Flutter与Native交互的方式
Flutter与Native交换主要是使用PlatformChannel功能
PlatformChannel
Platformchannle分为三种类型
- BasicMessageChannel
- MethodChannel
- EventChannel
用于传递数据。Flutter与原生项目的资源是不共享的，可以通过BasicMessageChannel 来获取Native项目的图标等资源MethodChannel
传递方法调用。Flutter主动调用Native的方法，并获取相应的返回值。比如获取系统电量，发起Toast等系统API，可以通过这个完成。EventChannel
传递事件。Native将时间通知到Flutter。比如Flutter需要监听网络情况。EventChannel可以将Flutter的一个监听器交给Native，Native去做网络广播的监听，当收到广播之后借助 EventChannel调用Flutter注册的监听，完成对Flutter的事件通知。具体实现 BasicMessageChannel
- Flutter
static const messageChannel = const BasicMessageChannel('samples.flutter.io/message', StandardMessageCodec()); static const messageChannel2 = const BasicMessageChannel('smaples.flutter.io/message2', StandardMessageCodec()); Future sendMessage() async { String reply = await messageChannel.send('发送给Native的数据'); print('reply: $reply'); return reply; }void receiveMessage() { messageChannel2.setMessageHandler((message) async { print('message : $message'); return '从Native端返回来的数据'； }); }@Override void initState() { super.initState(); receiveMessage(); sendMessage(); }
- iOS 先不动
- Android
BasicMessageChanngl messageChannel = new BasicMessageChannel
- Flutter
static const platform = const MethodChannel('samples.flutter.io/battery'); Future_getBatteryLevel() async { String batteryLevel; try { final int result = awai platform.invokeMethod('getBatteryLevel'); batteryLevel = 'BatteryLevel at $result %'; } on PlatformException catch(e) { batterylevel = 'Failed to get battery levet: "${e.message}".'; }setState(（） { _batteryLevel = batterLevel; })； }
- iOS先不动
- Android
new MethodChannel(getFlutterView(), "samples.flutter.io/battery").setMethodCallHandler(new MethodCallHandler() { @Override public void onMethodCall(MethodCall call, Result result) { if (call.method.equals("getBatteryLevel")) { int batteryLevel = _getBatteryLevel(); if (batteryLevel != -1) { result.success(batteryLevel); } else { result.error("UNAVAILABLE", "Battery level is not available.", null); } } else { result.notImplemented(); } } }); private int getBatterylevel() { // 实现Android平台的 getBatteryLevel 代码即可 }
- Flutter
static const EventChannel _eventChannel = const EventChannel('samples.flutter.io/test'); void _onEvent(Object event) { print('从Native发送过来的消息内容: $event'); }void _onError(Object error) { print('从Native发送过来的错误')； }@Override void initState() { super.initState(); _eventChannel.receiveBroadcastStream().listen(_onEvent, onError: _onError); }
- iOS先不动
- 【Flutter与Native交互的方式】Android
new EventChannel(getFlutterView(), "samples.flutter.io/test").setStreanHandler( new EventChannel.StreamHandler() { @Override public void onListen(Object o, EventChannel.EventSink eventSink) { this.eventSink = eventSink; }@Override public void onCancel(Object o) {}}); private EventChannel.EventSink eventSink; private int count = 0; private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { super.handleMessage(); eventSink.success((count++) + "主动发送消息到Flutter")； } }
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