UICollectionView how to deselect all

Question

I have a FollowVC and FollowCell Setup with collection View. I can display all the datas correctly into my uIcollection view cell using the following code with no problem.

Answer 1

Not all of the selected cells may be on screen at the point when you are clearing the selection status, so collectionView.cellForItemAtIndexPath(indexPath) may return nil. Since you have a force downcast you will get an exception in this case.

You need to modify your code to handle the potential nil condition but you can also make your code more efficient by using the indexPathsForSelectedItems property of UICollectionView

 let selectedItems = followCollectionView.indexPathsForSelectedItems
 for (indexPath in selectedItems) {
     followCollectionView.deselectItemAtIndexPath(indexPath, animated:true)
     if let cell = followCollectionView.cellForItemAtIndexPath(indexPath) as? FollowCell {
        cell.checkImg.hidden = true
     }
 }