timer - 如何在特定时间内显示小部件？

Question

我在主屏幕上使用一个图标来向用户显示某个进程正在进行中。我希望此图标在特定时间(比如 100 秒)内可见。用户可能会导航到各种屏幕，但当他返回主屏幕时，他应该能够看到该图标，并且该图标应在 100 秒后消失。我该怎么做？

Answer 1

class AnimatedFlutterLogo extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => new _AnimatedFlutterLogoState();
}

class _AnimatedFlutterLogoState extends State<AnimatedFlutterLogo> {
  Timer _timer;
  FlutterLogoStyle _logoStyle = FlutterLogoStyle.markOnly;

  _AnimatedFlutterLogoState() {
    _timer = new Timer(const Duration(milliseconds: 100), () {
      setState(() {
        _logoStyle = FlutterLogoStyle.horizontal;
      });
    });
  }

  @override
  void dispose() {
    super.dispose();
    _timer.cancel();
  }

  @override
  Widget build(BuildContext context) {
    return new FlutterLogo(
      size: 200.0,
      textColor: Palette.white,
      style: _logoStyle,
    );
  }
}

请参阅此链接 How to run code after some delay in Flutter?

或者，您可以使用以下代码来实现延迟状态更新:

Future.delayed(const Duration(milliseconds: 100), () {
  setState(() {
    // Here you can write your code to update the state to show/hide the icon
  });
});