Animation

Animation.dart

  AnimationController animationController;
  Animation<double> animation;

  @override
  void initState() {
    super.initState();
    _setupAnimation();
  }

  _setupAnimation() {
    animationController =
        AnimationController(vsync: this, duration: Duration(seconds: 1));
    animation = Tween(begin: 50.0, end: 150.0).animate(animationController);
  }