add hasCameraPermission getter

example/lib/barcode_scanner_controller.dart

@@ -60,7 +60,7 @@ class _BarcodeScannerWithControllerState
 
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
-    if (!controller.value.isInitialized) {
+    if (!controller.value.hasCameraPermission) {
       return;
     }
 

lib/src/mobile_scanner.dart

@@ -281,8 +281,7 @@ class _MobileScannerState extends State<MobileScanner>
 
   @override
   void didChangeAppLifecycleState(AppLifecycleState state) {
-    if (widget.controller != null) return;
-    if (!controller.value.isInitialized) {
+    if (widget.controller != null || !controller.value.hasCameraPermission) {
       return;
     }
 

lib/src/objects/mobile_scanner_state.dart

@@ -1,6 +1,7 @@
 import 'dart:ui';
 
 import 'package:mobile_scanner/src/enums/camera_facing.dart';
+import 'package:mobile_scanner/src/enums/mobile_scanner_error_code.dart';
 import 'package:mobile_scanner/src/enums/torch_state.dart';
 import 'package:mobile_scanner/src/mobile_scanner_exception.dart';
 
@@ -43,7 +44,8 @@ class MobileScannerState {
 
   /// Whether the mobile scanner has initialized successfully.
   ///
-  /// This is `true` if the camera is ready to be used.
+  /// This does not indicate that the camera permission was granted.
+  /// To check if the camera permission was granted, use [hasCameraPermission].
   final bool isInitialized;
 
   /// Whether the mobile scanner is currently running.
@@ -60,6 +62,12 @@ class MobileScannerState {
   /// The current zoom scale of the camera.
   final double zoomScale;
 
+  /// Whether permission to access the camera was granted.
+  bool get hasCameraPermission {
+    return isInitialized &&
+        error?.errorCode != MobileScannerErrorCode.permissionDenied;
+  }
+
   /// Create a copy of this state with the given parameters.
   MobileScannerState copyWith({
     int? availableCameras,