Fix buttons for Android Auto (and probably wear too).

android/app/src/main/java/com/audiobookshelf/app/data/DeviceClasses.kt

@@ -39,7 +39,7 @@ data class DeviceSettings(
   @get:JsonIgnore
   val jumpBackwardsTimeMs get() = (jumpBackwardsTime ?: default().jumpBackwardsTime) * 1000L
   @get:JsonIgnore
-  val jumpForwardTimeMs get() = (jumpForwardTime ?: default().jumpBackwardsTime) * 1000L
+  val jumpForwardTimeMs get() = (jumpForwardTime ?: default().jumpForwardTime) * 1000L
 }
 
 data class DeviceData(

android/app/src/main/java/com/audiobookshelf/app/player/MediaSessionCallback.kt

@@ -239,6 +239,8 @@ class MediaSessionCallback(var playerNotificationService:PlayerNotificationServi
     when (action) {
       CUSTOM_ACTION_JUMP_FORWARD -> onFastForward()
       CUSTOM_ACTION_JUMP_BACKWARD -> onRewind()
+      CUSTOM_ACTION_SKIP_FORWARD -> onSkipToNext()
+      CUSTOM_ACTION_SKIP_BACKWARD -> onSkipToPrevious()
     }
   }
 }

android/app/src/main/java/com/audiobookshelf/app/player/PlayerConstants.kt

@@ -2,3 +2,5 @@ package com.audiobookshelf.app.player
 
 const val CUSTOM_ACTION_JUMP_FORWARD = "com.audiobookshelf.customAction.jump_forward";
 const val CUSTOM_ACTION_JUMP_BACKWARD = "com.audiobookshelf.customAction.jump_backward";
+const val CUSTOM_ACTION_SKIP_FORWARD = "com.audiobookshelf.customAction.skip_forward";
+const val CUSTOM_ACTION_SKIP_BACKWARD = "com.audiobookshelf.customAction.skip_backward";

android/app/src/main/java/com/audiobookshelf/app/player/PlayerNotificationService.kt

@@ -45,6 +45,8 @@ import kotlin.concurrent.schedule
 
 
 const val SLEEP_TIMER_WAKE_UP_EXPIRATION = 120000L // 2m
+const val PLAYER_CAST = "cast-player";
+const val PLAYER_EXO = "exo-player";
 
 class PlayerNotificationService : MediaBrowserServiceCompat()  {
 
@@ -256,6 +258,10 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
 
     mediaSessionConnector = MediaSessionConnector(mediaSession)
     val queueNavigator: TimelineQueueNavigator = object : TimelineQueueNavigator(mediaSession) {
+      override fun getSupportedQueueNavigatorActions(player: Player): Long {
+        return PlaybackStateCompat.ACTION_PLAY_PAUSE or PlaybackStateCompat.ACTION_PLAY or PlaybackStateCompat.ACTION_PAUSE
+      }
+
       override fun getMediaDescription(player: Player, windowIndex: Int): MediaDescriptionCompat {
         if (currentPlaybackSession == null) {
           Log.e(tag,"Playback session is not set - returning blank MediaDescriptionCompat")
@@ -296,11 +302,6 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
     mediaSessionConnector.setQueueNavigator(queueNavigator)
     mediaSessionConnector.setPlaybackPreparer(MediaSessionPlaybackPreparer(this))
 
-    mediaSessionConnector.setCustomActionProviders(
-      JumpForwardCustomActionProvider(),
-      JumpBackwardCustomActionProvider(),
-    )
-
     mediaSession.setCallback(MediaSessionCallback(this))
 
     initializeMPlayer()
@@ -343,19 +344,34 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
     }
 
     isClosed = false
+    val customActionProviders = mutableListOf(
+      JumpBackwardCustomActionProvider(),
+      JumpForwardCustomActionProvider(),
+    )
+    val metadata = playbackSession.getMediaMetadataCompat()
+    mediaSession.setMetadata(metadata)
+    val mediaItems = playbackSession.getMediaItems()
     val playbackRateToUse = playbackRate ?: initialPlaybackRate ?: 1f
     initialPlaybackRate = playbackRate
 
+    if (playbackSession.mediaPlayer != PLAYER_CAST && mediaItems.size > 1) {
+      customActionProviders.addAll(listOf(
+        SkipBackwardCustomActionProvider(),
+        SkipForwardCustomActionProvider(),
+      ));
+    }
+    mediaSessionConnector.setCustomActionProviders(*customActionProviders.toTypedArray());
+
     playbackSession.mediaPlayer = getMediaPlayer()
 
-    if (playbackSession.mediaPlayer == "cast-player" && playbackSession.isLocal) {
+    if (playbackSession.mediaPlayer == PLAYER_CAST && playbackSession.isLocal) {
       Log.w(tag, "Cannot cast local media item - switching player")
       currentPlaybackSession = null
       switchToPlayer(false)
       playbackSession.mediaPlayer = getMediaPlayer()
     }
 
