From 6d69dfddcff783bca20e688211868d7acf47b7c9 Mon Sep 17 00:00:00 2001
From: Shan Ma <shanma@alumni.usc.edu>
Date: Tue, 29 Jun 2021 16:45:36 -0700
Subject: [PATCH] add documentation and remove unecessary didSet trigger

---
 .../Examples/Custom-User-Location.swift           | 15 +++++++--------
 1 file changed, 7 insertions(+), 8 deletions(-)

diff --git a/Navigation-Examples/Examples/Custom-User-Location.swift b/Navigation-Examples/Examples/Custom-User-Location.swift
index 4d8bdd88..1367906d 100644
--- a/Navigation-Examples/Examples/Custom-User-Location.swift
+++ b/Navigation-Examples/Examples/Custom-User-Location.swift
@@ -8,6 +8,7 @@ class CustomUserLocationViewController: UIViewController, NavigationMapViewDeleg
     
     var navigationMapView: NavigationMapView! {
         didSet {
+            // After the start of active turn-by-turn navigation, the previous `navigationMapView` should be `nil` and removed from super view. It could avoid the location update in the background to disturb the turn-by-turn navigation guidance.
             if let navigationMapView = oldValue {
                 navigationMapView.removeFromSuperview()
             }
@@ -46,13 +47,7 @@ class CustomUserLocationViewController: UIViewController, NavigationMapViewDeleg
         }
     }
     
-    var waypoints: [Waypoint] = [] {
-        didSet {
-            waypoints.forEach {
-                $0.coordinateAccuracy = -1
-            }
-        }
-    }
+    var waypoints: [Waypoint] = []
     
     var startButtonHighlighted:Bool = false {
         didSet {
@@ -139,6 +134,8 @@ class CustomUserLocationViewController: UIViewController, NavigationMapViewDeleg
         
         let waypoint = Waypoint(coordinate: destinationCoordinate, name: "Dropped Pin #\(waypoints.endIndex + 1)")
         waypoint.targetCoordinate = destinationCoordinate
+        // Change the coordinate accuracy of `Waypoint` to negative beofre add it to the `waypoints`. Thus the route requested on the `waypoints` is considered viable.
+        waypoint.coordinateAccuracy = -1
         waypoints.append(waypoint)
 
         requestRoute()
@@ -152,6 +149,8 @@ class CustomUserLocationViewController: UIViewController, NavigationMapViewDeleg
         }
         
         let userWaypoint = Waypoint(location: currentLocation)
+        // Change the coordinate accuracy of `Waypoint` to negative beofre add it to the `waypoints`. Thus the route requested on the `waypoints` is considered viable.
+        userWaypoint.coordinateAccuracy = -1
         waypoints.insert(userWaypoint, at: 0)
         let navigationRouteOptions = NavigationRouteOptions(waypoints: waypoints)
         
@@ -293,7 +292,7 @@ class CustomUserLocationViewController: UIViewController, NavigationMapViewDeleg
         navigationViewController.navigationMapView?.mapView.mapboxMap.style.uri = navigationMapView.mapView?.mapboxMap.style.uri
         
         present(navigationViewController, animated: true) {
-            self.navigationMapView.removeFromSuperview()
+            // When start navigation, the previous `navigationMapView` should be `nil` and removed from super view. The niled out `navigationMapView` could avoid the location provider sending location update in the background, which will disturb the turn-by-turn navigation guidance.
             self.navigationMapView = nil
         }
     }