Swift compiler error: Cannot invoke 'lockForConfiguration' with an argument list of type '(() -> ())'

Question

This is Swift 2. I can't seem to find anything on this. I am getting the error

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Cannot invoke 'lockForConfiguration' with an argument list of type '(() -> ())'

On the second line here.

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if let device = captureDevice {
            device.lockForConfiguration() {
                device.videoZoomFactor = 1.0 + CGFloat(ratioValue)
                device.unlockForConfiguration()
        }
        print(ratioValue)
    }

Answer 1

In Swift 2 the method lockForConfiguration doesn't take any arguments but instead can throw an NSError. You should wrap it in a do-try-catch statement.

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do {
    try device.lockForConfiguration()
} catch {
    // handle error
    return
}

// When this point is reached, we can be sure that the locking succeeded
device.videoZoomFactor = 1.0 + CGFloat(ratioValue)
device.unlockForConfiguration()