Check whether cell at indexPath is visible on screen UICollectionView

Question

I have a CollectionView which displays images to the user. I download these in the background, and when the download is complete I call the following func to update

Answer 1

Nested UICollectionViews need oft to not scroll at all, so that no contentOffset is ever provided and thus iOS understands all cells as being always visible. In that case it is possible to take the screen boundaries as reference:

    let cellRect = cell.contentView.convert(cell.contentView.bounds, to: UIScreen.main.coordinateSpace)
    if UIScreen.main.bounds.intersects(cellRect) {
        print("cell is visible")
    }