Defining the Flip Animation

flip_animation_controller.dart

 AnimationController _controller;
  Animation _myAnimation;
  AnimationStatus _animationStatus = AnimationStatus.dismissed;

  @override
  void initState() {

    super.initState();
    _controller =
        AnimationController(vsync: this, duration: Duration(seconds: 1));
    _myAnimation = Tween(end: 1.0, begin: 0.0).animate(_controller)
      ..addListener(() {
        setState(() {});
      })
      ..addStatusListener((status) {
        _animationStatus = status;
      });
  }