Swift 2.0类型'（）'不符合协议

Question

I'm implementing this method while using the camera in a view controller

let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

//... code
if let device = captureDevice {
            do {
                if (try device.lockForConfiguration()) {
                    device.focusPointOfInterest = focusPoint
                    device.focusMode = AVCaptureFocusMode.ContinuousAutoFocus
                    device.exposurePointOfInterest = focusPoint
                    device.exposureMode = AVCaptureExposureMode.ContinuousAutoExposure
                    device.unlockForConfiguration()
                }
            }
            catch {
                print("Error")
            }
        }
//... code

Trying to convert to Swift 2.0 I found this error Type '()' does not conform to protocol to 'BooleanType' at line

if (try device.lockForConfiguration())

Actually I'm trying to figure out how to solve this, how can I make this a 'BooleanType' ? In Swift 1.2 my code was simply

if (device.lockForConfiguration())

Thanks in advance.

Answer 1

It looks that lockForConfiguration returns Void and throws, so return value does not conform to BooleanType.

I think that the following code should work for you:

if let device = captureDevice {
    do {
        try device.lockForConfiguration()
        device.focusPointOfInterest = focusPoint
        device.focusMode = AVCaptureFocusMode.ContinuousAutoFocus
        device.exposurePointOfInterest = focusPoint
        device.exposureMode = AVCaptureExposureMode.ContinuousAutoExposure
        device.unlockForConfiguration()
    }
    catch {
        print("Error")
    }
}