Flutter Expanded, Flexible

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp()); //앱 구동시켜주세요
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);
  @override
  Widget build(BuildContext context) {

    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('appBar 임'),
        ),
        body: Column(
          children: [
            Container(color: Colors.red, height: 200,),
            Container(color: Colors.blue,height: 200,),
            Container(color: Colors.green,height: 200,),
          ],
        ),
      ),
    );
  }
}