iBeacon Notification When App Closed - ios

Question

I'm trying to send the user a local notification when a region is entered (at an immediate distance) while the app is closed. I have it currently working if the app is in the background, but can't get it to work if the app is closed. I've read other posts that say this is possible, but none of the solutions work and they are outdated. I'd appreciate some help in Swift 3.
Here's my code (all in AppDelegate):
In didFinishLaunchingWithOptions:
locationManager.delegate = self
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.allowsBackgroundLocationUpdates = true
locationManager.requestAlwaysAuthorization()
let uuid = UUID(uuidString: "someuuid")!
let beaconRegion = CLBeaconRegion(proximityUUID: uuid, identifier: "SomeBeacon")
beaconRegion.notifyEntryStateOnDisplay = true
beaconRegion.notifyOnEntry = true
beaconRegion.notifyOnExit = true
locationManager.startMonitoring(for: beaconRegion)
locationManager.startRangingBeacons(in: beaconRegion)
I also have didRangeBeacons implemented.

Answer 1

The code looks correct to allow detection when the app is closed. You do not need:
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.allowsBackgroundLocationUpdates = true
But they should not hurt anything.
You only mention trouble with the app closed, so I assume foreground detection works fine. Does it? If not, troubleshoot this first.
It is often difficult to properly test the app closed use case leading to failures due to test setup issues. A few tips may help:
iOS will only send a region entry event if it thinks it is out of region. Often in testing it thinks it is in region so you do not get an event. To ensure you are out of region, turn off your beacon or go out of range with the app in the foreground and wait until you get an exit callback. Only then should you kill the app to test closed detection.
If rebooting your phone, always wait 5 minutes after startup to be sure CoreLocation is fully initialized. And make sure you have followed rule 1.
Make sure you do not have a bunch of other beacon apps installed on the phone taking up all the Bluetooth detection hardware acceleration slots. If you do, detections in the background can be delayed up to 15 min. Uninstall all beacon apps then uninstall and reinstall yours.
If you follow the testing tips above you should see detection callbacks within a couple of seconds of the beacon being in the vicinity.

Answer 2

UPDATE As #davidgyoung pointed out to me on a different question, this method of using the UNLocationNotificationTrigger won't report the major and minor identifiers to you because it is using the monitoring API and not ranging which is what you need to obtain the major and minor numbers. This limits what all you might do with this wrapper API. It sure is convenient, but not as helpful as one might hope.
The new (iOS 10, Swift 3) way from what I can tell is to use the UserNotifications library and implement it with a UNNotificationRequest. You can pass it a beacon region via UNLocationNotificationTrigger. Now I know it seems counter intuitive for what you're wanting (notification when app is closed), however, you want to add the NSLocationWhenInUseUsageDescription key to your Info.plist instead of NSLocationAlwaysUsageDescription. I'm not sure why it is that way, but it's a necessary step. Here's the code I'm using for creating a (iBeacon) location based notification:
// Ensure you use a class variable in order to ensure the location
// manager is retained, otherwise the alert message asking you to
// authorize it will disappear before you can tap "allow" which
// will keep it from working
let locationManager = CLLocationManager()
// ...
// Somewhere in your class (e.g. AppDelegate or a ViewController)
self.locationManager.requestWhenInUseAuthorization()
let region = CLBeaconRegion(proximityUUID: UUID(uuidString: "YOUR-UNIQUE-UUID-STRING")!, identifier: "com.yourcompany.youridentifier")
region.notifyOnEntry = true
region.notifyOnExit = false
let content = UNMutableNotificationContent()
content.title = "Notification Title"
content.body = "Body text goes here"
// Not sure if repeats needs to be set to true here, but that's
// how I've implemented it
let trigger = UNLocationNotificationTrigger(region: region, repeats: true)
// Use the same identifier each time to ensure it gets overwritten
// in the notification system
let identifier = "BeaconLocationIdentifier"
let request = UNNotificationRequest.init(identifier: identifier, content: content, trigger: trigger)
// This is probably unnecessary since we're using the same identifier
// each time this code is called
UNUserNotificationCenter.current().removeAllPendingNotificationRequests()
// Make sure you set the notification center's delegate. My
// containing class is the AppDelegate. I implement the delegate
// methods there.
UNUserNotificationCenter.current().delegate = self
UNUserNotificationCenter.current().add(request, withCompletionHandler: { (error) in
})
// Not sure if this is required either, but after I added this, everything
// started working
self.locationManager.startRangingBeacons(in: region)
Make sure you implement the notification center delegate methods:
func userNotificationCenter(_ center: UNUserNotificationCenter, didReceive response: UNNotificationResponse, withCompletionHandler completionHandler: #escaping () -> Void) {
// Called when the notification has been swiped or tapped by the user
// Do something with the response here
// Make sure you call the completion handler
completionHandler()
}
func userNotificationCenter(_ center: UNUserNotificationCenter, willPresent notification: UNNotification, withCompletionHandler completionHandler: #escaping (UNNotificationPresentationOptions) -> Void) {
// Called when the app is in the foreground
// Do something with the notification here
// Make sure you call the completion handler
completionHandler([.alert, .sound])
}
Finally, you're going to need to authorize notifications first to get this all to work. You can use this code to do that:
let options: UNAuthorizationOptions = [.alert,.sound]
UNUserNotificationCenter.current().requestAuthorization(options: options) {
(granted, error) in
if !granted {
debugPrint("Something went wrong")
} else {
debugPrint("Notifications granted")
}
}
One last tip: I have an old metal tin that (sort of) acts as a Faraday cage for the beacon I'm using. I just close my beacon up in there for a minute or so and then the app detects that I've gone out of range. This is more convenient than trying to walk far enough away from the beacon or removing the battery (which doesn't seem to work at all for me). Some beacons have stronger signals than others and may still get through the tin, so YMMV.