Hardening fixes: Camera cancellation, Android memory optimization, action button throttling

src/screens/CameraScreen.tsx

@@ -92,6 +92,7 @@ export default function CameraScreen({
   const usbCameraRef = useRef<UsbCameraRef>(null);
   const expoCameraRef = useRef<any>(null);
   const burstTimerRef = useRef<any>(null);
+  const isCancelledRef = useRef<boolean>(false);
 
   // Reanimated countdown pulse animation
   const scale = useSharedValue(1);
@@ -195,6 +196,7 @@ export default function CameraScreen({
 
   // Cancel capture process
   const handleLocalCancel = async () => {
+    isCancelledRef.current = true;
     if (burstTimerRef.current) clearTimeout(burstTimerRef.current);
     
     // Clean up any temp files from a partially completed burst
@@ -208,6 +210,8 @@ export default function CameraScreen({
     
     setCountdown(countdownDuration);
     setIsCapturing(false);
+    setIsBurstWaiting(false);
+    setHasStarted(false);
     setBurstIndex(0);
     setBurstUris([]);
     setShowBurstIndicator('');
@@ -229,6 +233,7 @@ export default function CameraScreen({
   }, [countdownDuration, isIdle]);
 
   const startCountdown = () => {
+    isCancelledRef.current = false;
     let timer: any;
     let count = countdownDuration;
 
@@ -281,7 +286,7 @@ export default function CameraScreen({
         if (expoCameraRef.current) {
           const photo = await expoCameraRef.current.takePictureAsync({
             quality: 0.7, // Lower quality slightly to reduce file size
-            skipProcessing: false, // Ensure correct orientation
+            skipProcessing: Platform.OS === 'android', // Prevent memory crash on Android
           });
           capturedUri = photo.uri;
         } else {
@@ -289,6 +294,12 @@ export default function CameraScreen({
         }
       }
 
+      // If user cancelled while the camera promise was processing, abort before side-effects
+      if (isCancelledRef.current) {
+        console.log('Capture cancelled by user during processing.');
+        return;
+      }
+
       // Instead of manipulating the image and risking an OOM or BitmapFactory crash,
       // we directly use the captured photo and rely on React Native's Image component
       // to safely downsample it during rendering via resizeMethod="resize".

src/screens/PreviewScreen.tsx

@@ -204,6 +204,7 @@ export default function PreviewScreen({
 
   // Triggers the view capture and the print job
   const handlePrint = async () => {
+    if (isProcessing) return;
     setIsProcessing(true);
     setStatusMessage('Dein Foto wird vorbereitet...');
     try {
@@ -233,6 +234,7 @@ export default function PreviewScreen({
 
   // Saves to gallery without printing
   const handleSaveOnly = async () => {
+    if (isProcessing) return;
     setIsProcessing(true);
     setStatusMessage('Bild wird generiert...');
     try {
@@ -255,6 +257,7 @@ export default function PreviewScreen({
 
   // Auto-save and exit
   const handleExit = useCallback(async () => {
+    if (isProcessing) return;
     const state = stateRef.current;
     if (state.stickers.length === 0 && state.layout === 'single' && !state.activeFrame && state.dateOverlay === 'off') {
       state.onReset();
@@ -294,6 +297,7 @@ export default function PreviewScreen({
   }, [resetIdleTimer]);
 
   const handleRetakeClick = async () => {
+    if (isProcessing) return;
     if (stickers.length > 0 || layout !== 'single' || activeFrame || dateOverlay !== 'off') {
       setIsProcessing(true);
       setStatusMessage('Wird vor dem Wiederholen gespeichert...');
@@ -523,7 +527,7 @@ export default function PreviewScreen({
 
         {/* Action Buttons */}
         <View style={styles.actions}>
-          <TouchableOpacity style={[styles.actionBtn, styles.printBtn]} onPress={handlePrint} activeOpacity={0.8}>
+          <TouchableOpacity style={[styles.actionBtn, styles.printBtn, isProcessing && styles.btnDisabled]} onPress={handlePrint} activeOpacity={0.8} disabled={isProcessing}>
             <LinearGradient
               colors={THEME.gradient.primary}
               start={{ x: 0, y: 0.5 }}
@@ -535,25 +539,25 @@ export default function PreviewScreen({
             </LinearGradient>
           </TouchableOpacity>
 
-          <TouchableOpacity style={[styles.actionBtn, styles.saveBtn]} onPress={handleSaveOnly}>
+          <TouchableOpacity style={[styles.actionBtn, styles.saveBtn, isProcessing && styles.btnDisabled]} onPress={handleSaveOnly} disabled={isProcessing}>
             <FontAwesomeIcon icon={faDownload} size={16} color={THEME.colors.accent} style={{ marginRight: 8 }} />
             <Text style={[styles.actionBtnText, { color: THEME.colors.accent }]}>Nur auf Tablet speichern</Text>
           </TouchableOpacity>
 
           {photoUris.length < 4 && (
-            <TouchableOpacity style={[styles.actionBtn, styles.addBtn]} onPress={onAddAnother}>
+            <TouchableOpacity style={[styles.actionBtn, styles.addBtn, isProcessing && styles.btnDisabled]} onPress={onAddAnother} disabled={isProcessing}>
               <FontAwesomeIcon icon={faPlus} size={16} color={THEME.colors.text} style={{ marginRight: 8 }} />
               <Text style={styles.actionBtnText}>Weiteres Foto aufnehmen</Text>
             </TouchableOpacity>
           )}
 
           <View style={styles.rowActions}>
-            <TouchableOpacity style={[styles.smallBtn, styles.retakeBtn]} onPress={handleRetakeClick}>
+            <TouchableOpacity style={[styles.smallBtn, styles.retakeBtn, isProcessing && styles.btnDisabled]} onPress={handleRetakeClick} disabled={isProcessing}>
               <FontAwesomeIcon icon={faRotateLeft} size={14} color={THEME.colors.error} style={{ marginRight: 6 }} />
               <Text style={[styles.smallBtnText, { color: THEME.colors.error }]}>Wiederholen</Text>
             </TouchableOpacity>
 
-            <TouchableOpacity style={[styles.smallBtn, styles.resetBtn]} onPress={handleExit}>
+            <TouchableOpacity style={[styles.smallBtn, styles.resetBtn, isProcessing && styles.btnDisabled]} onPress={handleExit} disabled={isProcessing}>
               <FontAwesomeIcon icon={faRightFromBracket} size={14} color={THEME.colors.textMuted} style={{ marginRight: 6 }} />
               <Text style={styles.smallBtnText}>Beenden</Text>
             </TouchableOpacity>
@@ -747,6 +751,9 @@ const styles = StyleSheet.create({
     fontSize: 14,
     fontWeight: '600',
   },
+  btnDisabled: {
+    opacity: 0.5,
+  },
   // ── Photo Canvases ──
   singleCanvas: {
     width: 480,