Access Method After UIImageView Animation Finish - iphone

Question

I have an array of images loaded into a UIImageView that I am animating through one cycle. After the images have been displayed, I would like a #selector to be called in order to dismiss the current view controller. The images are animated fine with this code:
NSArray * imageArray = [[NSArray alloc] initWithObjects:
[UIImage imageNamed:#"HowTo1.png"],
[UIImage imageNamed:#"HowTo2.png"],
nil];
UIImageView * instructions = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
instructions.animationImages = imageArray;
[imageArray release];
instructions.animationDuration = 16.0;
instructions.animationRepeatCount = 1;
instructions.contentMode = UIViewContentModeBottomLeft;
[instructions startAnimating];
[self.view addSubview:instructions];
[instructions release];
After the 16 seconds, I would like a method to be called. I looked into the UIView class method setAnimationDidStopSelector: but I cannot get it to work with my current animation implementation. Any suggestions?
Thanks.

Answer 1

Use performSelector:withObject:afterDelay::
[self performSelector:#selector(animationDidFinish:) withObject:nil
afterDelay:instructions.animationDuration];
or use dispatch_after:
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, instructions.animationDuration * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
[self animationDidFinish];
});

Answer 2

You can simple use this category UIImageView-AnimationCompletionBlock
And for Swift version: UIImageView-AnimationImagesCompletionBlock
Take a look on ReadMe file in this class..
Add UIImageView+AnimationCompletion.h and UIImageView+AnimationCompletion.m files in project and them import UIImageView+AnimationCompletion.h file where you want to use this..
For eg.
NSMutableArray *imagesArray = [[NSMutableArray alloc] init];
for(int i = 10001 ; i<= 10010 ; i++)
[imagesArray addObject:[UIImage imageNamed:[NSString stringWithFormat:#"%d.png",i]]];
self.animatedImageView.animationImages = imagesArray;
self.animatedImageView.animationDuration = 2.0f;
self.animatedImageView.animationRepeatCount = 3;
[self.animatedImageView startAnimatingWithCompletionBlock:^(BOOL success){
NSLog(#"Animation Completed",);}];

Answer 3

There is no way to do this precisely with UIImageView. Using a delay will work most of the time, but there can be some lag after startAnimating is called before the animation happens on screen so its not precise. Rather than using UIImageView for this animation try using a CAKeyframeAnimation which will call a delegate method when the animation is finished. Something along these lines:
NSArray * imageArray = [[NSArray alloc] initWithObjects:
(id)[UIImage imageNamed:#"HowTo1.png"].CGImage,
(id)[UIImage imageNamed:#"HowTo2.png"].CGImage,
nil];
UIImageView * instructions = [[UIImageView alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
//create animation
CAKeyframeAnimation *anim = [CAKeyframeAnimation animation];
[anim setKeyPath:#"contents"];
[anim setValues:imageArray];
[anim setRepeatCount:1];
[anim setDuration:1];
anim.delegate = self; // delegate animationDidStop method will be called
CALayer *myLayer = instructions.layer;
[myLayer addAnimation:anim forKey:nil];
Then just implement the animationDidStop delegate method

Answer 4

With this method you avoid timers to fire while the imageView is still animating due to slow image loading.
You could use both performSelector: withObject: afterDelay: and GCD in this way:
[self performSelector:#selector(didFinishAnimatingImageView:)
withObject:imageView
afterDelay:imageView.animationDuration];
/!\ self.imageView.animationDuration has to bet configured before startAnimating, otherwise it will be 0
Than if -(void)didFinishAnimatingImageView:create a background queue, perform a check on the isAnimating property, than execute the rest on the main queue
- (void)didFinishAnimatingImageView:(UIImageView*)imageView
{
dispatch_queue_t backgroundQueue = dispatch_queue_create("com.yourcompany.yourapp.checkDidFinishAnimatingImageView", 0);
dispatch_async(backgroundQueue, ^{
while (self.imageView.isAnimating)
NSLog(#"Is animating... Waiting...");
dispatch_async(dispatch_get_main_queue(), ^{
/* All the rest... */
});
});
}

Answer 5

Created Swift Version from GurPreet_Singh Answer (UIImageView+AnimationCompletion)
I wasn't able to create a extension for UIImageView but I believe this is simple enough to use.
class AnimatedImageView: UIImageView, CAAnimationDelegate {
var completion: ((_ completed: Bool) -> Void)?
func startAnimate(completion: ((_ completed: Bool) -> Void)?) {
self.completion = completion
if let animationImages = animationImages {
let cgImages = animationImages.map({ $0.cgImage as AnyObject })
let animation = CAKeyframeAnimation(keyPath: "contents")
animation.values = cgImages
animation.repeatCount = Float(self.animationRepeatCount)
animation.duration = self.animationDuration
animation.delegate = self
self.layer.add(animation, forKey: nil)
} else {
self.completion?(false)
}
}
func animationDidStop(_ anim: CAAnimation, finished flag: Bool) {
completion?(flag)
}
}
let imageView = AnimatedImageView(frame: CGRect(x: 50, y: 50, width: 200, height: 135))
imageView.image = images.first
imageView.animationImages = images
imageView.animationDuration = 2
imageView.animationRepeatCount = 1
view.addSubview(imageView)
imageView.startAnimate { (completed) in
print("animation is done \(completed)")
imageView.image = images.last
}

Answer 6

You can create a timer to fire after the duration of your animation. The callback could process your logic you want to execute after the animation finishes. In your callback be sure check the status of the animation [UIImageView isAnimating] just in case you want more time to let the animation finish.

Answer 7

in ImageView.m
- (void) startAnimatingWithCompleted:(void (^)(void))completedHandler {
if (!self.isAnimating) {
[self startAnimating];
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, self.animationDuration * NSEC_PER_SEC);
dispatch_after(popTime, dispatch_get_main_queue(),completedHandler);
}}