Why is the animation set back when it's finished?

[Robert Paulson]

Hey everyone,

haven't posted here for ages, how have you guys been?

I am working on an app at the moment and I need to rotate an image. I have found some code over at StackOverflow that does rotate my UIImageView but the problem is that once the animation is finished, the image returns to it's initial position. I don't get it. How can I make it stay where it was in the end of the animation? Because I want to be able to call the same method again afterwards and continue the rotation from where I left it last time. For example, I the image to rotate by x degrees/radians every time I call the method.

Can someone help? Here's the code I've been using (see link above)...

-(void) rotateImage {
	CABasicAnimation* rotationAnimation;
    rotationAnimation = [CABasicAnimation animationWithKeyPath:@"transform.rotation.z"];
    rotationAnimation.toValue = [NSNumber numberWithFloat: 1.0f];
    rotationAnimation.duration = 3.0;
    rotationAnimation.cumulative = YES;
    rotationAnimation.repeatCount = 1.0; 
    rotationAnimation.timingFunction = [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseOut];
	
    [self.theImageView.layer addAnimation:rotationAnimation forKey:@"rotationAnimation"];
}

Thanks in advance!

Cheers,
Bob

[Robert Paulson]

*Bump*

Anyone? Anything?

[harrytheshark]

You need to set the final position before calling the animation.
Then make sure to set the fromValue in your animation code.

[Robert Paulson]

Hi,

thanks harrytheshark! Your post made me google in the right direction, hehe.

I needed to add these lines to make it work:

rotationAnimation.fillMode = kCAFillModeForwards;
rotationAnimation.removedOnCompletion = NO;

Solution found here.

Thanks!

[harrytheshark]

Right, but you needn't add those lines if you just set the position before performing the animation.

If you don't remove the animation layer, your memory allocation will increase everytime you run the animation.

What you could do is remove the layer when the animation is finished yourself, after setting the new position, but I would definitely recommend removing it at some point.

[Robert Paulson]

Thanks for the hint.

I added this line:

[self.theImageView.layer removeAllAnimations];

Then I set up the *animation and then I addAnimation: animation. Everything works perfectly now. Thanks for your help, mate.

Cheers,
Bob