CustomMessage handling: send and receive;

Code re-organization: CastDialogOpener, MethodNames;

android/src/main/kotlin/com/gianlucaparadise/flutter_cast_framework/FlutterCastFrameworkPlugin.kt

@@ -7,6 +7,8 @@ import androidx.lifecycle.OnLifecycleEvent
 import androidx.lifecycle.ProcessLifecycleOwner
 import androidx.mediarouter.app.MediaRouteChooserDialog
 import androidx.mediarouter.app.MediaRouteControllerDialog
+import com.gianlucaparadise.flutter_cast_framework.cast.CastDialogOpener
+import com.gianlucaparadise.flutter_cast_framework.cast.MessageCastingChannel
 import com.google.android.gms.cast.framework.CastContext
 import com.google.android.gms.cast.framework.CastSession
 import com.google.android.gms.cast.framework.SessionManager
@@ -28,23 +30,6 @@ class FlutterCastFrameworkPlugin(private val registrar: Registrar, private val c
         }
     }
 
-    private object MethodNames {
-        const val onCastStateChanged = "CastContext.onCastStateChanged"
-        const val showCastDialog = "showCastDialog"
-
-        // region SessionManager
-        const val onSessionStarting = "SessionManager.onSessionStarting"
-        const val onSessionStarted = "SessionManager.onSessionStarted"
-        const val onSessionStartFailed = "SessionManager.onSessionStartFailed"
-        const val onSessionEnding = "SessionManager.onSessionEnding"
-        const val onSessionEnded = "SessionManager.onSessionEnded"
-        const val onSessionResuming = "SessionManager.onSessionResuming"
-        const val onSessionResumed = "SessionManager.onSessionResumed"
-        const val onSessionResumeFailed = "SessionManager.onSessionResumeFailed"
-        const val onSessionSuspended = "SessionManager.onSessionSuspended"
-        // end-region
-    }
-
     init {
         ProcessLifecycleOwner.get().lifecycle.addObserver(this)
 
@@ -57,16 +42,32 @@ class FlutterCastFrameworkPlugin(private val registrar: Registrar, private val c
     private lateinit var mSessionManager: SessionManager
     private val mSessionManagerListener = CastSessionManagerListener()
 
+    private val mMessageCastingChannel = MessageCastingChannel(channel)
+
+    private var mCastSession: CastSession? = null
+        set(value) {
+            Log.d(TAG, "Updating mCastSession - castSession changed: ${field != value}")
+            // if (field == value) return // Despite the instances are the same, I need to re-attach the listener to every new session instance
+
+            val result = NamespaceResult(oldSession = field, newSession = value)
+
+            field = value
+
+            channel.invokeMethod(MethodNames.getSessionMessageNamespaces, null, result)
+        }
+
     @OnLifecycleEvent(Lifecycle.Event.ON_CREATE)
     fun onCreate() {
         Log.d(TAG, "App: ON_CREATE")
         mSessionManager = CastContext.getSharedInstance(registrar.activeContext()).sessionManager
+        mCastSession = mSessionManager.currentCastSession
     }
 
     @OnLifecycleEvent(Lifecycle.Event.ON_RESUME)
     fun onResume() {
         Log.d(TAG, "App: ON_RESUME")
         mSessionManager.addSessionManagerListener(mSessionManagerListener, CastSession::class.java)
+        mCastSession = mSessionManager.currentCastSession
     }
 
     @OnLifecycleEvent(Lifecycle.Event.ON_PAUSE)
@@ -76,39 +77,53 @@ class FlutterCastFrameworkPlugin(private val registrar: Registrar, private val c
                 mSessionManagerListener,
                 CastSession::class.java
         )
+        // I can't set this to null because I need the cast session to send commands from notification
+        // mCastSession = null
     }
 
     override fun onMethodCall(call: MethodCall, result: Result) {
-        when (call.method) {
+        val method = call.method
-            MethodNames.showCastDialog -> showCastDialog()
+        val arguments = call.arguments
+
+        when (method) {
+            MethodNames.showCastDialog -> CastDialogOpener.showCastDialog(registrar)
+            MethodNames.sendMessage -> this.mMessageCastingChannel.sendMessage(mCastSession, arguments)
             else -> result.notImplemented()
         }
     }
 
-    private fun showCastDialog() {
+    private inner class NamespaceResult(val oldSession: CastSession?, val newSession: CastSession?) : Result {
-        val castContext = CastContext.getSharedInstance(registrar.activeContext())
+        override fun notImplemented() {
-        val castSession = castContext.sessionManager.currentCastSession
+            Log.d(TAG, "Updating mCastSession - notImplemented")
+        }
 
