本文共 4801 字，大约阅读时间需要 16 分钟。

（本文只列出与Android Native的交互，iOS使用相同的Api，处理方式类似）。主要就是 MethodChannel的使用，因为native端和flutter端都有 methodChannel的setMethodCallHandler()，和invokeMethod()方法，所以两端都可以使用methodChannel进行通信。

Dart调用Native源码：

import 'dart:async';import 'package:flutter/material.dart';import 'package:flutter/services.dart';...class _MyHomePageState extends State
   
     {  static const platform = const MethodChannel('samples.flutter.dev/battery');  // Get battery level.}// Get battery level.  String _batteryLevel = 'Unknown battery level.';  Future
    
      _getBatteryLevel() async {    String batteryLevel;    try {      final int result = await platform.invokeMethod('getBatteryLevel');      batteryLevel = 'Battery level at $result % .';    } on PlatformException catch (e) {      batteryLevel = "Failed to get battery level: '${e.message}'.";    }    setState(() {      _batteryLevel = batteryLevel;    });  }
    
   

//Native端，Android Java.(Kotlin类似)。交互代码运行在mainThread主线程。

import io.flutter.app.FlutterActivity;import io.flutter.plugin.common.MethodCall;import io.flutter.plugin.common.MethodChannel;import io.flutter.plugin.common.MethodChannel.MethodCallHandler;import io.flutter.plugin.common.MethodChannel.Result;public class MainActivity extends FlutterActivity {    private static final String CHANNEL = "samples.flutter.dev/battery";    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        GeneratedPluginRegistrant.registerWith(this);        new MethodChannel(getFlutterView(), CHANNEL).setMethodCallHandler(                new MethodCallHandler() {                    @Override                    public void onMethodCall(MethodCall call, Result result) {                        // Note: this method is invoked on the main thread.                        if (call.method.equals("getBatteryLevel")) {                            int batteryLevel = getBatteryLevel();                            if (batteryLevel != -1) {                                result.success(batteryLevel);                            } else {                                result.error("UNAVAILABLE", "Battery level not available.", null);                            }                        } else {                            result.notImplemented();                        }                    }                });    }}

Native发送给flutter数据：（同样使用methodChannel机制）

const val CONNECTION_CHANNEL = "com.demo.flutter.connection"val methodChannel = MethodChannel(flutterView, CONNECTION_CHANNEL)        methodChannel.setMethodCallHandler { methodCall, result ->            when (methodCall.method) {                "activityFinish" -> {                    goBack() //关闭当前页面                    result.success(null) //标识调用成功                }                "showToastMessage" -> showShortToast(methodCall.argument
   
    ("message"))            }        }//使用注册的方法channel调用dart端方法名称，并传递参数。        Handler().postDelayed({            methodChannel.invokeMethod("aaa", "c")        }, 5000)；
   

//dart端

static const _platform = const MethodChannel("com.whitehorse.flutter.connection");  _AboutPageState() {    _platform.setMethodCallHandler((handler) {      switch (handler.method) {        case "aaa":          _platform.invokeMethod("showToastMessage", {"message": "您调用了dart里的方法"});          break;      }    });  }  void _goBack() {//    _platform.invokeMethod("activityFinish");  }

另一种方式，实现native flutter通信：

基于 EventChannel，使用事件流 event stream 驱动，更适合长久耗时的方法调用。

//Native端，android.

public class MainActivity extends FlutterActivity {    public static final String STREAM = "com.yourcompany.eventchannelsample/stream";     @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        new EventChannel(getFlutterView(), STREAM).setStreamHandler(                new EventChannel.StreamHandler() {                    @Override                    public void onListen(Object args, final EventChannel.EventSink events) {                        Log.w(TAG, "adding listener");                    }                    @Override                    public void onCancel(Object args) {                        Log.w(TAG, "cancelling listener");                    }                }        );    }}

//flutter,dart端

static const stream =    const EventChannel('com.yourcompany.eventchannelsample/stream');StreamSubscription _timerSubscription = null;void _enableTimer() {  if (_timerSubscription == null) {    _timerSubscription = stream.receiveBroadcastStream().listen(_updateTimer); // 添加监听  }}void _disableTimer() {  if (_timerSubscription != null) {    _timerSubscription.cancel();    _timerSubscription = null;  }}

* flutter receiveBroadcastStream([arguments]) 返回一个 broadcast stream对象。使用API进行操作。

转载地址：http://fnegi.baihongyu.com/