LimitedBox 限制盒

可容纳一个子组件，通过指定最大宽高来限定子组件容身区域。

相关组件

ConstrainedBox

LimitedBox基本使用

   <br />【child】 : 孩子组件   【Widget】<br />【maxHeight】 : 最大高   【double】<br />【maxWidth】 : 最大宽   【double】<br />![189.gif](https://cdn.nlark.com/yuque/0/2020/gif/326147/1589508133558-632d3521-daa1-45a9-bf65-5370288cf3a4.gif#align=left&display=inline&height=202&margin=%5Bobject%20Object%5D&name=189.gif&originHeight=202&originWidth=397&size=112571&status=done&style=none&width=397)

import 'package:flutter/material.dart';
class CustomLimitedBox extends StatefulWidget {
  @override
  _CustomLimitedBoxState createState() => _CustomLimitedBoxState();
}

class _CustomLimitedBoxState extends State<CustomLimitedBox> {
  var _text = '';

  @override
  Widget build(BuildContext context) {
    var child = Container(
      alignment: Alignment.center,
      color: Colors.cyanAccent,
      width: 50,
      height: 50,
      child: Text("Static"),
    );

    var box = LimitedBox(
      maxHeight: 60,
      maxWidth: 100,
      child: Container(color: Colors.orange, child: Text(_text)),
    );
    return Column(
      children: <Widget>[
        Container(
          color: Colors.grey.withAlpha(22),
          width: 300,
          height: 100,
          child: Row(
            children: <Widget>[child, UnconstrainedBox(child: box), child],
          ),
        ),
        _buildInput()
      ],
    );
  }

  Widget _buildInput() {
    return Padding(
      padding: const EdgeInsets.all(18.0),
      child: TextField(
        decoration: InputDecoration(
          border: OutlineInputBorder(),
          hintText: '请输入',
        ),
        onChanged: (v) {
          setState(() {
            _text = v;
          });
        },
      ),
    );
  }
}