Flutter布局的时候基本都使用行和列,基本都是按照相同比列进行排列显示的.如果想让其中一个拉伸并填充余下的空间,只需要在子控件外加上Expanded即可.
设置fix可以增加子控件的权重.

import 'package:flutter/material.dart';

class GoogleExpand extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        Row(
          children: <Widget>[
            Container(
              width: 50.0,
              height: 50.0,
              color: Colors.green,
            ),
            Expanded(
              flex: 1,
              child: Container(
                width: 50.0,
                height: 50.0,
                color: Colors.red,
                child: Text('flex: 1'),
              ),
            ),
            Container(
              width: 50.0,
              height: 50.0,
              color: Colors.orange,
            ),
          ],
        ),
        SizedBox(
          height: 20.0,
        ),
        Row(
          children: <Widget>[
            Container(
              width: 50.0,
              height: 50.0,
              color: Colors.green,
            ),
            Expanded(
              flex: 2,
              child: Container(
                width: 50.0,
                height: 50.0,
                color: Colors.red,
                child: Text('flex: 2'),
              ),
            ),

            Container(
              width: 50.0,
              height: 50.0,
              color: Colors.orange,
            ),
            Expanded(
              flex: 1,
              child: Container(
                width: 50.0,
                height: 50.0,
                color: Colors.blue,
                child: Text('flex: 1'),
              ),
            ),
          ],
        )
      ],
    );
  }
}

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