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