TabBar和TabBarView实现顶部滑动导航

 home.dart子页面主要代码：

import 'package:flutter/material.dart';

class HomePage extends StatefulWidget {
  const HomePage({super.key});

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage>
    with SingleTickerProviderStateMixin {
  late TabController _tabController;

  //生命周期函数：初始化时触发
  @override
  void initState() {
    super.initState();
    _tabController = TabController(length: 9, vsync: this);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        //背景颜色
        backgroundColor: Colors.white,
        //阴影高度
        elevation: 0,
        title: TabBar(
          //是否可滚动
          isScrollable: true,
          controller: _tabController,
          //指示器高度
          indicatorWeight: 1,
          //指示器边距
          // indicatorPadding: const EdgeInsets.all(2),
          //选中字体颜色
          labelColor: Colors.white,
          //未选中字体颜色
          unselectedLabelColor: Colors.grey,
          //指示器宽度，默认tab:撑满选项卡宽度; label:宽度跟随内容，不撑满选项卡
          // indicatorSize: TabBarIndicatorSize.label,
          //指示器颜色
          // indicatorColor: Colors.white,
          //指示器Decoration
          indicator: BoxDecoration(
            color: Colors.blue,
            borderRadius: BorderRadius.circular(10),
          ),
          //选中label样式
          labelStyle: const TextStyle(fontSize: 15),
          //未选中label样式
          unselectedLabelStyle: const TextStyle(fontSize: 14),
          tabs: const [
            Tab(
              child: Text("关注"),
            ),
            Tab(
              child: Text("热门"),
            ),
            Tab(
              child: Text("视频"),
            ),
            Tab(
              child: Text("关注"),
            ),
            Tab(
              child: Text("热门"),
            ),
            Tab(
              child: Text("视频"),
            ),
            Tab(
              child: Text("关注"),
            ),
            Tab(
              child: Text("热门"),
            ),
            Tab(
              child: Text("视频"),
            ),
          ],
        ),
      ),
      body: TabBarView(
        controller: _tabController,
        children: const [
          Center(
            child: Text("关注"),
          ),
          Center(
            child: Text("热门"),
          ),
          Center(
            child: Text("视频"),
          ),
          Center(
            child: Text("关注"),
          ),
          Center(
            child: Text("热门"),
          ),
          Center(
            child: Text("视频"),
          ),
          Center(
            child: Text("关注"),
          ),
          Center(
            child: Text("热门"),
          ),
          Center(
            child: Text("视频"),
          ),
        ],
      ),
    );
  }
}

首先需要with SingleTickerProviderStateMixin方法，然后initState生命周期函数中设置Tab长度，最后在Scaffold中设置TabBar和TabBarView。

appBar高度设置：

appBar: PreferredSize(
  //appBar高度设置
  preferredSize: const Size.fromHeight(40),
  child: AppBar(
    //背景颜色
    backgroundColor: Colors.transparent,
    //阴影高度
    elevation: 0,
    title: TabBar(
      //是否可滚动
      isScrollable: true,
      controller: _tabController,
      //指示器高度
      // indicatorWeight: 1,
      //指示器边距
      indicatorPadding: const EdgeInsets.all(5),
      //选中字体颜色
      labelColor: Colors.red,
      //指示器颜色
      indicatorColor: Colors.red,
      //指示器Decoration
      /* indicator: BoxDecoration(
        color: Colors.blue,
        borderRadius: BorderRadius.circular(10),
      ),*/
      //未选中字体颜色
      unselectedLabelColor: Colors.black,
      //指示器宽度，默认tab:撑满选项卡宽度; label:宽度跟随内容，不撑满选项卡
      indicatorSize: TabBarIndicatorSize.label,
      //选中label样式
      labelStyle: const TextStyle(fontSize: 15),
      //未选中label样式
      unselectedLabelStyle: const TextStyle(fontSize: 15),
      //只监听点击事件，多次点击同一个tab且每次都会监听
      /*onTap: (index) {
        print(index);
      },*/
      tabs: const [
        Tab(
          child: Text("关注"),
        ),
        Tab(
          child: Text("热门"),
        ),
        Tab(
          child: Text("视频"),
        ),
        Tab(
          child: Text("关注"),
        ),
        Tab(
          child: Text("热门"),
        ),
        Tab(
          child: Text("视频"),
        ),
        Tab(
          child: Text("关注"),
        ),
        Tab(
          child: Text("热门"),
        ),
        Tab(
          child: Text("视频"),
        ),
      ],
    ),
  ),
),

