UITableViewCell loading incorrect image after reuse - ios

Question

I have a tableview that populates its cells with data from firebase. Each cell posses an image and each image is loaded asynchronously and cached. The problem is that random cells will use the wrong image, although the other data in the cell is correct. If I scroll so that the cell goes off view, the correct image then loads.
Research:
Images in UITableViewCells are loading wrong (Dont really understand Obj C)
What is the correct way to use prepareForReuse?
Image Cache:
import Foundation
import UIKit
let imageCache = NSCache<NSString, AnyObject>()
extension UIImageView {
func loadImageUsingCache(urlString: String) {
self.image = #imageLiteral(resourceName: "logo3")
if let cachedImage = imageCache.object(forKey: urlString as NSString) as? UIImage {
self.image = cachedImage
return
}
let url = URL(string: urlString)
URLSession.shared.dataTask(with: url!, completionHandler: {(data, response, error) in
if error != nil {
print(error!)
return
}
DispatchQueue.main.async(execute: {
if let downloadedImage = UIImage(data: data!) {
imageCache.setObject(downloadedImage, forKey: urlString as NSString)
self.image = downloadedImage
}
})
}).resume()
}
}
Tableview Cell
import Foundation
import Firebase
class GroupCell: UITableViewCell {
var group: Groups!
var members = [String]()
#IBOutlet weak var groupImage: UIImageView!
#IBOutlet weak var groupName: UILabel!
#IBOutlet weak var groupRep: UILabel!
#IBOutlet weak var memberCount: UILabel!
override func awakeFromNib() {
super.awakeFromNib()
}
func configureCell(group: Groups) {
self.group = group
self.groupName.text = group.name
self.groupRep.text = "\(group.groupScore)"
if let groupImage = group.groupImage {
self.groupImage.loadImageUsingCache(urlString: groupImage)
} else {
self.groupImage.image = //random image
}
for member in group.members {
self.members.append(member.key)
}
self.memberCount.text = "\(members.count)"
}
}
TableView
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if let cell = tableView.dequeueReusableCell(withIdentifier: "groupCell") as? GroupCell {
let group = FriendSystem.system.activeGroups[indexPath.row]
cell.configureCell(group: group)
return cell
}
return UITableViewCell()
}

Answer 1

Sounds like you need to add the prepareForReuse method to your GroupCell class.
In that method add self.groupImage.image = nil It will reset your image view to empty until the correct image is set.