lib/main.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:google_fonts/google_fonts.dart';
 import 'package:meals/screens/CategoriesScreen.dart';
 import 'package:meals/screens/tabs.dart';
@@ -13,7 +14,7 @@ final theme = ThemeData(
 );
 
 void main() {
-  runApp(const App());
+  runApp(const ProviderScope(child: App()));
 }
 
 class App extends StatelessWidget {

lib/providers/favorites_provider.dart

@@ -0,0 +1,20 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:meals/models/Meal.dart';
+
+class FavoriteMealsNotifier extends StateNotifier<List<Meal>> {
+  FavoriteMealsNotifier(List<Meal>? initialList) : super(initialList ?? []);
+
+  bool toggleMealFavoriteStatus(Meal meal) {
+    if (state.contains(meal)) {
+      state = state.where((Meal m) => m.id != meal.id).toList();
+      return false;
+    }
+
+    state = [...state, meal];
+    return true;
+  }
+}
+
+final favoriteMealsProvider =
+StateNotifierProvider<FavoriteMealsNotifier, List<Meal>>(
+        (ref) => FavoriteMealsNotifier([]));

lib/providers/filters_provider.dart

@@ -0,0 +1,55 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:meals/providers/meals_provider.dart';
+import 'package:meals/screens/filters.dart';
+
+enum Filter {
+  glutenFree,
+  lactoseFree,
+  veggie,
+  vegan,
+}
+
+class FiltersNotifier extends StateNotifier<Map<Filter, bool>> {
+  FiltersNotifier()
+      : super({
+          Filter.glutenFree: false,
+          Filter.lactoseFree: false,
+          Filter.veggie: false,
+          Filter.vegan: false,
+        });
+
+  void setFilter(Filter filter, bool isActive) {
+    state = {
+      ...state,
+      filter: isActive,
+    };
+  }
+
+  void setFilters(Map<Filter, bool> newFilters) {
+    state = newFilters;
+  }
+}
+
+final filtersProvider =
+    StateNotifierProvider<FiltersNotifier, Map<Filter, bool>>(
+        (ref) => FiltersNotifier());
+
+final filteredMealsProvider = Provider((ref) {
+  final meals = ref.watch(mealsProvider);
+  final activeFilters = ref.watch(filtersProvider);
+  return meals.where((meal) {
+    if (activeFilters[Filter.glutenFree]! && !meal.isGlutenFree) {
+      return false;
+    }
+    if (activeFilters[Filter.lactoseFree]! && !meal.isLactoseFree) {
+      return false;
+    }
+    if (activeFilters[Filter.veggie]! && !meal.isVegetarian) {
+      return false;
+    }
+    if (activeFilters[Filter.vegan]! && !meal.isVegan) {
+      return false;
+    }
+    return true;
+  }).toList();
+});

lib/providers/meals_provider.dart

@@ -0,0 +1,4 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:meals/data/dummy_categories.dart';
+
+final mealsProvider = Provider((ref) => dummyMeals);

lib/screens/CategoriesScreen.dart

@@ -7,11 +7,11 @@ import 'package:meals/widgets/CategoryGridItem.dart';
 
 class CategoriesScreen extends StatelessWidget {
   final List<Meal> availableMeals;
-  final void Function(Meal meal) onToggleFavorite;
 
-  const CategoriesScreen({super.key,
+  const CategoriesScreen({
+    super.key,
     required this.availableMeals,
-    required this.onToggleFavorite});
+  });
 
   void _selectCategory(BuildContext context, Category category) {
     final meals = availableMeals
@@ -21,11 +21,9 @@ class CategoriesScreen extends StatelessWidget {
     Navigator.push(
         context,
         MaterialPageRoute(
-            builder: (ctx) =>
+            builder: (ctx) => MealsScreen(
-                MealsScreen(
                   title: category.title,
                   meals: meals,
-                  onToggleFavorite: onToggleFavorite,
                 )));
   }
 

lib/screens/MealsScreen.dart

@@ -6,13 +6,12 @@ import 'package:meals/widgets/MealItem.dart';
 class MealsScreen extends StatelessWidget {
   final String? title;
   final List<Meal> meals;
-  final void Function(Meal meal) onToggleFavorite;
 