-    if (playbackSession.mediaPlayer == "cast-player") {
+    if (playbackSession.mediaPlayer == PLAYER_CAST) {
       // If cast-player is the first player to be used
       mediaSessionConnector.setPlayer(castPlayer)
       playerNotificationManager.setPlayer(castPlayer)
@@ -366,10 +382,6 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
 
     clientEventEmitter?.onPlaybackSession(playbackSession)
 
-    val metadata = playbackSession.getMediaMetadataCompat()
-    mediaSession.setMetadata(metadata)
-    val mediaItems = playbackSession.getMediaItems()
-
     if (mediaItems.isEmpty()) {
       Log.e(tag, "Invalid playback session no media items to play")
       currentPlaybackSession = null
@@ -751,7 +763,7 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
   }
 
   fun getMediaPlayer():String {
-    return if(currentPlayer == castPlayer) "cast-player" else "exo-player"
+    return if(currentPlayer == castPlayer) PLAYER_CAST else PLAYER_EXO
   }
 
   fun getDeviceInfo(): DeviceInfo {
@@ -1011,5 +1023,39 @@ class PlayerNotificationService : MediaBrowserServiceCompat()  {
       ).build()
     }
   }
+
+  inner class SkipForwardCustomActionProvider : CustomActionProvider {
+    override fun onCustomAction(player: Player, action: String, extras: Bundle?) {
+      /*
+      This does not appear to ever get called. Instead, MediaSessionCallback.onCustomAction() is
+      responsible to reacting to a custom action.
+       */
+    }
+
+    override fun getCustomAction(player: Player): PlaybackStateCompat.CustomAction? {
+      return PlaybackStateCompat.CustomAction.Builder(
+        CUSTOM_ACTION_SKIP_FORWARD,
+        getContext().getString(R.string.action_skip_forward),
+        R.drawable.skip_next_24
+      ).build()
+    }
+  }
+
+  inner class SkipBackwardCustomActionProvider : CustomActionProvider {
+    override fun onCustomAction(player: Player, action: String, extras: Bundle?) {
+      /*
+      This does not appear to ever get called. Instead, MediaSessionCallback.onCustomAction() is
+      responsible to reacting to a custom action.
+       */
+    }
+
+    override fun getCustomAction(player: Player): PlaybackStateCompat.CustomAction? {
+      return PlaybackStateCompat.CustomAction.Builder(
+        CUSTOM_ACTION_SKIP_BACKWARD,
+        getContext().getString(R.string.action_skip_backward),
+        R.drawable.skip_previous_24
+      ).build()
+    }
+  }
 }
 

android/app/src/main/res/drawable-anydpi/skip_next_24.xml

@@ -0,0 +1,15 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+  android:width="24dp"
+  android:height="24dp"
+  android:viewportWidth="24"
+  android:viewportHeight="24"
+  android:tint="#FFFFFF">
+  <group android:scaleX="1.127451"
+    android:scaleY="1.127451"
+    android:translateX="-1.5294118"
+    android:translateY="-1.5294118">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M6,18l8.5,-6L6,6v12zM16,6v12h2V6h-2z"/>
+  </group>
+</vector>

android/app/src/main/res/drawable-anydpi/skip_previous_24.xml

@@ -0,0 +1,15 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+  android:width="24dp"
+  android:height="24dp"
+  android:viewportWidth="24"
+  android:viewportHeight="24"
+  android:tint="#FFFFFF">
+  <group android:scaleX="1.127451"
+    android:scaleY="1.127451"
+    android:translateX="-1.5294118"
+    android:translateY="-1.5294118">
+    <path
+        android:fillColor="@android:color/white"
+        android:pathData="M6,6h2v12L6,18zM9.5,12l8.5,6L18,6z"/>
+  </group>
+</vector>

android/app/src/main/res/drawable/skip_next_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+  android:tint="#FFFFFF">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M6,18l8.5,-6L6,6v12zM16,6v12h2V6h-2z"/>
+</vector>

android/app/src/main/res/drawable/skip_previous_24.xml

@@ -0,0 +1,10 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="24dp"
+    android:height="24dp"
+    android:viewportWidth="24"
+    android:viewportHeight="24"
+    android:tint="#FFFFFF">
+  <path
+      android:fillColor="@android:color/white"
+      android:pathData="M6,6h2v12L6,18zM9.5,12l8.5,6L18,6z"/>
+</vector>

android/app/src/main/res/values/strings.xml

@@ -8,4 +8,6 @@
     <string name="app_widget_description">Simple widget for audiobookshelf playback</string>
     <string name="action_jump_forward">Jump Forward</string>
     <string name="action_jump_backward">Jump Backward</string>
+    <string name="action_skip_forward">Skip Forward</string>
+    <string name="action_skip_backward">Skip Backward</string>
 </resources>