Full-Screen iOS Loading Animation in Swift

This post shows how to implement a LoadingViewController and fade-in the LoadingViewController to show the app is performing some activity, like a network request.

Create A Loading View Controller

The first step is to subclass UIViewController and add a few placeholders. LoadingViewController will be implemented with a UIActivityIndicatorView to help inform the user progress is occurring, and a UIVisualEffectView to create a darkened blur.

class LoadingViewController: UIViewController {
    var loadingActivityIndicator: UIActivityIndicatorView = {
        // UIActivityIndicatorView Configuration
    }()
    
    var blurEffectView: UIVisualEffectView = {
        // UIVisualEffectView Configuration
    }()
    
    override func viewDidLoad() {
        // View Configuration
    }
}

Add A White Spinner

For this LoadingViewController, a large, white, and animating UIActivityIndicatorView will be used.

var loadingActivityIndicator: UIActivityIndicatorView = {
    let indicator = UIActivityIndicatorView()
    
    indicator.style = .large
    indicator.color = .white
        
    // The indicator should be animating when
    // the view appears.
    indicator.startAnimating()
        
    // Setting the autoresizing mask to flexible for all
    // directions will keep the indicator in the center
    // of the view and properly handle rotation.
    indicator.autoresizingMask = [
        .flexibleLeftMargin, .flexibleRightMargin,
        .flexibleTopMargin, .flexibleBottomMargin
    ]
        
    return indicator
}()

Add A Dark, Blurred Background

For this LoadingViewController, the UIVisualEffectView will be dark and partially transparent.

var blurEffectView: UIVisualEffectView = {
    let blurEffect = UIBlurEffect(style: .dark)
    let blurEffectView = UIVisualEffectView(effect: blurEffect)
    
    blurEffectView.alpha = 0.8
    
    // Setting the autoresizing mask to flexible for
    // width and height will ensure the blurEffectView
    // is the same size as its parent view.
    blurEffectView.autoresizingMask = [
        .flexibleWidth, .flexibleHeight
    ]
    
    return blurEffectView
}()

Override ViewDidLoad

To tie the components of LoadingViewController together, override viewDidLoad.

override func viewDidLoad() {
    super.viewDidLoad()
    
    view.backgroundColor = UIColor.black.withAlphaComponent(0.5)
    
    // Add the blurEffectView with the same
    // size as view
    blurEffectView.frame = self.view.bounds
    view.insertSubview(blurEffectView, at: 0)
    
    // Add the loadingActivityIndicator in the
    // center of view
    loadingActivityIndicator.center = CGPoint(
        x: view.bounds.midX,
        y: view.bounds.midY
    )
    view.addSubview(loadingActivityIndicator)
}

Loading View Controller With Fade In Animation

That’s it! To display LoadingViewController, use the following:

let loadingVC = LoadingViewController()

// Animate loadingVC over the existing views on screen
loadingVC.modalPresentationStyle = .overCurrentContext

// Animate loadingVC with a fade in animation
loadingVC.modalTransitionStyle = .crossDissolve
       
present(loadingVC, animated: true, completion: nil)

FREE all Swift loading animations.

Loading Animation Example

Follow AdvancedSwift and immediately get access to commented code for these animations that you can use in your projects.

The result is an animating activity indicator and darkened screen blur that can be used to inform a user that progress is occurring:

iOS Loading Overlay With Activity Indicator And Fade-In Animation Example In Swift