I am building an app where I want to keep track of updated user location whenever the app comes back from background.
I wrote my location tracking code in AppDelegate's didFinishLaunchingWithOptions method
//Core Location Administration
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.distanceFilter = 70
locationManager.requestAlwaysAuthorization()
locationManager.pausesLocationUpdatesAutomatically = false
locationManager.startMonitoringVisits()
locationManager.delegate = self
Since I was not able to validate Visits, I added the standard location tracking too
locationManager.allowsBackgroundLocationUpdates = true
locationManager.startUpdatingLocation()
I created CLLocationManagerDelegate block and added the following code
extension AppDelegate: CLLocationManagerDelegate {
func locationManager(_ manager: CLLocationManager, didVisit visit: CLVisit) {
let clLocation = CLLocation(latitude: visit.coordinate.latitude, longitude: visit.coordinate.longitude)
// Get location description
AppDelegate.geoCoder.reverseGeocodeLocation(clLocation) { placemarks, _ in
if let place = placemarks?.first {
let description = "\(place)"
self.newVisitReceived(visit, description: description)
}
}
}
func newVisitReceived(_ visit: CLVisit, description: String) {
let location = Location(visit: visit, descriptionString: description)
LErrorHandler.shared.logInfo("\(location.latitude), \(location.longitude)")
UserModal.shared.setUserLocation(location)
UserModal.shared.userLocationUpdated = Date()
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.first else {
return
}
locationManager.stopUpdatingLocation()
let uL = Location(location:location.coordinate, descriptionString: "")
LErrorHandler.shared.logInfo("\(uL.latitude), \(uL.longitude)")
UserModal.shared.setUserLocation(uL)
UserModal.shared.userLocationUpdated = Date()
}
}
I added this code to begin location tracking when the app comes to foreground
func applicationWillEnterForeground(_ application: UIApplication) {
// Called as part of the transition from the background to the active state; here you can undo many of the changes made on entering the background.
locationManager.startUpdatingLocation()
}
If I am on a ViewController and the application goes back to the background, it does not refresh the location when the app comes to foreground.
Can someone suggest a better way to do this?
You should write code for location in didbecomeActive method of App delegate not in didFinishLaunchingWithOptions. Try this hope it will help.
Related
I am developing ios app using Swift4 and in that, I need to fetch user location continuously after few seconds in all states i.e. background, foreground or even app is killed. I tried a lot of codes available but none seems work.
Capture location in all states
For app delegate :
if ((launchOptions?[UIApplication.LaunchOptionsKey.location]) != nil) {
print ("abhishek testing termination")
fromTerminated = true
locationManager.requestAlwaysAuthorization()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation
locationManager.allowsBackgroundLocationUpdates = true
locationManager.startUpdatingLocation()
locationManager.startMonitoringSignificantLocationChanges() //THIS IS WHERE THE MAGIC HAPPENS
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if(fromTerminated)
{
let newlocation : CLLocation = locations.last!
let locValue:CLLocationCoordinate2D = newlocation.coordinate
// let theaccuracy : CLLocationAccuracy = newlocation.horizontalAccuracy
print ("background location\(locValue.latitude)")
print ("terminated location\(locValue.longitude)")
// self.postdatatoserver()
}
}
I am making an app that trace all the trips made by a user.
The app works perfectly when it is in background or in foreground but I am looking for a way to get it worked even if the app is not running.
I followed exactly this answer : Receiving Location even when app is not running in Swift
But this doesn't work as expected.
I have two property in my AppDelegate
var lastLocation:CLLocation?
