将Flutter BottomNavigationBar视为单独文件中的子小部件时，无法单击

import 'package:flutter/material.dart';

class MyBottomNavigationBar extends StatefulWidget {
  @override
  _MyBottomNavigationBarState createState() => _MyBottomNavigationBarState();
}

class _MyBottomNavigationBarState extends State<MyBottomNavigationBar> {
  int _currentIndex = 0;

  void _onItemTapped(int index) {
    setState(() {
      _currentIndex = index;
    });

    // 执行相应的操作，例如切换页面或更新数据
    // ...
  }

  @override
  Widget build(BuildContext context) {
    return BottomNavigationBar(
      currentIndex: _currentIndex,
      onTap: _onItemTapped,
      items: [
        BottomNavigationBarItem(
          icon: Icon(Icons.home),
          label: 'Home',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.search),
          label: 'Search',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.person),
          label: 'Profile',
        ),
      ],
    );
  }
}

import 'package:flutter/material.dart';
import 'package:your_app/my_bottom_navigation_bar.dart';

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('My App'),
      ),
      body: Center(
        child: Text('Hello, World!'),
      ),
      bottomNavigationBar: MyBottomNavigationBar(),
    );
  }
}