Is there a way to change the animation speed for UICollectionViews?

Question

I am talking about things like insertItemsAtIndexPaths or moveItemAtIndexPath:toIndexPath: I tried wrapping it in an animation block, but that didn't work. The animations seem to be stuck for 0.25 or 0.3 seconds, but I would like to slow this down. Except that the implementation process itself, which is not worth the trouble, does anyone know if this is possible using public APIs?

Answer 1

Absolutely! But you cannot do it right using the UIView animation UIView . You need to delve into Core Animation.

In the collection view, animations are added to CALayer that support each UICollectionViewCell . But if you implement your own layout (or a subclass of an existing one), you can make all the necessary changes for these animations in the finalizeCollectionViewUpdates method.

From the documentation of the UICollectionViewLayout class:

The collection view calls this method as the last step before the previous one to animate any changes.

Here is an example of how to replace the default position animation with your own:

 - (void)finalizeCollectionViewUpdates { for (UICollectionViewCell *cell in [self.collectionView visibleCells]) { CAAnimation *positionAnimation = [cell.layer animationForKey:@"position"]; if (positionAnimation) { [cell.layer removeAnimationForKey:@"position"]; CALayer *presentationLayer = cell.layer.presentationLayer; CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"]; [animation setFromValue:[NSValue valueWithCGPoint:presentationLayer.position]]; [animation setToValue:[NSValue valueWithCGPoint:cell.layer.position]]; [animation setDuration:0.4]; [cell.layer addAnimation:animation forKey:@"position"]; } } } 

Look at the animation-related methods on CALayer to find out how you can delve into what kind of animations are currently running on your layer.

Using this approach, you can even get creative and add overshoot / bounce effects using CAKeyframeAnimation or anything else you can think of. You can also do things like selectively turn off some animations (like size) and save others (like position).

Answer 2

Copy this here: fooobar.com/questions/691271 / ...

You can change any animation speed using CALayer. So for a UICollectionView, it looks like this:

 [self.collectionView.viewForBaselineLayout.layer setSpeed:0.1f]; 

And you can change the speed of the original:

 [self.collectionView.viewForBaselineLayout.layer setSpeed:1.0f]; 

To do this, you may need to import QuartzCore:

 #import <QuartzCore/QuartzCore.h> 

Just keep in mind that it affects any other animations on the same layer, including animated UIImageViews and, therefore, they may need compensation.