Flutter:更改背景颜色抽屉菜单而不更改颜色appbar

import 'package:flutter/material.dart';

class MyApp extends StatefulWidget {
  @override
  _MyAppState createState() => _MyAppState();
}

class _MyAppState extends State<MyApp> {
  Color drawerBackgroundColor = Colors.blue; // 设置初始背景颜色为蓝色
  // ...
}

@override
Widget build(BuildContext context) {
  return MaterialApp(
    home: Scaffold(
      appBar: AppBar(
        title: Text('Flutter App'),
      ),
      drawer: Drawer(
        child: Container(
          color: drawerBackgroundColor, // 设置抽屉菜单的背景颜色
          // ...
        ),
      ),
      // ...
    ),
  );
}

FlatButton(
  onPressed: () {
    setState(() {
      drawerBackgroundColor = Colors.red; // 点击按钮后将背景颜色更改为红色
    });
  },
  child: Text('更改背景颜色'),
),