-  const MealsScreen(
+  const MealsScreen({
-      {super.key,
+    super.key,
     this.title,
     required this.meals,
-      required this.onToggleFavorite});
+  });
 
   void _selectMeal(BuildContext buildContext, Meal meal) {
     Navigator.push(
@@ -20,7 +19,6 @@ class MealsScreen extends StatelessWidget {
         MaterialPageRoute(
           builder: (ctx) => MealDetailScreen(
             meal: meal,
-            onToggleFavorite: onToggleFavorite,
           ),
         ));
   }

lib/screens/filters.dart

@@ -1,65 +1,26 @@
-import 'package:flutter/material.dart';
+import 'dart:developer';
-import 'package:meals/screens/tabs.dart';
-import 'package:meals/widgets/main_drawer.dart';
-
-enum Filter {
-  glutenFree,
-  lactoseFree,
-  veggie,
-  vegan,
-}
 
-class FiltersScreen extends StatefulWidget {
+import 'package:flutter/material.dart';
-  final Map<Filter, bool> currentFilters;
+import 'package:flutter_riverpod/flutter_riverpod.dart';
-
-  const FiltersScreen({Key? key, required this.currentFilters})
-      : super(key: key);
-
-  @override
-  State<FiltersScreen> createState() => _FiltersScreenState();
-}
 
-class _FiltersScreenState extends State<FiltersScreen> {
+import '../providers/filters_provider.dart';
-  bool _glutenFreeFilterSet = false;
-  bool _lactoseFreeFilterSet = false;
-  bool _veggieFilterSet = false;
-  bool _veganFilterSet = false;
 
-  @override
+class FiltersScreen extends ConsumerWidget {
-  void initState() {
+  const FiltersScreen({Key? key}) : super(key: key);
-    super.initState();
-    setState(() {
-      _glutenFreeFilterSet = widget.currentFilters[Filter.glutenFree]!;
-      _lactoseFreeFilterSet = widget.currentFilters[Filter.lactoseFree]!;
-      _veggieFilterSet = widget.currentFilters[Filter.veggie]!;
-      _veganFilterSet = widget.currentFilters[Filter.vegan]!;
-    });
-  }
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
     return Scaffold(
         appBar: AppBar(
           title: const Text('Your filters'),
         ),
-        body: WillPopScope(
+        body: Column(
-          onWillPop: () async {
-            Navigator.of(context).pop({
-              Filter.glutenFree: _glutenFreeFilterSet,
-              Filter.lactoseFree: _lactoseFreeFilterSet,
-              Filter.veggie: _veggieFilterSet,
-              Filter.vegan: _veganFilterSet,
-            });
-
-            return false;
-          },
-          child: Column(
           children: [
             SwitchListTile(
-                value: _glutenFreeFilterSet,
+              value: ref.watch(filtersProvider)[Filter.glutenFree]!,
-                onChanged: (checked) => setState(() {
+              onChanged: (checked) => ref
-                  _glutenFreeFilterSet = checked;
+                  .read(filtersProvider.notifier)
-                }),
+                  .setFilter(Filter.glutenFree, checked),
               title: Text(
                 'Gluten free',
                 style: Theme.of(context).textTheme.titleLarge!.copyWith(
@@ -74,10 +35,10 @@ class _FiltersScreenState extends State<FiltersScreen> {
               contentPadding: const EdgeInsets.only(left: 34, right: 22),
             ),
             SwitchListTile(
-                value: _lactoseFreeFilterSet,
+              value: ref.watch(filtersProvider)[Filter.lactoseFree]!,
-                onChanged: (checked) => setState(() {
+              onChanged: (checked) => ref
-                  _lactoseFreeFilterSet = checked;
+                  .read(filtersProvider.notifier)
-                }),
+                  .setFilter(Filter.lactoseFree, checked),
               title: Text(
                 'Lactose free',
                 style: Theme.of(context).textTheme.titleLarge!.copyWith(
@@ -92,10 +53,10 @@ class _FiltersScreenState extends State<FiltersScreen> {
               contentPadding: const EdgeInsets.only(left: 34, right: 22),
             ),
             SwitchListTile(
-                value: _veggieFilterSet,
+              value: ref.watch(filtersProvider)[Filter.veggie]!,
-                onChanged: (checked) => setState(() {
+              onChanged: (checked) => ref
-                  _veggieFilterSet = checked;
+                  .read(filtersProvider.notifier)
-                }),
+                  .setFilter(Filter.veggie, checked),
               title: Text(
                 'Veggie',
                 style: Theme.of(context).textTheme.titleLarge!.copyWith(
@@ -110,10 +71,10 @@ class _FiltersScreenState extends State<FiltersScreen> {
               contentPadding: const EdgeInsets.only(left: 34, right: 22),
             ),
             SwitchListTile(
-                value: _veganFilterSet,
+              value: ref.watch(filtersProvider)[Filter.vegan]!,
-                onChanged: (checked) => setState(() {
+              onChanged: (checked) => ref
-                  _veganFilterSet = checked;
+                  .read(filtersProvider.notifier)
-                }),
+                  .setFilter(Filter.vegan, checked),
               title: Text(
                 'Vegan',
                 style: Theme.of(context).textTheme.titleLarge!.copyWith(
@@ -128,7 +89,6 @@ class _FiltersScreenState extends State<FiltersScreen> {
               contentPadding: const EdgeInsets.only(left: 34, right: 22),
             )
           ],
-          ),
         ));
   }
 }

