自定义CLLocationManager didUpdateLocations函数

Question

I read the Radar.io ( https://radar.io/documentation/sdk#ios ) iOS SDK documentation and I'm curious how I create a custom

locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) function.

class ViewController: UIViewController, RadarDelegate {

  override func viewDidLoad() {
      super.viewDidLoad()

      Radar.setDelegate(self)
  }
}

And

Radar.trackOnce(completionHandler: { (status: RadarStatus, location: CLLocation?, events: [RadarEvent]?, user: RadarUser?) in
   // do something with status, location, events, user
})

source: https://radar.io/documentation/sdk#ios

How i get location update and control CLLocationManager in a custom class like this?

 protocol MyRadarCloneDelegate {

 }

 class MyRadarClone {
   static func setDelegate(_ delegate:)  {

   }

   static func startTracking()  {

   }
   // some other function for control CLLocationManager
 }

Answer 1

If I understand your question correctly you want to access your location from Radar.trackOnce into your custom class.

You can do it this way.

Update your startTracking method this way:

func startTracking(location: CLLocation)  {
    //do somtrhing with your location
    print(location)
}

And into your Radar.trackOnce method add below code:

guard let userLocation = location else {return}
let myRadar = MyRadarClone()
myRadar.startTracking(location: userLocation)

Hope this will help.

Note: Code is not tested.

Answer 2

Don't create any custom protocols or functions for this

1. Create a NotificationCenter
2. Post from locationDidUpdate
3. Observe where you want

I think this is a best idea

Answer 3

I'm assuming the objective is to create a custom lifecycle method that acts like viewDidLayoutSubviews but is instead locationManagerDidGetLocation , or something, that is called only once in any view controller you put it in. If instead you simply want to extend the location manager's delegate to other view controllers, the strategy is the same (with a small adjustment at the end):

class SomeViewController: UIViewController {

    func locationManagerDidGetLocation() {

        doSomethingThatRequiresUserLocation()

    }

}

CLLocationManagerDelegate has a method for new location data (and one for new location value). Simply post a notification from it:

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    NotificationCenter.default.post(name: .locationManagerDidUpdateLocations, object: nil)

}

You can also share the value of the location across your app in a static structure variable or in the app's delegate:

struct CurrentLocation {

    static var coordinate: CLLocationCoordinate2D?

}

And update it through the delegate:

func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {

    // update shared property
    let lastLocation = locations.last!
    CurrentLocation.coordinate = lastLocation.coordinate

    // post app-wide notification
    NotificationCenter.default.post(name: .locationManagerDidUpdateLocations, object: nil)

}

To access that value just call CurrentLocation.coordinate anywhere in your app.

Then simply add a notification observer to an object, like a UIViewController , listening for that post:

class SomeViewController: UIViewController {

    func addNotificationObservers() {

        NotificationCenter.default.addObserver(self, selector: #selector(locationManagerDidUpdateLocationsHandler), name: .locationManagerDidUpdateLocations, object: nil)

    }

}

And when the first post arrives, remove the observer, so it only gets called once, and call your custom method:

@objc func locationManagerDidUpdateLocationsHandler() {

    NotificationCenter.default.removeObserver(self, name: .locationManagerDidUpdateLocations, object: nil)

    locationManagerDidGetLocation()

}

And now it works like a regular lifecycle method that is fired only once when the user's location is available:

class SomeViewController: UIViewController {

    func locationManagerDidGetLocation() {

        doSomethingThatRequiresUserLocation()

    }

}

You can, of course, not remove the observer and have it function like an extended delegate of the location manager. And don't forget to remove all observers in deinit if these view controllers don't persist the life of the app.