Flutter动画基础 #

class _MyWidgetState extends State<MyWidget> 
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  
  @override
  void initState() {
    super.initState();
    _controller = AnimationController(
      duration: Duration(seconds: 2),
      vsync: this,
    );
  }
  
  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
}

Animation<double> animation = Tween<double>(
  begin: 0,
  end: 300,
).animate(_controller);

class AnimatedBox extends AnimatedWidget {
  AnimatedBox({required Animation<double> animation})
      : super(listenable: animation);
  
  @override
  Widget build(BuildContext context) {
    final animation = listenable as Animation<double>;
    return Container(
      width: animation.value,
      height: animation.value,
      color: Colors.blue,
    );
  }
}