I have written the below code that has a timer that calls a callback function every minute. When the app goes to the background I have started another timer that calls the same callback method, but the background timer works for only three minutes.
I understand that Apple allows background tasks for only three minutes. My app is more like a tracking app that tracks the location of the user every minute even when the app is in background, so I need to implement this functionality.
I learned that beginBackgroundTaskWithExpirationHandler is to be used but I don't know whether my implementation is correct.
Note: I have Required background modes in plist toApp registers for location updates.
Any working code or links are much appreciated.
override func viewDidLoad() {
super.viewDidLoad()
timeInMinutes = 1 * 60
self.locationManager.requestAlwaysAuthorization()
self.locationManager.requestWhenInUseAuthorization()
if CLLocationManager.locationServicesEnabled() {
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
locationManager.startUpdatingLocation()
}
var timer = NSTimer.scheduledTimerWithTimeInterval( timeInMinutes, target: self, selector: "updateLocation", userInfo: nil, repeats: true)
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){
let locValue:CLLocationCoordinate2D = manager.location!.coordinate
self.latitude = locValue.latitude
self.longitude = locValue.longitude
if UIApplication.sharedApplication().applicationState == .Active {
} else {
backgroundTaskIdentifier = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler({ () -> Void in
self.backgroundTimer.invalidate()
self.backgroundTimer = NSTimer.scheduledTimerWithTimeInterval( 60.0, target: self, selector: "updateLocation", userInfo: nil, repeats: true)
})
}
}
func updateLocation() {
txtlocationLabel.text = String(n)
self.n = self.n+1
var timeRemaining = UIApplication.sharedApplication().backgroundTimeRemaining
print(timeRemaining)
if timeRemaining > 60.0 {
self.GeoLogLocation(self.latitude,Longitude: self.longitude) {
results in
print("View Controller: \(results)")
self.CheckResult(String(results))
}
} else {
if timeRemaining == 0 {
UIApplication.sharedApplication().endBackgroundTask(backgroundTaskIdentifier)
}
backgroundTaskIdentifier2 = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler({ () -> Void in
self.backgroundTimer.invalidate()
self.backgroundTimer = NSTimer.scheduledTimerWithTimeInterval( 60.0, target: self, selector: "updateLocation", userInfo: nil, repeats: true)
})
}
}