iOS - UIActivityIndicatorView not stopping - ios

Question

I am starting UIActivityIndicatorView in a func and want to stop it on success, for some reason it dosent happening:
func imageCaller(url: String , success: #escaping (UIImage) -> Void, failure: #escaping () -> Void) {
self.imageLoaderIndicator.startAnimating()
let handler = AuthenticateHandler()
self.urlSession = URLSession(configuration: URLSessionConfiguration.default, delegate: handler, delegateQueue: OperationQueue.main)
self.imageThumbnailTask = urlSession?.dataTask(with: URL(string:url)!) { data, res, err in
if err != nil {
guard let dataResponse = data,
err == nil else {
print("error from dataResponse:\(err?.localizedDescription ?? "Response Error")")
return
}
if let imageData = data {
if let image = UIImage(data: imageData) {
success(image)
}
}
}
self.imageThumbnailTask?.resume()
}
the code above is the network call.
This one is the method calling:
func imageThumbnailcall() {
self.imageCaller( url: self.isShowingThermal ? self.thermalUrl : self.visualUrl, success: { (image) in
self.imageLoaderIndicator.stopAnimating()
self.backGroundImageView.image = image
if self.isInVC {
self.imageThumbnailcall()
}
}) {
self.imageLoaderIndicator.stopAnimating()
}
}
Also in the storyboard i checked "hide when stopped" and also tried wrapping it with DispatchQueue.main.async {}

Answer 1

You have a lot of branches in your function that doesn't call either the success or the failure blocks and you also need to stop the activity indicator in the failure callback. You should also make sure that you dispatch all UI related activity to the main thread.
func imageCaller(url: String , success: #escaping (UIImage) -> Void, failure: #escaping () -> Void) {
self.imageLoaderIndicator.startAnimating()
let handler = AuthenticateHandler()
self.urlSession = URLSession(configuration: URLSessionConfiguration.default, delegate: handler, delegateQueue: OperationQueue.main)
self.imageThumbnailTask = urlSession?.dataTask(with: URL(string:url)!) { data, res, err in
if err != nil {
guard let dataResponse = data, err == nil else {
print("error from dataResponse:\(err?.localizedDescription ?? "Response Error")")
failure()
return
}
do{
//here dataResponse received from a network request
let jsonResponse = try JSONSerialization.jsonObject(with: dataResponse, options: [])
print("erro after parsing data:\(jsonResponse)") //Response result
failure()
} catch let parsingError {
failure()
print("Error", parsingError)
}
} else if let imageData = data, let image = UIImage(data: imageData) {
success(image)
} else {
failure()
}
}
self.imageThumbnailTask?.resume()
}
And then call stopAnimating from the failure block as well:
func imageThumbnailcall() {
self.imageCaller(url: self.isShowingThermal ? self.thermalUrl : self.visualUrl, success: { image in
DispatchQueue.main.async{
self.imageLoaderIndicator.stopAnimating()
self.backGroundImageView.image = image
}
if self.isInVC {
self.imageThumbnailcall()
}
}, failure: { _ in
DispatchQueue.main.async{
self.imageLoaderIndicator.stopAnimating()
}
})
}
Not sure what is isInVC or how it is set, but you call the same method again based on its value, which might result in an infinite loop of imageThumbnailcall calling itself from the success completion handler.

Answer 2

Try;
func imageThumbnailcall() {
self.imageCaller( url: self.isShowingThermal ? self.thermalUrl : self.visualUrl, success: { (image) in
self.imageLoaderIndicator.stopAnimating()
self.backGroundImageView.image = image
if self.isInVC {
self.imageThumbnailcall()
}
}) {
self.imageLoaderIndicator.stopAnimating()
}
}

Answer 3

Callback of URLSession.dataTask is in background queue so
DispatchQueue.main.async {
self.imageLoaderIndicator.stopAnimating()
}
and make sure to handle both success and failure