I'm looking for a way to get a background location update every n minutes in my iOS application. I'm using iOS 4.3 and the solution should work for non-jailbroken iPhones.
I tried / considered following options:
CLLocationManager startUpdatingLocation/startMonitoringSignificantLocationChanges: This works in the background as expected, based on the configured properties, but it seems not possible to force it to update the location every n minutes
NSTimer: Does work when the app is running in the foreground but doesn't seem to be designed for background tasks
Local notifications: Local notifications can be scheduled every n minutes, but it's not possible to execute some code to get the current location (without the user having to launch the app via the notification). This approach also doesn't seem to be a clean approach as this is not what notifications should be used for.
UIApplication:beginBackgroundTaskWithExpirationHandler: As far as I understand, this should be used to finish some work in the background (also limited in time) when an app is moved to the background rather than implementing "long-running" background processes.
How can I implement these regular background location updates?
I found a solution to implement this with the help of the Apple Developer Forums:
Specify location background mode
Create an NSTimer in the background with UIApplication:beginBackgroundTaskWithExpirationHandler:
When n is smaller than UIApplication:backgroundTimeRemaining it will work just fine. When n is larger, the location manager should be enabled (and disabled) again before there is no time remaining to avoid the background task being killed.
This works because location is one of the three allowed types of background execution.
Note: I lost some time by testing this in the simulator where it doesn't work. However, it works fine on my phone.
On iOS 8/9/10 to make background location update every 5 minutes do the following:
Go to Project -> Capabilities -> Background Modes -> select Location updates
Go to Project -> Info -> add a key NSLocationAlwaysUsageDescription with empty value (or optionally any text)
To make location working when your app is in the background and send coordinates to web service or do anything with them every 5 minutes implement it like in the code below.
I'm not using any background tasks or timers. I've tested this code with my device with iOS 8.1 which was lying on my desk for few hours with my app running in the background. Device was locked and the code was running properly all the time.
#interface LocationManager () <CLLocationManagerDelegate>
#property (strong, nonatomic) CLLocationManager *locationManager;
#property (strong, nonatomic) NSDate *lastTimestamp;
#end
#implementation LocationManager
+ (instancetype)sharedInstance
{
static id sharedInstance = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
sharedInstance = [[self alloc] init];
LocationManager *instance = sharedInstance;
instance.locationManager = [CLLocationManager new];
instance.locationManager.delegate = instance;
instance.locationManager.desiredAccuracy = kCLLocationAccuracyBest; // you can use kCLLocationAccuracyHundredMeters to get better battery life
instance.locationManager.pausesLocationUpdatesAutomatically = NO; // this is important
});
return sharedInstance;
}
- (void)startUpdatingLocation
{
CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
if (status == kCLAuthorizationStatusDenied)
{
NSLog(#"Location services are disabled in settings.");
}
else
{
// for iOS 8
if ([self.locationManager respondsToSelector:#selector(requestAlwaysAuthorization)])
{
[self.locationManager requestAlwaysAuthorization];
}
// for iOS 9
if ([self.locationManager respondsToSelector:#selector(setAllowsBackgroundLocationUpdates:)])
{
[self.locationManager setAllowsBackgroundLocationUpdates:YES];
}
[self.locationManager startUpdatingLocation];
}
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
CLLocation *mostRecentLocation = locations.lastObject;
NSLog(#"Current location: %# %#", #(mostRecentLocation.coordinate.latitude), #(mostRecentLocation.coordinate.longitude));
NSDate *now = [NSDate date];
NSTimeInterval interval = self.lastTimestamp ? [now timeIntervalSinceDate:self.lastTimestamp] : 0;
if (!self.lastTimestamp || interval >= 5 * 60)
{
self.lastTimestamp = now;
NSLog(#"Sending current location to web service.");
}
}
#end
I did this in an application I'm developing. The timers don't work when the app is in the background but the app is constantly receiving the location updates. I read somewhere in the documentation (i can't seem to find it now, i'll post an update when i do) that a method can be called only on an active run loop when the app is in the background. The app delegate has an active run loop even in the bg so you dont need to create your own to make this work.
