AnimatedContainerWidget（每日Flutter 小部件）

import ‘package:flutter/material.dart‘;

class AnimatedContainerWidget extends StatefulWidget {
  AnimatedContainerWidget({Key key}) : super(key: key);

  _AnimatedContainerWidgetState createState() =>
      _AnimatedContainerWidgetState();
}

class _AnimatedContainerWidgetState extends State<AnimatedContainerWidget> {
  double _opacity = 1.0;
  Matrix4 _transform = Matrix4.translationValues(0, 0, 0);

  void _onTapHandle() {
    setState(() {
      _opacity = _opacity == 1.0 ? 0.0 : 1.0;
      _transform = _opacity == 0.0
          ? Matrix4.translationValues(-300, 0, 0)
          : Matrix4.translationValues(0, 0, 0);
    });
  }

  @override
  Widget build(BuildContext context) {
    return Stack(
        children: <Widget>[
          Center(
              child: Column(children: <Widget>[
              AnimatedContainer(
              alignment: Alignment.center,
                  padding: EdgeInsets.all(5),
                  foregroundDecoration: BoxDecoration(
                      color: Colors.transparent),
                  width: 200,
                  height: 200,
                  constraints: BoxConstraints(minHeight: 200),
                  curve: Curves.easeInToLinear,
                  duration: Duration(milliseconds: 500),
              transform: _transform,
              child: Container(
                alignment: Alignment.center,
                width: 100,
                height: 50,
                color: Colors.blue,
              ))
        ]),
    ),
    Positioned(
    bottom: 1,
    right: 1,
    child: InkWell(
    child: Container(
    width: 30,
    height: 30,
    margin: EdgeInsets.fromLTRB(0, 0, 10, 10),
    decoration: BoxDecoration(
    borderRadius: BorderRadius.circular(30),
    color: Colors.pink,
    ),
    child: Icon(
    Icons.play_arrow,
    color: Colors.white,
    ),
    ),
    onTap: _onTapHandle,
    ),
    )
    ],
    );
  }
}