-        val activity = this.registrar.activity()
+        override fun error(p0: String?, p1: String?, p2: Any?) {
-        val themeResId = activity.packageManager.getActivityInfo(activity.componentName, 0).themeResource
+            Log.d(TAG, "Updating mCastSession - error - $p0 $p1 $p2")
+        }
 
-        try {
+        override fun success(args: Any?) {
-            if (castSession != null) {
+            Log.d(TAG, "Updating mCastSession - success - param: $args")
-                // This dialog allows the user to control or disconnect from the currently selected route.
+            if (oldSession == null && newSession == null) return // nothing to do here
-                MediaRouteControllerDialog(registrar.activeContext(), themeResId)
+            if (args == null) return // nothing to do here
-                        .show()
+
-            } else {
+            if (args !is ArrayList<*>)
-                // This dialog allows the user to choose a route that matches a given selector.
+                throw IllegalArgumentException("${MethodNames.getSessionMessageNamespaces} method expects an ArrayList<String>")
-                MediaRouteChooserDialog(registrar.activeContext(), themeResId).apply {
+
-                    routeSelector = castContext.mergedSelector
+            if (!args.any()) return  // nothing to do here
-                    show()
+
+            if (args[0] !is String)
+                throw IllegalArgumentException("${MethodNames.getSessionMessageNamespaces} method expects an ArrayList<String>")
+
+            val namespaces = args as ArrayList<String>
+            namespaces.forEach {
+                try {
+                    oldSession?.removeMessageReceivedCallbacks(it)
+                    newSession?.setMessageReceivedCallbacks(it, mMessageCastingChannel)
+                }
+                catch (e: java.lang.Exception) {
+                    Log.e(TAG, "Updating mCastSession - Exception while creating channel", e)
                 }
             }
-        } catch (ex: IllegalArgumentException) {
-            Log.d(TAG, "Exception while opening Dialog")
-            throw IllegalArgumentException("Error while opening MediaRouteDialog." +
-                    " Did you use AppCompat theme on your activity?" +
-                    " Check https://developers.google.com/cast/docs/android_sender/integrate#androidtheme", ex)
         }
     }
 
@@ -123,11 +138,15 @@ class FlutterCastFrameworkPlugin(private val registrar: Registrar, private val c
         override fun onSessionStarting(session: CastSession?) {
             Log.d(TAG, "onSessionStarting")
             channel.invokeMethod(MethodNames.onSessionStarting, null)
+
+            mCastSession = session
         }
 
         override fun onSessionResuming(session: CastSession?, p1: String?) {
             Log.d(TAG, "onSessionResuming")
             channel.invokeMethod(MethodNames.onSessionResuming, null)
+
+            mCastSession = session
         }
 
         override fun onSessionEnding(session: CastSession?) {
@@ -148,11 +167,15 @@ class FlutterCastFrameworkPlugin(private val registrar: Registrar, private val c
         override fun onSessionStarted(session: CastSession, sessionId: String) {
             Log.d(TAG, "onSessionStarted")
             channel.invokeMethod(MethodNames.onSessionStarted, null)
+
+            mCastSession = session
         }
 
         override fun onSessionResumed(session: CastSession, wasSuspended: Boolean) {
             Log.d(TAG, "onSessionResumed")
             channel.invokeMethod(MethodNames.onSessionResumed, null)
+
+            mCastSession = session
         }
 
         override fun onSessionEnded(session: CastSession, error: Int) {

android/src/main/kotlin/com/gianlucaparadise/flutter_cast_framework/MethodNames.kt

@@ -0,0 +1,22 @@
+package com.gianlucaparadise.flutter_cast_framework
+
+object MethodNames {
+    const val onCastStateChanged = "CastContext.onCastStateChanged"
+    const val showCastDialog = "showCastDialog"
+
+    // region SessionManager
+    const val onSessionStarting = "SessionManager.onSessionStarting"
+    const val onSessionStarted = "SessionManager.onSessionStarted"
+    const val onSessionStartFailed = "SessionManager.onSessionStartFailed"
+    const val onSessionEnding = "SessionManager.onSessionEnding"
+    const val onSessionEnded = "SessionManager.onSessionEnded"
+    const val onSessionResuming = "SessionManager.onSessionResuming"
+    const val onSessionResumed = "SessionManager.onSessionResumed"
+    const val onSessionResumeFailed = "SessionManager.onSessionResumeFailed"
+    const val onSessionSuspended = "SessionManager.onSessionSuspended"
+    // end-region
+
+    const val getSessionMessageNamespaces = "CastSession.getSessionMessageNamespaces"
+    const val onMessageReceived = "CastSession.onMessageReceived"
+    const val sendMessage = "CastSession.sendMessage"
+}

android/src/main/kotlin/com/gianlucaparadise/flutter_cast_framework/cast/CastDialogOpener.kt