//And a location manager
var locationManager = CLLocationManager()
In my DidFinishLaunchingWithOptions I configure the CLLocationManager
locationManager.delegate = self
locationManager.requestAlwaysAuthorization()
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters
In my applicationWillTerminate :
lastLocation = HomeController.locations.last
createRegion(location: lastLocation)
Here is the rest :
func createRegion(location:CLLocation?) {
if CLLocationManager.isMonitoringAvailable(for: CLCircularRegion.self) {
let coordinate = CLLocationCoordinate2DMake((location?.coordinate.latitude)!, (location?.coordinate.longitude)!)
let regionRadius = 50.0
let region = CLCircularRegion(center: CLLocationCoordinate2D(
latitude: coordinate.latitude,
longitude: coordinate.longitude),
radius: regionRadius,
identifier: "aabb")
region.notifyOnExit = true
region.notifyOnEntry = true
//Send your fetched location to server
UserDefaults.standard.set(UserDefaults.standard.integer(forKey: "nbLocNotrunning") + 1, forKey: "nbLocNotrunning")
//Stop your location manager for updating location and start regionMonitoring
self.locationManager.stopUpdatingLocation()
self.locationManager.startMonitoring(for: region)
} else {
print("System can't track regions")
}
}
func locationManager(_ manager: CLLocationManager, didEnterRegion region: CLRegion) {
print("Entered Region")
}
func locationManager(_ manager: CLLocationManager, didExitRegion region: CLRegion) {
print("Exited Region")
locationManager.stopMonitoring(for: region)
//Start location manager and fetch current location
locationManager.startUpdatingLocation()
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if UIApplication.shared.applicationState != .inactive {
} else {
//App is in BG/ Killed or suspended state
//send location to server
// create a New Region with current fetched location
let location = locations.last
lastLocation = location
//Make region and again the same cycle continues.
self.createRegion(location: lastLocation)
}
}
I wonder where the mistake can come from and why I never enter in the function didExitRegion.
For now, I just increment a variable in UserDefaut "nbLocNotrunning" in order to know how many times I leave a region but this number never increase when I stop my app.
I have a simple button, when I press the button, I'm making a call to another class, my Location class to get the user's current location.
After getting the location, I want to update a label text I have to show the location.
This is my location class:
class LocationManager: NSObject, CLLocationManagerDelegate {
var locationManager: CLLocationManager!
var geoCoder = CLGeocoder()
var userAddress: String?
override init() {
super.init()
locationManager = CLLocationManager()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.activityType = .other
locationManager.requestWhenInUseAuthorization()
}
func getUserLocation(completion: #escaping(_ result: String) -> ()){
if CLLocationManager.locationServicesEnabled(){
locationManager.requestLocation()
}
guard let myResult = self.userAddress else { return }
completion(myResult)
}
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){
let userLocation: CLLocation = locations[0] as CLLocation
geoCoder.reverseGeocodeLocation(userLocation) { (placemarks, err) in
if let place = placemarks?.last{
self.userAddress = place.name!
}
}
}
func locationManager(_ manager: CLLocationManager, didFailWithError error: Error) {
print(error)
}
}
and this is where I call the method and updating the label:
func handleEnter() {
mView.inLabel.isHidden = false
location.getUserLocation { (theAddress) in
print(theAddress)
self.mView.inLabel.text = "\(theAddress)"
}
}
My problem is that when I click my button (and firing handleEnter()), nothing happens, like it won't register the tap. only after tapping it the second time, I get the address and the labels update's.
I tried to add printing and to use breakpoint to see if the first tap registers, and it does.
I know the location may take a few seconds to return an answer with the address and I waited, but still, nothing, only after the second tap it shows.
It seems like in the first tap, It just didn't get the address yet. How can I "notify" when I got the address and just then try to update the label?
Since didUpdateLocations & reverseGeocodeLocation methods are called asynchronously, this guard may return as of nil address
guard let myResult = self.userAddress else { return }
completion(myResult)
Which won't trigger the completion needed to update the label , instead you need
var callBack:((String)->())?
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]){
let userLocation: CLLocation = locations[0] as CLLocation
geoCoder.reverseGeocodeLocation(userLocation) { (placemarks, err) in
if let place = placemarks?.last{
callBack?(place.name!)
}
}
}
Then use
location.callBack = { [weak self] str in
print(str)
DispatchQueue.main.async { // reverseGeocodeLocation callback is in a background thread
// any ui
}
}
I am building an app where the user clicks a button and for 60mins (or any amount of time) we keep track of them by uploading their location to a server. Currently we are using 'Did Update Locations' function to send the users location to firebase in real-time.
