Why are my annotations not appearing in my map view? - ios

Question

I have created a set of "IssueLocation"'s, a class which conforms to the MKAnnotation protocol. Why are my annotations (built from API JSON data) not appearing in my map view ?
Here is the code behind it all:
Class code:
class IssueLocation: NSObject, MKAnnotation {
var locationName: String
var campusName: String
var latitude: Double
var longitude: Double
var coordinate: CLLocationCoordinate2D
init(locationName: String, campusName: String, latitude: Double, longitude: Double, coordinate: CLLocationCoordinate2D) {
self.locationName = locationName
self.campusName = campusName
self.latitude = latitude
self.longitude = longitude
self.coordinate = coordinate
super.init()
}
var subtitle: String? {
if (latitude == 44.22438242146097) {
return "West Campus"
} else {
return "Main Campus"
}
}
var title: String? {
return locationName
}
func mapItem() -> MKMapItem {
let addressDictionary = [String(kABPersonAddressStreetKey): locationName]
let placemark = MKPlacemark(coordinate: coordinate, addressDictionary: addressDictionary)
let mapItem = MKMapItem(placemark: placemark)
mapItem.name = locationName
return mapItem
}
}
Creating a set of IssueLocations:
func populateMapObjects() {
if populatingMapObjects {
return
}
populatingMapObjects = true
self.loadingIndicator.startAnimating()
var index = 0
Alamofire.request(GWNetworking.Router.MapObjects).responseJSON() { response in
if let JSON = response.result.value {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_LOW, 0)) {
/* Making an array of all the node IDs from the JSON file */
if (JSON .isKindOfClass(NSArray)) {
for _ in JSON as! [Dictionary<String,AnyObject>] {
if let issueLocation: IssueLocation = IssueLocation(locationName: "Center of the universe", campusName: "Queen's University", latitude: 44.22661586877309, longitude: -76.49380087852478, coordinate: CLLocationCoordinate2D(latitude: 44.22661586877309, longitude: -76.49380087852478)) {
if let locationName = JSON[index]["name"] as? String {
issueLocation.locationName = locationName
}
if let latitude = JSON[index]["coordinates"]!![1] as? Double {
issueLocation.latitude = latitude
}
if let longitude = JSON[index]["coordinates"]!![0] as? Double {
issueLocation.longitude = longitude
}
issueLocation.coordinate = CLLocationCoordinate2D(latitude: issueLocation.latitude, longitude: issueLocation.longitude)
index = index+1
self.mapObjects.append(issueLocation)
}
}
}
dispatch_async(dispatch_get_main_queue()) {
self.loadingIndicator.stopAnimating()
self.populatingMapObjects = false
print(self.mapObjects.count)
}
}
}
}
}
And finally, this is where I try to add the annotations to the map view:
func loadObjectsIntoMapView() {
for mapObject in mapObjects {
let temporaryMapAnnotation = IssueLocation(locationName: mapObject.locationName, campusName: "Main Campus", latitude: mapObject.latitude, longitude: mapObject.longitude, coordinate: mapObject.coordinate)
if (temporaryMapAnnotation.longitude < -76.50921821594238) {
temporaryMapAnnotation.campusName = "West Campus"
}
self.mapView.addAnnotation(temporaryMapAnnotation)
}
}

Answer 1

Move loadObjectsIntoMapView() into this block:
dispatch_async(dispatch_get_main_queue()) {
self.loadingIndicator.stopAnimating()
self.populatingMapObjects = false
print(self.mapObjects.count)
}
Calling loadObjectsIntoMapView() in viewDidLoad will have it execute immediately and the data has not come down from the server yet so you will have no mapObject in mapObjects hence no annotations.