Explicit with Mixin.dart

class _ExplicitState extends State<Explicit>
    with TickerProviderStateMixin {
  AnimationController _repeatingAnimationShort;
  AnimationController _repeatingAnimationLong;
  AnimationController _loopingAnimationShort;
  AnimationController _loopingAnimationLong;

  Animatable<double> _scaleCurve;
  Animatable<Offset> _slideCurve;
  Animatable<Offset> _reverseSlide;
  Animatable<double> _scaleCurveSlow;

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

    _repeatingAnimationShort = AnimationController(
      duration: const Duration(milliseconds: 3600),
      vsync: this,
    )..repeat();

    _repeatingAnimationLong = AnimationController(
      duration: const Duration(seconds: 15),
      vsync: this,
    )..repeat();

    _loopingAnimationShort = AnimationController(
      duration: const Duration(milliseconds: 3600),
      vsync: this,
    )
      ..addStatusListener((status) {
        if (status == AnimationStatus.completed) {
          _loopingAnimationShort.reverse();
        } else if (status == AnimationStatus.dismissed) {
          _loopingAnimationShort.forward();
        }
      })
      ..forward();

    _loopingAnimationLong = AnimationController(
      duration: const Duration(seconds: 30),
      vsync: this,
    )
      ..addStatusListener((status) {
        if (status == AnimationStatus.completed) {
          _loopingAnimationLong.reverse();
        } else if (status == AnimationStatus.dismissed) {
          _loopingAnimationLong.forward();
        }
      })
      ..forward();
  }