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POSelectively overriding CALayer implicit animations
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copied!<p>I have a CALayer subclass that is constrained to the width of the parent layer, but a fixed height. I want the implicit animation disabled for resizing the window but enabled whenever I set the height of the layer.</p> <p>To disable the animation when the window is resized I set the layers actions to</p> <pre><code>NSMutableDictionary *actions = [[NSMutableDictionary alloc] initWithObjectsAndKeys:[NSNull null], @"bounds", [NSNull null], @"position", nil]; </code></pre> <p>and this seems to work. Then I've overridden the actionForKey: method in my layer subclass</p> <pre><code>- (id<CAAction>)actionForKey:(NSString *)event { if ([event isEqualToString:@"frame.size.height"]) { CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"frame.size.height"]; [animation setDuration:0.5f]; return animation; } return nil; } </code></pre> <p>but then when I change the height of my layer with</p> <pre><code>[layer setValue:[NSNumber numberForFloat:50.0] forKey:@"frame.size.height"]; </code></pre> <p>the height changes but is not animated. I see the actionForKey: method being called with frame.size.height but no matter what I return it is never animated. The height animates correctly if I don't set the actions, or have the actionForKey: method, but then the window resizes are also animated, which I don't want.</p> <p>Also, maybe I'm misunderstanding, but I thought returning nil from actionForKey: would make the default animations run, but it appears that even the presence of the method stops all implicit animations (whether the actions dictionary is set or not). </p> <p>What is it am I missing here, I'll be grateful for any pointers.</p>

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