Can't use AVCaptureDevice with a flash

Question

I am having difficult times, for something which I think ought to be simple. I just want to light the flash when taking a picture in my iOS app. And all I tried failed or works

Answer 1

I noticed, configuring the AVCaptureDevice, while the AVCaptureSession contained an AVCaptureDeviceInput reference caused this error. My solution was: before configuring an AVCaptureDevice object, remove the AVCaptureDeviceInput reference in the AVCaptureSession and read it when completed. I would no longer get the error with this approach. Example:

self.input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:&error];

. .

[self.session removeInput:self.input];
if ([device lockForConfiguration:NULL]) {
   device.focusMode = AVCaptureFocusModeContinuousAutoFocus;
   [device unlockForConfiguration];
}
[self.session addInput:self.input];