朋友们，你们好。我像下面这样创建了BottomNavigationBar，但是我想创建一个像底部这样的顶部导航栏，我该怎么做呢？

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('顶部导航栏示例'),
          bottom: TabBar(
            tabs: [
              Tab(icon: Icon(Icons.home), text: '首页'),
              Tab(icon: Icon(Icons.person), text: '个人资料'),
              Tab(icon: Icon(Icons.settings), text: '设置'),
            ],
          ),
        ),
        body: DefaultTabController(
          length: 3,
          child: TabBarView(
            children: [
              Center(child: Text('首页内容')),
              Center(child: Text('个人资料内容')),
              Center(child: Text('设置内容')),
            ],
          ),
        ),
      ),
    );
  }
}