Question

I animate 2 views, each one with its CAAnimationGroup that contains 2 CAAnimations. They are launched at the same time (if computing time is negligible), and have the same duration.

How may I do to know when both grouped animation is finished.

I put the - (void)animationDidStop:(CAAnimation *)theAnimation finished:(BOOL)flag delegate method, but… What may I test ? Sounds simple, but I don’t see the way of doing this.

Answer 1

You can use two variables to track whether the animations have completed:

BOOL firstAnimFinished;
BOOL secondAnimFinished;

then in your animationDidStop delegate you check which animation is calling the method and set the flags appropriately. The catch is that you’ll need to add a key to identify the animations when they call the delegate (the animations you created will not be the ones calling the delegate, which is a subject for another question/rant). For example:

// when you create the animations
[firstAnmim setValue: @"FirstAnim" ForKey: @"Name"];
[secondAnmim setValue: @"SecondAnim" ForKey: @"Name"];

// Your delegate
- (void)animationDidStop:(CAAnimation*)theAnimation finished:(BOOL)flag {
    NSString* name = [theAnimation valueForKey: @"Name"];
    if ([name isEqualToString: @"FirstAnim"]) {
        firstAnimFinished = YES;
    } else if ([name isEqualToString: @"SecondAnim"]) {
        secondAnimFinished = YES;
    }
    if (firstAnimFinished && secondAnimFinished) {
        // ALL DONE...
    }
}