小视频源码，Flutter事件传递

小视频源码&＃xff0c;Flutter 事件传递实现的相关代码

typedef void EventCallback(arg);class EventBus{EventBus._internal();static EventBus _singleton &＃61; new EventBus._internal();factory EventBus() &＃61;> _singleton;var _eMap &＃61; new Map>();/// 添加订阅者void register(eventName, EventCallback f) {if (eventName &＃61;&＃61; null || f &＃61;&＃61; null) {return;}_eMap[eventName] ??&＃61; new List();_eMap[eventName].add(f);}/// 移除订阅者void unRegister(eventName, [EventCallback f]) {var list &＃61; _eMap[eventName];if (eventName &＃61;&＃61; null || list &＃61;&＃61; null) return;if (f &＃61;&＃61; null) {_eMap[eventName] &＃61; null;} else {list.remove(f);}}/// 触发事件&＃xff0c;事件触发后该事件所有订阅者会被调用void post(eventName, [arg]) {var list &＃61; _eMap[eventName];if (list &＃61;&＃61; null) return;int len &＃61; list.length - 1;//反向遍历&＃xff0c;防止订阅者在回调中移除自身带来的下标错位for (var i &＃61; len; i > -1; --i) {list[i](arg);}}
}


使用&＃xff1a;
主页:

class EventBusMainPage extends StatefulWidget{&＃64;overrideState createState() {return _EventBusPageState();}
}class _EventBusPageState extends State{String textRes &＃61; "";&＃64;overridevoid initState() {}&＃64;overridevoid deactivate() {super.deactivate();EventBus().register("testEvent", (arg){setState(() {textRes &＃61; "${arg}";});});}&＃64;overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text("EventBus事件接收页"),),body: Column(children: [Text("参数&＃xff1a;${textRes}"),RaisedButton(onPressed: (){Navigator.pushNamed(context, "/EventBusNotifyPage");},child: Text("去传递页"),)],));}&＃64;overridevoid dispose() {super.dispose();EventBus().unRegister("testEvent");}
}


传递页:

class EventBusNotifyPage extends StatelessWidget{&＃64;overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text("通知"),),body: RaisedButton(onPressed: (){EventBus().post("testEvent", "我是参数");},child: Text("发送消息"),),);}
}


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