Add overlay to CollectionViewCell once it's clicked - ios

Question

It's there a way to add an semi transparent overlay to a CollectionViewCell on it's clicked? (I want to "darken" the entire cell when a user taps on the cell).
I found a way to change the background color but I don't know if there'a way to add an overlay.
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
[UIView animateWithDuration:0.1 delay:0 options:(UIViewAnimationOptionAllowUserInteraction) animations:^{ [cell setBackgroundColor:[UIColor colorWithRed:232/255.0f green:232/255.0f blue:232/255.0f alpha:1]]; } completion:nil];
}
EDIT
I added an UIView with a semi transparent background to the Cell once it's tapped:
- (void)collectionView:(UICollectionView *)collectionView didHighlightItemAtIndexPath:(NSIndexPath *)indexPath {
UICollectionViewCell *cell = [collectionView cellForItemAtIndexPath:indexPath];
UIView *overlay = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 172, 210)];
overlay.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.1];
[cell addSubview:overlay];
}

Answer 1

The simplest solution, I find, is to add to the cell, right from the start, a UIImageView with no image but with a highlighted image:
UIImageView* iv = [[UIImageView alloc] initWithImage:nil highlightedImage:im];
iv.userInteractionEnabled = NO;
[cell addSubview: iv];
The result is that the image im magically becomes visible in the cell when - and only when - the cell is highlighted (selected).