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