thing.swift

import UIKit

protocol LocationManagerDelegate {
    func retrievedMapLocation(location: Int)
}

class LocationManager {
    var delegate: LocationManagerDelegate?

    func getLocations() {
        // TODO: Get locations
        let locations = [1,2,3,4]

        locations.forEach { (location) -> () in
            self.delegate?.retrievedMapLocation(location)
        }
    }
}

class ViewController: UIViewController, LocationManagerDelegate {

    let manager = LocationManager()

    override func viewDidLoad() {
        manager.delegate = self
    }

    func retrievedMapLocation(location: Int) {
        // TODO: Update our map
    }
}

/cc @hetony