Expanded 03

03_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: ExpandedExample03(),
    );
  }
}

class ExpandedExample03 extends StatelessWidget {
  @override 
  Widget build(BuildContext context) {
    return Column(
      children: [
        Expanded(
          flex: 1,
          child: WidgetRed(),
        ),
        Expanded(
          flex: 2,
          child: WidgetBlue(),
        ),
      ],
    );
  }
}

class WidgetRed extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.red,
    );
  }
}

class WidgetBlue extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      color: Colors.blue[900],
    );
  }
}