在 Flutter 中使用 NavigationRail 和 BottomNavigationBar

在Flutter中，你可以创建一个使用NavigationRail和BottomNavigationBar的应用，其中NavigationRail用于侧边导航，而BottomNavigationBar用于底部导航。以下是一个简单的示例代码：

import 'package:flutter/material.dart';
 
void main() => runApp(MyApp());
 
class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: HomePage(),
    );
  }
}
 
class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}
 
class _HomePageState extends State<HomePage> {
  int _selectedIndex = 0;
 
  void _onItemTapped(int index) {
    setState(() {
      _selectedIndex = index;
    });
  }
 
  List<Widget> _buildPages() {
    return [
      Icon(Icons.home),
      Icon(Icons.favorite),
      Icon(Icons.shopping_cart),
      Icon(Icons.person),
    ];
  }
 
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: NavigationRail(
        selectedIndex: _selectedIndex,
        onDestinationSelected: _onItemTapped,
        leading: NavigationRailLogo(),
        destinations: [
          NavigationRailDestination(
            icon: Icon(Icons.home),
            label: Text('Home'),
          ),
          NavigationRailDestination(
            icon: Icon(Icons.favorite),
            label: Text('Favorites'),
          ),
          NavigationRailDestination(
            icon: Icon(Icons.shopping_cart),
            label: Text('Cart'),
          ),
          NavigationRailDestination(
            icon: Icon(Icons.person),
            label: Text('Profile'),
          ),
        ],
        body: const Text('Select a destination'),
      ),
      bottomNavigationBar: BottomNavigationBar(
        selectedItemColor: Colors.blue,
        unselectedItemColor: Colors.grey,
        selectedIconTheme: IconThemeData(size: 24),
        unselectedIconTheme: IconThemeData(size: 22),
        items: [
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: 'Home',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.favorite),
            label: 'Favorites',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.shopping_cart),
            label: 'Cart',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.perso