App location in background on iOS 8

Question

I want get a user's location in app background. It works fine if I use a timer of 9 or less seconds. If I use 10 and more seconds I can't get the user's location...

My AppDelegate.swift :

import UIKit
import CoreLocation

@UIApplicationMain
class AppDelegate: UIResponder, UIApplicationDelegate, CLLocationManagerDelegate {
    var window: UIWindow?
    var backgroundTaskIdentifier: UIBackgroundTaskIdentifier = UIBackgroundTaskInvalid
    var myTimer: NSTimer?

    var locationManager = CLLocationManager()

    func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        // Override point for customization after application launch.
        return true
    }

    func isMultitaskingSupported() -> Bool {
        return UIDevice.currentDevice().multitaskingSupported
    }

    func timerMethod(sender: NSTimer) {
        let backgroundTimerRemainig = UIApplication.sharedApplication().backgroundTimeRemaining

        self.locationManager.startUpdatingLocation()

        if backgroundTimerRemainig == DBL_MAX {
            println("test1")
        } else {
            println("test")
            self.locationManager.delegate = self
            self.locationManager.startUpdatingLocation()
        }
    }

    func applicationWillResignActive(application: UIApplication) {

    }

    func applicationDidEnterBackground(application: UIApplication){
        if !isMultitaskingSupported() {
            return
        }

        myTimer = NSTimer.scheduledTimerWithTimeInterval(60.0,
            target: self,
            selector: "timerMethod:",
            userInfo: nil,
            repeats: true)

        backgroundTaskIdentifier = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler {
            () -> Void in
            UIApplication.sharedApplication().endBackgroundTask(self.backgroundTaskIdentifier)
        }
    }

    func endBackgroundTask() {
        let mainQueue = dispatch_get_main_queue()

        dispatch_async(mainQueue) { 
            [weak self] in
            if let timer = self!.myTimer {
                timer.invalidate()
                self!.myTimer = nil
                UIApplication.sharedApplication().endBackgroundTask(self!.backgroundTaskIdentifier)
                self!.backgroundTaskIdentifier = UIBackgroundTaskInvalid
            }
        }
    }

    func applicationWillEnterForeground(application: UIApplication) {
        if backgroundTaskIdentifier != UIBackgroundTaskInvalid {
            endBackgroundTask()
        }
    }

    func applicationDidBecomeActive(application: UIApplication) {

    }

    func applicationWillTerminate(application: UIApplication) {
        // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.
    }

    func locationManager(manager: CLLocationManager!, didUpdateToLocation locations: [AnyObject]) {
        var latValue = locationManager.location.coordinate.latitude
        var lonValue = locationManager.location.coordinate.longitude
    }
}

Why can't I get the user's location when I use 10 and more seconds?

Answer 1

Because approximately after 10 seconds after calling didEnterBackground the app gets suspended .

The app is in the background but is not executing code. The system moves apps to this state automatically and does not notify them before doing so. While suspended, an app remains in memory but does not execute any code.

It's the iOS app lifecycle .

If you want to get location updates in background you have two options:

• background task - but it only keeps the app running for 3 minutes maximum
• Run update locations background mode .