Object retaining position after CAKeyframeAnimation

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Level 1

10 points

Object retaining position after CAKeyframeAnimation

Hello All,

I have an imageView that I am moving around with a CAKeyframeAnimation. After the animation completes the object warps back to the place it was before the animation started but i want to have it stay where it was animated to. I am reading through the docs but I am not seeing what I am doing wrong; any help you could offer would be much appreciated. Thank you.

Mac OS X (10.5.4)

Posted on Oct 13, 2008 5:52 PM

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Answer 1

brackeen

Level 1

0 points

Oct 13, 2008 6:06 PM in response to scotopia

I had the same problem. I'm not sure the official way to do it, but this worked for me on the iPhone: after setting the animation, set the last value.

[view.layer addAnimation: keyFrameAnimation forKey: @"myAnim"];
[view.layer setValue: finalValue forKeyPath: keyPath];

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Answer 2

scotopia Author

Level 1

10 points

Oct 13, 2008 7:48 PM in response to brackeen

I understand what this is supposed to do but I keep getting errors when I try to add this last line (trying every relevant thing I can think of for the paramater of setValue and forKeyPath

I apologize for my apparent stupidity but can you help me a little more specifically? My relevant code is:

CGMutablePathRef thePath = CGPathCreateMutable();
CGPathMoveToPoint(thePath,NULL,160,375);
CGPathAddCurveToPoint(thePath,NULL,160,375,
160,100,
160.0,100);

CAKeyframeAnimation *theAnimation;

theAnimation=[CAKeyframeAnimation animationWithKeyPath:@"position"];
theAnimation.path=thePath;
theAnimation.duration=3.0;
CFRelease(thePath);
[pictureView.layer addAnimation:theAnimation forKey:@"position"];

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Answer 3

scotopia Author

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10 points

Oct 13, 2008 10:03 PM in response to scotopia

I ended up accomplishing this by moving the imageView center, but I am still curious what the best way was. Thanks.

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Answer 4

scotopia Author

Level 1

10 points

Oct 15, 2008 9:02 AM in response to brackeen

Actually my solution didn't work exactly right; there is a quick moment where you see the object back to its first locations before it gets shifted back. Please assist; thank you.

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Answer 5

scotopia Author

Level 1

10 points

Oct 15, 2008 10:06 AM in response to scotopia

This is driving me nuts; I've tried everything I can think of! Surely this has to be some single line of code or property that just tells it to "stay" when its done. I tried setting removedOnComplete = false but that didn't do it. Please someone help me.

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Answer 6

scotopia Author

Level 1

10 points

Oct 15, 2008 11:38 AM in response to scotopia

ARRGH!! ...that was a shameless bump...i need help.

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Answer 7

scotopia Author

Level 1

10 points

Oct 17, 2008 12:13 PM in response to scotopia

Brackeen are you still around? Anyone else?

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Answer 8

Oct 28, 2008 3:23 AM in response to scotopia

I had the same problem. First I tried solving it by setting the fill mode:

{{{
bounceAnimation.fillMode = kCAFillModeForwards;
}}}

But this did not do the job (perhaps it will work for you)

So what I ended up doing is:
1. Using a timing array, which defines how log it takes from one key frame to another: bounceAnimation.keyTimes = keyTimesArray; (where keyTimesArray is a simple mutable array with NSNumber objects with valies [0..1]
2. At the end of the animation added another keyframe and set the timing to a very long time (so it does stay there for a very long time)

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