【Flutter 混合开发】与原生通信-BasicMessageChannel

平台通信的3中方式

• MethodChannel：Flutter 与 Native 端相互调用，调用后可以返回结果，可以 Native 端主动调用，也可以Flutter主动调用，属于双向通信。此方式为最常用的方式， Native 端调用需要在主线程中执行。
• BasicMessageChannel：用于使用指定的编解码器对消息进行编码和解码，属于双向通信，可以 Native 端主动调用，也可以Flutter主动调用。
• EventChannel：用于数据流（event streams）的通信， Native 端主动发送数据给 Flutter，通常用于状态的监听，比如网络变化、传感器数据等。

Flutter 端

var channel = BasicMessageChannel('com.flutter.guide.BasicMessageChannel',StandardMessageCodec());

var result = await channel.send({'name': 'laomeng','age': 18});

• 参数类型任意，多个参数通常使用Map。
• 返回 Future，原生端返回的数据。

class BasicMessageChannelDemo extends StatefulWidget {
  @override
  _BasicMessageChannelDemoState createState() => _BasicMessageChannelDemoState();
}

class _BasicMessageChannelDemoState extends State<BasicMessageChannelDemo> {
  var channel = BasicMessageChannel('com.flutter.guide.BasicMessageChannel',StandardMessageCodec());

  var _data;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(),body: Column(
        children: [
          SizedBox(
            height: 50,),RaisedButton(
            child: Text('发送数据到原生'),onPressed: () async {
              var result = await channel.send({'name': 'laomeng','age': 18});
              var name = result['name'];
              var age = result['age'];
              setState(() {
                _data = '$name,$age';
              });
            },Text('原生返回数据：$_data'),],);
  }
}

Android 端

class BasicMessageChannelDemo(messenger: BinaryMessenger) : BasicMessageChannel.MessageHandler<Any> {

    private var channel: BasicMessageChannel<Any>

    init {
        channel = BasicMessageChannel(messenger,"com.flutter.guide.BasicMessageChannel",StandardMessageCodec())
        channel.setMessageHandler(this)
    }

    override fun onMessage(message: Any?,reply: BasicMessageChannel.Reply<Any>) {
        val name = (message as Map<String,Any>)["name"]
        val age = (message as Map<String,Any>)["age"]

        var map = mapOf("name" to "hello,$name","age" to "$age"
        )

        reply.reply(map)
    }
}

override fun onMessage(message: Any?,"age" to "$age"
        )

        reply.reply(map)
    }

• message 是传入的参数，由于 Flutter 端传入的是 Map，所以上面的解析按照 Map 解析。
• reply.reply() 是返回给 Flutter 的结果。

var result = await channel.send({'name': 'laomeng','age': 18});
var name = result['name'];
var age = result['age'];

class MainActivity : FlutterActivity() {

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        BasicMessageChannelDemo(flutterEngine.dartExecutor.binaryMessenger)
        flutterEngine.plugins.add(MyPlugin())
    }
}

iOS 端

import Flutter
import UIKit

public class BasicMessageChannelDemo {
    
    var channel:FlutterBasicMessageChannel
    
    init(messenger: FlutterBinaryMessenger) {
        channel = FlutterBasicMessageChannel(name: "com.flutter.guide.BasicMessageChannel",binaryMessenger: messenger)
        channel.setMessageHandler { (message,reply) in
            if let dict = message as? Dictionary<String,Any> {
                let name:String = dict["name"] as? String ?? ""
                let age:Int = dict["age"] as? Int ?? -1
                reply(["name":"hello,\(name)","age":age])
            }
        }  
    }  
}

import UIKit
import Flutter

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    
    let controller : FlutterViewController = window?.rootViewController as! FlutterViewController
    MethodChannelDemo(messenger: controller.binaryMessenger)
    BasicMessageChannelDemo(messenger: controller.binaryMessenger)
    GeneratedPluginRegistrant.register(with: self)

    return super.application(application,didFinishLaunchingWithOptions: launchOptions)
  }
}

原生端主动发送消息给Flutter

Flutter 端接收数据

@override
  void initState() {
    super.initState();
    channel.setMessageHandler((message) {
      setState(() {
        _nativeData = message['count'];
      });
    });
  }

Android 发送数据

class BasicMessageChannelDemo(var activity: Activity,messenger: BinaryMessenger) : BasicMessageChannel.MessageHandler<Any> {

    private var channel: BasicMessageChannel<Any>
    private var count = 0

    init {
        channel = BasicMessageChannel(messenger,StandardMessageCodec())
        channel.setMessageHandler(this)
        startTimer()
    }


    fun startTimer() {
        var timer = Timer().schedule(timerTask {
            activity.runOnUiThread {
                var map = mapOf("count" to count++)
                channel.send(map,object :BasicMessageChannel.Reply<Any>{
                    override fun reply(reply: Any?) {

                    }
                })
            }
        },1000)

    }

    override fun onMessage(message: Any?,"age" to "$age"
        )

        reply.reply(map)
    }
}

class MainActivity : FlutterActivity() {

    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        BasicMessageChannelDemo(this,flutterEngine.dartExecutor.binaryMessenger)
        flutterEngine.plugins.add(MyPlugin())
    }
}

iOS 发送数据

import Flutter
import UIKit

public class BasicMessageChannelDemo {
    
    var channel:FlutterBasicMessageChannel
    var count =  0
    
    init(messenger: FlutterBinaryMessenger) {
        channel = FlutterBasicMessageChannel(name: "com.flutter.guide.BasicMessageChannel","age":age])
            }
        }
        startTimer()
    }
    
    func startTimer() {
        var timer = Timer.scheduledTimer(timeInterval:1,target: self,selector:#selector(self.tickDown),userInfo:nil,repeats: true)
    }
    @objc func tickDown(){
        count += 1
        var args = ["count":count]
        channel.sendMessage(args) { (reply) in
            
        }
    }
}