fix offline mode and layout bugs

src-tauri/android/src/main/java/com/dtourolle/jellytau/player/JellyTauPlaybackService.kt

@@ -295,6 +295,14 @@ class JellyTauPlaybackService : MediaSessionService() {
         // Update MediaSession playback state
         session.setPlaybackState(buildPlaybackState(isPlaying, position))
 
+        // While casting, re-assert the remote volume provider. Metadata pushes
+        // arrive on the session poller thread and can race with (or arrive
+        // before) enableRemoteVolume(); this keeps the session routed to the
+        // remote (absolute) volume slider instead of the local media stream.
+        if (isRemoteVolumeEnabled) {
+            volumeProvider?.let { session.setPlaybackToRemote(it) }
+        }
+
         // Update the notification
         updateNotification(title, artist, isPlaying)
     }
@@ -326,8 +334,17 @@ class JellyTauPlaybackService : MediaSessionService() {
      *
      * The reported playback speed is 1.0 while playing and 0.0 while paused so
      * Android does not extrapolate the position past a paused track.
+     *
+     * While remote volume control is enabled (casting), the state is forced to
+     * STATE_PLAYING regardless of [isPlaying]. Android only surfaces the remote
+     * (absolute) volume slider for a session that is actively playing; if a
+     * periodic metadata/position push reports paused (e.g. before the remote
+     * session has actually started), reporting STATE_PAUSED here makes the
+     * system tear down the remote slider set up by setPlaybackToRemote() and
+     * fall back to the local media-stream volume.
      */
     private fun buildPlaybackState(isPlaying: Boolean, position: Long): PlaybackStateCompat {
+        val playing = isPlaying || isRemoteVolumeEnabled
         return PlaybackStateCompat.Builder()
             .setActions(
                 PlaybackStateCompat.ACTION_PLAY or
@@ -338,9 +355,9 @@ class JellyTauPlaybackService : MediaSessionService() {
                 PlaybackStateCompat.ACTION_SEEK_TO
             )
             .setState(
-                if (isPlaying) PlaybackStateCompat.STATE_PLAYING else PlaybackStateCompat.STATE_PAUSED,
+                if (playing) PlaybackStateCompat.STATE_PLAYING else PlaybackStateCompat.STATE_PAUSED,
                 position,
-                if (isPlaying) 1.0f else 0.0f
+                if (playing) 1.0f else 0.0f
             )
             .build()
     }