Swift UITableViewCell - Cell Image changes if I scroll down too fast, but only on the first attempt - swift

Question

I am parsing a JSON within my viewDidLoad method. One of the keys within this JSON is the image URL, which goes into a a string array called "allCImages"
This is just a string. Therefore to populate the image into the cell, in my cellForRowAt method, I have the following:
cell.vcCellImage.downloadImage(from: allCImages[indexPath.section])
Note: vcCellImage is the IBOutlet of my cell image view.
The "downloadImage" method is part of the following extension:
extension UIImageView {
func downloadImage(from imgURL: String!) {
let theUrl = URLRequest(url: URL(string: imgURL)!)
// set initial image to nil so it doesn't use the image from a reused cell
image = nil
// check if the image is already in the cache
if let imageToCache = vc1ImageCache.object(forKey: imgURL! as NSString) {
self.image = imageToCache
print("Image is in Cache")
return
}
// download the image asynchronously
let task = URLSession.shared.dataTask(with: theUrl) { (data, response, error) in
if error != nil {
print(error!)
return
}
DispatchQueue.main.async {
// create UIImage
let imageToCache = UIImage(data: data!)
// add image to cache
vc1ImageCache.setObject(imageToCache!, forKey: imgURL! as NSString)
self.image = imageToCache
}
}
task.resume()
}
This is working almost perfectly. For example:
1) If I scroll down my tableview slowly, all the cells contain the correct image
2) If I scroll up my tableview, slowly or quickly, all the cells contain the correct image. This is proven by the fact that my console is printing the following:
Image is in Cache
Image is in Cache
Image is in Cache
I.e, the tableview is getting my image from the cache (since to scroll up, I must have scrolled down before)
3) The issue is if I scroll down my tableview really quickly, on the first attempt. Since the image has not cached yet, the cell will display the wrong image, before changing to the correct image. Classic problem
Therefore I am missing this small piece of logic. How to resolve this?
EDIT: I tried this but the issue remains:
class VCTableViewCell: UITableViewCell {
override func prepareForReuse() {
super.prepareForReuse()
vcCellImage.image = nil
}

Answer 1

This occurs because of
1- cell dequeueing : cells are re-used inside the tableView
2- when you scroll before a request happens it may cause a new 1 with same url
Best option is using SDWebImage

Answer 2

I have faced the similar issue.
I have fixed this issue by cancelling the image request in the prepareForReuse method.
Can you try the same?

Answer 3

first off all if you are appending your api or any data like this just remove this
var arr = [string]()
viewDidLoad()
{
arr.append("s","sd","sd)
}
accept this
var arr = [string]()
viewWillAppear()
{
arr.removeAll()
//call api
//append Data
arr.append("s","sd","sd)
}
I have similar problem then I solve it like this, may be it helpful for you also.