Add user and product providers

lib/app.dart

@@ -1,8 +1,10 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:thesis_shop/route_key.dart';
 import 'package:thesis_shop/screens/cart/cart_screen.dart';
 import 'package:thesis_shop/screens/product_list/product_list_screen.dart';
 import 'package:thesis_shop/service/product_service.dart';
+import 'package:thesis_shop/stores/product_service_provider.dart';
 import 'package:thesis_shop/utils/map_keys_extension.dart';
 
 class ThesisShopApp extends StatelessWidget {
@@ -12,18 +14,23 @@ class ThesisShopApp extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    return MaterialApp(
-      title: 'Thesis Shop',
-      theme: ThemeData(primarySwatch: Colors.red),
-      darkTheme: ThemeData(
-        primarySwatch: Colors.red,
-        brightness: Brightness.dark,
+    return ProviderScope(
+      overrides: [
+        productServiceProvider.overrideWithValue(productService),
+      ],
+      child: MaterialApp(
+        title: 'Thesis Shop',
+        theme: ThemeData(primarySwatch: Colors.red),
+        darkTheme: ThemeData(
+          primarySwatch: Colors.red,
+          brightness: Brightness.dark,
+        ),
+        routes: {
+          RouteKey.products: (context) => const ProductListScreen(),
+          RouteKey.cart: (context) => const CartScreen(),
+        }.mapKeys((key) => key.name),
+        initialRoute: 'products',
       ),
-      routes: {
-        RouteKey.products: (context) => const ProductListScreen(),
-        RouteKey.cart: (context) => const CartScreen(),
-      }.mapKeys((key) => key.name),
-      initialRoute: 'products',
     );
   }
 }

lib/models/product.dart

@@ -8,4 +8,6 @@ class Product {
   String get priceAsString => price.toStringAsFixed(2);
 
   const Product({required this.title, required this.price});
+
+  Product copyWithDiscount() => Product(title: title, price: price * 0.8);
 }

lib/screens/cart/cart_screen.dart

@@ -20,7 +20,7 @@ class CartScreen extends StatelessWidget {
     return Scaffold(
       appBar: AppBar(
         title: const Text('Warenkorb'),
-        actions: [UserSwitch(isOn: true, onChanged: (_) {})],
+        actions: const [UserSwitch()],
       ),
       body: Column(
         mainAxisSize: MainAxisSize.max,

lib/screens/product_list/product_list_screen.dart

@@ -1,31 +1,28 @@
 import 'package:flutter/material.dart';
-import 'package:thesis_shop/models/product.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:thesis_shop/stores/product_list_provider.dart';
 import 'package:thesis_shop/widgets/user_switch.dart';
 
 import 'cart_button_overlay.dart';
 import 'product_list.dart';
 
-const _productPlaceholder = [
-  Product(title: 'Bananen', price: 3),
-  Product(title: 'Äpfel', price: 2),
-  Product(title: 'Birnen', price: 2.5),
-  Product(title: 'Kirschen', price: 1.2),
-];
-
-class ProductListScreen extends StatelessWidget {
+class ProductListScreen extends ConsumerWidget {
   const ProductListScreen({Key? key}) : super(key: key);
 
   @override
-  Widget build(BuildContext context) {
-    const products = _productPlaceholder;
+  Widget build(BuildContext context, ref) {
     return Scaffold(
       appBar: AppBar(
         title: const Text('Thesis Shop'),
-        actions: [UserSwitch(isOn: true, onChanged: (_) {})],
-      ),
-      body: const CartButtonOverlay(
-        child: ProductList(products: products),
+        actions: const [UserSwitch()],
       ),
+      body: ref.watch(productListProvider).when(
+            data: (products) => CartButtonOverlay(
+              child: ProductList(products: products),
+            ),
+            error: (error, _) => Center(child: Text(error.toString())),
+            loading: () => const Center(child: CircularProgressIndicator()),
+          ),
     );
   }
 }

lib/stores/product_list_provider.dart

@@ -0,0 +1,13 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:thesis_shop/models/product.dart';
+import 'package:thesis_shop/stores/product_loading_provider.dart';
+import 'package:thesis_shop/stores/user_store.dart';
+
+final productListProvider = Provider<AsyncValue<List<Product>>>((ref) {
+  final isSignedIn = ref.watch(userStoreProvider);
+  if (!isSignedIn) {
+    return ref.watch(productLoadingProvider);
+  }
+  return ref.watch(productLoadingProvider).whenData(
+      (products) => products.map((pro) => pro.copyWithDiscount()).toList());
+});

