(focusChange: Int) {
+            when (focusChange) {
+                AudioManager.AUDIOFOCUS_GAIN -> onGain()
+                AudioManager.AUDIOFOCUS_LOSS_TRANSIENT_CAN_DUCK -> onDuck()
+                AudioManager.AUDIOFOCUS_LOSS, AudioManager.AUDIOFOCUS_LOSS_TRANSIENT -> onLoss()
+            }
+        }
+
+        private fun onGain() {
+            if (settingsManager.doAudioFocus) {
+                if (player.volume == VOLUME_DUCK && playbackManager.isPlaying) {
+                    player.volume = VOLUME_DUCK
+                    animateVolume(VOLUME_DUCK, VOLUME_FULL)
+                } else {
+                    playbackManager.setPlayingStatus(true)
+                }
+            }
+        }
+
+        private fun onLoss() {
+            if (settingsManager.doAudioFocus) {
+                playbackManager.setPlayingStatus(false)
+            }
+        }
+
+        private fun onDuck() {
+            if (settingsManager.doAudioFocus) {
+                player.volume = VOLUME_DUCK
+            }
+        }
+
+        private fun animateVolume(from: Float, to: Float) {
+            ValueAnimator().apply {
+                setFloatValues(from, to)
+                duration = DUCK_DURATION
+                addListener(
+                    onStart = { player.volume = from },
+                    onCancel = { player.volume = to },
+                    onEnd = { player.volume = to }
+                )
+                addUpdateListener {
+                    player.volume = it.animatedValue as Float
+                }
+                start()
+            }
+        }
+    }
+
     /**
      * A [BroadcastReceiver] for receiving system events from the media notification or the headset.
      */
@@ -593,5 +648,9 @@ class PlaybackService : Service(), Player.EventListener, PlaybackStateManager.Ca
     companion object {
         private const val DISCONNECTED = 0
         private const val CONNECTED = 1
+
+        private const val VOLUME_DUCK = 0.2f
+        private const val DUCK_DURATION = 1500L
+        private const val VOLUME_FULL = 1.0f
     }
 }

app/src/main/java/org/oxycblt/auxio/recycler/viewholders/Highlightable.kt

@@ -1,4 +1,4 @@
-package org.oxycblt.auxio.recycler
+package org.oxycblt.auxio.recycler.viewholders
 
 /**
  * Interface that allows the highlighting of certain ViewHolders

app/src/main/java/org/oxycblt/auxio/settings/SettingsManager.kt

@@ -10,7 +10,7 @@ import org.oxycblt.auxio.ui.ACCENTS
 
 /**
  * Wrapper around the [SharedPreferences] class that writes & reads values without a context.
- * TODO: Add option to play song from genre, now that its possible
+ * TODO: Add option to hide covers
  * @author OxygenCobalt
  */
 class SettingsManager private constructor(context: Context) :
@@ -165,10 +165,6 @@ class SettingsManager private constructor(context: Context) :
             Keys.KEY_LIBRARY_DISPLAY_MODE -> callbacks.forEach {
                 it.onLibDisplayModeUpdate(libraryDisplayMode)
             }
-
-            Keys.KEY_AUDIO_FOCUS -> callbacks.forEach {
-                it.onAudioFocusUpdate(doAudioFocus)
-            }
         }
     }
 
@@ -248,7 +244,7 @@ class SettingsManager private constructor(context: Context) :
     }
 
     /**
-     * An safe interface for receiving some preference updates. Use/Extend this instead of
+     * An interface for receiving some preference updates. Use/Extend this instead of
      * [SharedPreferences.OnSharedPreferenceChangeListener] if possible, as it doesn't require a
      * context.
      */
@@ -256,6 +252,5 @@ class SettingsManager private constructor(context: Context) :
         fun onColorizeNotifUpdate(doColorize: Boolean) {}
         fun onNotifActionUpdate(useAltAction: Boolean) {}
         fun onLibDisplayModeUpdate(displayMode: DisplayMode) {}
-        fun onAudioFocusUpdate(doAudioFocus: Boolean) {}
     }
 }