Image not loading in collection view cell - ios

Question

I've programmatically setup a collection view that should display an image from an API onto a cell. However, once the cells are displayed and data is called the cells remain empty.
Cells returning an empty image view
Current setup
override func viewDidLoad() {
super.viewDidLoad()
collectionView.register(ImageCell.self, forCellWithReuseIdentifier: imageCellId)
loadImageData(numberOfItems: numberOfItems)
}
func loadImageData(numberOfItems: Int) {
client.getImageData(items: numberOfItems, completion: { (error,data) in
if error != nil {
print("Error parsing image data")
} else {
self.per_page = data.perPage
self.total_results = data.totalResults
self.images = data.photos
for image in self.images {
self.userNameArray.append(image.photographer)
self.urlArray.append(image.url)
}
self.imageLinkArray = self.urlArray
DispatchQueue.main.async {
self.collectionView.reloadData()
}
}
})
}
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: imageCellId, for: indexPath) as! ImageCell
let imageString = String(imageLinkArray[indexPath.row])
let url = URL(string: imageString)
let data = try? Data(contentsOf: url!)
if let imageData = data {
let imageFromDatabase = UIImage(data: imageData)
cell.imageView.image = imageFromDatabase
}
return cell
}
Tried:
Made sure the URLs are coming back using a print statement for the url constant in cellForItemAt.
I've also tested out the cell layout by using a placeholder image.
Called collectionView.reloadData() in viewDidAppear().
Collection View Cells not appearing
Images not displayed in collection view cell

Answer 1

You should use Kingfisher as an image caching library
https://github.com/onevcat/Kingfisher
First, add the pod to your project:
pod 'Kingfisher'
Replace this:
let url = URL(string: imageString)
let data = try? Data(contentsOf: url!)
if let imageData = data {
let imageFromDatabase = UIImage(data: imageData)
cell.imageView.image = imageFromDatabase
}
with this
let url = URL(string: imageString)
imageView.kf.setImage(with: url)