如何在Flutter中不在所有屏幕上添加底部导航？

import 'package:flutter/material.dart';

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int currentIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('App Title'),
      ),
      body: IndexedStack(
        index: currentIndex,
        children: <Widget>[
          // 第一个屏幕页面
          if (currentIndex != 0) FirstScreen(),
          // 第二个屏幕页面
          if (currentIndex != 1) SecondScreen(),
          // 其他屏幕页面...
        ],
      ),
      bottomNavigationBar: buildBottomNavigationBar(),
    );
  }

  Widget buildBottomNavigationBar() {
    return BottomNavigationBar(
      currentIndex: currentIndex,
      onTap: (index) {
        setState(() {
          currentIndex = index;
        });
      },
      items: [
        BottomNavigationBarItem(
          icon: Icon(Icons.home),
          label: 'Home',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.settings),
          label: 'Settings',
        ),
      ],
    );
  }
}

class FirstScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('First Screen'),
    );
  }
}

class SecondScreen extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Container(
      child: Text('Second Screen'),
    );
  }
}

// 其他屏幕页面...