QR image not detected by CIDetector - ios

Question

I am developing an app where I have displayed the detected data from a QR code but the problem is that QR code is not detected. I have used this code:
NSDictionary *detectorOptions = #{ CIDetectorAccuracy : CIDetectorAccuracyHigh };
CIDetector *faceDetector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:detectorOptions];
NSArray *features = [faceDetector featuresInImage:chosenImage.CIImage];
CIQRCodeFeature *faceFeature;
for(faceFeature in features)
{
qrcodedetected = YES;
self.decodedstr = [NSString stringWithFormat:#"%#",faceFeature.messageString];
break;
}
I have searched a lot but not succeeded. I have used this code from Apple default form. Every time I will get nil in result. If anybody has any solution regarding this then please share with me. It would be appreciated. Thanks in advance.

Answer 1

// initialize
AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
// create session
AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
dispatch_queue_t dispatchQueue = dispatch_queue_create("QRCodeQueue", NULL);
[captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
[captureMetadataOutput setMetadataObjectTypes:[captureMetadataOutput availableMetadataObjectTypes]];
[self.captureSession addOutput:captureMetadataOutput];
// add camera view layer
AVCaptureVideoPreviewLayer *captureLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
[captureLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
[captureLayer setFrame:self.view.layer.bounds];
[self.view.layer addSublayer:captureLayer];
// delegate method
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
// Specify the barcodes you want to read here:
NSArray *supportedBarcodeTypes = #[AVMetadataObjectTypeUPCECode, AVMetadataObjectTypeCode39Code, AVMetadataObjectTypeCode39Mod43Code, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode93Code, AVMetadataObjectTypeCode128Code, AVMetadataObjectTypePDF417Code, AVMetadataObjectTypeQRCode, AVMetadataObjectTypeAztecCode];
for (AVMetadataObject *barcodeMetadata in metadataObjects) {
for (NSString *supportedBarcode in supportedBarcodeTypes) {
if ([supportedBarcode isEqualToString:barcodeMetadata.type]) {
// get barcode object AVMetadataMachineReadableCodeObject
AVMetadataMachineReadableCodeObject *barcodeObject = (AVMetadataMachineReadableCodeObject *)[self.captureLayer transformedMetadataObjectForMetadataObject:barcodeMetadata];
NSString *capturedBarcode = [barcodeObject stringValue];
// do what you want...
}
}
}
}