Xcode and Swift: Colors and Object ID not being applied to map markers? - ios

Question

I'm making a test app that is taking in geological points of interest from a JSON file and plotting the points on a map (you can see the info I am getting here: https://maine.hub.arcgis.com/datasets/ff3e487fb782464684f8c1f8a1b7e58d_0/about and you can see the JSON file there as well). I've been trying to color-code the points to correspond to the category of geological feature (bedrock is red, coastal is green, surficial is purple, etc.). However, when I try to apply the colors, it doesn't work. The app runs just fine, and I can see all the points, they're just not color-coded or labeled as their object ID.
This is the file I used for each item (titled Artwork because this project was previously locations of artworks in Oahu, but changed to geological formations in Maine):
import Foundation
import MapKit
import Contacts
import SwiftUI
class Artwork: NSObject, MKAnnotation {
let title: String?
let locationName: String?
let type: String?
let coordinate: CLLocationCoordinate2D
let objectID: Int?
init(title: String?, locationName: String?, type: String?, coordinate: CLLocationCoordinate2D, objectID: Int?) {
self.title = title
self.locationName = locationName
self.type = type
self.coordinate = coordinate
self.objectID = objectID
super.init()
}
init?(feature: MKGeoJSONFeature) {
guard
let point = feature.geometry.first as? MKPointAnnotation,
let propertiesData = feature.properties,
let json = try? JSONSerialization.jsonObject(with: propertiesData),
let properties = json as? [String: Any]
else {
return nil
}
title = properties["SITE_NAME"] as? String
locationName = properties["TOWN"] as? String
type = properties["CATEGORY"] as? String
coordinate = point.coordinate
objectID = properties["OBJECTID"] as? Int
super.init()
}
var subtitle: String? {
return locationName
}
var mapItem: MKMapItem? {
guard let location = locationName else {
return nil
}
let addressDict = [CNPostalAddressStreetKey: location]
let placemark = MKPlacemark(coordinate: coordinate, addressDictionary: addressDict)
let mapItem = MKMapItem(placemark: placemark)
mapItem.name = title
return mapItem
}
//This is where I code the method for choosing the color
var markerTintColor: UIColor {
switch type {
case "Bedrock":
return .red
case "Coastal":
return .green
case "Surficial":
return .purple
case "Bedrock, Surficial":
return .blue
case "Bedrock, Surficial, Coastal":
return .cyan
case "Surficial, Coastal":
return .magenta
case "Bedrock, Coastal":
return .orange
default:
return .gray
}
}
}
Here is another file that might be important, ArtworkViews.swift:
import Foundation
import MapKit
import SwiftUI
class ArtworkViews: MKMarkerAnnotationView {
override var annotation: MKAnnotation? {
willSet {
guard let artwork = newValue as? Artwork else {
return
}
canShowCallout = true
calloutOffset = CGPoint(x: -5, y: 5)
rightCalloutAccessoryView = UIButton(type: .detailDisclosure)
//This is where the color and ID are applied
markerTintColor = artwork.markerTintColor
if let ID = artwork.objectID {
glyphText = String(ID)
}
}
}
}
And here is where I implement the colors in ViewController.swift (this the viewDidLoad() function):
let initialLocation = CLLocation(latitude: 44.883427, longitude: -68.670815)
mapView.centerToLocation(initialLocation)
let maineCenter = CLLocation(latitude: 44.883427, longitude: -68.670815)
let region = MKCoordinateRegion(center: maineCenter.coordinate, latitudinalMeters: 600000, longitudinalMeters: 300000)
mapView.setCameraBoundary(MKMapView.CameraBoundary(coordinateRegion: region), animated: true)
let zoomRange = MKMapView.CameraZoomRange(maxCenterCoordinateDistance: 1400000)
mapView.setCameraZoomRange(zoomRange, animated: true)
mapView.delegate = self
//This is where the color is ultimately applied
mapView.register(ArtworkViews.self, forAnnotationViewWithReuseIdentifier: MKMapViewDefaultAnnotationViewReuseIdentifier)
loadInitialData()
mapView.addAnnotations(artworks)