iOS Swift delegates - swift

Question

I'm very new to Swift, and I'm having trouble using delegates. When the user taps on a table row in AdminAddCatTableViewController, I want to drop a pin on the map at the user's current location in AdminViewController, and I'm trying to do this using a delegate. Obviously there's something wrong with my code, as the pin does not get dropped.
In AdminAddCatTableViewController, I have
import UIKit
import Firebase
protocol AddCatDelegate: class {
func addPin(sender: AdminAddCatTableViewController)
}
class AdminAddCatTableViewController: UITableViewController {
weak var delegate:AddCatDelegate?
let admin = "secret-number"
let ref = Firebase(url: "firease_url")
#IBOutlet weak var snowballGPSLabel: UILabel!
#IBOutlet weak var smokeyGPSLabel: UILabel!
#IBOutlet weak var shadowGPSLabel: UILabel!
#IBOutlet weak var spotsGPSLabel: UILabel!
#IBOutlet weak var sunnyGPSLabel: UILabel!
var catRefArray: [AnyObject] = []
var coord:String = ""
let shareData = ShareData.sharedInstance
func updateCoord() {
if let bar = self.shareData.someString {
self.coord = bar
}
}
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
NSTimer.scheduledTimerWithTimeInterval(0.5, target: self, selector: "updateCoord", userInfo: nil, repeats: true)
var catNameArray: [AnyObject] = []
catNameArray.append("Snowball")
catNameArray.append("Smokey")
catNameArray.append("Shadow")
catNameArray.append("Spots")
catNameArray.append("Sunny")
for i in 0...4 {
catRefArray.append(self.ref.childByAppendingPath("admin").childByAppendingPath(self.admin).childByAppendingPath(catNameArray[i] as! String))
}
catRefArray[0].observeEventType(.Value, withBlock: { snapshot in
if let value:String = snapshot.value as? String {
self.snowballGPSLabel.text = value
}
}, withCancelBlock: { error in
print(error.description)
// same for the other rows
})
}
override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
if (indexPath.row == 0) {
let ref0 = self.ref.childByAppendingPath("admin").childByAppendingPath(self.admin)
ref0.updateChildValues(["Snowball": self.coord])
delegate?.addPin(self)
}
// same for other rows
}
In AdminViewController, I have
import UIKit
import MapKit
import CoreLocation
class AdminViewController: UIViewController, CLLocationManagerDelegate, MKMapViewDelegate {
#IBAction func logOutDidTouch(sender: AnyObject) {
performSegueWithIdentifier("adminToLogin", sender: self)
}
#IBOutlet weak var mapView: MKMapView!
var locationManager: CLLocationManager!
var previousLocation : CLLocation!
var latitude = 0.0;
var longitude = 0.0;
//Declare Class Variable
let shareData = ShareData.sharedInstance
override func viewDidLoad() {
super.viewDidLoad()
//On loading the screen the map kit view is shown and the current location is found and is being updated.
locationManager = CLLocationManager()
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.delegate = self;
let status = CLLocationManager.authorizationStatus()
if status == .NotDetermined || status == .Denied || status == .AuthorizedWhenInUse {
locationManager.requestAlwaysAuthorization()
locationManager.requestWhenInUseAuthorization()
}
locationManager.startUpdatingLocation()
locationManager.startUpdatingHeading()
mapView.delegate = self
mapView.showsUserLocation = true
mapView.mapType = MKMapType(rawValue: 0)!
mapView.userTrackingMode = MKUserTrackingMode(rawValue: 2)!
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
mapView.mapType = MKMapType(rawValue: 0)!
}
override func viewWillAppear(animated: Bool) {
//updates the location
locationManager.startUpdatingHeading()
locationManager.startUpdatingLocation()
}
override func viewWillDisappear(animated: Bool) {
locationManager.stopUpdatingHeading()
locationManager.stopUpdatingLocation()
}
func locationManager(manager: CLLocationManager, didUpdateToLocation newLocation: CLLocation, fromLocation oldLocation: CLLocation) {
self.latitude = newLocation.coordinate.latitude
self.longitude = newLocation.coordinate.longitude
self.shareData.someString = "\(self.latitude)" + "," + "\(self.longitude)"
print(self.shareData.someString)
}
}
extension AdminViewController: AddCatDelegate {
func addPin(sender:AdminAddCatTableViewController) {
// drop a pin
self.mapView.delegate = self
let coordinate = mapView.userLocation.coordinate
let dropPin = MKPointAnnotation()
dropPin.coordinate = coordinate
dropPin.title = "Cat"
mapView.addAnnotation(dropPin)
}
}

Answer 1

Well you are never setting the delegate on your AdminAddCatTableViewController, so it is always nil and never called.
Why do you even have an extension of AdminViewController? Just remove the extension and make AdminViewController implement the delegate. To set the delegate implement something like this in your AdminViewController:
override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
super.prepareForSegue(segue, sender: sender)
if segue.identifier == "YourSegueIdentifier" {
if let vc = segue.destinationViewController as? AdminAddCatTableViewController {
vc.delegate = self
}
}
}