Extension for UIViewController to show a loading indicator centered within the main view using frame animation built into UIImageView.

loading.zip

UIViewController+LoadingAnimation.swift

// UIViewController+LoadingAnimation.swift
//
// Created by GigabiteLabs on 4/16/20
// Swift Version: 5.0
//

// Description:
// An extension for UIViewController using gif-like frame animation support 
// in UIImageView to show a loading indicator centered within the main view.

// Note: 
// This code assumes you have an imageset within your asset catalog
// where each image is numerically sequential (representing one frame each),
// and following the naming convention: "loading\(i)", where the initial image
// is named "loading0", and the last image is named "loading30".


import Foundation

extension UIViewController {
    func presentLoadingAnimation() {
        // Instantiate Image
        let animatedView = UIImageView()
        animatedView.frame.size = CGSize(width: 100, height: 100)
        animatedView.center = view.center
        animatedView.layer.cornerRadius = 13
        animatedView.backgroundColor = .clear
        animatedView.tag = 99999
        animatedView.layer.zPosition = 0
        
        // Add GIF
        var imageArray: [UIImage] = []
        
        for i in -1...30 {
            if let image = UIImage(named: "loading\(i)"){
                imageArray.append(image)
            }
        }
        
        animatedView.animationImages = imageArray
        animatedView.animationDuration = 0.5
        animatedView.startAnimating()
        
        //Add as Subview
        view.addSubview(animatedView)
        animatedView.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        animatedView.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        
        view.isUserInteractionEnabled = false
    }
    
    func hideLoadingAnimation() {
        view.viewWithTag(99999)?.removeFromSuperview()
        view.isUserInteractionEnabled = true
    }
}