gistfile1.swift

func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
        
        let cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(kCellIdentifier) as UITableViewCell
        
        var rowData: NSDictionary = self.tableData[indexPath.row] as NSDictionary
        
        // Add a check to make sure this exists
        let cellText: String? = rowData["trackName"] as? String
        cell.textLabel.text = cellText
        cell.imageView.image = UIImage(named: "Blank52")
        
        
        // Get the formatted price string for display in the subtitle
        let formattedPrice: NSString = rowData["formattedPrice"] as NSString
        
        // Grab the artworkUrl60 key to get an image URL for the app's thumbnail
        let urlString: NSString = rowData["artworkUrl60"] as NSString
        
        // Check our image cache for the existing key. This is just a dictionary of UIImages
        //var image: UIImage? = self.imageCache.valueForKey(urlString) as? UIImage
        var image = self.imageCache[urlString]
        
        if( !image? ) {
            dispatch_async(dispatch_get_global_queue( DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
                // Jump in to a background thread to get the image for this item
                
                
                // If the image does not exist, we need to download it
                var imgURL: NSURL = NSURL(string: urlString)
                
                // Download an NSData representation of the image at the URL
                let request: NSURLRequest = NSURLRequest(URL: imgURL)
                let urlConnection: NSURLConnection = NSURLConnection(request: request, delegate: self)
                NSURLConnection.sendAsynchronousRequest(request, queue: NSOperationQueue.mainQueue(), completionHandler: {(response: NSURLResponse!,data: NSData!,error: NSError!) -> Void in
                    if !error? {
                        image = UIImage(data: data)
                        
                        // Store the image in to our cache
                        self.imageCache[urlString] = image
                        cell.imageView.image = image
                    }
                    else {
                        println("Error: \(error.localizedDescription)")
                    }
                })
                
                
            })
        } else {
            cell.imageView.image = image
        }
        
        cell.detailTextLabel.text = formattedPrice
        
        return cell
    }