| // Copyright 2014 The Flutter Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| // Template: dev/snippets/config/templates/stateless_widget_material.tmpl |
| // |
| // Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring |
| // of samples, and may be ignored if you are just exploring the sample. |
| |
| // Flutter code sample for TabController |
| // |
| //*************************************************************************** |
| //* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| // This example shows how to listen to page updates in [TabBar] and [TabBarView] |
| // when using [DefaultTabController]. |
| |
| //* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //*************************************************************************** |
| |
| import 'package:flutter/material.dart'; |
| |
| void main() => runApp(const MyApp()); |
| |
| /// This is the main application widget. |
| class MyApp extends StatelessWidget { |
| const MyApp({Key? key}) : super(key: key); |
| |
| static const String _title = 'Flutter Code Sample'; |
| |
| @override |
| Widget build(BuildContext context) { |
| return const MaterialApp( |
| title: _title, |
| home: MyStatelessWidget(), |
| ); |
| } |
| } |
| |
| //***************************************************************************** |
| //* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| const List<Tab> tabs = <Tab>[ |
| Tab(text: 'Zeroth'), |
| Tab(text: 'First'), |
| Tab(text: 'Second'), |
| ]; |
| |
| //* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //***************************************************************************** |
| |
| /// This is the stateless widget that the main application instantiates. |
| class MyStatelessWidget extends StatelessWidget { |
| const MyStatelessWidget({Key? key}) : super(key: key); |
| |
| @override |
| //******************************************************************** |
| //* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker) |
| |
| Widget build(BuildContext context) { |
| return DefaultTabController( |
| length: tabs.length, |
| // The Builder widget is used to have a different BuildContext to access |
| // closest DefaultTabController. |
| child: Builder(builder: (BuildContext context) { |
| final TabController tabController = DefaultTabController.of(context)!; |
| tabController.addListener(() { |
| if (!tabController.indexIsChanging) { |
| // Your code goes here. |
| // To get index of current tab use tabController.index |
| } |
| }); |
| return Scaffold( |
| appBar: AppBar( |
| bottom: const TabBar( |
| tabs: tabs, |
| ), |
| ), |
| body: TabBarView( |
| children: tabs.map((Tab tab) { |
| return Center( |
| child: Text( |
| '${tab.text!} Tab', |
| style: Theme.of(context).textTheme.headline5, |
| ), |
| ); |
| }).toList(), |
| ), |
| ); |
| }), |
| ); |
| } |
| |
| //* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker) |
| //******************************************************************** |
| |
| } |