[Im not sure if this is the correct explanation but thats how I understood from what i read]
First of all, add the location object for the key UIBackgroundModes in your app's info.plist. Now, what you need to do is start the location updates anywhere in your app:
CLLocationManager locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;//or whatever class you have for managing location
[locationManager startUpdatingLocation];
Next, write a method to handle the location updates,
say -(void)didUpdateToLocation:(CLLocation*)location, in the app delegate. Then implement the method locationManager:didUpdateLocation:fromLocation of CLLocationManagerDelegate in the class in which you started the location manager (since we set the location manager delegate to 'self'). Inside this method you need to check if the time interval after which you have to handle the location updates has elapsed. You can do this by saving the current time every time. If that time has elapsed, call the method UpdateLocation from your app delegate:
NSDate *newLocationTimestamp = newLocation.timestamp;
NSDate *lastLocationUpdateTiemstamp;
int locationUpdateInterval = 300;//5 mins
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
if (userDefaults) {
lastLocationUpdateTiemstamp = [userDefaults objectForKey:kLastLocationUpdateTimestamp];
if (!([newLocationTimestamp timeIntervalSinceDate:lastLocationUpdateTiemstamp] < locationUpdateInterval)) {
//NSLog(#"New Location: %#", newLocation);
[(AppDelegate*)[UIApplication sharedApplication].delegate didUpdateToLocation:newLocation];
[userDefaults setObject:newLocationTimestamp forKey:kLastLocationUpdateTimestamp];
}
}
}
This will call your method every 5 mins even when your app is in background.
Imp: This implementation drains the battery, if your location data's accuracy is not critical you should use [locationManager startMonitoringSignificantLocationChanges]
Before adding this to your app, please read the Location Awareness Programming Guide
Now that iOS6 is out the best way to have a forever running location services is...
- (void)applicationWillResignActive:(UIApplication *)application
{
/*
Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
*/
NSLog(#"to background");
app.isInBackground = TRUE;
UIApplication *app = [UIApplication sharedApplication];
// Request permission to run in the background. Provide an
// expiration handler in case the task runs long.
NSAssert(bgTask == UIBackgroundTaskInvalid, nil);
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
// Synchronize the cleanup call on the main thread in case
// the task actually finishes at around the same time.
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
});
}];
// Start the long-running task and return immediately.
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
locationManager.distanceFilter = 100;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
[locationManager startMonitoringSignificantLocationChanges];
[locationManager startUpdatingLocation];
NSLog(#"App staus: applicationDidEnterBackground");
// Synchronize the cleanup call on the main thread in case
// the expiration handler is fired at the same time.
dispatch_async(dispatch_get_main_queue(), ^{
if (bgTask != UIBackgroundTaskInvalid)
{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
});
});
NSLog(#"backgroundTimeRemaining: %.0f", [[UIApplication sharedApplication] backgroundTimeRemaining]);
}
Just tested it like that:
I started the app, go background and move in the car by some minutes. Then I go home for 1 hour and start moving again (without opening again the app). Locations started again. Then stopped for two hours and started again. Everything ok again...
DO NOT FORGET USING the new location services in iOS6
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
CLLocation *loc = [locations lastObject];
// Lat/Lon
float latitudeMe = loc.coordinate.latitude;
float longitudeMe = loc.coordinate.longitude;
}
To someone else having nightmare figure out this one. I have a simple solution.
look this example from raywenderlich.com-> have sample code, this works perfectly, but unfortunately no timer during background location. this will run indefinitely.
Add timer by using :
-(void)applicationDidEnterBackground {
[self.locationManager stopUpdatingLocation];
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
self.timer = [NSTimer scheduledTimerWithTimeInterval:intervalBackgroundUpdate
target:self.locationManager
selector:#selector(startUpdatingLocation)
userInfo:nil
repeats:YES];
}
Just don't forget to add "App registers for location updates" in info.plist.
