Loading animation stucked/freezed when webview loads - ios

Question

I load the progress loading animation and when the response from Alamofire comes I use part of the response to construct the full url I need to load in the wkwebview and then I trigger webview.load(..).
My problem is that the progress loading animation gets stuck as soon as webview.load(..) starts to happen and remain stuck till I hide() it.
How can I actually have my animation to keep moving meanwhile the webview starts loading the page?
MyViewController.swift
class MyViewController: UIViewController, WKScriptMessageHandler {
var webView: WKWebView?
#IBOutlet weak var webViewContainer: UIView!
var webConfig:WKWebViewConfiguration {
get {
let webCfg:WKWebViewConfiguration = WKWebViewConfiguration()
let userController:WKUserContentController = WKUserContentController()
userController.add(self, name: "mycontroller")
webCfg.userContentController = userController;
return webCfg;
}
}
override func viewDidLoad() {
super.viewDidLoad()
webView = WKWebView (frame: webViewContainer.bounds, configuration: webConfig)
webView!.autoresizingMask = [.flexibleWidth, .flexibleHeight]
webView?.scrollView.isScrollEnabled = false
webViewContainer.addSubview(webView!)
loadWebview()
}
func loadWebview(){
Loading.shared.show(self.view)
Alamofire.request(MYAPI, method: .post, parameters: parameters, encoding: JSONEncoding.default, headers: nil)
.responseJSON { response in
let url = URL(string: "https://path-to-load/\(response.key)")
self.webView!.load(URLRequest(url: url!))
}
}
func userContentController(_ userContentController: WKUserContentController, didReceive message: WKScriptMessage) {
let message = message.body as! [String:AnyObject]
let event = message["event"] as? String ?? "empty"
switch (event){
case "loading-finished":
DispatchQueue.main.async {
Loading.shared.hide(animated: true)
}
break
default:
break
}
}
}
Loading.swift
public class Loading {
var blurredEffectView = UIVisualEffectView(effect: UIBlurEffect(style: .light))
let imageView = UIImageView(image: UIImage(named: "loading_image"))
class var shared: Loading {
struct LoadingStatic {
static let instance: Loading = Loading()
}
return LoadingStatic.instance
}
init() {
imageView.frame = CGRect(x: 0, y: 0, width: 100, height: 100)
imageView.contentMode = .scaleToFill
blurredEffectView.contentView.addSubview(imageView)
}
public func show(_ view: UIView, inView: Bool = false) {
var window: UIView!
if inView == false, let w = view.window {
window = w
} else {
window = view
}
if blurredEffectView.superview == window {
return
}
let rotation: CABasicAnimation = CABasicAnimation(keyPath: "transform.rotation.z")
rotation.toValue = NSNumber(value: Double.pi * 2)
rotation.duration = 1
rotation.isCumulative = true
rotation.repeatCount = Float.greatestFiniteMagnitude
imageView.layer.add(rotation, forKey: "rotationAnimation")
imageView.center = window.center
blurredEffectView.frame = window.bounds
window.addSubview(blurredEffectView)
blurredEffectView.fadeIn()
}
}

Answer 1

Possible solutions:
1) Make the loading happens in Application Window when you want a full screen Loading (inview == false by default) and keep loadWebview() in viewDidLoad
public func show(_ view: UIView? = nil, inView: Bool = false) {
var window: UIView!
if inView == false, let w = UIApplication.shared.delegate?.window {
window = w
} else {
window = view
}
...
2) Move loadWebview() from viewDidLoad to viewDidAppear
The important part that is moving here is Loading.shared.show(self.view). I wasn't able to animate the components of my view until it has finished laying out (which happens exactly in viewDidAppear()).
More details: viewDidLoad is called after the MyViewController has been initialised and has initialised the main view but before the view is presented to the UI. This means that viewDidLoad allows me to setup the ViewController and the View, before it is shown to the user for interactions.
Although it was a nice and quick solution, in some situation this may not work as expected as viewDidAppear can be called twice, and hence showing the loading view twice which will result in a weird ux.