From http://stackoverflow.com/questions/1255086/how-to-identify-caanimation-within-the-animationdidstop-delegate

CAAnimation Completion Block

//I created a typedef for a block:

typedef void (^animationCompletionBlock)(void);

// And a key that I use to add a block to an animation:
#define kAnimationCompletionBlock @"animationCompletionBlock"

// Then, if I want to run animation completion code after a CAAnimation finishes, I set myself as the delegate of the animation, and add a block of code to the animation using setValue:forKey:
animationCompletionBlock theBlock = ^void(void)
{
  //Code to execute after the animation completes goes here    
};
[theAnimation setValue: theBlock forKey: kAnimationCompletionBlock];
// Then, I implement an animationDidStop:finished: method, that checks for a block at the specified key and executes it if found:

- (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag
{
  animationCompletionBlock theBlock = [theAnimation valueForKey: kAnimationCompletionBlock];
  if (theBlock)
    theBlock();
}