Animation End Callback for CALayer?

Question

I'm wondering where the callbacks are (or if there are anything) for animations in a CALayer. Specifically, for implied animations like altering the frame, position, etc. In a UIView, you could do something like this:

[UIView beginAnimations:@"SlideOut" context:nil];
[UIView setAnimationDuration:.3];
[UIView setAnimationDelegate:self];
[UIView setAnimationDidStopSelector:@selector(animateOut:finished:context:)];
CGRect frame = self.frame;
frame.origin.y = 480;
self.frame = frame;
[UIView commitAnimations];

Specifically, the setAnimationDidStopSelector is what I want for an animation in a CALayer. Is there anything like that?

TIA.

Answer 1

Wasted 4 hours with this garbage, just to do a fade in fade out. Note the comment in the code.

   [CATransaction begin];
    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
    animation.duration = 0.3;
    animation.fromValue = [NSNumber numberWithFloat:0.0f];
    animation.toValue = [NSNumber numberWithFloat:1.0f];
    animation.removedOnCompletion = NO;
    animation.fillMode = kCAFillModeBoth;
  ///  [box addAnimation:animation forKey:@"j"]; Animation will not work if added here. Need to add this only after the completion block.

    [CATransaction setCompletionBlock:^{

        CABasicAnimation *animation2 = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation2.duration = 0.3;
        animation2.beginTime = CACurrentMediaTime()+1;
        animation2.fromValue = [NSNumber numberWithFloat:1.0f];
        animation2.toValue = [NSNumber numberWithFloat:0.0f];
        animation2.removedOnCompletion = NO;
        animation2.fillMode = kCAFillModeBoth;
        [box addAnimation:animation2 forKey:@"k"];

    }];

    [box addAnimation:animation forKey:@"j"];

    [CATransaction commit];

Answer 2

You could use a CATransaction, it has a completion block handler.

[CATransaction begin];
CABasicAnimation *pathAnimation = [CABasicAnimation animationWithKeyPath:@"strokeEnd"];
[pathAnimation setDuration:1];
[pathAnimation setFromValue:[NSNumber numberWithFloat:0.0f]];    
[pathAnimation setToValue:[NSNumber numberWithFloat:1.0f]];
[CATransaction setCompletionBlock:^{_lastPoint = _currentPoint; _currentPoint = CGPointMake(_lastPoint.x + _wormStepHorizontalValue, _wormStepVerticalValue);}];
[_pathLayer addAnimation:pathAnimation forKey:@"strokeEnd"];
[CATransaction commit];

Answer 3

Here is an answer in Swift 3.0 based on bennythemink's solution:

    // Begin the transaction
    CATransaction.begin()
    let animation = CABasicAnimation(keyPath: "strokeEnd")
    animation.duration = duration //duration is the number of seconds
    animation.fromValue = 0
    animation.toValue = 1
    animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionLinear)
    circleLayer.strokeEnd = 1.0

    // Callback function
    CATransaction.setCompletionBlock { 
        print("end animation")
    }

    // Do the actual animation and commit the transaction
    circleLayer.add(animation, forKey: "animateCircle")
    CATransaction.commit()