Handle error states and accessibility improvements

src/components/form/ManualSearchInput.js

@@ -3,20 +3,21 @@ import { StyleSheet, TextInput, View } from 'react-native';
 import PrimaryButton from '../PrimaryButton';
 import { colors } from '../../utils/constants';
 
-export default function ManualSearchInput({ value, onChangeText, onSubmit, placeholder = 'Produktname oder Barcode' }) {
+export default function ManualSearchInput({ value, onChangeText, onSubmit, disabled = false, placeholder = 'Produktname oder Barcode' }) {
   return (
     <View style={styles.row}>
       <TextInput
         autoCapitalize="none"
         onChangeText={onChangeText}
         onSubmitEditing={onSubmit}
+        editable={!disabled}
         placeholder={placeholder}
         placeholderTextColor={colors.muted}
         returnKeyType="search"
         style={styles.input}
         value={value}
       />
-      <PrimaryButton label="Suchen" onPress={onSubmit} />
+      <PrimaryButton disabled={disabled} label="Suchen" onPress={onSubmit} />
     </View>
   );
 }

src/components/layout/AppHeader.js

@@ -7,7 +7,7 @@ export default function AppHeader({ title, subtitle, onBack, rightAction }) {
     <View style={styles.header}>
       <View style={styles.row}>
         {onBack ? (
-          <Pressable accessibilityRole="button" onPress={onBack} style={styles.backButton}>
+          <Pressable accessibilityLabel="Zurück" accessibilityRole="button" onPress={onBack} style={styles.backButton}>
             <Text style={styles.backText}>‹</Text>
           </Pressable>
         ) : null}

src/components/layout/BottomTabBar.js

@@ -16,6 +16,7 @@ export default function BottomTabBar({ activeTab, onChange }) {
         const isActive = activeTab === tab.id;
         return (
           <Pressable
+            accessibilityLabel={`${tab.label} öffnen`}
             accessibilityRole="button"
             key={tab.id}
             onPress={() => onChange(tab.id)}

src/screens/HomeScreen.js

@@ -1,4 +1,4 @@
-import { StyleSheet, Text, View } from 'react-native';
+import { Pressable, StyleSheet, Text, View } from 'react-native';
 
 import PrimaryButton from '../components/PrimaryButton';
 import AppHeader from '../components/layout/AppHeader';
@@ -8,7 +8,7 @@ import ProductCard from '../components/product/ProductCard';
 import { calculateProductRating } from '../services/ratingService';
 import { colors } from '../utils/constants';
 
-export default function HomeScreen({ preferences, recentProducts, onStartScan, onOpenProduct }) {
+export default function HomeScreen({ preferences, recentProducts, shoppingList, onStartScan, onOpenProduct, onOpenList }) {
   const frequentProducts = [...recentProducts]
     .filter((product) => (product.scanCount || 0) > 1)
     .sort((a, b) => (b.scanCount || 0) - (a.scanCount || 0))
@@ -28,6 +28,14 @@ export default function HomeScreen({ preferences, recentProducts, onStartScan, o
           Prüfe Allergien, Ernährung, Budget und Nachhaltigkeit direkt am Regal.
         </Text>
         <PrimaryButton label="Produkt scannen" onPress={onStartScan} />
+        {shoppingList?.items?.length > 0 ? (
+          <Pressable accessibilityRole="button" onPress={onOpenList} style={styles.listShortcut}>
+            <Text style={styles.listShortcutTitle}>Einkaufsliste</Text>
+            <Text style={styles.listShortcutCopy}>
+              {shoppingList.items.filter((item) => !item.checked).length} offene Produkte
+            </Text>
+          </Pressable>
+        ) : null}
       </View>
 
