Migrate Android Auto support to audio_service

android/app/src/main/AndroidManifest.xml

@@ -81,24 +81,21 @@
             </intent-filter>
         </activity>
 
-        <!-- Media Browser Service for Android Auto -->
+        <!-- audio_service: media browser service used by Android Auto and
+             the media notification. Hosts a headless Flutter engine when the
+             car connects while the app UI is closed. -->
         <service
-            android:name=".MusicService"
+            android:name="com.ryanheise.audioservice.AudioService"
             android:exported="true"
-            android:enabled="true"
-            android:stopWithTask="false"
             android:foregroundServiceType="mediaPlayback">
             <intent-filter>
                 <action android:name="android.media.browse.MediaBrowserService"/>
             </intent-filter>
-            <meta-data
-                android:name="android.media.browse.SEARCH_SUPPORTED"
-                android:value="true"/>
         </service>
-        
-        <!-- Media Button Receiver -->
+
+        <!-- audio_service media button receiver -->
         <receiver
-            android:name="androidx.media.session.MediaButtonReceiver"
+            android:name="com.ryanheise.audioservice.MediaButtonReceiver"
             android:exported="true">
             <intent-filter>
                 <action android:name="android.intent.action.MEDIA_BUTTON"/>

android/app/src/main/kotlin/com/musly/musly/AndroidSystemPlugin.kt

@@ -115,28 +115,8 @@ object AndroidSystemPlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
                 result.success(null)
             }
             "updatePlaybackState" -> {
-                val songId = call.argument<String>("songId")
-                val title = call.argument<String>("title") ?: ""
-                val artist = call.argument<String>("artist") ?: ""
-                val album = call.argument<String>("album") ?: ""
-                val artworkUrl = call.argument<String>("artworkUrl")
-                val duration = call.argument<Number>("duration")?.toLong() ?: 0L
-                val position = call.argument<Number>("position")?.toLong() ?: 0L
-                val playing = call.argument<Boolean>("playing") ?: false
-
-                // Ensure the service is running before updating state
-                val pushState = {
-                    MusicService.getInstance()?.updatePlaybackState(
-                        songId, title, artist, album, artworkUrl, duration, position, playing
-                    )
-                }
-                if (MusicService.getInstance() == null) {
-                    Log.d(TAG, "MusicService not running, requesting start via AndroidAutoPlugin")
-                    AndroidAutoPlugin.startMusicService()
-                    handler.postDelayed({ pushState() }, 200)
-                } else {
-                    pushState()
-                }
+                // Media session metadata/state is now handled by audio_service
+                // (MuslyAudioHandler); nothing to do on this channel anymore.
                 result.success(null)
             }
             "setNotificationColor" -> {
@@ -167,17 +147,6 @@ object AndroidSystemPlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
             "getAndroidSdkVersion" -> {
                 result.success(Build.VERSION.SDK_INT)
             }
-            "setRemotePlayback" -> {
-                val isRemote = call.argument<Boolean>("isRemote") ?: false
-                val volume = call.argument<Int>("volume") ?: 50
-                MusicService.getInstance()?.setRemoteVolume(isRemote, volume)
-                result.success(null)
-            }
-            "updateRemoteVolume" -> {
-                val volume = call.argument<Int>("volume") ?: 50
-                MusicService.getInstance()?.updateRemoteVolume(volume)
-                result.success(null)
-            }
             "dispose" -> {
                 dispose()
                 result.success(null)
@@ -199,26 +168,49 @@ object AndroidSystemPlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
         Log.d(TAG, "AndroidSystemPlugin initialized")
     }
 
-    private fun requestAudioFocus(): Boolean {
-        if (!handleAudioFocus) return true
-
-        val am = audioManager ?: return false
-
+    /**
+     * Returns "granted", "delayed", or "failed". "delayed" means the OS will
+     * asynchronously deliver AUDIOFOCUS_GAIN via [audioFocusListener] once the
+     * current focus holder yields (common on Android Auto / automotive audio
+     * routing, which is why [setAcceptsDelayedFocusGain] is set below).
+     */
+    private fun requestAudioFocus(): String {
+        if (!handleAudioFocus) {
+            hasAudioFocus = true
+            return "granted"
+        }
+
+        val am = audioManager ?: return "failed"
+
         return if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
             val audioAttributes = AudioAttributes.Builder()
                 .setUsage(AudioAttributes.USAGE_MEDIA)
                 .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
                 .build()
-            
+
             audioFocusRequest = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
                 .setAudioAttributes(audioAttributes)
                 .setAcceptsDelayedFocusGain(true)
                 .setOnAudioFocusChangeListener(audioFocusListener, handler)
                 .build()
-            
+
             val result = am.requestAudioFocus(audioFocusRequest!!)
-            hasAudioFocus = result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED
-            hasAudioFocus
+            when (result) {
+                AudioManager.AUDIOFOCUS_REQUEST_GRANTED -> {
+                    hasAudioFocus = true
+                    "granted"
+                }
+                AudioManager.AUDIOFOCUS_REQUEST_DELAYED -> {
+                    // Keep audioFocusRequest/listener registered — the deferred
+                    // AUDIOFOCUS_GAIN will arrive later through audioFocusListener.
+                    hasAudioFocus = false
+                    "delayed"
+                }
+                else -> {
+                    hasAudioFocus = false
+                    "failed"
+                }
+            }
         } else {
             @Suppress("DEPRECATION")
             val result = am.requestAudioFocus(
@@ -227,7 +219,7 @@ object AndroidSystemPlugin : FlutterPlugin, MethodChannel.MethodCallHandler {
                 AudioManager.AUDIOFOCUS_GAIN
             )
             hasAudioFocus = result == AudioManager.AUDIOFOCUS_REQUEST_GRANTED
-            hasAudioFocus
+            if (hasAudioFocus) "granted" else "failed"
         }
     }
 

android/app/src/main/kotlin/com/musly/musly/BluetoothMediaHelper.kt

@@ -255,10 +255,6 @@ class BluetoothMediaHelper(private val context: Context) {
         currentPosition = position
         isPlaying = playing
 
-        MusicService.getInstance()?.apply {
-            updatePlaybackState(songId, title, artist, album, artworkUrl, duration, position, playing)
-        }
-
         artworkUrl?.let { url ->
             loadArtworkAsync(url)
         }