iOS Programming: The Big Nerd Ranch Guide, 6th Edition

Creating a Custom UICollectionViewCell

Next you are going to create a custom UICollectionViewCell subclass to display the photos. While the image data is downloading, the collection view cell will display a spinning activity indicator using the UIActivityIndicatorView class.

Create a new Swift file named PhotoCollectionViewCell and define PhotoCollectionViewCell as a subclass of UICollectionViewCell. Then add outlets to reference the image view and the activity indicator view.

import Foundation
import UIKit

class PhotoCollectionViewCell: UICollectionViewCell {

    @IBOutlet var imageView: UIImageView!
    @IBOutlet var spinner: UIActivityIndicatorView!

}

The activity indicator view should only spin when the cell is not displaying an ...