I just want to turn the flash on for stitching photo's I'm trying to use AVCaptureDevice and AVCaptureFlashModeOn

Question

-(IBAction)turningFlashOn:(id)sender
{
AVCaptureSession *captureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice *videoCaptureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *videoInput = [AVCaptureDeviceInput deviceInputWithDevice:videoCaptureDevice error:&error];

if (videoInput) {
    [captureSession addInput:videoInput];



    AVCaptureVideoDataOutput* videoOutput = [[AVCaptureVideoDataOutput alloc] init];
    [videoOutput setSampleBufferDelegate:self queue:dispatch_get_current_queue()];
    [captureSession addOutput:videoOutput];
    [captureSession startRunning];
    videoCaptureDevice.torchMode = AVCaptureFlashModeOn;
}
}

I am being asked to use lockForConfiguration but it doesn't work or maybe i'm using it wrong. Can anyone please tell me what I'm doing wrong?

Answer 1

if([videoCaptureDevice lockForConfiguration]) {
  [videoCaptureDevice setTorchMode:AVCaptureTorchModeOn];
  [videoCaptureDevice unlockForConfiguration];
 }