Here is what I use:
import Foundation
import CoreLocation
import UIKit
class BackgroundLocationManager :NSObject, CLLocationManagerDelegate {
static let instance = BackgroundLocationManager()
static let BACKGROUND_TIMER = 150.0 // restart location manager every 150 seconds
static let UPDATE_SERVER_INTERVAL = 60 * 60 // 1 hour - once every 1 hour send location to server
let locationManager = CLLocationManager()
var timer:NSTimer?
var currentBgTaskId : UIBackgroundTaskIdentifier?
var lastLocationDate : NSDate = NSDate()
private override init(){
super.init()
locationManager.delegate = self
locationManager.desiredAccuracy = kCLLocationAccuracyKilometer
locationManager.activityType = .Other;
locationManager.distanceFilter = kCLDistanceFilterNone;
if #available(iOS 9, *){
locationManager.allowsBackgroundLocationUpdates = true
}
NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(self.applicationEnterBackground), name: UIApplicationDidEnterBackgroundNotification, object: nil)
}
func applicationEnterBackground(){
FileLogger.log("applicationEnterBackground")
start()
}
func start(){
if(CLLocationManager.authorizationStatus() == CLAuthorizationStatus.AuthorizedAlways){
if #available(iOS 9, *){
locationManager.requestLocation()
} else {
locationManager.startUpdatingLocation()
}
} else {
locationManager.requestAlwaysAuthorization()
}
}
func restart (){
timer?.invalidate()
timer = nil
start()
}
func locationManager(manager: CLLocationManager, didChangeAuthorizationStatus status: CLAuthorizationStatus) {
switch status {
case CLAuthorizationStatus.Restricted:
//log("Restricted Access to location")
case CLAuthorizationStatus.Denied:
//log("User denied access to location")
case CLAuthorizationStatus.NotDetermined:
//log("Status not determined")
default:
//log("startUpdatintLocation")
if #available(iOS 9, *){
locationManager.requestLocation()
} else {
locationManager.startUpdatingLocation()
}
}
}
func locationManager(manager: CLLocationManager, didUpdateLocations locations: [CLLocation]) {
if(timer==nil){
// The locations array is sorted in chronologically ascending order, so the
// last element is the most recent
guard let location = locations.last else {return}
beginNewBackgroundTask()
locationManager.stopUpdatingLocation()
let now = NSDate()
if(isItTime(now)){
//TODO: Every n minutes do whatever you want with the new location. Like for example sendLocationToServer(location, now:now)
}
}
}
func locationManager(manager: CLLocationManager, didFailWithError error: NSError) {
CrashReporter.recordError(error)
beginNewBackgroundTask()
locationManager.stopUpdatingLocation()
}
func isItTime(now:NSDate) -> Bool {
let timePast = now.timeIntervalSinceDate(lastLocationDate)
let intervalExceeded = Int(timePast) > BackgroundLocationManager.UPDATE_SERVER_INTERVAL
return intervalExceeded;
}
func sendLocationToServer(location:CLLocation, now:NSDate){
//TODO
}
func beginNewBackgroundTask(){
var previousTaskId = currentBgTaskId;
currentBgTaskId = UIApplication.sharedApplication().beginBackgroundTaskWithExpirationHandler({
FileLogger.log("task expired: ")
})
if let taskId = previousTaskId{
UIApplication.sharedApplication().endBackgroundTask(taskId)
previousTaskId = UIBackgroundTaskInvalid
}
timer = NSTimer.scheduledTimerWithTimeInterval(BackgroundLocationManager.BACKGROUND_TIMER, target: self, selector: #selector(self.restart),userInfo: nil, repeats: false)
}
}
I start the tracking in AppDelegate like that:
BackgroundLocationManager.instance.start()
Unfortunately, all of your assumptions seem correct, and I don't think there's a way to do this. In order to save battery life, the iPhone's location services are based on movement. If the phone sits in one spot, it's invisible to location services.
