Flutter 动画 AnimationController AnimatedWidget

import 'package:flutter/material.dart';

class AnimationDemo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("AnimationDone"),
        elevation: 0.0,
      ),
      body: AnimationHome(),
    );
  }
}

class AnimationHome extends StatefulWidget {
  @override
  _AnimationHomeState createState() => _AnimationHomeState();
}

class _AnimationHomeState extends State<AnimationHome>
    with TickerProviderStateMixin {
  AnimationController animationDemoController;
  Animation _animation;
  Animation _animationColor;
  int _animValue = 32;
  var _curve;

  @override
  void initState() {
    super.initState();
    animationDemoController = AnimationController(
      duration: Duration(milliseconds: 3000),
      vsync: this,
      // lowerBound: 32.0,
      // value: 32.0,
      // upperBound: 100.0
    );
    _curve = CurvedAnimation(
        parent: animationDemoController, curve: Curves.bounceInOut);
    _animation = Tween(begin: 32.0, end: 100.0).animate(_curve);
    _animationColor = ColorTween(begin: Colors.red, end: Colors.red[900])
        .animate(animationDemoController);

    animationDemoController.addListener(() {
      setState(() {});
    });

    animationDemoController.addStatusListener((status) {
      print(status);
    });
  }

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

  @override
  Widget build(BuildContext context) {
    return Center(
      child: AnimatedHeart(
          animations: [_animation, _animationColor],
          controller: animationDemoController),
    );
  }
}

class AnimatedHeart extends AnimatedWidget {
  final List<Animation> animations;
  final AnimationController controller;

  AnimatedHeart({this.animations, this.controller})
      : super(listenable: controller);

  @override
  Widget build(BuildContext context) {
    return IconButton(
      icon: Icon(Icons.favorite),
      iconSize: animations[0].value,
      color: animations[1].value,
      onPressed: () {
        controller.forward();
        switch (controller.status) {
          case AnimationStatus.completed:
            controller.reverse();
            break;
            defalut:
            controller.forward();
        }
      },
    );
  }
}