How to setup a "Check-In" alert using Geofencing and CLCircularRegion? - ios

Question

I'm trying to set up an alert that once a user enters a specific location the alert pops up and allows users to "Check-in". After the user checks in the app then notifies an api endpoint that the user successfully checked in. This is my first time working with geofencing and corelocation. I get the basic idea of how to set it up but am not entirely sure how the check-in alert and geofence tie together. Here is my code:
import UIKit
import CoreLocation
class ViewController: UIViewController, CLLocationManagerDelegate{
var manager = CLLocationManager()
override func viewDidLoad() {
super.viewDidLoad()
// Core Location
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
var latitude: CLLocationDegrees = 43.039278
var longitude: CLLocationDegrees = -87.932479
var center: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
var radius: CLLocationDistance = CLLocationDistance(10.0)
var identifier: String = "storeID"
var geoRegion: CLCircularRegion = CLCircularRegion(center: center, radius: radius, identifier: identifier)
}
func showSimpleAlertWithTitle(title: String!, message: String!, viewController: UIViewController) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
let action = UIAlertAction(title: "Check-In", style: .Cancel , handler: nil)
alert.addAction(action)
viewController.presentViewController(alert, animated: true, completion: nil)
}
}

Answer 1

Set notifyOnEntry = true on the CLCircularRegion to be notified when entering or exiting the region.
Implement locationManager:didEnterRegion: delegate method to handle the event.
Example:
override func viewDidLoad() {
super.viewDidLoad()
manager.delegate = self
manager.desiredAccuracy = kCLLocationAccuracyBest
manager.requestWhenInUseAuthorization()
manager.startUpdatingLocation()
var latitude: CLLocationDegrees = 43.039278
var longitude: CLLocationDegrees = -87.932479
var center: CLLocationCoordinate2D = CLLocationCoordinate2DMake(latitude, longitude)
var radius: CLLocationDistance = CLLocationDistance(10.0)
var identifier: String = "storeID"
var geoRegion: CLCircularRegion = CLCircularRegion(center: center, radius: radius, identifier: identifier)
geoRegion.notifyOnEntry = true
manager.startMonitoringForRegion(geoRegion)
}
func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) {
showSimpleAlertWithTitle("Entered region \(region.identifier)", message: nil)
}
func showSimpleAlertWithTitle(title: String!, message: String!) {
let alert = UIAlertController(title: title, message: message, preferredStyle: .Alert)
let action = UIAlertAction(title: "Check-In", style: .Cancel , handler: nil)
alert.addAction(action)
presentViewController(alert, animated: true, completion: nil)
}
See: CLRegion.notifyOnEntry