initState.dart

initState.dart

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

    final animationCurve = CurvedAnimation(
        curve: Curves.easeInExpo,
        reverseCurve: Curves.easeIn,
        parent: _animationController);
    _animation = Tween<double>(begin: 5, end: 6).animate(animationCurve)
      ..addStatusListener((status) {
        if (status == AnimationStatus.completed) {
          _animationController.reverse();
        } else if (status == AnimationStatus.dismissed) {
          _animationController.forward();
        }
      });

    animatedStar1 = Tween(begin: 0.0, end: 1.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.0, 0.5)));
    animatedStar1.addListener(() {
      setState(() {});
    });
    animatedStar2 = Tween(begin: 0.0, end: 1.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.5, 1.0)));
    animatedStar2.addListener(() {
      setState(() {});
    });
    animatedStar3 = Tween(begin: 1.0, end: 0.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.0, 0.5)));
    animatedStar3.addListener(() {
      setState(() {});
    });
    animatedStar4 = Tween(begin: 1.0, end: 0.0).animate(CurvedAnimation(
        parent: _animationController, curve: Interval(0.5, 1.0)));
    animatedStar4.addListener(() {
      setState(() {});
    });

    for (int i = 0; i < 100; i++) {
      listStar.add(WhereStar(
          left: Random().nextDouble() * 500,
          bottom: Random().nextDouble() * 500,
          top: Random().nextDouble() * 500,
          extraSize: Random().nextDouble() * 4,
          angle: Random().nextDouble(),
          typeFade: Random().nextInt(4)));
    }
    _animationController.forward();
  }