在BottomNavigationBar上更改选项卡时禁用重建页面

import 'package:flutter/material.dart';

class BottomNavigationBarPage extends StatefulWidget {
  @override
  _BottomNavigationBarPageState createState() => _BottomNavigationBarPageState();
}

class _BottomNavigationBarPageState extends State<BottomNavigationBarPage> {
  int currentIndex = 0;

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Bottom Navigation Bar'),
      ),
      body: IndexedStack(
        index: currentIndex,
        children: [
          // 页面1
          Container(
            child: Center(
              child: Text('Page 1'),
            ),
          ),
          // 页面2
          Container(
            child: Center(
              child: Text('Page 2'),
            ),
          ),
          // 页面3
          Container(
            child: Center(
              child: Text('Page 3'),
            ),
          ),
        ],
      ),
      bottomNavigationBar: BottomNavigationBar(
        currentIndex: currentIndex,
        onTap: _onItemTapped,
        items: [
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: 'Page 1',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.search),
            label: 'Page 2',
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.person),
            label: 'Page 3',
          ),
        ],
      ),
    );
  }
}