How to pause UIView Animations - ios

Question

in iOS5.0 using blocks, say if we have an UIViewAnimationOptionAutoreverse animation, and need to put in a delay before the reverse animation starts.. how can we do this?
Thanks for your help on this

Answer 1

The best way to pause and resume animation :
add QuartzCore framework
then use the following apple's code
-(void) pause
{
CFTimeInterval pausedTime = [m_pCustomImageBtnObj.layer convertTime:CACurrentMediaTime() fromLayer:nil];
obj.layer.speed = 0.0;
obj.layer.timeOffset = pausedTime;
}
-(void) resume
{
CFTimeInterval pausedTime = [obj.layer timeOffset];
obj.layer.speed = 1.0;
obj.layer.timeOffset = 0.0;
obj.layer.beginTime = 0.0;
CFTimeInterval timeSincePause = [obj.layer convertTime:CACurrentMediaTime() fromLayer:nil] - pausedTime;
obj.layer.beginTime = timeSincePause;
}

Answer 2

You can try animation completion block like this:
[UIView animateWithDuration:0.6 animations:^(void)
{
self.label.bounds = CGRectMake(10, 10, 200, 200);
}completion:^(BOOL finished) {
[UIView animateWithDuration:0.6 animations:^(void)
{
self.label.bounds = CGRectMake(10, 10, 100, 100);
}completion:^(BOOL finished) {
}];
}];

Answer 3

You should use keyframe animation for that. Here is a piece of code to do rotation with reversing:
self.animations = [NSDictionary dictionaryWithObjects:
[NSArray arrayWithObjects:
[CAKeyframeAnimation animationWithKeyPath:#"transform.rotation.z"],
[CAKeyframeAnimation animationWithKeyPath:#"transform.rotation.z"]
, nil ]
forKeys:
[NSArray arrayWithObjects: THERE_ANIM_KEY, BACK_AGAIN_ANIM_KEY , nil ]];
CAKeyframeAnimation *kfAnim = [animations objectForKey: THERE_ANIM_KEY];
kfAnim.duration = 2;
kfAnim.repeatCount = 1;
kfAnim.values = [NSArray arrayWithObjects:
[NSNumber numberWithFloat: 0.0 * M_PI],
[NSNumber numberWithFloat: 1.0 * M_PI],
[NSNumber numberWithFloat: 2.0 * M_PI],
[NSNumber numberWithFloat: 2.0 * M_PI], //here is delay
[NSNumber numberWithFloat: 1.0 * M_PI],
[NSNumber numberWithFloat: 0.0 * M_PI],
nil];
kfAnim.keyTimes = [NSArray arrayWithObjects:
[NSNumber numberWithFloat: 0.0 ],
[NSNumber numberWithFloat: 0.3 ],
[NSNumber numberWithFloat: 0.5 ], //time of delaying in proportion of general animation duration
[NSNumber numberWithFloat: 0.5 ],
[NSNumber numberWithFloat: 0.8 ],
[NSNumber numberWithFloat: 1.0 ], nil];
Also you can use remember initial state and animate back in
(void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
animation delegate method with using performSelector:withObject:afterDelay:. This is much simplier and easy to set up delay.

Answer 4

Not sure if this is exactly what you're trying to do, but here's what I'm using to move a view onto the screen, pause for 1 second, and then move view off the screen.
[UIView animateWithDuration:0.5 animations:^{
self.view.frame = viewFrameOnScreen;
self.view.alpha = 1.0;
} completion:^(BOOL finished){
[UIView animateWithDuration:0.5 delay:1 options:0 animations:^{
self.view.frame = viewFrameOffScreen;
self.view.alpha = 0.0f;
} completion:^(BOOL finished){}];
}];

Answer 5

RIAZ answer in Swift 3:
func pauseAnimation() {
let pausedTime = obj.layer.convertTime(CACurrentMediaTime(), from: nil)
obj.layer.speed = 0.0
obj.layer.timeOffset = pausedTime
}
func resumeAnimation() {
let pausedTime = obj.layer.timeOffset
obj.layer.speed = 1.0
obj.layer.timeOffset = 0.0
obj.layer.beginTime = 0.0
let timeSincePause = obj.layer.convertTime(CACurrentMediaTime(), from: nil) - pausedTime
obj.layer.beginTime = timeSincePause
}