lib/screens/meal_details.dart

@@ -1,24 +1,36 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:meals/providers/favorites_provider.dart';
 
 import '../models/Meal.dart';
 
-class MealDetailScreen extends StatelessWidget {
+class MealDetailScreen extends ConsumerWidget {
   final Meal meal;
-  final void Function(Meal meal) onToggleFavorite;
 
-  const MealDetailScreen(
+  const MealDetailScreen({Key? key, required this.meal}) : super(key: key);
-      {Key? key, required this.meal, required this.onToggleFavorite})
-      : super(key: key);
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, WidgetRef ref) {
+    final favoriteMeals = ref.watch(favoriteMealsProvider);
+
+    final isIntoFavorite = favoriteMeals.contains(meal);
+
     return Scaffold(
         appBar: AppBar(
           title: Text(meal.title),
           actions: [
             IconButton(
-                onPressed: () => onToggleFavorite(meal),
+                onPressed: () {
-                icon: const Icon(Icons.star))
+                  final wasAdded = ref
+                      .read(favoriteMealsProvider.notifier)
+                      .toggleMealFavoriteStatus(meal);
+                  ScaffoldMessenger.of(context).clearSnackBars();
+                  ScaffoldMessenger.of(context).showSnackBar(SnackBar(
+                      content: Text(wasAdded
+                          ? 'Meal has been added to your favorite.'
+                          : 'Meal is no longer as a favorite.')));
+                },
+                icon: Icon(isIntoFavorite ? Icons.star : Icons.star_border))
           ],
         ),
         body: SingleChildScrollView(

lib/screens/tabs.dart

@@ -1,36 +1,22 @@
 import 'package:flutter/material.dart';
-import 'package:meals/data/dummy_categories.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:meals/providers/favorites_provider.dart';
 import 'package:meals/screens/CategoriesScreen.dart';
 import 'package:meals/screens/MealsScreen.dart';
 import 'package:meals/screens/filters.dart';
 import 'package:meals/widgets/main_drawer.dart';
 
-import '../models/Meal.dart';
+import '../providers/filters_provider.dart';
 
-const kDefaultFilters = {
+class TabsScreen extends ConsumerStatefulWidget {
-  Filter.glutenFree: false,
-  Filter.lactoseFree: false,
-  Filter.veggie: false,
-  Filter.vegan: false,
-};
-
-class TabsScreen extends StatefulWidget {
   const TabsScreen({Key? key}) : super(key: key);
 
   @override
-  State<TabsScreen> createState() => _TabsScreenState();
+  ConsumerState<TabsScreen> createState() => _TabsScreenState();
 }
 
