ios - How to show a collectionView like facebook upload image using swift 4?

Question

Hello i want to show the collectionView exactly as the above image. I know that it responsible for UICollectionViewFlowLayout, but unable to do it. Help is much appreciated. Here is my code

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
     let yourWidth = (collectionView.bounds.width - 4) / 3.0
     let yourHeight = yourWidth
     return CGSize(width: yourWidth, height: yourHeight)
}

Answer 1

Your answer is in your question bro some short of conditions

func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {

        switch indexPath.item {
        case 0,1:
            return CGSize(width: (UIScreen.main.bounds.width - 16) / 2, height: (UIScreen.main.bounds.width - 16) / 2)
        default:
            return CGSize(width: (UIScreen.main.bounds.width - 32) / 3, height:  (UIScreen.main.bounds.width) / 3)
        }
    }