Releasing Memory from MapView - ios

Question

In my project I am using a mapView to render locations from Lat-Lon received from an API. My project has a button which does the follow:
When clicked, it fires a timer that retrieves coordinates from the web and then plots on the mapview
When clicked again, it stops the timer and no data is retrieved.
However even when the timer is stopped it consumes a lot of memory around 100mbs if not more. So I want to release the memory when user is not using map and when they are map should come back again. I did the following to release memory:
self.mapView.delegate = nil;
self.mapView.removeFromSuperview()
self.mapView = nil;
This removes map and my memory comes back to 20mbs, normal. However is this the correct way to release memory? and how do I get it back once the button is pressed?.

Answer 1

To add a map you can do this:
import UIKit
import MapKit
class ViewController: UIViewController {
var mapView: MKMapView?
#IBOutlet weak var framer: UIView!//uiview to put map into
var coordinate = CLLocationCoordinate2D(){
willSet{
print("removing annotation...")
if let m = mapView{
m.removeAnnotation(anno)
}
}
didSet{
print("did set called, adding annotation...")
anno.coordinate = coordinate
if let m = mapView{
m.addAnnotation(anno)
}
}
}
override func viewDidLoad() {
super.viewDidLoad()
}
#IBAction func start(_ sender: Any) {
let mk = MKMapView()
mk.bounds = framer.bounds
mk.mapType = MKMapType.standard
mk.isZoomEnabled = true
mk.isScrollEnabled = true
// Or, if needed, we can position map in the center of the view
mk.center = framer.center
mapView = mk
if let mk2 = mapView{
framer.addSubview(mk2)
}
}
To remove
#IBAction func stop(_ sender: UIButton) {
if mapView != nil{
if let mk2 = mapView{
mk2.delegate = nil;
mk2.removeFromSuperview()
mapView = nil;
}
}
}
}