Flutter_学习记录_Tab的简单Demo~真的很简单

1. Tab的简单使用了解

要实现tab(选项卡或者标签视图)需要用到三个组件：

• TabBar
• TabBarView
• TabController

这一块，我也不知道怎么整理了，直接提供代码吧：

import 'package:flutter/material.dart';void main() {runApp(MyApp());
}class MyApp extends StatelessWidget {const MyApp({super.key});@overrideWidget build(BuildContext context) {return  MaterialApp(debugShowCheckedModeBanner: true,home: Home(),theme: ThemeData(appBarTheme: AppBarTheme(backgroundColor: Colors.yellow, // 设置导航栏颜色为蓝色)),);}
}class Home extends StatelessWidget {const Home({super.key});@overrideWidget build(BuildContext context) {return DefaultTabController(length: 3, child: Scaffold(appBar: AppBar(leading: IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.menu),tooltip: "Navigation",),actions: [IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.search),tooltip: "search",)],title: Text("App Demo"),elevation: 0.0,bottom: TabBar(unselectedLabelColor: Colors.black38,indicatorColor: Colors.black54,indicatorSize: TabBarIndicatorSize.label,indicatorWeight: 1.0,tabs: [Tab(icon: Icon(Icons.local_florist)),Tab(icon: Icon(Icons.change_history)),Tab(icon: Icon(Icons.directions_bike)),]),),body: TabBarView(children: [Icon(Icons.local_florist, size: 128.0, color: Colors.black12),Icon(Icons.change_history, size: 128.0, color: Colors.black12),Icon(Icons.directions_bike, size: 128.0, color: Colors.black12),]),));}
}

效果图如下:

2. Drawer 侧边栏简单使用

在手势在屏幕进行左滑手势时，可以通过设置drawer属性，来实现侧边栏显示的效果。

侧边栏代码的实现如下（为了避免代码太长，新建一个实现Drawer视图的文件）：

import 'package:flutter/material.dart';class DrawerDemo extends StatelessWidget {const DrawerDemo({super.key});@overrideWidget build(BuildContext context) {return Drawer(child: ListView(padding: EdgeInsets.zero,children: [// DrawerHeader(//   decoration: BoxDecoration(//     color: Colors.greenAccent//   ),//   child: Text("Header".toUpperCase()),// ),UserAccountsDrawerHeader(accountName: Text("zhuzhu", style: TextStyle(fontWeight: FontWeight.bold, color: Colors.black)), accountEmail: Text("[e-mail]", style: TextStyle(color: Colors.black),),currentAccountPicture: CircleAvatar(backgroundImage: NetworkImage("https://img1.baidu.com/it/u=1368815763,3761060632&fm=253&fmt=auto&app=138&f=JPEG?w=760&h=434"),),decoration: BoxDecoration(image: DecorationImage(image: NetworkImage("https://i-blog.csdnimg.cn/blog_migrate/41635df939e6dd13c6d5e2af785d358b.jpeg"),fit: BoxFit.cover,colorFilter: ColorFilter.mode(Colors.yellow.withAlpha(150), BlendMode.srcOver))),),ListTile(title: Text("Message", textAlign: TextAlign.right),trailing: Icon(Icons.message, color: Colors.black12, size: 22.0),onTap: () => Navigator.pop(context), // 关闭抽屉),ListTile(title: Text("Favorite", textAlign: TextAlign.right),trailing: Icon(Icons.favorite, color: Colors.black12, size: 22.0),onTap: () => Navigator.pop(context), // 关闭抽屉),ListTile(title: Text("Settings", textAlign: TextAlign.right),trailing: Icon(Icons.settings, color: Colors.black12, size: 22.0),onTap: () => Navigator.pop(context), // 关闭抽屉),],),);}
}

然后将DrawerDemo 添加到drawer属性里，代码如下：

import 'package:flutter/material.dart';
import 'Demo/Drawer_demo.dart'; // 导入DrawerDemo所在的文件void main() {runApp(MyApp());
}class MyApp extends StatelessWidget {const MyApp({super.key});@overrideWidget build(BuildContext context) {return  MaterialApp(debugShowCheckedModeBanner: true,home: Home(),theme: ThemeData(appBarTheme: AppBarTheme(backgroundColor: Colors.yellow, // 设置导航栏颜色为蓝色)),);}
}class Home extends StatelessWidget {const Home({super.key});@overrideWidget build(BuildContext context) {return DefaultTabController(length: 3, child: Scaffold(appBar: AppBar(leading: IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.menu),tooltip: "Navigation",),actions: [IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.search),tooltip: "search",)],title: Text("App Demo"),elevation: 0.0,bottom: TabBar(unselectedLabelColor: Colors.black38,indicatorColor: Colors.black54,indicatorSize: TabBarIndicatorSize.label,indicatorWeight: 1.0,tabs: [Tab(icon: Icon(Icons.local_florist)),Tab(icon: Icon(Icons.change_history)),Tab(icon: Icon(Icons.directions_bike)),]),),body: TabBarView(children: [Icon(Icons.local_florist, size: 128.0, color: Colors.black12),Icon(Icons.change_history, size: 128.0, color: Colors.black12),Icon(Icons.directions_bike, size: 128.0, color: Colors.black12),]),// 添加侧边栏， 用扫动的手势来显示这个侧边栏drawer: DrawerDemo()));}
}

