Left to right animation not working after upgrade to Swift 3.0

Question

So I just upgraded to Swift 3.0 from 2.3. Everything else about my project is fine except for this line of code and its error:

        if let delegate: AnyObject = completionDelegate {
        leftToRightTransition.delegate = delegate //ERROR MESSAGE
    }

The error message says:

Cannot assign value of type 'AnyObject' to type CAAnimation

Below is the full related block of code. Essentially this code is the animation. Elsewhere in my project (which I'm positive is not related to the problem, but just for context) there's code that allows the user to swipe through an array of images. This block is the animation part of it (the 'swipe away' animation'):

extension UIView {
func rightToLeftAnimation(_ duration: TimeInterval = 0.5, completionDelegate: AnyObject? = nil) {
    // Create a CATransition object
    let rightToLeftTransition = CATransition()

    // Set its callback delegate to the completionDelegate that was provided
    if let delegate: AnyObject = completionDelegate {
        rightToLeftTransition.delegate = delegate //ERROR MESSAGE ON THIS LINE
    }

    rightToLeftTransition.type = kCATransitionPush
    rightToLeftTransition.subtype = kCATransitionFromLeft
    rightToLeftTransition.duration = duration
    rightToLeftTransition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
    rightToLeftTransition.fillMode = kCAFillModeRemoved

    // Add the animation to the View's layer
    self.layer.add(rightToLeftTransition, forKey: "rightToLeftTransition")
}

This worked just fine in Swift 2.3 but now it doesn't work. It's little stuff like this that drives me nuts... Any help would be appreciated ;)

Answer 1

It's now a CAAnimationDelegate :

if let delegate = completionDelegate as? CAAnimationDelegate {
    rightToLeftTransition.delegate = delegate
}

Or just:

func rightToLeftAnimation(_ duration: TimeInterval = 0.5, completionDelegate: CAAnimationDelegate? = nil) {
    // Create a CATransition object
    let rightToLeftTransition = CATransition()

    // Set its callback delegate to the completionDelegate that was provided
    rightToLeftTransition.delegate = completionDelegate

    rightToLeftTransition.type = kCATransitionPush
    rightToLeftTransition.subtype = kCATransitionFromLeft
    rightToLeftTransition.duration = duration
    rightToLeftTransition.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseInEaseOut)
    rightToLeftTransition.fillMode = kCAFillModeRemoved

    // Add the animation to the View's layer
    layer.add(rightToLeftTransition, forKey: "rightToLeftTransition")
}

Answer 2

Try this , Its working in my code:

 let swipeRight:UISwipeGestureRecognizer = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.swipedRight))
        swipeRight.direction = .right
        SLIDEVIEW.addGestureRecognizer(swipeRight)


        let swipeLeft:UISwipeGestureRecognizer = UISwipeGestureRecognizer(target: self, action: #selector(ViewController.swipedLeft))
        swipeLeft.direction = .left
        SLIDEVIEW.addGestureRecognizer(swipeLeft)

func swipedRight()
    {
        print("swiped right")
        updateFrames(towards: "right")
    }

    func swipedLeft()
    {
        print("swiped left")
        updateFrames(towards: "left")
    }