Imran Shams Imran Shams - 1 year ago 83
iOS Question

Swift: load images Async in UITableViewCell

I have a

that I created with code (without

class MSContentVerticalList: MSContent,UITableViewDelegate,UITableViewDataSource {
var tblView:UITableView!
var dataSource:[MSC_VCItem]=[]

init(Frame: CGRect,DataSource:[MSC_VCItem]) {
super.init(frame: Frame)
self.dataSource = DataSource
tblView = UITableView(frame: Frame, style: .Plain)
tblView.delegate = self
tblView.dataSource = self

func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return dataSource.count
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell = UITableViewCell(style: .Subtitle, reuseIdentifier: nil)

let record = dataSource[indexPath.row]
cell.textLabel!.text = record.Title
cell.imageView!.downloadFrom(link: record.Icon, contentMode: UIViewContentMode.ScaleAspectFit)
cell.imageView!.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
cell.detailTextLabel!.text = record.SubTitle
return cell

and in other class I have an extension method for download images Async:

extension UIImageView
func downloadFrom(link link:String?, contentMode mode: UIViewContentMode)
contentMode = mode
if link == nil
self.image = UIImage(named: "default")
if let url = NSURL(string: link!)
print("\nstart download: \(url.lastPathComponent!)")
NSURLSession.sharedSession().dataTaskWithURL(url, completionHandler: { (data, _, error) -> Void in
guard let data = data where error == nil else {
print("\nerror on download \(error)")
dispatch_async(dispatch_get_main_queue()) { () -> Void in
print("\ndownload completed \(url.lastPathComponent!)")
self.image = UIImage(data: data)
self.image = UIImage(named: "default")

I used this function in other places and worked correctly, Based on my logs I understand that images downloaded without problem (when the cell is rendered) and after download of image, The cell UI not updated.

Also I tried to use caching library like Haneke but problem is exist and not change.

Please help me to understand mistakes


Answer Source

After setting the image you should call self.layoutSubviews()

edit: corrected from setNeedsLayout to layoutSubviews

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