Swift 2 Beacon scan in background

Question

I'm trying to run a beacon background detection in my app. I created a dedicated class for this and launch it in my ViewController:

    override func viewDidLoad() {
      super.viewDidLoad()
      beaconSharedInstance
      ....
    }

and here is the code of my class:

let beaconSharedInstance = iBeacon();

class iBeacon: NSObject, UIApplicationDelegate, CLLocationManagerDelegate {

var locationManager: CLLocationManager!
var beaconRegion:CLBeaconRegion!

override init(){

    super.init()

    let uuidString = "FDA50693-A4E2-4FB1-AFCF-C6EB07640978"
    let beaconIdentifier = "uby-06B524"
    let beaconUUID:NSUUID = NSUUID(UUIDString: uuidString)!
    beaconRegion = CLBeaconRegion(proximityUUID: beaconUUID, identifier: beaconIdentifier)

    locationManager = CLLocationManager()
    locationManager.delegate = self

    if(CLLocationManager.authorizationStatus() != CLAuthorizationStatus.AuthorizedAlways){
        locationManager.requestAlwaysAuthorization()
    }

    locationManager.allowsBackgroundLocationUpdates = true
    locationManager!.startRangingBeaconsInRegion(beaconRegion)
}


func locationManager(manager: CLLocationManager,
                     didRangeBeacons beacons: [CLBeacon],
                                     inRegion region: CLBeaconRegion)  {
    print("didRangeBeacons");

    if(beacons.count > 0) {

        print("Discovered beacon \(beacons[0].rssi) dBM name: \(beacons[0].proximityUUID)")
    }


}

}

this class is working perfectly in foreground, but as soon as my app is becoming inactive, I can see in the log files:

Ending background task

and the CLLocatioManager stops...

I set Location updates in the Background mode of my project as well as NSLocationAlwaysUsageDescription in my info.plist file but I still have the same behavior, my thread stops when app is inactive.

I also tried to launch my Thread like this:

let qualityOfServiceClass = DISPATCH_QUEUE_PRIORITY_DEFAULT
    let backgroundQueue = dispatch_get_global_queue(qualityOfServiceClass, 0)
    dispatch_async(backgroundQueue, {
        print("Running beacon detection in the background queue")
        beaconSharedInstance
    })

but in that case CLLocationManager never starts...any idea ?

Answer 1

The background task needs to have a loop, otherwise it will simply exit. Try:

dispatch_async(backgroundQueue, {
    print("Running beacon detection in the background queue")
    beaconSharedInstance
    while(true) {
      NSThread.sleepForTineInterval(1)
      print("running...")
    }
})