Add user switch

lib/screens/cart/cart_screen.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart';
+import 'package:thesis_shop/widgets/user_switch.dart';
 
 class CartScreen extends StatelessWidget {
   const CartScreen({Key? key}) : super(key: key);
@@ -6,7 +7,10 @@ class CartScreen extends StatelessWidget {
   @override
   Widget build(BuildContext context) {
     return Scaffold(
-      appBar: AppBar(title: const Text('Warenkorb')),
+      appBar: AppBar(
+        title: const Text('Warenkorb'),
+        actions: [UserSwitch(isOn: true, onChanged: (_) {})],
+      ),
     );
   }
 }

lib/screens/product_list/product_list_screen.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:thesis_shop/models/product.dart';
+import 'package:thesis_shop/widgets/user_switch.dart';
 
 import 'cart_button_overlay.dart';
 import 'product_list.dart';
@@ -18,7 +19,10 @@ class ProductListScreen extends StatelessWidget {
   Widget build(BuildContext context) {
     const products = _productPlaceholder;
     return Scaffold(
-      appBar: AppBar(title: const Text('Thesis Shop')),
+      appBar: AppBar(
+        title: const Text('Thesis Shop'),
+        actions: [UserSwitch(isOn: true, onChanged: (_) {})],
+      ),
       body: const CartButtonOverlay(
         child: ProductList(products: _productPlaceholder),
       ),

lib/widgets/user_switch.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+
+class UserSwitch extends StatelessWidget {
+  final bool isOn;
+  final ValueChanged<bool> onChanged;
+  const UserSwitch({
+    Key? key,
+    required this.isOn,
+    required this.onChanged,
+  }) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisSize: MainAxisSize.min,
+      children: [
+        const Icon(Icons.account_circle),
+        Switch(
+          value: isOn,
+          onChanged: onChanged,
+          activeColor: Colors.green,
+        )
+      ],
+    );
+  }
+}