merged a simple logic for the basket

Frontend-user/lib/basket.dart

@@ -3,13 +3,12 @@ import 'package:flutter/services.dart';
 import 'sample_data.dart';
 
 class ShowBasket extends StatelessWidget {
-  final int index;
+  final Basket basket;
   final bool editable;
-  const ShowBasket(this.index, {this.editable = false, super.key});
+  const ShowBasket(this.basket, {this.editable = false, super.key});
 
   @override
   Widget build(BuildContext context) {
-    final List<Basket> basket = SampleData().transactions[index].basket!;
     return Column(
       children: [
         Expanded(
@@ -24,7 +23,7 @@ class ShowBasket extends StatelessWidget {
               'Kosten:',
             ),
             subtitle: Text(
-              '${SampleData().transactions[index].amount / 100}',
+              '${basket.price}',
             ),
             trailing: editable
                 ? Row(
@@ -47,19 +46,19 @@ class ShowBasket extends StatelessWidget {
     );
   }
 
-  ListView getBasket(List<Basket> basket) {
+  ListView getBasket(Basket basket) {
     return ListView.builder(
-      itemCount: basket.length,
+      itemCount: basket.purchases.length,
       itemBuilder: (context, index) {
         return Card(
           child: ListTile(
               leading: Text(
-                basket[index].products.category.icon,
+                basket.purchases.keys.elementAt(index).category.icon,
                 style: const TextStyle(fontSize: 24),
               ),
-              title: Text(basket[index].products.name),
+              title: Text(basket.purchases.keys.elementAt(index).name),
               subtitle: Text(
-                  '${basket[index].amount} ${basket[index].products.unit}'),
+                  '${basket.purchases.values.elementAt(index)} ${basket.purchases.keys.elementAt(index).unit}'),
               trailing: editable
                   ? SizedBox(
                       width: 100,

Frontend-user/lib/finance.dart

@@ -43,7 +43,9 @@ class Finance extends StatelessWidget {
                               showBottomSheet(
                                   context: context,
                                   builder: (BuildContext context) {
-                                    return ShowBasket(index);
+                                    return ShowBasket(SampleData()
+                                        .transactions[index]
+                                        .basket!);
                                   });
                             }
                           : null));
@@ -68,8 +70,7 @@ class Finance extends StatelessWidget {
   Text getSubtitle(Transaction transaction) {
     String text = '${transaction.amount / 100}';
     text += '€  ';
-    text += DateFormat("EEEE, dd. MMMM yyyy HH:mm")
+    text += DateFormat("EEEE, dd. MMMM yyyy HH:mm").format(transaction.date);
-        .format(transaction.date);
     if (transaction.description != null) {
       (text += '\n${transaction.description}');
     }
@@ -98,7 +99,8 @@ class Finance extends StatelessWidget {
           showBottomSheet(
               context: context,
               builder: (BuildContext context) {
-                return ShowBasket(index, editable: true);
+                return ShowBasket(SampleData().transactions[index].basket!,
+                    editable: true);
               });
         },
       );

Frontend-user/lib/sample_data.dart

@@ -1,3 +1,5 @@
+import 'package:uuid/uuid.dart';
+
 final DateTime now = DateTime.now();
 
 enum TransaktionArt { monatlBeitrag, aufladung, einkauf, korrektur }
@@ -15,7 +17,7 @@ class Transaction {
   int amount;
   TransaktionArt type;
   DateTime date;
-  List<Basket>? basket;
+  Basket? basket;
   String? description;
   Transaction(
       {required this.type,
@@ -28,17 +30,31 @@ class Transaction {
 class Product {
   final int id = 0;
   final String name;
-  final Unit unit;
+  final Unit unit; //pro Kg oder Stück
-  final double price; //pro Kilogramm oder Stück
+  final double price;
   final double vat;
   final Category category;
   const Product(this.name, this.unit, this.price, this.vat, this.category);
 }
 
 class Basket {
-  Product products;
+  Map<Product, int> purchases;
-  int amount;
+  double price;
-  Basket(this.products, this.amount);
+  String guid;
+  Basket(this.purchases, this.price) : guid = const Uuid().v4();
+
+  void addItem(Product product, int quantity) {
+    if (purchases.containsKey(product)) {
+      purchases.update(
+          product, (existingQuantity) => existingQuantity + quantity);
+    } else {
+      purchases[product] = quantity;
+    }
+  }
+
+  void removeItem(Product product) {
+    purchases.remove(product);
+  }
 }
 
 class SampleData {
@@ -63,39 +79,41 @@ class SampleData {
     Product('Flaschenpfand', Unit.stueck, -0.15, 0, categories[3])
   ];
 
