Flutter——最详细原生交互（MethodChannel、EventChannel、BasicMessageChannel）使用教程

MethodChannel（方法通道）
用途：实现双向通信，用于调用原生平台提供的 API 并获取返回结果。
场景：适合一次性操作，如调用相机、获取设备信息等。

使用步骤：

Flutter 端：通过 MethodChannel监听事件流。

dart 复制代码

  static const platform =
      MethodChannel('com.example.fltest.plugin.DeviceInfoPlugin');

Android 端（Kotlin）

kotlin 复制代码

    private var methodChannel: MethodChannel? = null
  val CHANNEL: String = "com.example.fltest.plugin.DeviceInfoPlugin"
  
  private fun getPhoneNumber(): Any? {
        val telephonyManager = context.getSystemService(Context.TELEPHONY_SERVICE) as TelephonyManager?
//        val phoneNumber = telephonyManager!!.line1Number
        val phoneNumber = "18627000332"
        return phoneNumber
    }

EventChannel（事件通道）
用途：实现单向数据流，用于原生平台向 Flutter 持续发送事件（如传感器数据）。
场景：适合实时数据流，如监听陀螺仪、GPS 位置更新等。
使用步骤：

Flutter 端：通过 EventChannel 监听事件流。

dart 复制代码

static const eventChannel =
      EventChannel('com.example.fltest.plugin.DeviceInfoPlugin/event');

  Stream<int> get _batteryLevelStream {
    return eventChannel.receiveBroadcastStream("111").cast<int>();
  }

Android 端（Kotlin）

kotlin 复制代码

 
class DeviceInfoPlugin(var context: Context) : EventChannel.StreamHandler, FlutterPlugin {

    private var eventChannel: EventChannel? = null
    val EVENT_CHANNEL: String = "com.example.fltest.plugin.DeviceInfoPlugin/event"

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
            result.notImplemented()
    }

    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        setupChannels(binding.binaryMessenger, binding.applicationContext)
    }

    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        teardownChannels()
    }

    private fun setupChannels(messenger: BinaryMessenger, context: Context) {
        this.context = context
        eventChannel = EventChannel(messenger, EVENT_CHANNEL)
        eventChannel?.setStreamHandler(this)
    }

    private fun teardownChannels() {
        eventChannel?.setStreamHandler(null)
        eventChannel = null
    }

    private val mainHandler = Handler(Looper.getMainLooper())

    override fun onListen(arguments: Any?, events: EventChannel.EventSink?) {
        Toast.makeText(context, arguments.toString(), Toast.LENGTH_SHORT).show()
        events?.let {
            sendBatteryLevel(it)
            events.success(1)
            mainHandler.postDelayed({
                events.success(2)
            }, 2000)
            mainHandler.postDelayed({ events.success(3) }, 4000)
        }
    }

    override fun onCancel(arguments: Any?) {

    }

    private fun sendBatteryLevel(events: EventChannel.EventSink) {
        val batteryLevel = -1
        if (batteryLevel != -1) {
            events.success(batteryLevel)
        } else {
            events.error("UNAVAILABLE", "Battery level not available.", null);
        }
    }
}

BasicMessageChannel（基础消息通道）
用途：支持异步消息传递，使用自定义编解码器传递数据。
场景：适合简单的数据交换（如 JSON、二进制数据）。

使用步骤：

Flutter 端：通过 BasicMessageChannel监听事件流。

dart 复制代码

  final BasicMessageChannel<String> messageChannel =
      BasicMessageChannel<String>(
    'com.example.fltest.plugin.DeviceInfoPlugin/basicMessage',
    StringCodec(),
  );
  
// 发送消息
Future<String> sendMessage(String message) async {
  return await messageChannel.send(message);
}

    @override
  void initState() {
    super.initState();
    // 设置消息处理器
    messageChannel.setMessageHandler((String? message) async {
      print('Received message from native: $message');
      return '$message';
    });
  }

Android 端（Kotlin）

kotlin 复制代码

package com.example.fltest.plugin

import android.content.Context
import android.os.Handler
import android.os.Looper
import android.telephony.TelephonyManager
import android.widget.Toast
import io.flutter.embedding.engine.plugins.FlutterPlugin
import io.flutter.plugin.common.BasicMessageChannel
import io.flutter.plugin.common.BasicMessageChannel.Reply
import io.flutter.plugin.common.BinaryMessenger
import io.flutter.plugin.common.EventChannel
import io.flutter.plugin.common.MethodCall
import io.flutter.plugin.common.MethodChannel
import io.flutter.plugin.common.MethodChannel.MethodCallHandler
import io.flutter.plugin.common.StandardMessageCodec
import io.flutter.plugin.common.StringCodec


class DeviceInfoPlugin(var context: Context) :  FlutterPlugin {

    private var basicMessageChannel: BasicMessageChannel<String>? = null
    val BASIC_MESSAGE_CHANNEL: String = "com.example.fltest.plugin.DeviceInfoPlugin/basicMessage"

    override fun onMethodCall(call: MethodCall, result: MethodChannel.Result) {
      
            result.notImplemented()
       
    }

    override fun onAttachedToEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        setupChannels(binding.binaryMessenger, binding.applicationContext)
    }

    override fun onDetachedFromEngine(binding: FlutterPlugin.FlutterPluginBinding) {
        teardownChannels()
    }

    private fun setupChannels(messenger: BinaryMessenger, context: Context) {
        this.context = context
        basicMessageChannel = BasicMessageChannel(messenger, BASIC_MESSAGE_CHANNEL, StringCodec.INSTANCE)
        basicMessageChannel?.setMessageHandler { message, reply ->
            println("Received message from Flutter: $message")
            reply.reply("Message received")
            basicMessageChannel?.send(message
            ) { reply -> Toast.makeText(context, reply.toString(), Toast.LENGTH_SHORT).show() }
        }
        // 发送消息
basicMessageChannel.send("Hello from Android") { reply ->
    Log.d("TAG", "Reply: $reply")
}
    }

    private fun teardownChannels() {
       
    }
    
    override fun onCancel(arguments: Any?) {

    }

}

在MainActivity初始化添加插件类

kotlin 复制代码

package com.example.fltest

import com.example.fltest.plugin.DeviceInfoPlugin
import io.flutter.embedding.android.FlutterActivity
import io.flutter.embedding.engine.FlutterEngine

class MainActivity: FlutterActivity(){
    override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
        super.configureFlutterEngine(flutterEngine)
        flutterEngine.plugins.add(DeviceInfoPlugin(this))
    }
}

总结：

方法	方向	使用场景
MethodChannel	双向	调用原生 API 并获取结果
EventChannel	单向（原生→Flutter）	监听持续事件（如传感器）
BasicMessageChannel	双向	简单消息传递（字符串、二进制数据）

根据具体需求选择合适的方式，可覆盖绝大多数跨平台交互场景。