main.dart

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
        title: '123',
        home: SafeArea(
          child: Container(
            color: Colors.teal,
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceBetween,
              mainAxisSize: MainAxisSize.max,
              crossAxisAlignment: CrossAxisAlignment.stretch,
              children: <Widget>[
                Container(
                  child: Text(
                    '1',
                    style: TextStyle(color: Colors.blue),
                  ),
                  width: 100,
                  color: Colors.red,
                ),
                Container(
                    child: Column(
                  mainAxisAlignment: MainAxisAlignment.center,
                  children: <Widget>[
                    Container(
                      color: Colors.yellow,
                      width: 100,
                      height: 100,
                    ),
                    Container(
                      color: Colors.greenAccent,
                      width: 100,
                      height: 100,
                    ),
                  ],
                )),
                Container(
                  child: Text(
                    '3',
                    style: TextStyle(color: Colors.blue),
                  ),
                  width: 100,
                  color: Colors.yellow,
                ),
              ],
            ),
          ),
        ));
  }
}