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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.
104 lines
3.5 KiB
Dart
104 lines
3.5 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/stateful_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 NavigationRail
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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 a [NavigationRail] used within a Scaffold with 3
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// [NavigationRailDestination]s. The main content is separated by a divider
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// (although elevation on the navigation rail can be used instead). The
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// `_selectedIndex` is updated by the `onDestinationSelected` callback.
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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: MyStatefulWidget(),
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);
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}
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}
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/// This is the stateful widget that the main application instantiates.
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class MyStatefulWidget extends StatefulWidget {
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const MyStatefulWidget({Key? key}) : super(key: key);
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@override
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State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
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}
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/// This is the private State class that goes with MyStatefulWidget.
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class _MyStatefulWidgetState extends State<MyStatefulWidget> {
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//********************************************************************
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//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
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int _selectedIndex = 0;
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@override
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Widget build(BuildContext context) {
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return Scaffold(
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body: Row(
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children: <Widget>[
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NavigationRail(
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selectedIndex: _selectedIndex,
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onDestinationSelected: (int index) {
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setState(() {
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_selectedIndex = index;
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});
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},
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labelType: NavigationRailLabelType.selected,
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destinations: const <NavigationRailDestination>[
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NavigationRailDestination(
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icon: Icon(Icons.favorite_border),
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selectedIcon: Icon(Icons.favorite),
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label: Text('First'),
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),
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NavigationRailDestination(
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icon: Icon(Icons.bookmark_border),
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selectedIcon: Icon(Icons.book),
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label: Text('Second'),
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),
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NavigationRailDestination(
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icon: Icon(Icons.star_border),
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selectedIcon: Icon(Icons.star),
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label: Text('Third'),
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),
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],
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),
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const VerticalDivider(thickness: 1, width: 1),
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// This is the main content.
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Expanded(
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child: Center(
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child: Text('selectedIndex: $_selectedIndex'),
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),
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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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