如何仅一次收集视图即可使单元出队

Question

在我的Swift应用程序中，我具有以下集合视图。 每次用户看到单元格时，它都会重新加载数据，并且每次从数据库中获取图像时，都会使应用程序变慢。 我怎样才能使一个单元出队一次？ 或者我怎么只能加载一次图像？

func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {


            selectedLocal = locals[indexPath.row - Int(indexPath.row / adsDensity)]

            let localCell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
            localCell.backgroundColor = currentTheme.backgroundColor

            localCell.layer.cornerRadius = localCell.frame.width / 32
            localCell.layer.shadowRadius = 5
            localCell.layer.shadowOpacity = 0.3
            localCell.layer.shadowOffset = CGSize(width: 5, height: 10)
            localCell.clipsToBounds = true

            localCell.coveImageView.layer.masksToBounds = true
            localCell.coveImageView.clipsToBounds = true
            localCell.coveImageView.setImageFromURl(stringImageUrl: “server_url”)

            localCell.titleLabel.text = selectedLocal.title
            localCell.placeLabel.text = selectedLocal.city
            localCell.timetableLabel.text = "Open"

            localCell.titleLabel.textColor = currentTheme.textColor
            localCell.placeLabel.textColor = currentTheme.textColor
            localCell.timetableLabel.textColor = currentTheme.textColor
            localCell.reviewLabel.textColor = currentTheme.textColor

            localCell.ratingView.backgroundColor = .clear
            localCell.ratingView.contentMode = .scaleAspectFit
            localCell.ratingView.emptyImage =  imageLiteral(resourceName: "emptyStar")
            localCell.ratingView.fullImage =  imageLiteral(resourceName: "fullyStar")
            localCell.ratingView.rating = selectedLocal.rating

            return localCell

}