How to find a UICollectionViewCell's coordinates relative to the App Window

Question

Is it possible to translate a UICollectionViewCell\'s coordinates from being relative to the UICollectionView to being relative to the superview<

Answer 1

If I understand you correctly, I think the problem is that you first have to correct for the scroll view's contentOffset, which is easy to do since UICollectionView is a subclass of UIScrollView.

CGRect frame = CGRectMake(0.0,
                          0.0,
                          cell.frame.size.width,
                          cell.frame.size.height);
CGPoint correctedOffset = 
 CGPointMake(cell.frame.origin.x - collectionView.contentOffset.x,
             cell.frame.origin.y - collectionView.contentOffset.y);
frame.origin = [cell convertPoint:correctedOffset toView:self.view];

I tested this in one of my UICollectionView demo apps and it seems to work. Give it a try.

Answer 2

Just in case if anybody looking for this, here is how it can be done in Swift:

let cellFrameInSuperview = collectionView.convertRect(collectionView.cellForItemAtIndexPath(indexPath)!.frame, toView: view)

Answer 3

This answer is very late, but hopefully it will help someone. Dan, you have the right idea, but it is even easier that what you have. Just replace

CGRect frame = CGRectMake(0.0, 0.0, cell.frame.size.width, cell.frame.size.height);
frame.origin = [cell convertPoint:cell.frame.origin toView:self.view];

with

CGRect frame = [collectionView convertRect:cell.frame toView:self.view];

The problem was that you were calling the convert method on the cell, not the collectionView.