swift - 向 tableview 单元格添加阴影会导致滚动滞后和重复阴影

Question

我在我的 tableview 单元格周围添加了空白区域，每次我滚动时，这个阴影会越来越大，当我第二次和第三次滚动时，它会变得滞后

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell", for: indexPath) as! CustomCell
    cell.backgroundColor = UIColor.clear
    cell.contentView.backgroundColor = UIColor.clear

    let whiteRoundedView : UIView = UIView(frame: CGRect(x:10,y: 5,width: self.view.frame.size.width - 20,height: 117))

    whiteRoundedView.layer.backgroundColor = CGColor(colorSpace: CGColorSpaceCreateDeviceRGB(), components: [1.0, 1.0, 1.0, 0.9])
    //whiteRoundedView.layer.masksToBounds = true
    whiteRoundedView.layer.cornerRadius = 5.0
    whiteRoundedView.layer.shadowOffset = CGSize(width: -1,height: 1)
    whiteRoundedView.layer.shadowOpacity = 0.2

    let shadowPath = UIBezierPath(rect: whiteRoundedView.layer.bounds)
    whiteRoundedView.layer.shouldRasterize = true
    whiteRoundedView.layer.shadowPath = shadowPath.cgPath
    cell.contentView.addSubview(whiteRoundedView)
    cell.contentView.sendSubview(toBack: whiteRoundedView)

    return cell
}

Answer 1

只需将代码放在 awakefrom nib 中

  class CustomCell: UITableViewCell {



        override func awakeFromNib() {
            super.awakeFromNib()
            // Initialization code
    self.backgroundColor = UIColor.clear
        self.contentView.backgroundColor = UIColor.clear

        let whiteRoundedView : UIView = UIView(frame: CGRect(x:10,y: 5,width: self.contentView.frame.size.width - 20,height: 117))

        whiteRoundedView.layer.backgroundColor = CGColor(colorSpace: CGColorSpaceCreateDeviceRGB(), components: [1.0, 1.0, 1.0, 0.9])
        //whiteRoundedView.layer.masksToBounds = true
        whiteRoundedView.layer.cornerRadius = 5.0
        whiteRoundedView.layer.shadowOffset = CGSize(width: -1,height: 1)
        whiteRoundedView.layer.shadowOpacity = 0.2

        let shadowPath = UIBezierPath(rect: whiteRoundedView.layer.bounds)
        whiteRoundedView.layer.shouldRasterize = true
        whiteRoundedView.layer.shadowPath = shadowPath.cgPath
        self.contentView.addSubview(whiteRoundedView)
        self.contentView.sendSubview(toBack: whiteRoundedView)

        }


    }