Flutter 与 Android 相互调用、传递参数

Flutter 调用原生

Android 定义插件

class MyFlutterPlugin implements MethodChannel.MethodCallHandler {
    private final Activity activity;
    public MyFlutterPlugin(Activity activity) {
        this.activity = activity;
    }
    @Override
    public void onMethodCall(MethodCall methodCall, MethodChannel.Result result) {
        if (methodCall.method.equals("getUser")) {
            Integer userId = methodCall.argument("userId");
            String mockUser = String.format("{\"name\":\"Wiki\",\"id\":%s}", userId);
            result.success(mockUser);
        }
    }
    public static void registerWith(PluginRegistry registry) {
        String CHANNEL = "com.example.flutter_app/plugin";
        PluginRegistry.Registrar registrar = registry.registrarFor(CHANNEL);
        MethodChannel methodChannel = new MethodChannel(registrar.messenger(), CHANNEL);
        MyFlutterPlugin myFlutterPlugin = new MyFlutterPlugin(registrar.activity());
        methodChannel.setMethodCallHandler(myFlutterPlugin);
    }
}

Android 插件注册

public class MainActivity extends FlutterActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GeneratedPluginRegistrant.registerWith(this);
        MyFlutterPlugin.registerWith(this);
    }
}

Flutter 调用原生插件

  static const myPlugin = const MethodChannel('com.example.flutter_app/plugin');
  void getUser() async {
    Map<String, Object> map = {"userId": 101};
    String result = await myPlugin.invokeMethod("getUser", map);
    print(result);
  }

原生调用 Flutter

Android 定义插件

class MyFlutterEventPlugin implements EventChannel.StreamHandler {
    public EventChannel.EventSink eventSink;

    public static MyFlutterEventPlugin registerWith(PluginRegistry registry) {
        String CHANNEL = "com.example.flutter_app/event_plugin";
        PluginRegistry.Registrar registrar = registry.registrarFor(CHANNEL);
        EventChannel eventChannel = new EventChannel(registrar.messenger(), CHANNEL);
        MyFlutterEventPlugin myFlutterEventPlugin = new MyFlutterEventPlugin();
        eventChannel.setStreamHandler(myFlutterEventPlugin);
        return myFlutterEventPlugin;
    }
    @Override
    public void onListen(Object o, EventChannel.EventSink eventSink) {
        this.eventSink = eventSink;
    }
    @Override
    public void onCancel(Object o) {
    }
}

Android 插件注册 & 调用

public class MainActivity extends FlutterActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GeneratedPluginRegistrant.registerWith(this);
        MyFlutterPlugin.registerWith(this);
        MyFlutterEventPlugin eventPlugin = MyFlutterEventPlugin.registerWith(this);
        new Thread(new Runnable() {
            @Override
            public void run() {
                int counter = 0;
                while (true){
                    try {
                        if (eventPlugin.eventSink != null) {
                            eventPlugin.eventSink.success(counter++);
                        }
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                        eventPlugin.eventSink.error("计时器异常","计时器异常",e.getMessage());
                    }
                }
            }
        }).start();
    }
}

Flutter 注册监听器接收来自原生的消息

  static const myEventPlugin = const EventChannel('com.example.flutter_app/event_plugin');
  @override
  void initState() {
    super.initState();
    myEventPlugin.receiveBroadcastStream().listen(_onEvent, onError: _onError);
  }
  void _onEvent(Object event) {
    print("onEvent: $event");
  }
  void _onError(Object error) {
    print("onError: $error");
  }

完整代码

Android

public class MainActivity extends FlutterActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        GeneratedPluginRegistrant.registerWith(this);
        MyFlutterPlugin.registerWith(this);
        MyFlutterEventPlugin eventPlugin = MyFlutterEventPlugin.registerWith(this);
        new Thread(new Runnable() {
            @Override
            public void run() {
                int counter = 0;
                while (true){
                    try {
                        if (eventPlugin.eventSink != null) {
                            eventPlugin.eventSink.success(counter++);
                        }
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                        eventPlugin.eventSink.error("计时器异常","计时器异常",e.getMessage());
                    }
                }
            }
        }).start();
    }
}

class MyFlutterPlugin implements MethodChannel.MethodCallHandler {
    private final Activity activity;
    public MyFlutterPlugin(Activity activity) {
        this.activity = activity;
    }
    @Override
    public void onMethodCall(MethodCall methodCall, MethodChannel.Result result) {
        if (methodCall.method.equals("getUser")) {
            Integer userId = methodCall.argument("userId");
            String mockUser = String.format("{\"name\":\"Wiki\",\"id\":%s}", userId);
            result.success(mockUser);
        }
    }
    public static void registerWith(PluginRegistry registry) {
        String CHANNEL = "com.example.flutter_app/plugin";
        PluginRegistry.Registrar registrar = registry.registrarFor(CHANNEL);
        MethodChannel methodChannel = new MethodChannel(registrar.messenger(), CHANNEL);
        MyFlutterPlugin myFlutterPlugin = new MyFlutterPlugin(registrar.activity());
        methodChannel.setMethodCallHandler(myFlutterPlugin);
    }
}

class MyFlutterEventPlugin implements EventChannel.StreamHandler {
    public EventChannel.EventSink eventSink;

    public static MyFlutterEventPlugin registerWith(PluginRegistry registry) {
        String CHANNEL = "com.example.flutter_app/event_plugin";
        PluginRegistry.Registrar registrar = registry.registrarFor(CHANNEL);
        EventChannel eventChannel = new EventChannel(registrar.messenger(), CHANNEL);
        MyFlutterEventPlugin myFlutterEventPlugin = new MyFlutterEventPlugin();
        eventChannel.setStreamHandler(myFlutterEventPlugin);
        return myFlutterEventPlugin;
    }
    @Override
    public void onListen(Object o, EventChannel.EventSink eventSink) {
        this.eventSink = eventSink;
    }
    @Override
    public void onCancel(Object o) {
    }
}

Flutter 代码

import 'package:flutter/material.dart';
import 'package:flutter/services.dart';

void main() => runApp(MyApp());

class MyHomePageState extends State<MyHomePage> {
  static const myPlugin = const MethodChannel('com.example.flutter_app/plugin');
  static const myEventPlugin = const EventChannel('com.example.flutter_app/event_plugin');

  @override
  void initState() {
    super.initState();
    myEventPlugin.receiveBroadcastStream().listen(_onEvent, onError: _onError);
  }

  void _onEvent(Object event) {
    print("onEvent: $event");
  }

  void _onError(Object error) {
    print("onError: $error");
  }

  void getUser() async {
    Map<String, Object> map = {"userId": 101};
    String result = await myPlugin.invokeMethod("getUser", map);
    print(result);
  }

  @override
  Widget build(BuildContext context) {
    return new Center(
      child: new RaisedButton(
        onPressed: () {
          getUser();
        },
        child: new Text("调用原生"),
      ),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() {
    return new MyHomePageState();
  }
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      title: 'Welcome to Flutter',
      home: new Scaffold(
        appBar: new AppBar(
          title: new Text('Welcome to Flutter'),
        ),
        body: MyHomePage(),
      ),
    );
  }
}