UICollectionView performance - _updateVisibleCellsNow

Question

I\'m working on a custom UICollectionViewLayout that displays cells organized by day/week/month.

It is not scrolling smooth, and it looks like the lag i

Answer 1

If you are implementing a grid layout you can work around this by using a single UICollectionViewCell for each row and add nested UIView's to the cell. I actually subclassed UICollectionViewCell and UICollectionReusableView and overrode the prepareForReuse method to remove all of the subviews. In collectionView:cellForItemAtIndexPath: I add in all of the subviews that originally were cells setting their frame to the x coordinate used in the original implementation, but adjusting it's y coordinate to be inside the cell. Using this method I was able to still use some of the niceties of the UICollectionView such as targetContentOffsetForProposedContentOffset:withScrollingVelocity: to align nicely on the top and left sides of a cell. I went from getting 4-6 FPS to a smooth 60 FPS.