flutter - 在 Flutter 中使用很棒的通知包在特定时间安排通知

Question

我正在使用showNotificationAtScheduleCronAwesome 通知包。它给了我计划创建但是当特定时间到来时没有通知并且也给我这个 [ERROR:flutter/lib/ui/ui_dart_state.cc(199)] Unhandled Exception: Bad state: Stream has already been listened to. 我想在特定时间发出通知并删除此错误。

  @override
  _LocalNotificationScreenState createState() => _LocalNotificationScreenState();
}
class _LocalNotificationScreenState extends State<LocalNotificationScreen > {
  @override
  void initState(){

    super.initState();
    AwesomeNotifications().isNotificationAllowed().then((isAllowed) {
      if (!isAllowed) {
        AwesomeNotifications().requestPermissionToSendNotifications();
      }
    });

  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('notify'),
      ),
      body: Center(
        child: TextButton(
          onPressed:()async{
         // await notification.delayNotification(0);
           //await notification.showBigPictureNotificationActionButtons(0);
            await notification.showNotificationAtScheduleCron(0, "title", 'body', DateTime(2021,7,19,12,10));
          AwesomeNotifications().displayedStream.listen((receivedNotification) {
            FlutterRingtonePlayer.playNotification(looping: true,asAlarm: true);
          });
          AwesomeNotifications().actionStream.listen((event) {

            if(event.buttonKeyPressed =='cancel')
              FlutterRingtonePlayer.stop();
            if (event.buttonKeyPressed=='snooze') {
              FlutterRingtonePlayer.stop();
              notification.delayNotification(0,"title", "body");
            }
          });
          } ,
          child: Text('SendNotification') ,

        ),
      ),
    );
  }
}