Issue setting CABasicAnimation delegate in Swift 3?

Question

I'm getting the following error

Cannot assign value of type 'StarButton' to type 'CAAnimationDelegate?'

on the last line of this CABasicAnimation block:

 let fillCircle = CABasicAnimation(keyPath: "opacity")
 fillCircle.toValue = 0
 fillCircle.duration = 0.3
 fillCircle.setValue(notFavoriteKey, forKey: starKey)
 fillCircle.delegate = self // this is where the error is thrown

self is a custom UIButton class. This wasn't an issue in previous versions of Swift... any suggestions on a solution?

UPDATE

Here is a downloadable link to the source file for the StarButton class for best reference:

https://www.dropbox.com/s/gvc2sky05f4p3au/StarButton.swift?dl=0

`UIButton` from the Apple Docs (https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIButton_Class/) doesn't conform to `CAAnimationDelegate`. Did you explicitly say that your subclass was a delegate? See http://stackoverflow.com/questions/24024466/how-do-i-make-a-class-conform-to-a-delegate-in-swift — Doc, Jul 28 '16 at 22:58
@Fogmeister well this is part of an open source component I grabbed & after examining the file it doesn't seem to have any protocol's.. however this worked perfectly fine in swift 2.xx — Jared Garcia, Jul 28 '16 at 23:07
@Doc well this is part of an open source component I grabbed & after examining the file it doesn't seem to have any protocol's.. however this worked perfectly fine in swift 2.xx — Jared Garcia, Jul 28 '16 at 23:08
Maybe Swift 3 made protocol casts strict? Anyways you should still add the protocol; if the class supports being a delegate it should say so in the declaration — Doc, Jul 28 '16 at 23:11
Adding a protocol is like adding another superclass; if you have something like `class StarButton: UIButton`, replace with `class StarButton: UIButton, CABasicAnimationDelegate` — Doc, Jul 28 '16 at 23:39
Just replace the line `class StarButton: UIButton {` with `class StarButton: UIButton, CAAnimationDelegate {`. You might need to import CoreAnimation also — Doc, Jul 28 '16 at 23:46
that did it! haha, wow something that seemed so trivial @Doc — Jared Garcia, Jul 28 '16 at 23:54

score 10 · Answer 1 · answered Oct 11 '16 at 14:44

As @Doc mentioned in the comments above, the solution is to replace

class StarButton: UIButton {

with

class StarButton: UIButton, CAAnimationDelegate {

It would seem that the CAAnimationDelegate protocol is no longer implied and must be specified explicitly.

Issue setting CABasicAnimation delegate in Swift 3?

1 Answers1