Loading Screen from any Class in Swift - ios

Question

I am trying to implement a loading screen in swift, that I can reuse from any class in the project (I have a few classes that will handle 'long running' activities)
The public function is, from another answer:
public class LoadingOverlay{
var overlayView = UIView()
var activityIndicator = UIActivityIndicatorView()
class var shared: LoadingOverlay {
struct Static {
static let instance: LoadingOverlay = LoadingOverlay()
}
return Static.instance
}
public func showOverlay(view: UIView) {
overlayView.frame = CGRectMake(0, 0, 80, 80)
overlayView.center = view.center
overlayView.backgroundColor = MyGlobalVariables.UICOLORGREEN
overlayView.clipsToBounds = true
overlayView.layer.cornerRadius = 10
activityIndicator.frame = CGRectMake(0, 0, 40, 40)
activityIndicator.activityIndicatorViewStyle = .WhiteLarge
activityIndicator.center = CGPointMake(overlayView.bounds.width / 2, overlayView.bounds.height / 2)
overlayView.addSubview(activityIndicator)
view.addSubview(overlayView)
activityIndicator.startAnimating()
}
public func hideOverlayView() {
activityIndicator.stopAnimating()
overlayView.removeFromSuperview()
}
}
Which works fine in FirstViewController.swift (Where it is located) by using:
LoadingOverlay.shared.showOverlay(self.view)
My question is, how do I use it in XYZ.swift? As self.view may not be referring to a view generated by that class. Is it possible to call and find the current super view, then add the loading screen on top of it?

Answer 1

You need to add your overlay to your main UIWindow class. In that case you will overlay all views.
public func showOverlay() {
if let appDelegate = UIApplication.sharedApplication().delegate as? AppDelegate,
let window = appDelegate.window {
overlayView.frame = CGRectMake(0, 0, 80, 80)
overlayView.center = CGPointMake(window.frame.width / 2.0, window.frame.height / 2.0)
overlayView.backgroundColor = MyGlobalVariables.UICOLORGREEN
overlayView.clipsToBounds = true
overlayView.layer.cornerRadius = 10
activityIndicator.frame = CGRectMake(0, 0, 40, 40)
activityIndicator.activityIndicatorViewStyle = .WhiteLarge
activityIndicator.center = CGPointMake(overlayView.bounds.width / 2, overlayView.bounds.height / 2)
overlayView.addSubview(activityIndicator)
window.addSubview(overlayView)
activityIndicator.startAnimating()
}
}
PS: you can move most of overlayView customization code to init function, because you don't need to update backgroundColor or other things every time on display.
PPS: There is great libraries for loading overlay like
https://github.com/TransitApp/SVProgressHUD
https://github.com/jdg/MBProgressHUD
and others. Just google it