import 'package:flutter/material.dart'; import 'tabs/Home.dart'; import 'tabs/Setting.dart'; import 'tabs/Category.dart';
class Tabs extends StatefulWidget {   Tabs({Key? key}) : super(key: key);
  @override   _TabsState createState() => _TabsState(); }
class _TabsState extends State<Tabs> {   int _currentIndex = 0;
  List _pageList = [     HomePage(),     CategoryPage(),     SeetingPage(),   ];   @override   Widget build(BuildContext context) {     return Scaffold(       appBar: AppBar(title: Text("flutter  Demo")),       body: this._pageList[this._currentIndex],       bottomNavigationBar: BottomNavigationBar(         currentIndex: this._currentIndex, // 配置选中的索引         onTap: (int index) {           print(index);           setState(() {             this._currentIndex = index;           });         },         iconSize: 36.0, // 设置图标大小         fixedColor: Colors.red, // 选中的颜色         type: BottomNavigationBarType.fixed, // 配置底部tabs 可以有多个按钮         items: [           BottomNavigationBarItem(             icon: Icon(Icons.home),             title: Text("首页"),           ),           BottomNavigationBarItem(             icon: Icon(Icons.category),             title: Text("分类"),           ),           BottomNavigationBarItem(             icon: Icon(Icons.settings),             title: Text("设置"),           ),         ],       ),     );   } } ---------------- import 'package:flutter/material.dart';
class HomePage extends StatefulWidget {   HomePage({Key? key}) : super(key: key);
  @override   _HomePageState createState() => _HomePageState(); }
class _HomePageState extends State<HomePage> {   @override   Widget build(BuildContext context) {     return Container(       child: Text("我是首页组件"),     );   } }