@override
  void initState() {
    super.initState();
    controller =
        AnimationController(duration: const Duration(seconds: 2), vsync: this);
    animation =

CurvedAnimation(parent: controller, curve: Curves.easeIn)
      ..addStatusListener((status) {
        if (status == AnimationStatus.completed) {
          controller.reverse();
        } else if (status == AnimationStatus.dismissed) {
          controller.forward();
        }
      });
    controller.forward();
  }

  @override
  Widget build(BuildContext context) => AnimatedLogo(animation: animation);

  @override
  void dispose() {
    controller.dispose();
    super.dispose();
  }
}

App source: animate5

Next steps