corrects problem where google cast was disconnected from player state when app launched from head unit

lib/casting_business_object.dart

@@ -20,6 +20,9 @@ class CastingBusinessObject extends ChangeNotifier {
   CastingPlaybackStatus _playbackStatus = CastingPlaybackStatus.unknown;
   String? _connectedDeviceName;
   String? _lastError;
+  
+  /// Callback for when native side requests local audio to stop
+  VoidCallback? onStopLocalAudioRequested;
 
   CastingStatus get status => _status;
   CastingPlaybackStatus get playbackStatus => _playbackStatus;
@@ -55,6 +58,18 @@ class CastingBusinessObject extends ChangeNotifier {
       },
     );
 
+    // Set up handler for native method calls (e.g., stopLocalAudio)
+    _methodChannel.setMethodCallHandler(_handleMethodCall);
+
+    await refreshStatus();
+  }
+
+  Future<void> refreshStatus() async {
+    if (!isSupportedOnThisPlatform) {
+      _setStatus(CastingStatus.unavailable);
+      return;
+    }
+
     try {
       final dynamic status = await _methodChannel.invokeMethod<dynamic>(
         'getStatus',
@@ -66,7 +81,12 @@ class CastingBusinessObject extends ChangeNotifier {
     }
   }
 
-  Future<void> showDevicePicker() async {
+  Future<void> showDevicePicker({
+    bool autoplay = false,
+    String? streamUrl,
+    String? title,
+    String? subtitle,
+  }) async {
     if (!isSupportedOnThisPlatform) {
       _setStatus(CastingStatus.unavailable);
       return;
@@ -77,7 +97,12 @@ class CastingBusinessObject extends ChangeNotifier {
     }
 
     try {
-      await _methodChannel.invokeMethod<void>('showDevicePicker');
+      await _methodChannel.invokeMethod<void>('showDevicePicker', {
+        'autoplay': autoplay,
+        'streamUrl': streamUrl,
+        'title': title,
+        'subtitle': subtitle,
+      });
     } on PlatformException catch (error) {
       _lastError = error.message ?? error.code;
       _setStatus(CastingStatus.error);
@@ -102,7 +127,10 @@ class CastingBusinessObject extends ChangeNotifier {
       });
     } on PlatformException catch (error) {
       _lastError = error.message ?? error.code;
-      _setStatus(CastingStatus.error);
+      // Do NOT set status to error here — native emits its own status events.
+      // Overriding status from Dart corrupts the UI when native considers the
+      // session still connected (e.g. during a retry after a race condition).
+      rethrow;
     }
   }
 
@@ -146,6 +174,8 @@ class CastingBusinessObject extends ChangeNotifier {
 
     if (deviceName != null && deviceName.isNotEmpty) {
       _connectedDeviceName = deviceName;
+    } else if (status != 'connected') {
+      _connectedDeviceName = null;
     }
 
     if (message != null && message.isNotEmpty) {
@@ -210,4 +240,22 @@ class CastingBusinessObject extends ChangeNotifier {
     _eventSubscription?.cancel();
     super.dispose();
   }
+
+  /// Handles method calls from native code
+  Future<dynamic> _handleMethodCall(MethodCall call) async {
+    switch (call.method) {
+      case 'stopLocalAudio':
+        onStopLocalAudioRequested?.call();
+        return null;
+      case 'stopAudioService':
+        // Stop the audio service directly (called when transferring to cast)
+        onStopLocalAudioRequested?.call();
+        return null;
+      case 'resumeLocalAudio':
+        // Audio service is resuming after cast disconnect; no action needed on Flutter side
+        return null;
+      default:
+        return null;
+    }
+  }
 }

lib/main.dart

@@ -73,12 +73,11 @@ class MainPage extends StatefulWidget {
   State<MainPage> createState() => _MainPageState();
 }
 
-class _MainPageState extends State<MainPage> {
+class _MainPageState extends State<MainPage> with WidgetsBindingObserver {
   StreamingAudioBusinessObject get _audio => widget.audio;
   CastingBusinessObject get _casting => widget.casting;
   final LiveInfoBusinessObject _liveInfo = LiveInfoBusinessObject();
   static const List<int> _intervalOptions = <int>[5, 10, 15, 30, 60];
-  bool _castStreamStartedForActiveSession = false;
   bool _isStartingCastStream = false;
   bool _pendingRemotePlay = false;
 