       {frequentProducts.length > 0 ? (
@@ -119,5 +127,20 @@ const styles = StyleSheet.create({
     fontSize: 14,
     lineHeight: 20,
     marginTop: 4
+  },
+  listShortcut: {
+    backgroundColor: '#eaf4ef',
+    borderRadius: 8,
+    gap: 2,
+    padding: 12
+  },
+  listShortcutTitle: {
+    color: colors.primaryDark,
+    fontSize: 15,
+    fontWeight: '800'
+  },
+  listShortcutCopy: {
+    color: colors.muted,
+    fontSize: 13
   }
 });

src/screens/ScanScreen.js

@@ -30,9 +30,15 @@ export default function ScanScreen({ preferences, productCache, onScanBarcode, o
 
     setIsScanning(false);
     setIsLoadingProduct(true);
-    const result = await onScanBarcode(event.data).finally(() => {
+    let result;
+
+    try {
+      result = await onScanBarcode(event.data);
+    } catch (error) {
+      result = { status: 'error', errorMessage: 'Das Produkt konnte gerade nicht geladen werden.' };
+    } finally {
       setIsLoadingProduct(false);
-    });
+    }
 
     if (result?.status !== 'found') {
       setScanError(result?.errorMessage || 'Der Barcode konnte nicht verarbeitet werden.');
@@ -41,10 +47,15 @@ export default function ScanScreen({ preferences, productCache, onScanBarcode, o
   }
 
   async function handleManualSearch() {
+    if (!manualSearchQuery.trim() || isSearching) return;
+
     setIsSearching(true);
-    const results = await searchProducts(manualSearchQuery, productCache, preferences.offlineModeEnabled);
-    setManualResults(results);
-    setIsSearching(false);
+    try {
+      const results = await searchProducts(manualSearchQuery, productCache, preferences.offlineModeEnabled);
+      setManualResults(results);
+    } finally {
+      setIsSearching(false);
+    }
   }
 
   function retryScan() {
@@ -98,6 +109,7 @@ export default function ScanScreen({ preferences, productCache, onScanBarcode, o
       <ManualSearchInput
         onChangeText={setManualSearchQuery}
         onSubmit={handleManualSearch}
+        disabled={isSearching}
         value={manualSearchQuery}
       />
       {isSearching ? <Text style={styles.note}>Suche läuft...</Text> : null}

src/screens/ShoppingListScreen.js

@@ -33,7 +33,7 @@ export default function ShoppingListScreen({
       <View style={styles.summary}>
         <Text style={styles.summaryTitle}>{shoppingList.title}</Text>
         <Text style={styles.summaryCopy}>
-          Produkte abhaken, löschen oder nach dem Einkauf abschließen.
+          Produkte abhaken, löschen oder nach dem Einkauf abschliessen.
         </Text>
         <View style={styles.budgetBox}>
           <View style={styles.budgetHeader}>
@@ -95,7 +95,7 @@ export default function ShoppingListScreen({
       )}
 
       {shoppingList.items.length > 0 ? (
-        <SecondaryButton label="Einkauf abschließen" onPress={onCompleteList} />
+        <SecondaryButton label="Einkauf abschliessen" onPress={onCompleteList} />
       ) : null}
     </ScreenContainer>
   );

src/services/storageService.js

@@ -9,12 +9,24 @@ const keys = {
 };
 
 async function readJson(key, fallbackValue) {
-  const rawValue = await AsyncStorage.getItem(key);
-  return rawValue ? JSON.parse(rawValue) : fallbackValue;
+  try {
+    const rawValue = await AsyncStorage.getItem(key);
+    return rawValue ? JSON.parse(rawValue) : fallbackValue;
+  } catch (error) {
+    // A damaged value should not prevent the app from starting. The next save
+    // will replace it with a valid value.
+    console.warn(`Shoppy konnte ${key} nicht laden.`, error);
+    return fallbackValue;
+  }
 }
 
 async function writeJson(key, value) {
-  await AsyncStorage.setItem(key, JSON.stringify(value));
+  try {
+    await AsyncStorage.setItem(key, JSON.stringify(value));
+  } catch (error) {
+    // Storage is best-effort; the in-memory state remains usable.
+    console.warn(`Shoppy konnte ${key} nicht speichern.`, error);
+  }
 }
 
 export const storageService = {