flutter/examples/api/lib/material/navigation_rail/navigation_rail.0.dart

// 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.

import 'package:flutter/material.dart';

/// Flutter code sample for [NavigationRail].

void main() => runApp(const NavigationRailExampleApp());

class NavigationRailExampleApp extends StatelessWidget {
  const NavigationRailExampleApp({super.key});

  @override
  Widget build(BuildContext context) {
    return const MaterialApp(home: NavRailExample());
  }
}

class NavRailExample extends StatefulWidget {
  const NavRailExample({super.key});

  @override
  State<NavRailExample> createState() => _NavRailExampleState();
}

class _NavRailExampleState extends State<NavRailExample> {
  int _selectedIndex = 0;
  NavigationRailLabelType labelType = NavigationRailLabelType.all;
  bool showLeading = false;
  bool showTrailing = false;
  double groupAlignment = -1.0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SafeArea(
        child: Row(
          children: <Widget>[
            NavigationRail(
              selectedIndex: _selectedIndex,
              groupAlignment: groupAlignment,
              onDestinationSelected: (int index) {
                setState(() {
                  _selectedIndex = index;
                });
              },
              labelType: labelType,
              leading:
                  showLeading
                      ? FloatingActionButton(
                        elevation: 0,
                        onPressed: () {
                          // Add your onPressed code here!
                        },
                        child: const Icon(Icons.add),
                      )
                      : const SizedBox(),
              trailing:
                  showTrailing
                      ? IconButton(
                        onPressed: () {
                          // Add your onPressed code here!
                        },
                        icon: const Icon(Icons.more_horiz_rounded),
                      )
                      : const SizedBox(),
              destinations: const <NavigationRailDestination>[
                NavigationRailDestination(
                  icon: Icon(Icons.favorite_border),
                  selectedIcon: Icon(Icons.favorite),
                  label: Text('First'),
                ),
                NavigationRailDestination(
                  icon: Badge(child: Icon(Icons.bookmark_border)),
                  selectedIcon: Badge(child: Icon(Icons.book)),
                  label: Text('Second'),
                ),
                NavigationRailDestination(
                  icon: Badge(label: Text('4'), child: Icon(Icons.star_border)),
                  selectedIcon: Badge(label: Text('4'), child: Icon(Icons.star)),
                  label: Text('Third'),
                ),
              ],
            ),
            const VerticalDivider(thickness: 1, width: 1),
            // This is the main content.
            Expanded(
              child: Column(
                mainAxisAlignment: MainAxisAlignment.center,
                children: <Widget>[
                  Text('selectedIndex: $_selectedIndex'),
                  const SizedBox(height: 20),
                  Text('Label type: ${labelType.name}'),
                  const SizedBox(height: 10),
                  SegmentedButton<NavigationRailLabelType>(
                    segments: const <ButtonSegment<NavigationRailLabelType>>[
                      ButtonSegment<NavigationRailLabelType>(
                        value: NavigationRailLabelType.none,
                        label: Text('None'),
                      ),
                      ButtonSegment<NavigationRailLabelType>(
                        value: NavigationRailLabelType.selected,
                        label: Text('Selected'),
                      ),
                      ButtonSegment<NavigationRailLabelType>(
                        value: NavigationRailLabelType.all,
                        label: Text('All'),
                      ),
                    ],
                    selected: <NavigationRailLabelType>{labelType},
                    onSelectionChanged: (Set<NavigationRailLabelType> newSelection) {
                      setState(() {
                        labelType = newSelection.first;
                      });
                    },
                  ),
                  const SizedBox(height: 20),
                  Text('Group alignment: $groupAlignment'),
                  const SizedBox(height: 10),
                  SegmentedButton<double>(
                    segments: const <ButtonSegment<double>>[
                      ButtonSegment<double>(value: -1.0, label: Text('Top')),
                      ButtonSegment<double>(value: 0.0, label: Text('Center')),
                      ButtonSegment<double>(value: 1.0, label: Text('Bottom')),
                    ],
                    selected: <double>{groupAlignment},
                    onSelectionChanged: (Set<double> newSelection) {
                      setState(() {
                        groupAlignment = newSelection.first;
                      });
                    },
                  ),
                  const SizedBox(height: 20),
                  SwitchListTile(
                    title: Text(showLeading ? 'Hide Leading' : 'Show Leading'),
                    value: showLeading,
                    onChanged: (bool value) {
                      setState(() {
                        showLeading = value;
                      });
                    },
                  ),
                  SwitchListTile(
                    title: Text(showTrailing ? 'Hide Trailing' : 'Show Trailing'),
                    value: showTrailing,
                    onChanged: (bool value) {
                      setState(() {
                        showTrailing = value;
                      });
                    },
                  ),
                ],
              ),
            ),
          ],
        ),
      ),
    );
  }
}