@@ -0,0 +1,37 @@
+package com.gianlucaparadise.flutter_cast_framework.cast
+
+import android.util.Log
+import androidx.mediarouter.app.MediaRouteChooserDialog
+import androidx.mediarouter.app.MediaRouteControllerDialog
+import com.gianlucaparadise.flutter_cast_framework.FlutterCastFrameworkPlugin
+import com.google.android.gms.cast.framework.CastContext
+import io.flutter.plugin.common.PluginRegistry
+
+object CastDialogOpener {
+    fun showCastDialog(registrar: PluginRegistry.Registrar) {
+        val castContext = CastContext.getSharedInstance(registrar.activeContext())
+        val castSession = castContext.sessionManager.currentCastSession
+
+        val activity = registrar.activity()
+        val themeResId = activity.packageManager.getActivityInfo(activity.componentName, 0).themeResource
+
+        try {
+            if (castSession != null) {
+                // This dialog allows the user to control or disconnect from the currently selected route.
+                MediaRouteControllerDialog(registrar.activeContext(), themeResId)
+                        .show()
+            } else {
+                // This dialog allows the user to choose a route that matches a given selector.
+                MediaRouteChooserDialog(registrar.activeContext(), themeResId).apply {
+                    routeSelector = castContext.mergedSelector
+                    show()
+                }
+            }
+        } catch (ex: IllegalArgumentException) {
+            Log.d(FlutterCastFrameworkPlugin.TAG, "Exception while opening Dialog")
+            throw IllegalArgumentException("Error while opening MediaRouteDialog." +
+                    " Did you use AppCompat theme on your activity?" +
+                    " Check https://developers.google.com/cast/docs/android_sender/integrate#androidtheme", ex)
+        }
+    }
+}

android/src/main/kotlin/com/gianlucaparadise/flutter_cast_framework/cast/MessageCastingChannel.kt

@@ -0,0 +1,49 @@
+package com.gianlucaparadise.flutter_cast_framework.cast
+
+import android.util.Log
+import com.gianlucaparadise.flutter_cast_framework.MethodNames
+import com.google.android.gms.cast.Cast
+import com.google.android.gms.cast.CastDevice
+import com.google.android.gms.cast.framework.CastSession
+import io.flutter.plugin.common.MethodChannel
+
+class MessageCastingChannel(private val channel: MethodChannel) : Cast.MessageReceivedCallback {
+    companion object {
+        const val TAG = "MessageCastingChannel"
+    }
+
+    override fun onMessageReceived(castDevice: CastDevice?, namespace: String?, message: String?) {
+        Log.d(TAG, "Message received: $message:")
+        val argsMap: HashMap<String, String?> = hashMapOf(
+                "namespace" to namespace,
+                "message" to message
+        )
+
+        channel.invokeMethod(MethodNames.onMessageReceived, argsMap)
+    }
+
+    fun sendMessage(castSession: CastSession?, arguments: Any) {
+        Log.d(TAG, "Send Message arguments: $arguments:")
+        val argsMap = arguments as HashMap<String, String?>
+        val namespace = argsMap["namespace"]
+        val message = argsMap["message"]
+
+        sendMessage(castSession, namespace, message)
+    }
+
+    private fun sendMessage(castSession: CastSession?, namespace: String?, message: String?) {
+        try {
+            if (castSession == null) {
+                Log.d(TAG, "No session")
+                return
+            }
+
+            castSession.sendMessage(namespace, message)
+
+        } catch (ex: Exception) {
+            Log.e(TAG, "Error while sending ${message}:")
+            Log.e(TAG, ex.toString())
+        }
+    }
+
+}

example/lib/main.dart

@@ -14,12 +14,25 @@ class MyApp extends StatefulWidget {
 class _MyAppState extends State<MyApp> {
   CastState _castState = CastState.idle;
   SessionState _sessionState = SessionState.idle;
+  String _message = '';
+
+  final textMessageController = TextEditingController();
 
