Rotate NSView 360 degrees

Question

I have this code below to rotate a UIView 360 degrees. It is an extension file of UIView.

extension NSView {
func rotate360Degrees(duration: CFTimeInterval = 0.5, completionDelegate: AnyObject? = nil) {
    let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
    rotateAnimation.fromValue = 0.0
    rotateAnimation.toValue = CGFloat(M_PI * 2.0)
    rotateAnimation.duration = duration

    if let delegate: AnyObject = completionDelegate {
        rotateAnimation.delegate = delegate
    }
    self.layer.addAnimation(rotateAnimation, forKey: nil)

}
}

When the button is clicked I then use refreshButton.rotate360Degrees() to start the animation.

I would like to recreate this for NSView but It does not seem to be working using the code above. Thanks

Answer 1

It works but you have to change two things:

extension NSView {
    func rotate360Degrees(duration: CFTimeInterval = 0.5, completionDelegate: AnyObject? = nil) {
        let rotateAnimation = CABasicAnimation(keyPath: "transform.rotation")
        rotateAnimation.fromValue = 0.0
        rotateAnimation.toValue = CGFloat(M_PI * 2.0)
        rotateAnimation.duration = duration
        if let delegate: AnyObject = completionDelegate {
            rotateAnimation.delegate = delegate
        }
        // `addAnimation` will execute *only* if the layer exists
        self.layer?.addAnimation(rotateAnimation, forKey: nil)
    }
}

• Add a ? after self.layer to allow conditional execution if the layer isn't available.

You could use if let ... if you prefer:

    if let theLayer = self.layer {
        theLayer.addAnimation(rotateAnimation, forKey: nil)
    } 

• Set wantsLayer to true for your view, to force the view to be layer-backed (views are not automatically layer-backed on OS X).