Adding shadow to tableview cell cause laggy scroll and duplicate shadow - swift

Question

I have added white space around my tableview cell and every time I scroll this shadows getting bigger and bigger when I scroll, and its get lag when I scroll for the second and third time with the bigger shadow
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

Just put code inside the awakefrom nib
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)
}
}

Answer 2

You keep adding shadow views on top of each other without ever removing them. If all your cells will need the shadow you can just add a tag and check if a view with that tag already exists like so:
whiteRoundedView.tag = 12345
if cell.contentView.viewWithTag(12345) == nil {
cell.contentView.addSubview(whiteRoundedView)
}
If some cells have the shadow but some cells don't you could do it like this:
if let shadowView = cell.contentView.viewWithTag(12345) && noShadow {
shadowView.removeFromSuperview
} else if !noShadow {
cell.contentView.addSubview(whiteRoundedView)
}
Alternatively like mentioned in the comments of the question you would add it to your custom cell class:
override func awakeFromNib() {
super.awakeFromNib()
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.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)
}

Answer 3

You are adding whiteRoundedView every time. If you are using a storyboard or Nib for designing your Cell UI then you can add whiteRoundedView there Or you can add a tag in whiteRoundedView and check if there are already any view added with that tag before adding the whiteRoundedView as subview.