acx3.dart

acx3.dart

class _WidgetWithAnimationState extends State<WidgetWithAnimation>
    with AnimationControllerMixin {
  Animation<double> width;

  @override
  void initState() {
    width = Tween(begin: 100.0, end: 200.0).animate(controller);
    controller.addTask(FromToTask(duration: Duration(seconds: 1), to: 1.0));
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Container(
      width: width.value,
    );
  }
}