Turn on torch/flash on iPhone

Question

I know that the only way to turn on the flash and keep it on on iPhone 4 is by turning the video camera on. I'm not too sure of the code though. Here is what I am trying:

-(IBAction)turnTorchOn {
    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 = AVCaptureTorchModeOn;
    }   
}

Does anybody know if this would work or am I missing anything? (I don't have an iPhone 4 yet to test on -just trying out some of the new API's).

Thanks

Answer 1

the lockforConfiguration is set in your code, where you declare your AVCaptureDevice is a property.

[videoCaptureDevice lockForConfiguration:nil];