ios - How to rotate orientation programmatically in Swift?

Question

I tried the next:

UIDevice.currentDevice().setValue(UIInterfaceOrientation.Portrait.rawValue, forKey: "orientation")

on

viewWillAppear

but it does not work. How can I rotate my screen on viewWillAppear?

UPDATE

I use the next code for locking an orientation:

var shouldRotate = true
func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> Int {
    if shouldRotate == true {
        return Int(UIInterfaceOrientationMask.Portrait.rawValue)
    } else {
        return Int(UIInterfaceOrientationMask.LandscapeLeft.rawValue)
    }
}

Swift 4.0

  private func application(application: UIApplication, supportedInterfaceOrientationsForWindow window: UIWindow?) -> Int {
        if shouldRotate == true {
            return Int(UIInterfaceOrientationMask.portrait.rawValue)
        } else {
            return Int(UIInterfaceOrientationMask.landscapeLeft.rawValue)
        }
    }

and in my FIRST controller in viewWillAppear I set:

if let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate {
    appDelegate.shouldRotate = true
}

in my SECOND controller:

if let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate {
    appDelegate.shouldRotate = false
}

so, when I back from SECOND controller to the FIRST:

I rotate it to left - does not rotate, rotate back to right - nothing, rotate to left, again - it rotates.

How can I fix it?

Answer 1

To change orientation programatically in swift 3, use the following way:

let value = UIInterfaceOrientation.landscapeRight.rawValue
UIDevice.current.setValue(value, forKey: "orientation")

You can use the orientations,

1. portrait 2. portraitUpsideDown 3. landscapeLeft 4. landscapeRight