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
}
This system works but it spams the server sending the location of the user to the server once every second.
This is too much data and we would only need to send the users location to the server once every 10-30 seconds.
What can we do send the users location once every 10-30 seconds?
class ViewController: UIViewController, CLLocationManagerDelegate {
private var locman = CLLocationManager()
private var startTime: Date? //An instance variable, will be used as a previous location time.
func locationManager(_ manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let loc = locations.last else { return }
let time = loc.timestamp
guard var startTime = startTime else {
self.startTime = time // Saving time of first location, so we could use it to compare later with second location time.
return //Returning from this function, as at this moment we don't have second location.
}
let elapsed = time.timeIntervalSince(startTime) // Calculating time interval between first and second (previously saved) locations timestamps.
if elapsed > 30 { //If time interval is more than 30 seconds
print("Upload updated location to server")
updateUser(location: loc) //user function which uploads user location or coordinate to server.
startTime = time //Changing our timestamp of previous location to timestamp of location we already uploaded.
}
}
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.
Apps normally get suspended (no longer get CPU time) a moment after being moved to the background. You can ask for extra background time, but the system only gives you 3 minutes.
Only a very limited class of apps are allowed to run in the background for longer than that. Mapping/GPS applications are one of those categories. However, your app is not a mapping/GPS application, so I doubt if Apple would approve it.
Bottom line: I think you might be out of luck running your location queries for more than 3 minutes.
EDIT:
As Paulw11 points out, you can use the significant location change service to get location updates when the device moves by large distances.
I'm trying to monitor user's significant location changes using a singleton locationManager called LocationService, it goes like that:
LocationService.Swift:
class var sharedInstance: LocationService {
struct Static {
static var onceToken: dispatch_once_t = 0
static var instance: LocationService? = nil
}
dispatch_once(&Static.onceToken) {
Static.instance = LocationService()
}
return Static.instance!
}
var locationManager: CLLocationManager?
var location: CLLocation?
var delegate: LocationServiceDelegate?
override init() {
super.init()
self.locationManager = CLLocationManager()
guard let locationManager = self.locationManager else {
return
}
if CLLocationManager.authorizationStatus() == .NotDetermined {
locationManager.requestAlwaysAuthorization()
}
locationManager.delegate = self
locationManager.distanceFilter = 10
locationManager.desiredAccuracy = kCLLocationAccuracyBest
locationManager.pausesLocationUpdatesAutomatically = false
if NSString(string: UIDevice.currentDevice().systemName).floatValue >= 9 {
locationManager.allowsBackgroundLocationUpdates = true
}
}
func startUpdatingLocation() {
print("Starting Location Updates")
self.locationManager?.startUpdatingLocation()
}
func startMonitoringSignificantLocationChanges() {
print("Starting Significant Location Updates")
self.locationManager?.startMonitoringSignificantLocationChanges()
}
// CLLocationManagerDelegate
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
guard let location = locations.last else {
return
}
// singleton for get last location
self.location = location
}
myVC.swift:
private let locationService = LocationService.sharedInstance
func prepareInformation() {
self.locationService.delegate = self
self.locationService.startMonitoringSignificantLocationChanges()
}
but didUpdateLocations being called just one time when the app is launched, and then it doesn't even being called. But when I switch the line:
self.locationService.startMonitoringSignificantLocationChanges()
to:
self.locationService.startUpdatingLocation()
it works great and called every time the user moves.
what can be the problem? Thank you!
According to Apple docs
After returning a current location fix, the receiver generates update
events only when a significant change in the user’s location is
detected. It does not rely on the value in the distanceFilter property
to generate events.
And
Apps can expect a notification as soon as the device moves 500 meters
or more from its previous notification. It should not expect
notifications more frequently than once every five minutes. If the
device is able to retrieve data from the network, the location manager
is much more likely to deliver notifications in a timely manner
I think you are expecting an event when the user changes its location by 10 meters, but this method doesn't depend on distanceFilter. Whoever when you use startUpdatingLocation() you will get events which will depend on distanceFilter property.
You can read more about this here.