Using delegation

Let's create a simple class that has a location manager, which will receive location updates:

class LocationAware: NSObject {
    let manager = CLLocationManager()

    override init() {
        super.init()
        manager.delegate = self
    }
}

Then, we need to mark LocationAware as being CLLocationManagerDelegate. Delegation uses protocols to ensure the methods that may be called are properly implemented on the delegate:

extension LocationAware: CLLocationManagerDelegate {
    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        // do something with the updated location
    }

    /* more delegation methods */
}

Now, with that example in mind, let's create our own delegation pattern that will facilitate communications between two objects.