lib/stores/product_loading_provider.dart

@@ -0,0 +1,6 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:thesis_shop/stores/product_service_provider.dart';
+
+final productLoadingProvider = FutureProvider(
+    (ref) => ref.read(productServiceProvider).fetchProducts(),
+    dependencies: [productServiceProvider]);

lib/stores/product_service_provider.dart

@@ -0,0 +1,16 @@
+import 'package:flutter_riverpod/flutter_riverpod.dart';
+import 'package:thesis_shop/models/product.dart';
+import 'package:thesis_shop/service/product_service.dart';
+
+class ProductServiceImplementationPlaceholder implements ProductService {
+  @override
+  Future<List<Product>> fetchProducts() {
+    throw UnimplementedError();
+  }
+
+  @override
+  String get url => throw UnimplementedError();
+}
+
+final productServiceProvider = Provider<ProductService>(
+    (ref) => ProductServiceImplementationPlaceholder());

lib/stores/user_store.dart

@@ -0,0 +1,12 @@
+import 'package:riverpod/riverpod.dart';
+
+class UserStore extends StateNotifier<bool> {
+  UserStore({bool initialSignInStatus = false}) : super(initialSignInStatus);
+
+  void changeSignInStatus(bool newStatus) {
+    state = newStatus;
+  }
+}
+
+final userStoreProvider =
+    StateNotifierProvider<UserStore, bool>((ref) => UserStore());

lib/widgets/user_switch.dart

@@ -1,24 +1,22 @@
 import 'package:flutter/material.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:thesis_shop/benchmark_counter.dart';
+import 'package:thesis_shop/stores/user_store.dart';
 
-class UserSwitch extends StatelessWidget {
-  final bool isOn;
-  final ValueChanged<bool> onChanged;
-  const UserSwitch({
-    required this.isOn,
-    required this.onChanged,
-  }) : super(key: const Key('user_switch'));
+class UserSwitch extends ConsumerWidget {
+  const UserSwitch() : super(key: const Key('user_switch'));
 
   @override
-  Widget build(BuildContext context) {
+  Widget build(BuildContext context, ref) {
+    final isSignedIn = ref.watch(userStoreProvider);
     BenchmarkCounters.userSwitch++;
     return Row(
       mainAxisSize: MainAxisSize.min,
       children: [
         const Icon(Icons.account_circle),
         Switch(
-          value: isOn,
-          onChanged: onChanged,
+          value: isSignedIn,
+          onChanged: ref.read(userStoreProvider.notifier).changeSignInStatus,
           activeColor: Colors.green,
         )
       ],

pubspec.lock

@@ -146,6 +146,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.0.4"
+  flutter_riverpod:
+    dependency: "direct main"
+    description:
+      name: flutter_riverpod
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.3"
   flutter_test:
     dependency: "direct dev"
     description: flutter
@@ -228,6 +235,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "2.1.0"
+  riverpod:
+    dependency: "direct main"
+    description:
+      name: riverpod
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "1.0.3"
   sky_engine:
     dependency: transitive
     description: flutter
@@ -247,6 +261,13 @@ packages:
       url: "https://pub.dartlang.org"
     source: hosted
     version: "1.10.0"
+  state_notifier:
+    dependency: transitive
+    description:
+      name: state_notifier
+      url: "https://pub.dartlang.org"
+    source: hosted
+    version: "0.7.2+1"
   stream_channel:
     dependency: transitive
     description:
@@ -305,3 +326,4 @@ packages:
     version: "3.1.0"
 sdks:
   dart: ">=2.16.1 <3.0.0"
+  flutter: ">=1.17.0"

pubspec.yaml

@@ -30,6 +30,8 @@ dependencies:
   flutter:
     sdk: flutter
   http: ^0.13.4
+  riverpod: 1.0.3
+  flutter_riverpod: 1.0.3
 dev_dependencies:
   flutter_test:
     sdk: flutter
@@ -40,7 +42,6 @@ dev_dependencies:
   # rules and activating additional ones.
   flutter_lints: ^1.0.0
   dart_code_metrics: ^4.10.1
-
 # For information on the generic Dart part of this file, see the
 # following page: https://dart.dev/tools/pub/pubspec