@@ -133,11 +132,33 @@ class _MainPageState extends State<MainPage> {
   @override
   void initState() {
     super.initState();
+    WidgetsBinding.instance.addObserver(this);
     _audio.addListener(_handleAudioStateChanged);
     _casting.addListener(_handleCastingStateChanged);
     _liveInfo.addListener(_handleLiveInfoChanged);
     _liveInfo.start();
     _playbackChannel.setMethodCallHandler(_handlePlaybackMethodCall);
+    
+    // When native code requests local audio to stop (cast media loaded)
+    _casting.onStopLocalAudioRequested = () {
+      unawaited(_audio.stop());
+    };
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    if (state == AppLifecycleState.resumed) {
+      // Re-initialize (not just refresh) to re-establish the EventChannel
+      // subscription. In a cold-start Android Auto scenario the Flutter engine
+      // boots headlessly before MainActivity.configureFlutterEngine() runs, so
+      // the native EventChannel StreamHandler is not yet registered when
+      // initialize() first fires. The "listen" message is dropped, eventSink
+      // stays null, and all subsequent emitStatus() calls are silently lost.
+      // Calling initialize() here cancels that dead subscription and creates a
+      // fresh one now that the handler is registered; onListen immediately
+      // re-emits statusPayload so the Dart state is fully re-synced.
+      unawaited(_casting.initialize());
+    }
   }
 
   Future<void> _handlePlaybackMethodCall(MethodCall call) async {
@@ -172,15 +193,27 @@ class _MainPageState extends State<MainPage> {
   }
 
   void _handleCastingStateChanged() {
+    final currentStatus = _casting.status;
+
+    if (_casting.isPlaying || _casting.isBuffering) {
+      _pendingRemotePlay = false;
+    }
+
+    if (currentStatus != CastingStatus.connected) {
+      _isStartingCastStream = false;
+    }
+
     if (_usesExternalCastPlayback &&
-        (!_castStreamStartedForActiveSession || _pendingRemotePlay) &&
+        _pendingRemotePlay &&
         !_isStartingCastStream) {
+      // Only load when _pendingRemotePlay was set by _play() while connecting.
+      // Do NOT trigger on justConnected — native pendingCastRequest handles
+      // all autoplay from showDevicePicker(autoplay: true).
       _startCastingLiveStream();
     }
 
-    if (!_usesExternalCastPlayback) {
-      _castStreamStartedForActiveSession = false;
-      _isStartingCastStream = false;
+    if (!_usesExternalCastPlayback &&
+        currentStatus != CastingStatus.connecting) {
       _pendingRemotePlay = false;
     }
 
@@ -203,21 +236,24 @@ class _MainPageState extends State<MainPage> {
         subtitle: _audio.currentSubtitle,
       );
 
-      _castStreamStartedForActiveSession = true;
       _pendingRemotePlay = false;
 
       if (_usesExternalCastPlayback && !_audio.isStopped) {
         await _audio.stop();
       }
     } catch (_) {
-      _castStreamStartedForActiveSession = false;
-      // State is already updated by the casting business object.
+      _pendingRemotePlay = !_audio.isStopped;
     } finally {
       _isStartingCastStream = false;
     }
   }
 
   Future<void> _play() async {
+    if (_casting.status == CastingStatus.connecting) {
+      _pendingRemotePlay = true;
+      return;
+    }
+
     if (_usesExternalCastPlayback) {
       if (_casting.isPlaying || _isStartingCastStream) {
         return;
@@ -227,12 +263,7 @@ class _MainPageState extends State<MainPage> {
       return;
     }
 
-    if (_usesExternalCastPlayback &&
-        _casting.status == CastingStatus.connecting) {
-      _pendingRemotePlay = true;
-      return;
-    }
-
+    _pendingRemotePlay = false;
     await _audio.play();
   }
 
@@ -251,7 +282,21 @@ class _MainPageState extends State<MainPage> {
       return;
     }
 
-    await _casting.showDevicePicker();
+    final shouldAutoplay = !_audio.isStopped;
+    // Do NOT set _pendingRemotePlay when native handles autoplay.
+    // The native pendingCastRequest already handles autoplay via
+    // showDevicePicker(autoplay: true). Setting _pendingRemotePlay here
+    // causes a duplicate load from Flutter that races the native load and
+    // corrupts the cast status (especially in the Android Auto path).
+    // _pendingRemotePlay is only set by _play() when the user explicitly
+    // presses Play while the cast session is still connecting.
+    _pendingRemotePlay = false;
+    await _casting.showDevicePicker(
+      autoplay: shouldAutoplay,
+      streamUrl: shouldAutoplay ? _audio.streamUrl : null,
+      title: shouldAutoplay ? _audio.currentTitle : null,
+      subtitle: shouldAutoplay ? _audio.currentSubtitle : null,
+    );
   }
 
   String _castingLabel() {
@@ -290,6 +335,7 @@ class _MainPageState extends State<MainPage> {
 
   @override
   void dispose() {
+    WidgetsBinding.instance.removeObserver(this);
     _audio.removeListener(_handleAudioStateChanged);
     _casting.removeListener(_handleCastingStateChanged);
     _liveInfo.removeListener(_handleLiveInfoChanged);
@@ -412,8 +458,7 @@ class _MainPageState extends State<MainPage> {
                       ),
                       ElevatedButton.icon(
                         onPressed:
-                            _casting.status == CastingStatus.connecting ||
-                                _casting.status == CastingStatus.unavailable
+                            _casting.status == CastingStatus.connecting
                             ? null
                             : _toggleCasting,
                         icon: Icon(_castingIcon()),