CABasicAnimation resets to initial value after animation completes

Question

I am rotating a CALayer and trying to stop it at its final position after animation is completed.

But after animation completes it resets to its initial position.

Answer 1

The easiest solution is to use implicit animations. This will handle all of that trouble for you:

self.layer?.backgroundColor = NSColor.red.cgColor;

If you want to customize e.g. the duration, you can use NSAnimationContext:

    NSAnimationContext.beginGrouping();
    NSAnimationContext.current.duration = 0.5;
    self.layer?.backgroundColor = NSColor.red.cgColor;
    NSAnimationContext.endGrouping();

Note: This is only tested on macOS.

I initially did not see any animation when doing this. The problem is that the layer of a view-backed layer does not implicit animate. To solve this, make sure you add a layer yourself (before setting the view to layer-backed).

An example how to do this would be:

override func awakeFromNib() {
    self.layer = CALayer();
    //self.wantsLayer = true;
}

Using self.wantsLayer did not make any difference in my testing, but it could have some side effects that I do not know of.