The CLLocationManager will only call locationManager:didUpdateToLocation:fromLocation: when the phone receives a location update, which only happens if one of the three location services (cell tower, gps, wifi) perceives a change.
A few other things that might help inform further solutions:
Starting & Stopping the services causes the didUpdateToLocation delegate method to be called, but the newLocation might have an old timestamp.
Region Monitoring might help
When running in the background, be aware that it may be difficult to get "full" LocationServices support approved by Apple. From what I've seen, they've specifically designed startMonitoringSignificantLocationChanges as a low power alternative for apps that need background location support, and strongly encourage developers to use this unless the app absolutely needs it.
Good Luck!
UPDATE: These thoughts may be out of date by now. Looks as though people are having success with #wjans answer, above.
I did write an app using Location services, app must send location every 10s.
And it worked very well.
Just use the "allowDeferredLocationUpdatesUntilTraveled:timeout" method, following Apple's doc.
What I did are:
Required: Register background mode for update Location.
1. Create LocationManger and startUpdatingLocation, with accuracy and filteredDistance as whatever you want:
-(void) initLocationManager
{
// Create the manager object
self.locationManager = [[[CLLocationManager alloc] init] autorelease];
_locationManager.delegate = self;
// This is the most important property to set for the manager. It ultimately determines how the manager will
// attempt to acquire location and thus, the amount of power that will be consumed.
_locationManager.desiredAccuracy = 45;
_locationManager.distanceFilter = 100;
// Once configured, the location manager must be "started".
[_locationManager startUpdatingLocation];
}
2. To keep app run forever using allowDeferredLocationUpdatesUntilTraveled:timeout method in background, you must restart updatingLocation with new parameter when app moves to background, like this:
- (void)applicationWillResignActive:(UIApplication *)application {
_isBackgroundMode = YES;
[_locationManager stopUpdatingLocation];
[_locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[_locationManager setDistanceFilter:kCLDistanceFilterNone];
_locationManager.pausesLocationUpdatesAutomatically = NO;
_locationManager.activityType = CLActivityTypeAutomotiveNavigation;
[_locationManager startUpdatingLocation];
}
3. App gets updatedLocations as normal with locationManager:didUpdateLocations: callback:
-(void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
// store data
CLLocation *newLocation = [locations lastObject];
self.userLocation = newLocation;
//tell the centralManager that you want to deferred this updatedLocation
if (_isBackgroundMode && !_deferringUpdates)
{
_deferringUpdates = YES;
[self.locationManager allowDeferredLocationUpdatesUntilTraveled:CLLocationDistanceMax timeout:10];
}
}
4. But you should handle the data in then locationManager:didFinishDeferredUpdatesWithError: callback for your purpose
- (void) locationManager:(CLLocationManager *)manager didFinishDeferredUpdatesWithError:(NSError *)error {
_deferringUpdates = NO;
//do something
}
5. NOTE: I think we should reset parameters of LocationManager each time app switches between background/forground mode.
if ([self.locationManager respondsToSelector:#selector(setAllowsBackgroundLocationUpdates:)]) {
[self.locationManager setAllowsBackgroundLocationUpdates:YES];
}
This is needed for background location tracking since iOS 9.
I used xs2bush's method of getting an interval (using timeIntervalSinceDate) and expanded on it a little bit. I wanted to make sure that I was getting the required accuracy that I needed and also that I was not running down the battery by keeping the gps radio on more than necessary.
I keep location running continuously with the following settings:
locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers;
locationManager.distanceFilter = 5;
this is a relatively low drain on the battery. When I'm ready to get my next periodic location reading, I first check to see if the location is within my desired accuracy, if it is, I then use the location. If it's not, then I increase the accuracy with this:
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
locationManager.distanceFilter = 0;
get my location and then once I have the location I turn the accuracy back down again to minimize the drain on the battery. I have written a full working sample of this and also I have written the source for the server side code to collect the location data, store it to a database and allow users to view gps data in real time or retrieve and view previously stored routes. I have clients for iOS, android, windows phone and java me. All clients are natively written and they all work properly in the background. The project is MIT licensed.
