extension UIView {
func addActivityIndicator() {
// creating a view (let's call it "loading" view) which will be added on top of the view you want to have activity indicator on (parent view)
let view = UIView()
// setting up a background for a view so it would make content under it look like not active
view.backgroundColor = UIColor.white.withAlphaComponent(0.7)
// adding "loading" view to a parent view
// setting up auto-layout anchors so it would cover whole parent view
self.addSubview(view)
view.translatesAutoresizingMaskIntoConstraints = false
view.topAnchor.constraint(equalTo: self.topAnchor).isActive = true
view.bottomAnchor.constraint(equalTo: self.bottomAnchor).isActive = true
view.leftAnchor.constraint(equalTo: self.leftAnchor).isActive = true
view.rightAnchor.constraint(equalTo: self.rightAnchor).isActive = true
// creating array with images, which will be animated
// in my case I have 30 images with names activity0.png ... activity29.png
var imagesArray = [UIImage(named: "activity(0)")!]
for i in 1..<30 {
imagesArray.append(UIImage(named: "activity(i)")!)
}
// creating UIImageView with array of images
// setting up animation duration and starting animation
let activityImage = UIImageView()
activityImage.animationImages = imagesArray
activityImage.animationDuration = TimeInterval(0.7)
activityImage.startAnimating()
// adding UIImageView on "loading" view
// setting up auto-layout anchors so it would be in center of "loading" view with 30x30 size
view.addSubview(activityImage)
activityImage.translatesAutoresizingMaskIntoConstraints = false
activityImage.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
activityImage.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
activityImage.widthAnchor.constraint(equalToConstant: 30).isActive = true
activityImage.heightAnchor.constraint(equalToConstant: 30).isActive = true
}
func removeActivityIndicator() {
// checking if a view has subviews on it
guard let lastSubView = self.subviews.last else { return }
// removing last subview with an assumption that last view is a "loading" view
lastSubView.removeFromSuperview()
} }