AppBar外嵌套PreferredSize组件，PreferredSize组件中通过preferredSize: const Size.fromHeight(40),属性设置AppBar的高度。

onTap属性只监听点击事件，多次点击同一个tab且每次都会监听。

TabController监听事件：

@override
void initState() {
  super.initState();
  _tabController = TabController(length: 9, vsync: this);
  //监听_tabController事件的改变(滑动和点击都会监听，且同一tab多次点击只监听一次)
  _tabController.addListener(() {
    if (_tabController.animation?.value == _tabController.index) {
      print(_tabController.index);
    }
  });
}

///生命周期函数，组件销毁时触发
@override
void dispose() {
  super.dispose();
  _tabController.dispose();
}

TabController滑动和点击都会监听，且同一tab多次点击只监听一次。

dispose()为生命周期销毁函数。

TabBar下的主要属性代码中已注释，更多属性请参考源码：

const TabBar({
    super.key,
    required this.tabs,
    this.controller,
    this.isScrollable = false,
    this.padding,
    this.indicatorColor,
    this.automaticIndicatorColorAdjustment = true,
    this.indicatorWeight = 2.0,
    this.indicatorPadding = EdgeInsets.zero,
    this.indicator,
    this.indicatorSize,
    this.dividerColor,
    this.labelColor,
    this.labelStyle,
    this.labelPadding,
    this.unselectedLabelColor,
    this.unselectedLabelStyle,
    this.dragStartBehavior = DragStartBehavior.start,
    this.overlayColor,
    this.mouseCursor,
    this.enableFeedback,
    this.onTap,
    this.physics,
    this.splashFactory,
    this.splashBorderRadius,
  }) : _isPrimary = true,
       assert(indicator != null || (indicatorWeight > 0.0));

main.dart首页代码：

import 'package:flutter/material.dart';
import 'package:flutter_demo/tabs/category.dart';
import 'package:flutter_demo/tabs/home.dart';
import 'package:flutter_demo/tabs/people.dart';
import 'package:flutter_demo/tabs/setting.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      //隐藏DEBUG图标
      debugShowCheckedModeBanner: false,
      theme: ThemeData(primarySwatch: Colors.blue),
      home: const Scaffold(
        body: MyHomePage(),
      ),
    );
  }
}

class MyHomePage extends StatelessWidget {
  const MyHomePage({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return const Tabs();
  }
}

class Tabs extends StatefulWidget {
  const Tabs({super.key});

  @override
  State<Tabs> createState() => _TabsState();
}

class _TabsState extends State<Tabs> {
  int currentIndex = 0;

  List<Widget> pages = const [
    HomePage(),
    CategoryPage(),
    SettingPage(),
    PeoplePage()
  ];

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text("Flutter"),
      ),
      body: pages[currentIndex],
      drawer: const Drawer(
        child: Column(
          children: [
            Row(
              children: [
                Expanded(
                  flex: 1,
                  child: UserAccountsDrawerHeader(
                    accountName: Text("张三"),
                    accountEmail: Text("[email protected]"),
                    currentAccountPicture: CircleAvatar(
                      backgroundImage: NetworkImage(
                          "https://www.itying.com/images/flutter/1.png"),
                    ),
                    decoration: BoxDecoration(
                      image: DecorationImage(
                        image: NetworkImage(
                            "https://www.itying.com/images/flutter/2.png"),
                        fit: BoxFit.cover,
                      ),
                    ),
                  ),
                ),
              ],
            ),
            ListTile(
              leading: CircleAvatar(
                child: Icon(
                  Icons.people,
                ),
              ),
              title: Text("个人中心"),
            ),
            Divider(),
            ListTile(
              leading: CircleAvatar(
                child: Icon(
                  Icons.settings,
                ),
              ),
              title: Text("系统设置"),
            )
          ],
        ),
      ),
      bottomNavigationBar: BottomNavigationBar(
        //选中菜单颜色
        fixedColor: Colors.blue,
        //图标大小，默认24.0
        iconSize: 30,
        //第几个菜单选中
        currentIndex: currentIndex,
        //当item数量大于3个时需要设置type属性
        type: BottomNavigationBarType.fixed,
        unselectedItemColor: Colors.grey.shade600,
        onTap: (index) {
          setState(() {
            currentIndex = index;
          });
        },
        items: const [
          BottomNavigationBarItem(
            icon: Icon(Icons.home),
            label: "首页",
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.category),
            label: "分类",
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.settings),
            label: "设置",
          ),
          BottomNavigationBarItem(
            icon: Icon(Icons.people),
            label: "用户",
          ),
        ],
      ),
    );
  }
}