Expanded 01

01_expanded.dart

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      debugShowCheckedModeBanner: false, 
      home: ExpandedExample01(),
    );
  }
}

class ExpandedExample01 extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Column(
      children: [
        Container(
          height: 200,
          color: Colors.pinkAccent,
        ),
        Expanded(
          child: Container(
            color: Colors.green,
          ),
        ),
      ],
    );
  }
}