Prototype cells are shaking or shivering when scrolling the table view in swift

Question

I am new to swift I have an issue that is when scrolling cells in table view cells are shaking or shivering when scrolling the table view .I follow the below code can any one tell me the reason .I tested in IOS simulator not in real time device .my question is why it is shaking in simulator

override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

var cell = tableView.dequeueReusableCellWithIdentifier("transportCell") as! UITableViewCell

cell.textLabel?.text = transportItems[indexPath.row]

var imageName = UIImage(named: transportItems[indexPath.row])
cell.imageView?.image = imageName

return cell


 }

Answer 1

I suggest you to perform the following changes: instead of the lines:

var imageName = UIImage(named: transportItems[indexPath.row])
cell.imageView?.image = imageName

use the lines:

let qos = Int(QOS_CLASS_USER_INITIATED.rawValue)
dispatch_async(dispatch_get_global_queue(qos, 0)) { () -> Void in
    if let imageName = UIImage(named: transportItems[indexPath.row])) {
       dispatch_async(dispatch_get_main_queue()) {
            self.cell.imageView?.image = imageName
       }
    }
}