Update Location in Background every n minutes forever in Swift 2.0 - background

Question

With the code below in AppDelegate.swift I can get location updates every 30 seconds. However, after 180 seconds the background execution is kicked by backgroundTimeRemaining. The plist has the "location"tag in UIBackgroundModes
I have two questions:
Why the backgroundTimeRemaining is not resetting?
If I do startUpdatingLocation() and then stopUpdatingLocation() to save battery then I will not get location updated ever again.
import UIKit
import CoreLocation
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, CLLocationManagerDelegate {
var window: UIWindow?
let locationManager = CLLocationManager()
var pos = 0
var LatitudeGPS = NSString()
var LongitudeGPS = NSString()
var speedGPS = NSString()
var Course = NSString()
var Altitude = NSString()
var bgtimer = NSTimer()
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
// Override point for customization after application launch.
return true
}
var backgroundUpdateTask: UIBackgroundTaskIdentifier!
func beginBackgroundUpdateTask() {
self.backgroundUpdateTask = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler({
self.endBackgroundUpdateTask()
})
}
func endBackgroundUpdateTask() {
UIApplication.sharedApplication().endBackgroundTask(self.backgroundUpdateTask)
self.backgroundUpdateTask = UIBackgroundTaskInvalid
}
func doBackgroundTask() {
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), {
self.beginBackgroundUpdateTask()
// Do something
self.StartupdateLocation()
self.bgtimer = NSTimer.scheduledTimerWithTimeInterval(30, target: self, selector: "bgtimer:", userInfo: nil, repeats: true)
NSRunLoop.currentRunLoop().addTimer(self.bgtimer, forMode: NSDefaultRunLoopMode)
NSRunLoop.currentRunLoop().run()
// End the background task.
self.endBackgroundUpdateTask()
})
}
func bgtimer(timer:NSTimer!){
print("Fired from Background ************************************")
updateLocation()
print("Position Report: \(pos)")
}
func applicationDidEnterBackground(application: UIApplication) {
self.doBackgroundTask()
}
func StartupdateLocation() {
locationManager.delegate = self
locationManager.startUpdatingLocation()
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.requestWhenInUseAuthorization()
locationManager.allowsBackgroundLocationUpdates = true
locationManager.pausesLocationUpdatesAutomatically = false
}
func updateLocation() {
pos++
//locationManager.startUpdatingLocation()
//locationManager.stopUpdatingLocation()
print("Latitude: \(LatitudeGPS)")
print("Longitude: \(LongitudeGPS)")
print("Speed: \(speedGPS)")
print("Heading: \(Course)")
print("Altitude BG: \(Altitude)")
print(UIApplication.sharedApplication().backgroundTimeRemaining)
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
LatitudeGPS = String(format: "%.10f", manager.location!.coordinate.latitude)
LongitudeGPS = String(format: "%.10f", manager.location!.coordinate.longitude)
speedGPS = String(format: "%.3f", manager.location!.speed)
Altitude = String(format: "%.3f", manager.location!.altitude)
Course = String(format: "%.3f", manager.location!.course)
}
}
EDIT ***
I solved the problem after I initialized the updateLocation in the ViewController.

Answer 1

import UIKit
import CoreLocation
#UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate,CLLocationManagerDelegate {
var window: UIWindow?
var locationManager = CLLocationManager()
var backgroundUpdateTask: UIBackgroundTaskIdentifier!
var bgtimer = Timer()
var latitude: Double = 0.0
var longitude: Double = 0.0
var current_time = NSDate().timeIntervalSince1970
var timer = Timer()
var f = 0
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
self.doBackgroundTask()
return true
}
func applicationWillResignActive(_ application: UIApplication) {
}
func applicationWillEnterForeground(_ application: UIApplication) {
print("Entering foreBackground")
}
func applicationDidBecomeActive(_ application: UIApplication) {
}
func applicationWillTerminate(_ application: UIApplication) {
}
func applicationDidEnterBackground(_ application: UIApplication) {
print("Entering Background")
// self.doBackgroundTask()
}
func doBackgroundTask() {
DispatchQueue.main.async {
self.beginBackgroundUpdateTask()
self.StartupdateLocation()
self.bgtimer = Timer.scheduledTimer(timeInterval:-1, target: self, selector: #selector(AppDelegate.bgtimer(_:)), userInfo: nil, repeats: true)
RunLoop.current.add(self.bgtimer, forMode: RunLoopMode.defaultRunLoopMode)
RunLoop.current.run()
self.endBackgroundUpdateTask()
}
}
func beginBackgroundUpdateTask() {
self.backgroundUpdateTask = UIApplication.shared.beginBackgroundTask(expirationHandler: {
self.endBackgroundUpdateTask()
})
}
func endBackgroundUpdateTask() {
UIApplication.shared.endBackgroundTask(self.backgroundUpdateTask)
self.backgroundUpdateTask = UIBackgroundTaskInvalid
}
func StartupdateLocation() {
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.distanceFilter = kCLDistanceFilterNone
locationManager.requestAlwaysAuthorization()
locationManager.allowsBackgroundLocationUpdates = true
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.startUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print("Error while requesting new coordinates")
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
let locValue:CLLocationCoordinate2D = manager.location!.coordinate
self.latitude = locValue.latitude
self.longitude = locValue.longitude
f+=1
print("New Coordinates: \(f) ")
print(self.latitude)
print(self.longitude)
}
#objc func bgtimer(_ timer:Timer!){
sleep(2)
/* if UIApplication.shared.applicationState == .active {
timer.invalidate()
}*/
self.updateLocation()
}
func updateLocation() {
self.locationManager.startUpdatingLocation()
self.locationManager.stopUpdatingLocation()
}}
I added the sleep function to delay of calling the location and send the information to server
Since this is running in both the app is active and goes to background. If you want only background process, remove or comment the function self.doBackgroundTask() from didFinishLaunchingWithOptions and remove the comment for self.doBackgroundTask() in the applicationdidEnterBackground. And then remove the comment in the function bgtimer(), since the background process has to stop once the app comes to active state.
Thank you using your code only i can able to made some
alternative solution to running continuously.