Add permission callback

@@ -9,6 +9,9 @@ class MobileScanner extends StatefulWidget {
   /// The controller of the camera.
   final MobileScannerController? controller;
 
+  /// Calls the provided [onPermissionSet] callback when the permission is set.
+  final Function(bool permissionGranted)? onPermissionSet;
+
   /// Function that gets called when a Barcode is detected.
   ///
   /// [barcode] The barcode object with all information about the scanned code.
@@ -34,6 +37,7 @@ class MobileScanner extends StatefulWidget {
     this.controller,
     this.fit = BoxFit.cover,
     this.allowDuplicates = false,
+    this.onPermissionSet,
   }) : super(key: key);
 
   @override
@@ -48,7 +52,7 @@ class _MobileScannerState extends State<MobileScanner>
   void initState() {
     super.initState();
     WidgetsBinding.instance.addObserver(this);
-    controller = widget.controller ?? MobileScannerController();
+    controller = widget.controller ?? MobileScannerController(onPermissionSet: widget.onPermissionSet);
   }
 
   @override
@@ -121,7 +125,7 @@ class _MobileScannerState extends State<MobileScanner>
       }
     } else {
       if (widget.controller == null) {
-        controller = MobileScannerController();
+        controller = MobileScannerController(onPermissionSet: widget.onPermissionSet);
       } else if (oldWidget.controller != widget.controller) {
         controller = widget.controller!;
       }

@@ -38,6 +38,7 @@ class MobileScannerController {
   int? _controllerHashcode;
   StreamSubscription? events;
 
+  Function(bool permissionGranted)? onPermissionSet;
   final ValueNotifier<MobileScannerArguments?> args = ValueNotifier(null);
   final ValueNotifier<TorchState> torchState = ValueNotifier(TorchState.off);
   late final ValueNotifier<CameraFacing> cameraFacingState;
@@ -60,6 +61,7 @@ class MobileScannerController {
     this.ratio,
     this.torchEnabled,
     this.formats,
+    this.onPermissionSet,
   }) {
     // In case a new instance is created before calling dispose()
     if (_controllerHashcode != null) {
@@ -142,11 +144,14 @@ class MobileScannerController {
           state = result
               ? MobileScannerState.authorized
               : MobileScannerState.denied;
+          onPermissionSet?.call(result);
           break;
         case MobileScannerState.denied:
           isStarting = false;
+          onPermissionSet?.call(false);
           throw PlatformException(code: 'NO ACCESS');
         case MobileScannerState.authorized:
+          onPermissionSet?.call(true);
           break;
       }
     }
@@ -177,6 +182,9 @@ class MobileScannerController {
     } on PlatformException catch (error) {
       debugPrint('${error.code}: ${error.message}');
       isStarting = false;
+      if (error.code == "MobileScannerWeb") {
+        onPermissionSet?.call(false);
+      }
       // setAnalyzeMode(AnalyzeMode.none.index);
       return;
     }
@@ -189,6 +197,8 @@ class MobileScannerController {
     hasTorch = startResult['torchable'] as bool;
 
     if (kIsWeb) {
+      onPermissionSet?.call(true);  // If we reach this line, it means camera permission has been granted
+
       args.value = MobileScannerArguments(
         webId: startResult['ViewID'] as String?,
         size: Size(
@@ -272,6 +282,7 @@ class MobileScannerController {
       events?.cancel();
       events = null;
       _controllerHashcode = null;
+      onPermissionSet = null;
     }
     barcodesController.close();
   }