flutter event_bus

//1.定義事件類
class JohwenEvent{

  static EventBus eventBus=new EventBus();
}
//2.定義事件結構體
class EventData{
  var str;

  EventData(this.str);

}
void initState() {
  super.initState();
　　//3.監聽事件
  JohwenEvent.eventBus.on<EventData>().listen((event) {
    setState(() {
      fuckIndex = event.str;
    });
  });
}
//4.觸發事件
JohwenEvent.eventBus.fire(new EventData("子類改變了父類文字"));