Unable to dismiss ZBarReaderViewController in imagePickerController didFinishPickingMediaWithInfo

Question

Hi I'm developing a QR code reader app and having so much trouble when dismissing the ZBarReaderViewController. I have a view controller with a button which creates the reader and presents it.

- (IBAction)scanAction:(id)sender {

    ZBarReaderViewController *reader = [ZBarReaderViewController new];


    reader.readerDelegate = self;
    [reader.scanner setSymbology: ZBAR_I25
                               config: ZBAR_CFG_ENABLE
                                   to: 0];
    reader.readerView.zoom = 1.0;

//    [self presentViewController:reader animated:YES completion:nil];
    [self presentModalViewController:reader animated:YES];
}

Then on the reader's delegate I'm doing this (I commented the results processing lines but I still get the same error):

- (void) imagePickerController: (UIImagePickerController*) reader
 didFinishPickingMediaWithInfo: (NSDictionary*) info
{
//    id<NSFastEnumeration> results =  [info objectForKey: ZBarReaderControllerResults];
//    
//    ZBarSymbol *symbol = nil;
//    NSURL *url;
//    NSString * textUrl;
//    
//    for(symbol in results){
//        textUrl = symbol.data;
//        NSLog(@"%@",textUrl);
//        url = [NSURL URLWithString:textUrl];
//        break;
//    }
//    
//    if (url != nil) {
////        NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
////        [self.webView loadRequest:requestObj];
//        [self.urlLabel setText:textUrl];
//    }

//    [reader dismissViewControllerAnimated:NO completion:nil];
    [reader dismissModalViewControllerAnimated:YES];
}

and this is the error I get randomly:

QR reader[10159:907] Warning: Attempt to dismiss from view controller <ViewController: 0x1ed4c930> while a presentation or dismiss is in progress!

Sometimes it scans and dismiss without any warning but when I get that warning the reader stays scanning, and the delegate gets called again until no more warnings are showed.

I tried some suggestions from other users having the same problem but it won't work in my particular case:

using dismissModalViewController instead of modal view which is deprecated.
sorrounding the results processing in the completion block of the dismissViewControllerAnimated method.

Thanks for reading :)

score 1 · Answer 1 · answered Nov 30 '13 at 22:47

Had the same issue and performSeletor:withObject:afterDelay: works fine for me.

- (void)imagePickerController:(UIImagePickerController *)reader didFinishPickingMediaWithInfo:(NSDictionary *)info {
     // do some userful stuff

     [self performSelector:@selector(dismissZBar) withObject:nil afterDelay:1];
}

- (void)dismissZBar {
     [self.presentedViewController dismissViewControllerAnimated:YES completion:^{
          // do some stuff after dismiss
      }];
}

Unable to dismiss ZBarReaderViewController in imagePickerController didFinishPickingMediaWithInfo

1 Answers1