计时器的值倒计时不会立即波动

如何解决计时器的值倒计时不会立即波动

我正在使用timer_count_down软件包。 （https://pub.dev/packages/timer_count_down），当我以新值（计时器秒）重新启动计时器时。计时器以旧值开始，而不是新值。简而言之，我的状态不会立即更新。并且计时器以旧值重新启动。请帮助我。

Widget build(BuildContext context) {
return Countdown(
  controller: contrl,//controller for timer
  seconds: time,//time is a state which store seconds.
  build: (BuildContext context,double time) => Text(time.toString()),interval: Duration(milliseconds: 100),onFinished: () {
    time = 30;//new time updated for timer
    contrl.restart();// this will restart mytimer// but timer is not taking new value it restarts with old value//
  },);

} }

解决方法

似乎该软件包并非设计用于这种方式（onFinished->重新启动）。这不是一个干净的解决方法，但是您可以尝试以下

Countdown(
        controller: contrl,//controller for timer
        seconds: time,//time is a state which store seconds.
        build: (BuildContext context,double time) => Text(time.toString()),interval: Duration(milliseconds: 100),onFinished: () {
          //new time updated for timer
          setState(() {
            time = 10;
          });
          Future.delayed(Duration(seconds: 1)).then((value) {
            contrl.restart();
          });

          // this will restart mytimer// but timer is not taking new value it restarts with old value//
        },),

或者像这样实现自己的倒数逻辑：

class NewPage extends StatefulWidget {
  @override
  _NewPageState createState() => _NewPageState();
}

class _NewPageState extends State<NewPage> {
  Duration time = Duration(seconds: 3);
  Timer _timer;

  void startTimer(Duration reStartTime,Duration interval) {
    _timer = Timer.periodic(interval,(Timer t) {
      if (time <= Duration()) {
        setState(() {
          time = reStartTime;
        });
      } else {
        setState(() {
          time -= interval;
        });
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          startTimer(Duration(seconds: 30),Duration(milliseconds: 100));
        },appBar: AppBar(
        title: Text('Second Page'),body: Center(child: Text('$time')),);
  }
}