如何锁定AVfoundation中的白平衡以获得快速？

Question

我正在尝试锁定我的iPhone，使相机的白平衡恢复到当前状态，但是从将Objective-c代码转换为swift方面我遇到了麻烦。这是objective-c中的代码：

[device setWhiteBalanceMode:AVCaptureWhiteBalanceModeLocked];

这就是我认为swift中的代码应该是这样的：

captureDevice.setWhiteBalanceMode(AVCaptureWhiteBalanceMode.Locked)

和Xcode告诉我：

'AVCaptureDevice' does not have a member named 'setWhiteBalanceMode'

Answer 1

        if captureDevice.lockForConfiguration(nil) {
            var gains: AVCaptureWhiteBalanceGains = AVCaptureWhiteBalanceGainsCurrent
            captureDevice.setWhiteBalanceModeLockedWithDeviceWhiteBalanceGains(gains, completionHandler:nil);
            captureDevice.unlockForConfiguration()
        }