Channel实现Flutter与原生平台之间的双向通信

    private void registerChannelFunction() {
        FlutterEngine flutterEngine = getFlutterEngine();
        if (flutterEngine == null) {
            Log.e("ERROR", "注册消息通道失败 FlutterEngine = null");
            return;
        }

        DartExecutor dartExecutor = flutterEngine.getDartExecutor();
        binaryMessenger = dartExecutor.getBinaryMessenger();
        messageChannelSendFunction();
        methodChannelSendFunction();
        eventChannelSendFunction();

    }

（一）通过MessageChannel实现Flutter与原生平台之间的双向通信

Flutter端实现MessageChannel通信步骤：

先定义messageChannel

static const basicMethodChannel = 
BasicMessageChannel("flutter_basic_method_channel", StandardMessageCodec());

发送message：

  Future<void> sendMessage(Map json) async {
    await basicMethodChannel.send(json);
  }

接收message：

  void receiveMessage() {
    basicMethodChannel.setMessageHandler((result) async {
        Map? map = result as Map?;
        int code = map?["code"];
        String message=map?["message"];
        setState(() {
          receive = "messageChannel receiveMessage 中的回调 code $code  message $message";
          print(receive);
          print("receiveMessage: code:$code message:$message");
        });
        return 'Flutter 已收到消息';

    });
  }

Android端实现MessageChannel通信步骤：

首先，先初始化 BasicMessageChannel 实例对象：

basicMessageChannel = new BasicMessageChannel<>(binaryMessenger, 
"flutter_basic_method_channel", StandardMessageCodec.INSTANCE);

然后为Message对象设置MessageHandler对象：

        basicMessageChannel.setMessageHandler(new BasicMessageChannel.MessageHandler() {
            @Override
            public void onMessage(@Nullable Object message, @NonNull BasicMessageChannel.Reply reply) {
                System.out.println("flutter 传来的数据为: "+message.toString());
                basicSendMessage();
            }
        });

（二）通过MethodChannel实现Flutter与原生平台之间的双向通信

Flutter端实现MessageChannel通信步骤：

定义methodChannel：

static const methodChannel = MethodChannel("flutter_method_channel");

然后通过methodChannel的invokeMethod进行消息的发送：

  static Future<dynamic> invokeNative(String method,
      {required Map<String, String> arguments}) async {
    if (arguments == null) {
      return await methodChannel.invokeMethod(method);
    } else {
      return await methodChannel.invokeMethod(method, arguments);
    }
  }

最后调用会返回一个结果，通过这个result拿到返回的数据：

    Map result = await invokeNative("test", arguments: {});
    int code = result["code"];
    String message = result["message"];
    setState(() {
      receive = "invokeNative 中的回调 code $code message $message";
      print(receive);
    });

Android端实现MessageChannel通信步骤：

先初始化MethodChannel的实例：

        mMethodChannel = new MethodChannel(binaryMessenger, channelName);

然后设置methodHandler，它会重写MethodCallHandler的onMethodCall方法：

    private MethodChannel.MethodCallHandler getMethodCallHandler() {
        return new MethodChannel.MethodCallHandler() {
            @Override
            public void onMethodCall(@NonNull MethodCall call, @NonNull MethodChannel.Result result) {
                String method = call.method;
                Object Arguments = call.arguments;
                Map<String, Object> arguments = null;

                if (null != Arguments) {
                    arguments = (Map<String, Object>) Arguments;
                }

                if ("test".equals(method)) {
                    Toast.makeText(this, "flutter 调用到了 android test 数据为 name :"+arguments.get("name") +" age : "+arguments.get("age"), Toast.LENGTH_SHORT).show();

                    Map<String, Object> objectMap = new HashMap<>();
                    objectMap.put("message", "result.success 返回给flutter的basic数据");
                    objectMap.put("code", 300);
                    result.success(objectMap);
                } else {
                    result.notImplemented();
                }
            }
        };
    }

（三）通过EventChannel实现Flutter与原生平台之间的双向通信

Flutter端实现EventChannel通信步骤：

首先 初始化EventChannel实例：

static const eventChannel = EventChannel("flutter_event_channel");

然后设置Stream：

    eventChannel.receiveBroadcastStream().listen((event) {
      // int code = event["code"];
      // String message = event["message"];
      setState(() {
        // receive += "code $code message $message  ";
        // print("eventMessageListener: "+receive);
        print(event);
      });
    }, onError: (event) {});

Android端实现EventChannel通信步骤：

初始化EventChannel：

String channelName = "flutter_event_channel";
EventChannel eventChannel = new EventChannel(binaryMessenger, channelName);

然后调用setStreamHandler为EventChannel设置一个处理器：

        eventChannel.setStreamHandler(new EventChannel.StreamHandler() {
            @Override
            public void onListen(Object arguments, EventChannel.EventSink events) {
                eventSink = events;
                startTimer();
            }

            @Override
            public void onCancel(Object arguments) {

            }
        });

EventSink 接口中 , 有 3 个方法 :

• success : 表示接收数据成功 ;
• error : 表示接收数据出现错误 ;
• endOfStream : 表示接收数据结束 ;

这样就完成了Flutter与Android原生之间的通信，IOS的不太熟，有需要可以搜一下，都大差不差，如果觉得博主写的对你有帮助，麻烦给个一键三连