I am trying to make a username generator (using flutter's own codelab) and while I was doing that I wanted to change something. I wanted to make the nav rail expand whenever I hovered on it but it is not working. Here is my code:
import 'package:english_words/english_words.dart';import 'package:flutter/material.dart';import 'package:provider/provider.dart';void main() { runApp(MyApp());}class MyApp extends StatelessWidget { const MyApp({super.key}); @override Widget build(BuildContext context) { return ChangeNotifierProvider( create: (context) => MyAppState(), child: MaterialApp( title: 'Namer App', theme: ThemeData( useMaterial3: true, colorScheme: ColorScheme.fromSeed(seedColor: Colors.blue), ), home: MyHomePage(), ), ); }}class MyAppState extends ChangeNotifier { var current = WordPair.random(); void getNext() { current = WordPair.random(); notifyListeners(); } var favorites = <WordPair>[]; void toggleFavorite() { if (favorites.contains(current)) { favorites.remove(current); } else { favorites.add(current); } notifyListeners(); }}class MyHomePage extends StatefulWidget { @override State<MyHomePage> createState() => _MyHomePageState();}class _MyHomePageState extends State<MyHomePage> { var selectedIndex = 0; @override Widget build(BuildContext context) { Widget page; switch (selectedIndex) { case 0: page = GeneratorPage(); break; case 1: page = Placeholder(); break; default: throw UnimplementedError('no widget for $selectedIndex'); } return LayoutBuilder(builder: (context, constraints) { return Scaffold( body: Row( children: [ SafeArea( child: NavigationRail( extended: constraints.maxWidth >= 600, destinations: [ NavigationRailDestination( icon: Icon(Icons.home), label: Text('Home'), ), NavigationRailDestination( icon: Icon(Icons.favorite), label: Text('Favorites'), ), NavigationRailDestination( icon: Icon(Icons.person), label: Text('Profile'), ), ], selectedIndex: selectedIndex, onDestinationSelected: (value) { setState(() { selectedIndex = value; }); }, ), ), Expanded( child: Container( color: Theme.of(context).colorScheme.primaryContainer, child: page, ), ), ], ), ); }); }}class GeneratorPage extends StatelessWidget { @override Widget build(BuildContext context) { var appState = context.watch<MyAppState>(); var pair = appState.current; IconData icon; if (appState.favorites.contains(pair)) { icon = Icons.favorite; } else { icon = Icons.favorite_border; } return Center( child: Column( mainAxisAlignment: MainAxisAlignment.center, children: [ BigCard(pair: pair), SizedBox(height: 10), Row( mainAxisSize: MainAxisSize.min, children: [ ElevatedButton.icon( onPressed: () { appState.toggleFavorite(); }, icon: Icon(icon), label: Text('Like'), ), SizedBox(width: 10), ElevatedButton( onPressed: () { appState.getNext(); }, child: Text('Next'), ), ], ), ], ), ); }}class BigCard extends StatelessWidget { const BigCard({ super.key, required this.pair, }); final WordPair pair; @override Widget build(BuildContext context) { var theme = Theme.of(context); var style = theme.textTheme.displayMedium!.copyWith( color: theme.colorScheme.onPrimary, ); return Card( color: theme.colorScheme.primary, child: Padding( padding: const EdgeInsets.all(20), child: Text( pair.asLowerCase, style: style, semanticsLabel: "${pair.first} ${pair.second}", ), ), ); }}I dont' really know what to do since I am knew to Flutter (and Dart). Here is the codelab I have been using: Flutter Codelab. I tried looking throught the flutter documentation but I couldn't find anything that would help me: Flutter Documenation