Fix location permissions warning issue

Fixed an issue where a location permissions warning alert controller was presented in all cases for a fresh install of the app.
The problem was that the app did not check if the location permissions were requested before, so even if the user was never presented with a prompt the warning case would trigger - meaning users would always be shown the permissions denied warning no matter what they chose.

The fix is to rely on the `CLLocationManagerDelegate` call back of `locationManagerDidChangeAuthorization(_ :)`
which is called both at initialization time of `CLLocationManager` and when permissions are changed.
The check at `appDidBecomeActive` time has been removed because the aforementioned delegate call accomplishes the same thing.

Author: SebastianWild

OpenGpxTracker-Watch Extension/InterfaceController.swift

@@ -331,16 +331,25 @@ class InterfaceController: WKInterfaceController {
     /// - Seealso: displayLocationServicesDisabledAlert, displayLocationServicesDeniedAlert
     ///
     func checkLocationServicesStatus() {
-        //Are location services enabled?
-        if !CLLocationManager.locationServicesEnabled() {
-            displayLocationServicesDisabledAlert()
+        let authorizationStatus = CLLocationManager.authorizationStatus()
+        
+        //Has the user already made a permission choice?
+        guard authorizationStatus != .notDetermined else {
+            //We should take no action until the user has made a choice
             return
         }
+        
         //Does the app have permissions to use the location servies?
-        if !([.authorizedAlways, .authorizedWhenInUse].contains(CLLocationManager.authorizationStatus())) {
+        guard [.authorizedAlways, .authorizedWhenInUse ].contains(authorizationStatus) else {
             displayLocationServicesDeniedAlert()
             return
         }
+        
+        //Are location services enabled?
+        guard CLLocationManager.locationServicesEnabled() else {
+            displayLocationServicesDisabledAlert()
+            return
+        }
     }
 
     ///

OpenGpxTracker/ViewController.swift

@@ -873,7 +873,6 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
         if !wasSentToBackground {
             return
         }
-        checkLocationServicesStatus()
         locationManager.startUpdatingLocation()
         locationManager.startUpdatingHeading()
     }
@@ -1164,16 +1163,26 @@ class ViewController: UIViewController, UIGestureRecognizerDelegate {
     /// - Seealso: displayLocationServicesDisabledAlert, displayLocationServicesDeniedAlert
     ///
     func checkLocationServicesStatus() {
-        //Are location services enabled?
-        if !CLLocationManager.locationServicesEnabled() {
-            displayLocationServicesDisabledAlert()
+        let authorizationStatus = CLLocationManager.authorizationStatus()
+        
+        //Has the user already made a permission choice?
+        guard authorizationStatus != .notDetermined else {
+            //We should take no action until the user has made a choice
+            //Note that we request location permission as part of the property `locationManager` init
             return
         }
+        
         //Does the app have permissions to use the location servies?
-        if !([.authorizedAlways, .authorizedWhenInUse].contains(CLLocationManager.authorizationStatus())) {
+        guard [.authorizedAlways, .authorizedWhenInUse ].contains(authorizationStatus) else {
             displayLocationServicesDeniedAlert()
             return
         }
+        
+        //Are location services enabled?
+        guard CLLocationManager.locationServicesEnabled() else {
+            displayLocationServicesDisabledAlert()
+            return
+        }
     }
     ///
     /// Displays an alert that informs the user that location services are disabled.
@@ -1288,8 +1297,6 @@ extension ViewController: PreferencesTableViewControllerDelegate {
         signalAccuracyLabel.text = kUnknownAccuracyText
     }}
 
-// MARK: location manager Delegate
-
 /// Extends `ViewController`` to support `GPXFilesTableViewControllerDelegate` function
 /// that loads into the map a the file selected by the user.
 extension ViewController: GPXFilesTableViewControllerDelegate {
@@ -1412,6 +1419,15 @@ extension ViewController: CLLocationManagerDelegate {
         map.updateHeading() // updates heading view's rotation
 
     }
+    
+    ///
+    /// Called by the system when `CLLocationManager` is created and when the user makes a permission choice
+    ///
+    /// We handle this delegate callback so that we can check if the user has allowed location access, else we show a warning
+    ///
+    func locationManagerDidChangeAuthorization(_ manager: CLLocationManager) {
+        checkLocationServicesStatus()
+    }
 }
 
 extension Notification.Name {