Question

I’d consider myself advanced in getting smooth scrolling performance, but this has stumped me. I have a UICollectionViewController that shows pictures from the camera roll. It was working just fine, then I added sections to show additional albums, using a different layout. Since then, the scrolling performance became extremely choppy. Setting the sections back to 1, it gets a little better. I’ve not been able to determine what’s holding things up, but I think it may be due to calculations in the layout (layoutAttributesForElementsInRect: and friends).

Now here’s the strange part–if I push a view onto the navigation stack, then pop back to this collection view controller, it’s perfectly smooth.

Nothing is modified other than pushing a view controller. The collection view controller is not dealloc’d or anything, and looks the same as before the push. Any ideas what could be causing this?

Answer 1

There appears to be a bug with subviews being kept around after layout changes.