TableView cells Image have images without images - swift

Question

I'm downloading the data from firebase and I managed to put the images to right cells but I get the images with getData and it requires file path for images and some of them does not have images on the stated path but some how I have images on every cell
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = self.tabelview.dequeueReusableCell(withIdentifier: "cell") as! TableCell
cell.commentButton.tag = indexPath.row
cell.nameLabel.text = annoucements[indexPath.row].Name
cell.announcementLabel.text = annoucements[indexPath.row].Announcement
cell.annoucementTitleLabel.text = annoucements[indexPath.row].AnnoucementTitle
cell.dateLabel.text = annoucements[indexPath.row].Date
cell.selectionStyle = .none
let storageRef = Storage.storage().reference()
let islandRef = storageRef.child("Announcement").child("\(annoucements[indexPath.row].key!).jpg")
if let cachedImage = imageCache.object(forKey: annoucements[indexPath.row].key! as AnyObject) as? UIImage{
cell.someImage.image = cachedImage
return cell
}
islandRef.getData(maxSize: 1 * 1024 * 1024) { data, error in
if error != nil {
// Uh-oh, an error occurred!
} else {
print(2)
let image = UIImage(data: data!)
DispatchQueue.main.async { // Adds the images to cache
if let downloadedImage = image {
imageCache.setObject(downloadedImage, forKey: annoucements[indexPath.row].key! as AnyObject)
cell.someImage.image = downloadedImage
}
}
cell.someImage.image = image
}
}
return cell
}

Answer 1

In tableview cell are reused so you don't need to surprise why you are getting image on cell even though no image at specific path .
If you can observe
when you call getData method from the cell which have no image i think the case where you are getting error nothing is set neither in cell.someImage nor in imageCache
My suggestion is to if you are going to show temporary image in your cell in case no image available then you should also set that placeholder image on cache when error block executed on getData method so it won't execute again and again. and you can set nil in override prepareForReuse of your custom cell so you won't get any repeating image.
Hope it is helpful

Answer 2

When you tableView.dequeueReusableCell, you actually reuse previously stored cell with its data,
You have to clear the cell of its content by calling prepareForReuse in your TableCell:
override func prepareForReuse() {
super.prepareForReuse()
someImage.image = nil // or some placeholder image
}

Answer 3

This how I accomplished that. Note the else statement with a placeholder image:
let cell = UITableViewCell(style: .default, reuseIdentifier: "CellID")
if let pic = PageDataSource.sharedInstance.angels[indexPath.row].photo {
cell.imageView?.image = pic
cell.setNeedsLayout()
} else if let imgURL = PageDataSource.sharedInstance.angels[indexPath.row].filepath {
Storage.storage().reference(forURL: imgURL).getData(maxSize: INT64_MAX, completion: { (data, error) in
guard error == nil else {
print("error downloading: \(error!)")
return
}
// render
let img = UIImage.init(data: data!)
// store to datasource
PageDataSource.sharedInstance.angels[indexPath.row].photo = img
// display img
if cell == tableView.cellForRow(at: indexPath){
DispatchQueue.main.async {
cell.imageView?.image = img
cell.setNeedsLayout()
}
}
})
} else {
// TODO: TODO: Change Image to a proper placeholder
cell.imageView?.image = UIImage(contentsOfFile: "Angels#2x.png")
}
cell.textLabel?.text = PageDataSource.sharedInstance.angels[indexPath.row].name
return cell
}