从Objective-C到Swift的翻译问题

Question

I'm trying to translate this simple line of code to Swift, but can't figure out how to write it:

AVCaptureConnection *videoConnection = nil;

I've tried:

    let videoConnection: AVCaptureConnection = nil

    let videoConnection: AVCaptureConnection = false

    var videoConnection:AVCaptureConnection = AVCaptureConnection()
            videoConnection = nil

    var videoConnection:AVCaptureConnection = AVCaptureConnection()
            videoConnection = false

var videoConnection:AVCaptureConnection = AVCaptureConnection()
            videoConnection.active = false

var videoConnection:AVCaptureConnection = AVCaptureConnection()
            videoConnection.active = nil

Any suggestions on how to write this is Swift would be appreciated.

Answer 1

If you want to "initialize" something with nil it has to be an Optional. So

var videoConnection: AVCaptureConnection? = nil

or

var videoConnection: AVCaptureConnection?

would be right.

Answer 2

I believe it would be:

let videoConnection: AVCaptureConnection = UnsafePointer<Int8>.null()

Since Swift sort of conceals pointers from you (except that objects are really pointer references to the objects) and direct pointer manipulation, you sometimes have to contort yourself a bit. :)