flutter_app_android/lib/presentation/navigation/bottom_nav_bar.dart

import 'package:flutter/material.dart';
import '../../core/constants/route_constants.dart';

class BottomNavBar extends StatefulWidget {
  final int initialIndex;
  
  const BottomNavBar({
    super.key,
    this.initialIndex = 0,
  });
  
  @override
  State<BottomNavBar> createState() => _BottomNavBarState();
}

class _BottomNavBarState extends State<BottomNavBar> {
  int _selectedIndex = 0;
  
  @override
  void initState() {
    super.initState();
    _selectedIndex = widget.initialIndex;
  }
  
  void _onItemTapped(int index) {
    
    setState(() {
      _selectedIndex = index;
    });
    
    switch (index) {
      case 0:
        if (ModalRoute.of(context)?.settings.name != RouteConstants.home) {
          Navigator.of(context).pushReplacementNamed(RouteConstants.home);
        }
        break;
      case 1:
        if (ModalRoute.of(context)?.settings.name != RouteConstants.news) {
          Navigator.of(context).pushReplacementNamed(RouteConstants.news);
        }
        break;
      case 2:
        if (ModalRoute.of(context)?.settings.name != RouteConstants.services) {
          Navigator.of(context).pushReplacementNamed(RouteConstants.services);
        }
        break;
      case 3:
        if (ModalRoute.of(context)?.settings.name != RouteConstants.profile) {
          Navigator.of(context).pushReplacementNamed(RouteConstants.profile);
        }
        break;
    }
  }
  
  @override
  Widget build(BuildContext context) {
    return BottomNavigationBar(
      items: const [
        BottomNavigationBarItem(
          icon: Icon(Icons.home_outlined),
          activeIcon: Icon(Icons.home),
          label: '首页',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.newspaper_outlined),
          activeIcon: Icon(Icons.newspaper),
          label: '推荐',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.work_outline),
          activeIcon: Icon(Icons.work),
          label: '服务',
        ),
        BottomNavigationBarItem(
          icon: Icon(Icons.person_outline),
          activeIcon: Icon(Icons.person),
          label: '我的',
        ),
      ],
      currentIndex: _selectedIndex,
      selectedItemColor: Theme.of(context).primaryColor,
      unselectedItemColor: Colors.grey,
      showUnselectedLabels: true,
      type: BottomNavigationBarType.fixed,
      onTap: _onItemTapped,
    );
  }
}