[Flutter] 使用 SingleChildScrollView 製作可滑動的 Widget

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

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

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

// HomePage
class HomePage extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("SingleChildScrollView Demo"),
      ),
      body: Column(
        children: <Widget>[

          // Upper component
          // ========================================================
          Expanded(
            child: Container(
              alignment: Alignment.center,
              width: MediaQuery.of(context).size.width,
              color: Colors.grey,
              child: Text("Upper component"),
            ),
            flex: 1,
          ),
          // ========================================================

          // SingleChildScrollView
          // ========================================================
          Expanded(
            child: SingleChildScrollView(
              child: Column(
                children: List.generate(20, (index) {
                  return ElevatedButton(
                    child: Text("Button ${index+1}"),
                    onPressed: () => Null,
                  );
                }),
              ),
            ),
            flex: 1,
          ),
          // ========================================================

          // Lower component
          // ========================================================
          Expanded(
            child: Container(
              alignment: Alignment.center,
              width: MediaQuery.of(context).size.width,
              color: Colors.grey,
              child: Text("Lower component"),
            ),
            flex: 1,
          ),
          // ========================================================
        ],
      )
    );
  }
}