CoreAnimation - Opacity Fade In and Out Animation Not Working

Question

I\'m attempting to create a fairly simple CoreAnimation for use in an AVComposition. My goal is to create a CALayer which, through various sublayer

Answer 1

Look at my answer https://stackoverflow.com/a/44204846/667483

In summary: to use beginTime you should set fillMode to kCAFillModeBackwards on you animation object.

Answer 2

The point is key name. You have to set the opacity key.

layer.add(animation, forKey: nil)         // Not Working
layer.add(animation, forKey: "opacity")   // Working

Check the sample code. I tested in Swift 4

    let animation                   = CAKeyframeAnimation()
    animation.duration              = 1.53
    animation.autoreverses          = false
    animation.keyTimes              = [0, 0.51, 0.85, 1.0]
    animation.values                = [0.5, 0.5, 1.0, 0.5]
    animation.beginTime             = 0
    animation.isRemovedOnCompletion = false
    animation.fillMode              = kCAFillModeBoth
    animation.repeatCount           = .greatestFiniteMagnitude
    layer.add(animation, forKey: "opacity")

Answer 3

Try:

fadeInAnimation.beginTime = CACurrentMediaTime()+1.0;

Answer 4

I'm faced the same issue and the problem is - one layer can't contain fade in and out. So you can add the other animation to the parent layer as i did

CALayer *parentLayer = [CALayer layer];
CALayer *animtingLayer = [CALayer layer];

//FADE IN
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation.beginTime = CMTimeGetSeconds(img.startTime);
        animation.duration = CMTimeGetSeconds(_timeline.transitionDuration);
        animation.fromValue = [NSNumber numberWithFloat:0.0f];
        animation.toValue = [NSNumber numberWithFloat:1.0f];
        animation.removedOnCompletion = NO;
        animation.fillMode = kCAFillModeBoth;
        animation.additive = NO;
        [parentLayer addAnimation:animation forKey:@"opacityIN"];

//FADE OUT
        CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"opacity"];
        animation.beginTime = CMTimeGetSeconds(CMTimeAdd(img.passTimeRange.start, img.passTimeRange.duration));
        animation.duration = CMTimeGetSeconds(_timeline.transitionDuration);
        animation.fromValue = [NSNumber numberWithFloat:1.0f];
        animation.toValue = [NSNumber numberWithFloat:0.0f];
        animation.removedOnCompletion = NO;
        animation.fillMode = kCAFillModeBoth;
        animation.additive = NO;
        [animtingLayer addAnimation:animation forKey:@"opacityOUT"];

    [parentLayer addSublayer:animtingLayer];

Answer 5

Man, so many complicated answers. The simplest way is just to add autoreverse. Voila.

CABasicAnimation *fadeInAndOut = [CABasicAnimation animationWithKeyPath:@"opacity"];
fadeInAndOut.duration = 5.0;
fadeInAndOut.autoreverses = YES;
fadeInAndOut.fromValue = [NSNumber numberWithFloat:0.0];
fadeInAndOut.toValue = [NSNumber numberWithFloat:1.0];
fadeInAndOut.repeatCount = HUGE_VALF;
fadeInAndOut.fillMode = kCAFillModeBoth;
[titleLayer addAnimation:fadeInAndOut forKey:@"myanimation"];