Swift iOS8 asynchronous image - ios

Question

I need to cache the image in Swift on iOS 8. I have a custom Table Cell View.
Here's my code:
import UIKit
class WorksTableViewCell: UITableViewCell {
#IBOutlet var workImage: UIImageView!
#IBOutlet var workTitle: UILabel!
#IBOutlet var workDescription: UILabel!
func configureCellWith(work: Work){
workTitle.text = work.title
workDescription.text = work.description
if let url = NSURL(string: work.image) {
if let data = NSData(contentsOfURL: url) {
var thumb = UIImage(data: data)
workImage.image = thumb
}
}
}
}

Answer 1

Create a dictionary mapping a String to a UIImage in the table's view controller and modify the data in the cellForRowAtIndexPath function. Jameson Quave has a nice tutorial on this very issue found here. It's updated to use new Swift 1.2 syntax as well.

Answer 2

Thanks I fixed like this:
import UIKit
class WorksTableViewCell: UITableViewCell {
#IBOutlet var workImage: UIImageView!
#IBOutlet var workTitle: UILabel!
#IBOutlet var workDescription: UILabel!
var imageCache = [String:UIImage]()
func configureCellWith(work: Work){
workTitle.text = work.title
workDescription.text = work.description
var imgURL = NSURL(string: work.image)
// If this image is already cached, don't re-download
if let img = imageCache[work.image] {
workImage.image = img
}else {
// The image isn't cached, download the img data
// We should perform this in a background thread
let request: NSURLRequest = NSURLRequest(URL: imgURL!)
let mainQueue = NSOperationQueue.mainQueue()
NSURLConnection.sendAsynchronousRequest(request, queue: mainQueue, completionHandler: { (response, data, error) -> Void in
if error == nil {
// Convert the downloaded data in to a UIImage object
let image = UIImage(data: data)
// Store the image in to our cache
self.imageCache[work.image] = image
// Update the cell
dispatch_async(dispatch_get_main_queue(), {
self.workImage.image = image
})
}else {
println("Error: \(error.localizedDescription)")
}
})
}
}
}

Answer 3

You can also create a UIImage extension and just call the async function in the configureCellWith function if you want a cleaner solution for Swift 3.
import Foundation
import UIKit
let imageCache = NSCache <AnyObject,AnyObject>()
extension UIImageView {
func loadUsingCache(_ theUrl: String) {
self.image = nil
//check cache for image
if let cachedImage = imageCache.object(forKey: theUrl as AnyObject) as? UIImage{
self.image = cachedImage
return
}
//otherwise download it
let url = URL(string: theUrl)
URLSession.shared.dataTask(with: url!, completionHandler: {(data, response, error) in
//print error
if (error != nil){
print(error!)
return
}
DispatchQueue.main.async(execute: {
if let downloadedImage = UIImage(data: data!){
imageCache.setObject(downloadedImage, forKey: theUrl as AnyObject)
self.image = downloadedImage
}
})
}).resume()
}
}