-class _TabsScreenState extends State<TabsScreen> {
+class _TabsScreenState extends ConsumerState<TabsScreen> {
   int _selectedPageIndex = 0;
-  final List<Meal> _favoriteMeals = [];
-  Map<Filter, bool> _selectedFilters = kDefaultFilters;
-
-  void _showInfoMessage(String message) {
-    ScaffoldMessenger.of(context).clearSnackBars();
-    ScaffoldMessenger.of(context)
-        .showSnackBar(SnackBar(content: Text(message)));
-  }
 
   void _selectPage(int index) {
     setState(() {
@@ -38,33 +24,13 @@ class _TabsScreenState extends State<TabsScreen> {
     });
   }
 
-  void _toggleFavoriteMeal(Meal meal) {
-    if (_favoriteMeals.contains(meal)) {
-      setState(() {
-        _favoriteMeals.remove(meal);
-      });
-      _showInfoMessage('Meal is no longer a favorite');
-    } else {
-      setState(() {
-        _favoriteMeals.add(meal);
-        _showInfoMessage('Meal has been added to your favorites');
-      });
-    }
-  }
-
   void _setScreen(String identifier) async {
     Navigator.of(context).pop();
 
     switch (identifier) {
       case 'filters':
-        final results = await Navigator.of(context)
+        await Navigator.of(context).push<Map<Filter, bool>>(
-            .push<Map<Filter, bool>>(MaterialPageRoute(
+            MaterialPageRoute(builder: (ctx) => const FiltersScreen()));
-                builder: (ctx) => FiltersScreen(
-                      currentFilters: _selectedFilters,
-                    )));
-        setState(() {
-          _selectedFilters = results ?? kDefaultFilters;
-        });
         break;
     }
   }
@@ -73,35 +39,19 @@ class _TabsScreenState extends State<TabsScreen> {
   Widget build(BuildContext context) {
     Widget activePage;
     String? activePageTitle;
-    final availableMeals = dummyMeals.where((meal) {
+    final availableMeals = ref.watch(filteredMealsProvider);
-      if (_selectedFilters[Filter.glutenFree]! && !meal.isGlutenFree) {
-        return false;
-      }
-      if (_selectedFilters[Filter.lactoseFree]! && !meal.isLactoseFree) {
-        return false;
-      }
-      if (_selectedFilters[Filter.veggie]! && !meal.isVegetarian) {
-        return false;
-      }
-      if (_selectedFilters[Filter.vegan]! && !meal.isVegan) {
-        return false;
-      }
-      return true;
-    }).toList();
 
     switch (_selectedPageIndex) {
       case 1:
         activePageTitle = 'Favorites';
         activePage = MealsScreen(
-          meals: _favoriteMeals,
+          meals: ref.watch(favoriteMealsProvider),
-          onToggleFavorite: _toggleFavoriteMeal,
         );
         break;
       default:
         activePageTitle = 'Pick your category';
         activePage = CategoriesScreen(
           availableMeals: availableMeals,
-          onToggleFavorite: _toggleFavoriteMeal,
         );
     }
 

pubspec.lock

@@ -94,6 +94,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "2.0.1"
+  flutter_riverpod:
+    dependency: "direct main"
+    description:
+      name: flutter_riverpod
+      sha256: b83ac5827baadefd331ea1d85110f34645827ea234ccabf53a655f41901a9bf4
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.6"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -243,6 +251,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "4.2.4"
+  riverpod:
+    dependency: transitive
+    description:
+      name: riverpod
+      sha256: "80e48bebc83010d5e67a11c9514af6b44bbac1ec77b4333c8ea65dbc79e2d8ef"
+      url: "https://pub.dev"
+    source: hosted
+    version: "2.3.6"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -264,6 +280,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.11.0"
+  state_notifier:
+    dependency: transitive
+    description:
+      name: state_notifier
+      sha256: "8fe42610f179b843b12371e40db58c9444f8757f8b69d181c97e50787caed289"
+      url: "https://pub.dev"
+    source: hosted
+    version: "0.7.2+1"
   stream_channel:
     dependency: transitive
     description:

pubspec.yaml

@@ -37,6 +37,7 @@ dependencies:
   cupertino_icons: ^1.0.2
   google_fonts: ^4.0.3
   transparent_image: ^2.0.1
+  flutter_riverpod: ^2.3.6
 
 dev_dependencies:
   flutter_test: