Saving map pins to array, Swift - ios

Question

I am creating a map type application, once the user presses a button a pin is dropped to the map at their current location. I am trying to save map pins to an array so that they remain once the app is closed.
Here is my code so far:
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location = locations.last
let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.004, longitudeDelta: 0.004))
self.placesMap?.setRegion(region, animated: true)
self.locationManager.stopUpdatingLocation()
}
func locationManager(manager: CLLocationManager, didFailWithError error: NSError)
{
print("Error code: " + error.localizedDescription)
}
// Add button action
#IBAction func addButton(sender: AnyObject) {
let annotation = MKPointAnnotation()
annotation.coordinate = CLLocationCoordinate2D(latitude: self.placesMap.userLocation.coordinate.latitude, longitude: self.placesMap.userLocation.coordinate.longitude)
self.placesMap.addAnnotation(annotation)
self.locationManager.startUpdatingLocation()
}
How can I save the pin information to an array which is reloaded each time the app is opened?

Answer 1

If you want to persist data between application launches, and you are not storing much data, the easy way is to use NSUserDefaults. You can do this by saying something like:
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let location = locations.last
let center = CLLocationCoordinate2D(latitude: location!.coordinate.latitude, longitude: location!.coordinate.longitude)
let region = MKCoordinateRegion(center: center, span: MKCoordinateSpan(latitudeDelta: 0.004, longitudeDelta: 0.004))
self.placesMap?.setRegion(region, animated: true)
self.locationManager.stopUpdatingLocation()
let locationDictionary:[String:Double] = ["latitude":center.latitude,"longitude":center.longitude]
var locationArray = [[String:Double]]()
if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
locationArray = NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]
}
locationArray.append(locationDictionary)
NSUserDefaults.standardUserDefaults().setObject(locationArray, forKey: "locationArray")
NSUserDefaults.standardUserDefaults().synchronize()
}
You will then need to read out those locations when the app relaunches. You can do that in viewDidLoad. For example:
override func viewDidLoad(){
super.viewDidLoad()
if NSUserDefaults.standardUserDefaults().objectForKey("locationArray") != nil {
for dictionary in NSUserDefaults.standardUserDefaults().objectForKey("locationArray") as! [[String:Double]]{
let center = CLLocationCoordinate2D(latitude: dictionary["latitude"]!, longitude: dictionary["longitude"]!)
let annotation = MKPointAnnotation()
annotation.coordinate = center
self.placesMap.addAnnotation(annotation)
}
}
}
If you want to remove all of the stored locations you can say something like:
func removeStoredLocations(){
NSUserDefaults.standardUserDefaults().removeObjectForKey("locationArray")
NSUserDefaults.standardUserDefaults().synchronize()
}