UICollectionView highlight

方法一

    func collectionView(_ collectionView: UICollectionView, willDisplay cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
        cell.backgroundColor = .white

        let backgroundView = UIView(frame: cell.frame)
        backgroundView.backgroundColor = UIColor(white: 0.9, alpha: 1)
        cell.selectedBackgroundView = backgroundView
    }
    
    func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
        collectionView.deselectItem(at: indexPath, animated: true)
    }

方法二(有延时)

    func collectionView(_ collectionView: UICollectionView, didHighlightItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath)
        cell?.contentView.backgroundColor = UIColor(white: 0.9, alpha: 1)
    }
    
    func collectionView(_ collectionView: UICollectionView, didUnhighlightItemAt indexPath: IndexPath) {
        let cell = collectionView.cellForItem(at: indexPath)
        cell?.contentView.backgroundColor = nil
    }