如何像TabBar一样改变IconButton的颜色？

import 'package:flutter/material.dart';

class CustomTabBar extends StatefulWidget {
  @override
  _CustomTabBarState createState() => _CustomTabBarState();
}

class _CustomTabBarState extends State<CustomTabBar> {
  int _selectedIndex = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Custom Tab Bar'),
      ),
      body: Center(
        child: Text('Content of tab ${_selectedIndex + 1}'),
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: _selectedIndex,
        onTap: (index) {
          setState(() {
            _selectedIndex = index;
          });
        },
        items: [
          BottomNavigationBarItem(
            icon: IconButton(
              icon: Icon(Icons.home),
              color: _selectedIndex == 0 ? Colors.blue : Colors.grey,
              onPressed: () {},
            ),
            label: 'Home',
          ),
          BottomNavigationBarItem(
            icon: IconButton(
              icon: Icon(Icons.search),
              color: _selectedIndex == 1 ? Colors.blue : Colors.grey,
              onPressed: () {},
            ),
            label: 'Search',
          ),
          BottomNavigationBarItem(
            icon: IconButton(
              icon: Icon(Icons.person),
              color: _selectedIndex == 2 ? Colors.blue : Colors.grey,
              onPressed: () {},
            ),
            label: 'Profile',
          ),
        ],
      ),
    );
  }
}

void main() {
  runApp(MaterialApp(
    home: CustomTabBar(),
  ));
}