Merge pull request #880 from navaronbracke/fix_android_permission

fix: Fix android permission bug

@@ -45,7 +45,7 @@ class MobileScannerPermissions {
         return if (hasPermission) {
             1
         } else {
-            0
+            2
         }
     }
 
@@ -70,6 +70,7 @@ class MobileScannerPermissions {
                 object: ResultCallback {
                     override fun onResult(errorCode: String?, errorDescription: String?) {
                         ongoing = false
+                        listener = null
                         callback.onResult(errorCode, errorDescription)
                     }
                 }

@@ -189,8 +189,9 @@ class MobileScannerController {
       final MobileScannerState state;
 
       try {
-        state = MobileScannerState
-            .values[await _methodChannel.invokeMethod('state') as int? ?? 0];
+        state = MobileScannerState.fromRawValue(
+          await _methodChannel.invokeMethod('state') as int? ?? 0,
+        );
       } on PlatformException catch (error) {
         isStarting = false;
 
@@ -205,32 +206,33 @@ class MobileScannerController {
       }
 
       switch (state) {
+        // Android does not have an undetermined permission state.
+        // So if the permission state is denied, just request it now.
         case MobileScannerState.undetermined:
-          bool result = false;
-
+        case MobileScannerState.denied:
           try {
-            result =
+            final bool granted =
                 await _methodChannel.invokeMethod('request') as bool? ?? false;
-          } catch (error) {
+
+            if (!granted) {
               isStarting = false;
               throw const MobileScannerException(
-              errorCode: MobileScannerErrorCode.genericError,
+                errorCode: MobileScannerErrorCode.permissionDenied,
               );
             }
-
-          if (!result) {
+          } on PlatformException catch (error) {
             isStarting = false;
-            throw const MobileScannerException(
-              errorCode: MobileScannerErrorCode.permissionDenied,
+            throw MobileScannerException(
+              errorCode: MobileScannerErrorCode.genericError,
+              errorDetails: MobileScannerErrorDetails(
+                code: error.code,
+                details: error.details as Object?,
+                message: error.message,
+              ),
             );
           }
 
           break;
-        case MobileScannerState.denied:
-          isStarting = false;
-          throw const MobileScannerException(
-            errorCode: MobileScannerErrorCode.permissionDenied,
-          );
         case MobileScannerState.authorized:
           break;
       }