-  static List<Basket> basket = [
+  //such a basket can not exist later. It is for testing purposes
-    Basket(products[0], 20),
+  // when scrolling through a long basket
-    Basket(products[1], 2200),
+  static Basket basket = Basket({
-    Basket(products[2], 2),
+    products[0]: 20,
-    Basket(products[3], 1),
+    products[1]: 2200,
-    Basket(products[4], 1),
+    products[2]: 2,
-    Basket(products[5], 2),
+    products[3]: 1,
-    Basket(products[6], 222),
+    products[4]: 1,
-    Basket(products[0], 20),
+    products[5]: 2,
-    Basket(products[1], 2200),
+    products[6]: 222,
-    Basket(products[2], 2),
+    products[0]: 20,
-    Basket(products[3], 1),
+    products[1]: 2200,
-    Basket(products[4], 1),
+    products[2]: 2,
-    Basket(products[5], 2),
+    products[3]: 1,
-    Basket(products[6], 222)
+    products[4]: 1,
-  ];
+    products[5]: 2,
+    products[6]: 222
+  }, 27.9);
 
-  static List<Basket> basket2 = [
+  static Basket basket2 = Basket({
-    Basket(products[0], 22),
+    products[0]: 22,
-    Basket(products[1], 2241),
+    products[1]: 2241,
-    Basket(products[3], 2),
+    products[3]: 2,
-    Basket(products[4], 4),
+    products[4]: 4,
-    Basket(products[6], 2),
+    products[6]: 2,
-    Basket(products[7], 5)
+    products[7]: 5,
-  ];
+  }, 34);
 
-  static List<Basket> basket3 = [
+  static Basket basket3 = Basket({
-    Basket(products[0], -2),
+    products[0]: 2,
-    Basket(products[1], 21),
+    products[1]: 21,
-    Basket(products[3], -4),
+    products[3]: 4,
-    Basket(products[4], 1),
+    products[4]: 1,
-    Basket(products[6], 5)
+    products[6]: 5,
-  ];
+  }, -1);
 
   List<Transaction> transactions = [
     Transaction(

Frontend-user/pubspec.lock

@@ -41,6 +41,14 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "1.17.1"
+  crypto:
+    dependency: transitive
+    description:
+      name: crypto
+      sha256: ff625774173754681d66daaf4a448684fb04b78f902da9cb3d308c19cc5e8bab
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.3"
   cupertino_icons:
     dependency: "direct main"
     description:
@@ -184,6 +192,22 @@ packages:
       url: "https://pub.dev"
     source: hosted
     version: "0.5.1"
+  typed_data:
+    dependency: transitive
+    description:
+      name: typed_data
+      sha256: facc8d6582f16042dd49f2463ff1bd6e2c9ef9f3d5da3d9b087e244a7b564b3c
+      url: "https://pub.dev"
+    source: hosted
+    version: "1.3.2"
+  uuid:
+    dependency: "direct main"
+    description:
+      name: uuid
+      sha256: "648e103079f7c64a36dc7d39369cabb358d377078a051d6ae2ad3aa539519313"
+      url: "https://pub.dev"
+    source: hosted
+    version: "3.0.7"
   vector_math:
     dependency: transitive
     description:

Frontend-user/pubspec.yaml

@@ -36,6 +36,7 @@ dependencies:
   # Use with the CupertinoIcons class for iOS style icons.
   cupertino_icons: ^1.0.2
   intl: ^0.18.1
+  uuid: ^3.0.7
 
 dev_dependencies:
   flutter_test: