How to get periodicaly new location when app is in background or killed

Question

I want to get new location every 1min when my app is in background or killed. Here is my code :

Location Service:

class LocationService: NSObject, CLLocationManagerDelegate {

    static let shared = LocationService()
    var locationManager = CLLocationManager()
    var significatLocationManager = CLLocationManager()
    var currentLocation: CLLocation!
    var timer = Timer()
    var bgTask = UIBackgroundTaskInvalid

    func startUpdatingLocation() {
        locationManager.requestAlwaysAuthorization()
        locationManager.desiredAccuracy = kCLLocationAccuracyBest
        locationManager.distanceFilter = kCLDistanceFilterNone
        if #available(iOS 9.0, *) {
            locationManager.allowsBackgroundLocationUpdates = true
        }
        locationManager.delegate = self
        locationManager.startUpdatingLocation()
    }

    func stopUpdatingLocation() {
        locationManager.stopUpdatingLocation()
        timer.invalidate()
    }

    func restartUpdatingLocation() {
        locationManager.stopMonitoringSignificantLocationChanges()
        timer.invalidate()
        startUpdatingLocation()
    }

    func startMonitoringLocation() {
        locationManager.stopUpdatingLocation()
        locationManager.startMonitoringSignificantLocationChanges()
        timer.invalidate()
    }

    func changeLocationAccuracy(){
        switch locationManager.desiredAccuracy {
        case kCLLocationAccuracyBest:
            locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers
            locationManager.distanceFilter = 99999
        case kCLLocationAccuracyThreeKilometers:
            locationManager.desiredAccuracy = kCLLocationAccuracyBest
            locationManager.distanceFilter = kCLDistanceFilterNone
        default: break
        }
    }

    func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
        bgTask = UIApplication.shared.beginBackgroundTask(expirationHandler: {
            UIApplication.shared.endBackgroundTask(self.bgTask)
            self.bgTask = UIBackgroundTaskInvalid
        })

        currentLocation = locations.last!

        let interval = currentLocation.timestamp.timeIntervalSinceNow
        let accuracy = self.locationManager.desiredAccuracy

        if abs(interval) < 60 && accuracy != kCLLocationAccuracyThreeKilometers {        
            timer = Timer.scheduledTimer(timeInterval: 60, target: self, selector: #selector(LocationService.changeLocationAccuracy), userInfo: nil, repeats: false)
            changeLocationAccuracy()
        }
    } 
}

App delegate:

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
     if launchOptions?[UIApplicationLaunchOptionsKey.location] != nil {
          LocationService.shared.restartUpdatingLocation()
     }
}

func applicationDidEnterBackground(_ application: UIApplication) {
     LocationService.shared.restartUpdatingLocation()
}

func applicationWillTerminate(_ application: UIApplication) {
     LocationService.shared.startMonitoringLocation()
}

View controller:

override func viewDidLoad() {
    LocationService.shared.startUpdatingLocation()
}

But my code is not working, i'm not getting new location after a few minutes when my app is in background. and same when my app is suspended or killed. Is there any solution for that ? please not that i'm using Swift 3 & xcode 8.1.

Thank's in advance

Answer 1

• If you call startUpdatingLocation when your app is already in the background, then you will only receive location updates for a few minutes.

• If you call startUpdatingLocation while your app is in the foreground and then your app moves to the background, you will continue to receive location updates indefinitely.

• If you call startMonitoringSignificantLocationChanges in the foreground and leave it enabled then you can call startUpdatingLocation in the background and receive updates indefinitely.

• If the user terminates your app (by swiping up in the app switcher) then you will no longer receive location updates until the user re-launches your app.

Since your code stops and starts location monitoring when it moves to the background of only get location updates for a few minutes. If you start location monitoring foreground and do nothing when the app moves to the background then you will continue to receive location updates.