Animation doesn't show - cocoa

Question

Here is my code snippet for cocoa application using core animation, somehow the animation doesn't show.
CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:#"position"];
[animation setDelegate:self];
NSRect pos = [imageView frame];
[animation setFromValue:[NSValue valueWithRect:pos]];
NSPoint point = NSMakePoint(pos.origin.x-40, pos.origin.y);
[animation setToValue:[NSValue valueWithPoint:point]];
[animation setDuration:2.0];
[[imageView animator] addAnimation:animation forKey:#"myTest"];
while this is the working code:
NSRect position = [imageView frame];
position.origin.x -= 40;
[[imageView animator] setFrame:position];
But autoReverse doesn't work.
Anything wrong with the first one? And how to make the reverse movement work in the 2nd one? Thanks!

Answer 1

I don't know for sure, but for the first one, position is a CGPoint, so you might try using that type for your fromValue and toValue. You're currently using an NSRect and an NSPoint (the latter of which should work, but not sure about the former).
For the second, how are you specifying auto-reverse? +setAnimationRepeatAutoreverses needs to be called from inside an animation block (after "beginAnimations")

Answer 2

(Note: I'm not very experienced with Cocoa since I'm chiefly an iOS developer; I haven't tested any of the following stuff)
I think the problem is that you're trying to mix CoreAnimation and Animator Proxy. You don't add the animation to the Animator, but to the layer:
[[imageView layer] addAnimation:animation forKey:#"myTest"];
Another possibility might be to use NSViewAnimation and chain them together. See the Animation Programming Guide for Cocoa, page 13. So you'd have one animation to go in one direction, and once it's finished it triggers the second one that goes back. It seems to work like this:
NSMutableDictionary *firstDict = [NSMutableDictionary dictionary];
[firstDict setObject:imageView forKey:NSViewAnimationTargetKey];
[firstDict setObject:[NSValue valueWithRect:originalFrame] forKey:NSViewAnimationStartFrameKey];
[firstDict setObject:[NSValue valueWithRect:targetFrame] forKey:NSViewAnimationEndFrameKey];
NSMutableDictionary *secondDict = [NSMutableDictionary dictionary];
[secondDict setObject:imageView forKey:NSViewAnimationTargetKey];
[secondDict setObject:[NSValue valueWithRect:targetFrame] forKey:NSViewAnimationStartFrameKey];
[secondDict setObject:[NSValue valueWithRect:originalFrame] forKey:NSViewAnimationEndFrameKey];
NSViewAnimation *firstAnimation = [[NSViewAnimation alloc] initWithViewAnimations:[NSArray arrayWithObject:firstDict]];
[firstAnimation setDuration:2.0];
NSViewAnimation *secondAnimation = [[NSViewAnimation alloc] initWithViewAnimations:[NSArray arrayWithObject:secondDict]];
[secondAnimation setDuration:2.0];
[secondAnimation startWhenAnimation:firstAnimation reachesProgress:1.0];
[firstAnimation startAnimation];
Then, in Lion (OS X 10.7) you can set a completion handler when using Animator Proxy. It should work like this:
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setDuration:2.0];
[[NSAnimationContext currentContext] setCompletionHandler:^(void) {
// Here comes your code for the reverse animation.
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setDuration:2.0];
[[aView animator] setFrameOrigin:originalPosition];
[NSAnimationContext endGrouping];
}];
[[aView animator] setFrameOrigin:position];
[NSAnimationContext endGrouping];