UICollectionViewCell not calling updateConstraints automatically when dequeued?

问题

I have a UICollectionViewCell subclass. I wrote an updateConstraints method as I've done a hundred times before. For some reason that is never called when the cell is dequeued. I had to add a manual call to [cell setNeedsUpdateConstraints] after dequeueing it.

Any idea what could be going on here?

回答1:

Implement this method and return YES. This could probably help.

+ (BOOL)requiresConstraintBasedLayout

For details:

https://stackoverflow.com/a/23616469/1300262

来源：https://stackoverflow.com/questions/23117248/uicollectionviewcell-not-calling-updateconstraints-automatically-when-dequeued