Zbar sdk scanner not working properly - ios

Question

In my application i have integrated Zbar SDK scanner, while scanning usually its working fine but my case is some times didfinishpickingmediawithInfo: delegate method firing twice. Here is my code which is in a singletone class.
-(void)scanProductBarCode
{
ZBarReaderViewController *reader = [ZBarReaderViewController new];
reader.readerDelegate = self;
if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
reader.supportedOrientationsMask = ZBarOrientationMaskLandscape;
else
reader.supportedOrientationsMask = ZBarOrientationMaskPortrait;
ZBarImageScanner *scanner = reader.scanner;
[scanner setSymbology: ZBAR_UPCA config: ZBAR_CFG_ENABLE to: 1];
[scanner setSymbology: ZBAR_CODE39 config: ZBAR_CFG_ADD_CHECK to: 0];
}
#pragma mark - Scanner delegate methods
- (void) imagePickerController: (UIImagePickerController*) reader didFinishPickingMediaWithInfo: (NSDictionary*) info
{
id<NSFastEnumeration> results = [info objectForKey: ZBarReaderControllerResults];
ZBarSymbol *symbol = nil;
for(symbol in results)
break;
barCodeString = [[NSString alloc] initWithString:symbol.data];
if(self.delegate)
[self.delegate getBarcodeString:barCodeString];
[reader dismissModalViewControllerAnimated:YES];
}
See this screen shot:
At background the scanner is still running like this in twice occuring case..

Answer 1

I ran into the same problem. I added a BOOL instance variable to my class named _processing. Then I did this:
- (void)imagePickerController:(UIImagePickerController*)reader didFinishPickingMediaWithInfo:(NSDictionary*)info
{
if (_processing) return;
id<NSFastEnumeration> results = [info objectForKey:ZBarReaderControllerResults];
ZBarSymbol *symbol = nil;
for(symbol in results) {
_processing = YES;
barCodeString = symbol.data;
if(self.delegate) {
[self.delegate getBarcodeString:barCodeString];
}
break;
}
[reader dismissModalViewControllerAnimated:YES];
}
This ensures that only the first call is processed. You may need to reset _processing if you plan to reuse the view controller more than once.

Answer 2

Since the ZBarReaderViewController scans the image in continuous mode, it could be that the image is scanned twice before you dismiss the ZBarReaderViewController. You may try making the reader (ZBarReaderViewController *reader ) an instance variable of your class, and in the delegate method:
- (void)imagePickerController:(UIImagePickerController*)reader didFinishPickingMediaWithInfo:(NSDictionary*)info
{
// Stop further scanning
[reader.readerView stop];
...
//Continue with processing barcode data.
}