Show wrong images in UICollectionView - ios

Question

there! I need your help. I have UIImage inside UICollectionView which lying inside UITableView. When I get data from API at the first time it shows images right, but when I start to scroll down and come back, it shows wrong images. My code looks like this:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! AllPostsOfUserCollectionViewCell
let post = allPostsOfUserArray[collectionView.tag]
if post.imageLinks.count != 0 {
let imageLink = post.imageLinks[indexPath.row]
if imageLink.imageLink != nil {
let url = URL(string: imageLink.imageLink!)
cell.imageOfAnimalInCollectionView.sd_setImage(with: url!, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
})
}
}
return cell
}
My model looks like this:
class UserContent {
var name = ""
var imageLinks = [UserImages]()
init(name: String, imageLinks: [UserImages]?) {
self.name = name
if imageLinks != nil {
self.imageLinks = imageLinks!
}
}
init() { }
deinit {
imageLinks.removeAll()
}
}
class UserImages {
var imageLink: String?
init(imageLink: String?) {
self.imageLink = imageLink
}
init() { }
deinit {
imageLink = ""
}
}
What I do in UITableView
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let index = indexPath.row
let cell = tableView.dequeueReusableCell(withIdentifier: "cell") as! AllPostsOfUserTableViewCell
cell.collectionView.tag = index
let post = allPostsOfUserArray[index]
if post.imageLinks.count == 0 {
cell.collectionView.isHidden = true
} else {
cell.collectionView.isHidden = false
}
return cell
}
UPD: I added cell.collectionView.reloadData() to func tableView(cellForRowAt indexPath). Now it works fine.

Answer 1

Could you try this code:
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! AllPostsOfUserCollectionViewCell
cell.imageOfAnimalInCollectionView.image = UIImage(named: "App-Default")
let post = allPostsOfUserArray[collectionView.tag]
if post.imageLinks.count != 0 {
let imageLink = post.imageLinks[indexPath.row]
if imageLink.imageLink != nil {
let url = URL(string: imageLink.imageLink!)
cell.imageOfAnimalInCollectionView.sd_setImage(with: url!, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
})
}
}
return cell
}

Answer 2

This problem is something like race condition.
You can reference my answer in similair question
You might need to find another module to download image and set to cell manually.

Answer 3

cell.imageOfAnimalInCollectionView.image = nil
if post.imageLinks.count != 0 {
let imageLink = post.imageLinks[indexPath.row]
if imageLink.imageLink != nil {
let url = URL(string: imageLink.imageLink!)
cell.imageOfAnimalInCollectionView.sd_setImage(with: url!, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
})
}
}
(Not tested, but should work. You can also use sd_image's method to assign an empty url, with a placeholder image to just show the placeholder image. Or just give an empty url string '' without the placeholder image)
Whenever you scroll, the cells are re-used, and the image assigned to the cell reappears because it is still on the cell.
You have to remove those images by using else clause for every if where you are assigning an image to the imageView.
Hope this helps.

Answer 4

You have to write else conditions like Below ..
func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath) as! AllPostsOfUserCollectionViewCell
let post = allPostsOfUserArray[collectionView.tag]
if post.imageLinks.count != 0 {
let imageLink = post.imageLinks[indexPath.row]
if imageLink.imageLink != nil {
let url = URL(string: imageLink.imageLink!)
cell.imageOfAnimalInCollectionView.sd_setImage(with: url!, placeholderImage: UIImage(named: "App-Default"),options: SDWebImageOptions(rawValue: 0), completed: { (image, error, cacheType, imageURL) in
})
}
else{
cell.imageOfAnimalInCollectionView = "defaultImage"
}
}
else{
cell.imageOfAnimalInCollectionView = "defaultImage"
}
return cell
}
Reason
after dequeueing cell cellectionView reuses the created cell for all next cells so if you not write an else condition or not use prepareForReuse method it will always data of previous cell that is in its cache.