Asynchronously Load Images in UITableView While Downloading - ios

Question

I am wondering if there is any way to keep reloading a tableView as items are being downloaded.
There are images and info associated with those images. When the user first opens the app, the app begins downloading images and data using HTTP. The user can only see downloaded items in the tableView as they're being downloaded if he/she keeps leaving the viewController and coming back to it.
I have tried doing something like this:
while downloading {
tableView.reloadData()
}
, however, this uses too much memory and it crashes the app.
How can I asynchronously populate a tableView with images and data as they are being downloaded while still remaining in the tableViewController?
P.S. If you're interested in which libraries or APIs I'm using, I use Alamofire to download and Realm for data persistence.

Answer 1

The correct and usual way to do this is reload data into table, than delegate the single cell to load asyncronously the image from a link.
In swift, you can extend UIImage
extension UIImageView {
func imageFromUrl(urlString: String) {
if let url = NSURL(string: urlString) {
let request = NSURLRequest(URL: url)
NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue()) {
(response: NSURLResponse?, data: NSData?, error: NSError?) -> Void in
if let imageData = data as NSData? {
self.image = UIImage(data: imageData)
}
}
}
}
}
And in your CellForRowAtIndexPath load the image from link using something like this
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
...
cell.image.imageFromUrl(dataArray[indexPath.row].imageUrl)
return cell
}