效果如下：

3. 底部导航栏的添加

底部导航栏的添加，可以通过属性bottomNavigationBar来设置，实现它需要用到这两个组件：

• BottomNavigationBar
• BottomNavigationBarItem

之前页面都是静态页面，创建的类也都是继承于StatelessWidget，但是点击tabbar需要根据点击改变状态，所以，就需要用新的组件StatefulWidget。这一次就先只记录怎么使用，后面有时间把这个控件的说明再补充上。

根据前面的代码，抽取出一些代码，并创建以下三个类：

• ExploreDemo

import 'package:flutter/material.dart';
import 'ListView_demo.dart';
import 'Drawer_demo.dart';class  ExploreDemo extends StatelessWidget {@overrideWidget build(BuildContext context) {return DefaultTabController(length: 3, child: Scaffold(appBar: AppBar(leading: IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.menu),tooltip: "Navigation",),actions: [IconButton(onPressed: () => debugPrint("navigation button is pressed."), icon: Icon(Icons.search),tooltip: "search",)],title: Text("App Demo"),elevation: 0.0,bottom: TabBar(unselectedLabelColor: Colors.black38,indicatorColor: Colors.black54,indicatorSize: TabBarIndicatorSize.label,indicatorWeight: 1.0,tabs: [Tab(icon: Icon(Icons.local_florist)),Tab(icon: Icon(Icons.change_history)),Tab(icon: Icon(Icons.directions_bike)),]),),body: TabBarView(children: [ListViewDemo(),Icon(Icons.change_history, size: 128.0, color: Colors.black12),Icon(Icons.directions_bike, size: 128.0, color: Colors.black12),]),// 添加侧边栏， 用扫动的手势来显示这个侧边栏drawer: DrawerDemo()));}
}

• HistoryDemo

import 'package:flutter/material.dart';class  HistoryDemo extends StatelessWidget {@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text("历史记录")),body: Container(child: Center(child: Text("历史记录"),),));}
}

• MyviewDemo

import 'package:flutter/material.dart';class  MyviewDemo extends StatelessWidget {@overrideWidget build(BuildContext context) {return Scaffold(appBar: AppBar(title: Text("个人主页")),body: Container(child: Center(child: Text("个人主页"),),));}
}

基础工作做好后，在main.dart 文件中，实现如下代码：

import 'package:flutter/material.dart';
import 'Demo/Explore_demo.dart';
import 'Demo/History_demo.dart';
import 'Demo/MyView_demo.dart';void main() {runApp(MyApp());
}class MyApp extends StatelessWidget {const MyApp({super.key});@overrideWidget build(BuildContext context) {return  MaterialApp(debugShowCheckedModeBanner: true,home: Home(),theme: ThemeData(appBarTheme: AppBarTheme(backgroundColor: Colors.yellow, // 设置导航栏颜色为蓝色)),);}
}class Home extends StatefulWidget {const Home({super.key});@overrideState<StatefulWidget> createState() {return _HomeState();}
}class _HomeState extends State<Home> {int _currentPageIndex = 0;// 提前创建3个视图，当点击tabbar的时候，调用setState的index来去对应的页面final List<Widget> pageLists = [ExploreDemo(),HistoryDemo(),MyviewDemo()];void _onTapHandler (int index) {// 更新状态setState(() {_currentPageIndex = index;});}@overrideWidget build(BuildContext context) {return Scaffold(// 根据_currentPageIndex展示视图body: pageLists[_currentPageIndex],// 设置底部tabbarbottomNavigationBar: BottomNavigationBar(currentIndex: _currentPageIndex,onTap: _onTapHandler,type: BottomNavigationBarType.fixed,fixedColor: Colors.black,items: [BottomNavigationBarItem(icon: Icon(Icons.explore),label: "explore"),BottomNavigationBarItem(icon: Icon(Icons.history),label: "history"),BottomNavigationBarItem(icon: Icon(Icons.person),label: "My"),]));}
}

效果图如下：