Swift detect json parsing detect end - json

Question

I am parsing a certain json url data to plot in a map and I need to detect that I have all the data to show a spinner while nothing is happening. I have created a variable that goes from false to true after I have all the data but that variable only exists as true inside the for loop
This is part of the code that gets the data
import SwiftUI
import MapKit
var locationsFillTest : Int = 0
var allLocations = [MKPointAnnotation]()
var doneGettingData : Bool = false
struct MapView: UIViewRepresentable {
var startdate : String
func makeUIView(context: Context) -> MKMapView{
MKMapView(frame: .zero)
}
func makeCoordinator() -> MapViewCoordinator{
MapViewCoordinator(self)
}
func updateUIView(_ uiView: MKMapView, context: Context){
uiView.removeAnnotations(allLocations)
allLocations = []
doneGettingData = false
print("Done = \(doneGettingData)")
let url = URL(string: "https://XXXXXX")!
URLSession.shared.dataTask(with: url) {(data,response,error) in
do {
if let d = data {
let decodedLists = try JSONDecoder().decode(emsc.self, from: d)
DispatchQueue.main.async {
locationsFillTest = allLocations.count
doneGettingData = false
for locations in decodedLists.features {
let lat = Double(locations.properties.lat)
let long = Double(locations.properties.lon)
let annotation = MKPointAnnotation()
annotation.coordinate = CLLocationCoordinate2D(latitude: lat , longitude: long )
if locationsFillTest == 0 {
allLocations.append(annotation)}
}
uiView.addAnnotations(allLocations)
uiView.delegate = context.coordinator
uiView.showAnnotations(allLocations, animated: true)
doneGettingData = true
print("Done = \(doneGettingData)")
}
}else {
print("No Data")
}
} catch {
print("Error decoding JSON: ", error, response!)
}
}.resume()
}
}
The variable doneGettingData becomes false and true by watching the print but if I need to use it for example to create a spinner its false all the time since its only true inside.
How can I make it global ?
Thank you

Answer 1

Unless you have another declaration for doneGettingData inside the closure the instance level property is getting set to true. It may be getting set later than you expect though. Try the following to see when it changes (and to get you setup to react to those changes):
var doneGettingData : Bool = false {
didSet {
if doneGettingData {
print("The instance property doneGettingData is now true.")
} else {
print("The instance property doneGettingData is now false.")
}
}
}
You may want to make this into a custom enum though with cases along the lines of fetching, done, noData, and jsonError. Right now if there is no data you will never have a trigger to either retry, move on, notify the user, etc. The same applies when there is a decoding error. Or at the very least set the flag to true at the very end of the loop so something happens no matter what.
Something like:
enum DataCollectionState {
case fetching, done, noData, jsonError
var doneGettingData : DataCollectionState = fetching {
didSet {
switch doneGettingData {
case fetching:
// Show a spinner or something
case done:
// Hide the spinner
case noData:
// Tell the user there was no data? Try again?
case jsonError:
// Tell the user there was an error? Try again?
}
}
}
Note: I don't have Xcode open right now so syntax may not be exact.