Drawerはアプリの左端または右端からスライドアウトするナビゲーションメニューです。
import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: const MyHomePage(title: 'Flutter Demo Home Page'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  const MyHomePage({Key? key, required this.title}) : super(key: key);

  final String title;

  @override
  State<MyHomePage> createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage> {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Drawer Demo'),
      ),
      drawer: Drawer(
        child: ListView(
          padding: EdgeInsets.zero,
          children: const <Widget>[
            DrawerHeader(
              decoration: BoxDecoration(
                color: Colors.blue,
              ),
              child: Text(
                'Drawer Header',
                style: TextStyle(
                  color: Colors.white,
                  fontSize: 24,
                ),
              ),
            ),
            ListTile(
              leading: Icon(Icons.message),
              title: Text('Messages'),
            ),
            ListTile(
              leading: Icon(Icons.account_circle),
              title: Text('Profile'),
            ),
            ListTile(
              leading: Icon(Icons.settings),
              title: Text('Settings'),
            ),
          ],
        ),
      ),
    );
}