UIView iPhone SDK nested animations - iphone

Question

I would like to have a nested animation for my view.
I have one animation stop selector which gets called just fine:
[UIView setAnimationDidStopSelector:#selector(growAnimationDidStop1:finished:context:)];
However inside of this selector I want to do more animation and when done yet another selector to be called:
- (void)growAnimationDidStop1:(NSString *)animationID finished:(NSNumber *)finished context:(void *)context
{
...
[UIView setAnimationDidStopSelector:#selector(growAnimationDidStop2:finished:context:)];
...
[UIView commitAnimations];
}
The problem is that growAnimationDidStop2 is never called. Why is this?

Answer 1

You can also do this with blocks, and Apple now recommends this. Consider the following as pseudo-code:
[UIView animateWithDuration:0.3
delay:0.0
options:UIViewAnimationCurveEaseInOut
animations:^{
[self doAnimationOne];
} completion:^(BOOL finished){
[UIView animateWithDuration:0.4
delay:0.0
options:UIViewAnimationCurveEaseInOut
animations:^{
[self doAnimationNine];
}
completion:^(BOOL finished) {
[UIView animateWithDuration:0.3
delay:0.0
options:UIViewAnimationCurveEaseInOut
animations:^{
[self doAnimationFive];
}
completion:^(BOOL finished) {}];
}];
}];
It's also good practice for your animations to be "social", for instance do:
BOOL userInteractionEnabled = [self isUserInteractionEnabled];
[self setUserInteractionEnabled:NO];
BOOL animationsEnabled = [UIView areAnimationsEnabled];
[UIView setAnimationsEnabled:YES];
before starting your animation, and then in the final completion block do:
[UIView setAnimationsEnabled:animationsEnabled];
[self setUserInteractionEnabled:userInteractionEnabled];

Answer 2

Oops, answered it myself. I had to start a brand new animation context in the first stop method

Answer 3

The best way to do multiple animations in sequence is with a queue of blocks.
See how clean the result is:
NSMutableArray* animationBlocks = [NSMutableArray new];
typedef void(^animationBlock)(BOOL);
// getNextAnimation
// removes the first block in the queue and returns it
animationBlock (^getNextAnimation)() = ^{
animationBlock block = (animationBlock)[animationBlocks firstObject];
if (block){
[animationBlocks removeObjectAtIndex:0];
return block;
}else{
return ^(BOOL finished){};
}
};
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
[UIView animateWithDuration:1.0 animations:^{
//...animation code...
} completion: getNextAnimation()];
}];
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
[UIView animateWithDuration:1.0 animations:^{
//...animation code...
} completion: getNextAnimation()];
}];
//add a block to our queue
[animationBlocks addObject:^(BOOL finished){;
NSLog(#"Multi-step Animation Complete!");
}];
// execute the first block in the queue
getNextAnimation()(YES);
Taken from: http://xibxor.com/objective-c/uiview-animation-without-nested-hell/