Recently appeared Apple’s technical note QA1673 describes how to pause/resume layer’s animation.
Pause and resume animations listing is below:
-(void)pauseLayer:(CALayer*)layer
{
CFTimeInterval pausedTime = [layer convertTime:CACurrentMediaTime() fromLayer:nil];
layer.speed = 0.0;
layer.timeOffset = pausedTime;
}
-(void)resumeLayer:(CALayer*)layer
{
CFTimeInterval pausedTime = [layer timeOffset];
layer.speed = 1.0;
layer.timeOffset = 0.0;
layer.beginTime = 0.0;
CFTimeInterval timeSincePause = [layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
layer.beginTime = timeSincePause;
}
Edit:
iOS 10 introduced new API – UIViewPropertyAnimator that allows to handle animations more interactively, for example it makes easy to pause and resume animation or ‘seek’ it to some particular progress value.