import 'package:flutter/material.dart';

/// create by 张风捷特烈 on 2020-04-01
/// contact me by email 1981462002@qq.com
/// 说明:

//    {
//      "widgetId": 201,
//      "name": 'AnimatedSize基本使用',
//      "priority": 1,
//      "subtitle":
//          "【child】 : 孩子组件   【Widget】\n"
//          "【duration】 : 动画时长   【Duration】\n"
//          "【alignment】 : 对齐方式   【AlignmentGeometry】\n"
//          "【curve】 : 动画曲线   【Duration】\n"
//          "【vsync】 : vsync   【TickerProvider】",
//    }

class CustomAnimatedSize extends StatefulWidget {
  @override
  _CustomAnimatedSizeState createState() => _CustomAnimatedSizeState();
}

class _CustomAnimatedSizeState extends State<CustomAnimatedSize>
    with SingleTickerProviderStateMixin {
  final double start = 100;
  final double end = 200;

  double _width;

  @override
  void initState() {
    _width = start;
    super.initState();
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        _buildSwitch(),
        Container(
          color: Colors.grey.withAlpha(22),
          width: 200,
          height: 100,
          alignment: Alignment.center,
          child: AnimatedSize(
            vsync: this,
            duration: Duration(seconds: 1),
            curve: Curves.fastOutSlowIn,
            alignment: Alignment(0, 0),
            child: Container(
              height: 40,
              width: _width,
              alignment: Alignment.center,
              color: Colors.blue,
              child: Text(
                '张风捷特烈',
                style: TextStyle(color: Colors.white),
              ),
            ),
          ),
        ),
      ],
    );
  }

  Widget _buildSwitch() => Switch(
      value: _width == end,
      onChanged: (v) {
        setState(() {
          _width = v ? end : start;
        });
      });
}