   @override
   void initState() {
     super.initState();
     FlutterCastFramework.castContext.state.addListener(_onCastStateChanged);
-    FlutterCastFramework.castContext.sessionManager.state.addListener(_onSessionStateChanged);
+    FlutterCastFramework.castContext.sessionManager.state
+        .addListener(_onSessionStateChanged);
+    FlutterCastFramework.castContext.sessionManager.onMessageReceived =
+        _onMessageReceived;
+  }
+
+  @override
+  void dispose() {
+    // Clean up the controller when the widget is disposed.
+    textMessageController.dispose();
+    super.dispose();
   }
 
   void _onCastStateChanged() {
@@ -32,10 +45,24 @@ class _MyAppState extends State<MyApp> {
   void _onSessionStateChanged() {
     debugPrint("Session state changed from example");
     setState(() {
-      _sessionState = FlutterCastFramework.castContext.sessionManager.state.value;
+      _sessionState =
+          FlutterCastFramework.castContext.sessionManager.state.value;
     });
   }
 
+  void _onMessageReceived(String namespace, String message) {
+    debugPrint("Message received from example");
+    setState(() {
+      _message = message;
+    });
+  }
+
+  void _onSendMessage() {
+    String message = this.textMessageController.text;
+    FlutterCastFramework.castContext.sessionManager
+        .sendMessage('urn:x-cast:cast-your-instructions', message);
+  }
+
   @override
   Widget build(BuildContext context) {
     return MaterialApp(
@@ -47,8 +74,30 @@ class _MyAppState extends State<MyApp> {
           child: Column(
             children: [
               CastButton(),
+              Text(
+                'States',
+                style: Theme.of(context).textTheme.title,
+              ),
               Text('Cast State: $_castState'),
               Text('Cast State: $_sessionState'),
+              Text(
+                'Message',
+                style: Theme.of(context).textTheme.title,
+              ),
+              Row(
+                children: [
+                  Expanded(
+                    child: TextField(
+                      controller: textMessageController,
+                    ),
+                  ),
+                  RaisedButton(
+                    child: Text('Send'),
+                    onPressed: _onSendMessage,
+                  )
+                ],
+              ),
+              Text('Received Message: $_message'),
             ],
           ),
         ),

lib/MethodNames.dart

@@ -11,4 +11,8 @@ class PlatformMethodNames {
   static const onSessionResumed = "SessionManager.onSessionResumed";
   static const onSessionResumeFailed = "SessionManager.onSessionResumeFailed";
   static const onSessionSuspended = "SessionManager.onSessionSuspended";
+
+  static const getSessionMessageNamespaces = "CastSession.getSessionMessageNamespaces";
+  static const onMessageReceived = "CastSession.onMessageReceived";
+  static const sendMessage = "CastSession.sendMessage";
 }

lib/cast/CastContext.dart

@@ -18,7 +18,13 @@ class CastContext {
     state.value = CastState.values[castState];
   }
 
-  SessionManager sessionManager = SessionManager();
+  SessionManager _sessionManager;
+  SessionManager get sessionManager {
+    if (_sessionManager == null) {
+      _sessionManager = SessionManager(_channel);
+    }
+    return _sessionManager;
+  }
 }
 
 enum CastState {

lib/cast/SessionManager.dart

@@ -1,7 +1,12 @@
 import 'package:flutter/foundation.dart';
+import 'package:flutter/services.dart';
 import 'package:flutter_cast_framework/MethodNames.dart';
 
 class SessionManager {
+  final MethodChannel _channel;
+
+  SessionManager(this._channel);
+
   final ValueNotifier<SessionState> state = ValueNotifier(SessionState.idle);
 
   void onSessionStateChanged(String method, dynamic arguments) {
@@ -35,8 +40,29 @@ class SessionManager {
         break;
     }
   }
+
+  MessageReceivedCallback onMessageReceived;
+
+  void platformOnMessageReceived(dynamic arguments) {
+    if (onMessageReceived == null) return;
+    final namespace = arguments['namespace'];
+    final message = arguments['message'];
+
+    onMessageReceived(namespace, message);
+  }
+
+  void sendMessage(String namespace, String message) {
+    final argsMap = {
+      'namespace': namespace,
+      'message': '{"message":"$message"}'
+    };
+    _channel.invokeMethod(PlatformMethodNames.sendMessage, argsMap);
+  }
 }
 
+typedef MessageReceivedCallback = void Function(
+    String namespace, String message);
+
 enum SessionState {
   idle,
   session_starting,

lib/flutter_cast_framework.dart

@@ -32,10 +32,19 @@ class FlutterCastFramework {
           castContext.sessionManager.onSessionStateChanged(method, arguments);
           break;
 
+        case PlatformMethodNames.getSessionMessageNamespaces:
+          return ["urn:x-cast:cast-your-instructions"];
+
+        case PlatformMethodNames.onMessageReceived:
+          castContext.sessionManager.platformOnMessageReceived(arguments);
+          break;
+
         default:
           debugPrint("Method not handled: $method");
           break;
       }
+
+      return null;
     });
   }