objective C unable to switch views after scanning a QR code using ZBar

Question

I am developping an App using XCode 4.2 that detects a QR code.

I am trying to make a switch view after QR code detection but it is not working at all

here is the code am using :

- (void) imagePickerController: (UIImagePickerController*) reader
 didFinishPickingMediaWithInfo: (NSDictionary*) info
{

     AudioServicesPlaySystemSound(kSystemSoundID_Vibrate);


    // ADD: get the decode results
    id<NSFastEnumeration> results =
    [info objectForKey: ZBarReaderControllerResults];
    ZBarSymbol *symbol = nil;   
    for(symbol in results)
        break;


    NSString *string=symbol.data;
    NSString *string2=@"1234";

    if ([string isEqualToString:string2]) {

//this is the part that is not working : it doesn t load the AboutView at all

        AboutView *about = [[AboutView alloc] initWithNibName:nil bundle:nil];
        [self presentModalViewController:about animated:YES];
    }

    else{
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" 
                                                        message:@"This is not a recognized QR code!" 
                                                       delegate:self 
                                              cancelButtonTitle:@"OK" 
                                              otherButtonTitles:nil];
        [alert show];

    }

    // ADD: dismiss the controller (NB dismiss from the *reader*!)
    [reader dismissModalViewControllerAnimated: YES];
}

thanks

Answer 1

The issue is that the reader is the presented view controller in zbar's example code

-(void)presentReaderInViewController:(UIViewController*)vc

and you are treating self as if it is presented

You should use reader to present your AboutView and only dismiss reader in the else block

if ([string isEqualToString:string2]) {

//this is the part that is not working : it doesn t load the AboutView at all

        AboutView *about = [[AboutView alloc] initWithNibName:nil bundle:nil];
        [reader presentModalViewController:about animated:YES];
    }

    else{
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error" 
                                                        message:@"This is not a recognized QR code!" 
                                                       delegate:self 
                                              cancelButtonTitle:@"OK" 
                                              otherButtonTitles:nil];
        [alert show];
        // ADD: dismiss the controller (NB dismiss from the *reader*!)
    [reader dismissModalViewControllerAnimated: YES];
    }

You might also want to wait to dismiss reader in the delegate method of your alert view (create a soft reference and dismiss that... myReader = reader; when you set up the alertview)

- (void)alertView:(UIAlertView *)alertView didDismissWithButtonIndex:(NSInteger)buttonIndex{
    [myReader dismissModalViewControllerAnimated: YES];

}