The iOS project is targeted for iOS 6 using a base SDK of iOS 7. You can get the code here.
Please file an issue on github if you see any problems with it. Thanks.
It seems that stopUpdatingLocation is what triggers the background watchdog timer, so I replaced it in didUpdateLocation with:
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyThreeKilometers];
[self.locationManager setDistanceFilter:99999];
which appears to effectively power down the GPS. The selector for the background NSTimer then becomes:
- (void) changeAccuracy {
[self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
[self.locationManager setDistanceFilter:kCLDistanceFilterNone];
}
All I'm doing is periodically toggling the accuracy to get a high-accuracy coordinate every few minutes and because the locationManager hasn't been stopped, backgroundTimeRemaining stays at its maximum value. This reduced battery consumption from ~10% per hour (with constant kCLLocationAccuracyBest in the background) to ~2% per hour on my device
There is a cocoapod APScheduledLocationManager that allows to get background location updates every n seconds with desired location accuracy.
let manager = APScheduledLocationManager(delegate: self)
manager.startUpdatingLocation(interval: 170, acceptableLocationAccuracy: 100)
The repository also contains an example app written in Swift 3.
In iOS 9 and watchOS 2.0 there's a new method on CLLocationManager that lets you request the current location: CLLocationManager:requestLocation(). This completes immediately and then returns the location to the CLLocationManager delegate.
You can use an NSTimer to request a location every minute with this method now and don't have to work with startUpdatingLocation and stopUpdatingLocation methods.
However if you want to capture locations based on a change of X meters from the last location, just set the distanceFilter property of CLLocationManger and to X call startUpdatingLocation().
Attached is a Swift solution based in:
Define App registers for location updates in the info.plist
Keep the locationManager running all the time
Switch kCLLocationAccuracy between BestForNavigation (for 5 secs to get the location) and ThreeKilometers for the rest of the wait period to avoid battery drainage
This example updates location every 1 min in Foreground and every 15 mins in Background.
The example works fine with Xcode 6 Beta 6, running in a iOS 7 device.
In the App Delegate (mapView is an Optional pointing to the mapView Controller)
func applicationDidBecomeActive(application: UIApplication!) {
if appLaunched! == false { // Reference to mapView used to limit one location update per timer cycle
appLaunched = true
var appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
var window = appDelegate.window
var tabBar = window?.rootViewController as UITabBarController
var navCon = tabBar.viewControllers[0] as UINavigationController
mapView = navCon.topViewController as? MapViewController
}
self.startInitialPeriodWithTimeInterval(60.0)
}
func applicationDidEnterBackground(application: UIApplication!) {
self.startInitialPeriodWithTimeInterval(15 * 60.0)
}
func startInitialPeriodWithTimeInterval(timeInterval: NSTimeInterval) {
timer?.invalidate() // reset timer
locationManager?.desiredAccuracy = kCLLocationAccuracyBestForNavigation
timer = NSTimer.scheduledTimerWithTimeInterval(5.0, target: self, selector: Selector("getFirstLocationUpdate:"), userInfo: timeInterval, repeats: false)
}
func getFirstLocationUpdate(sender: NSTimer) {
let timeInterval = sender.userInfo as Double
timer?.invalidate()
mapView?.canReportLocation = true
timer = NSTimer.scheduledTimerWithTimeInterval(timeInterval, target: self, selector: Selector("waitForTimer:"), userInfo: timeInterval, repeats: true)
}
func waitForTimer(sender: NSTimer) {
let time = sender.userInfo as Double
locationManager?.desiredAccuracy = kCLLocationAccuracyBestForNavigation
finalTimer = NSTimer.scheduledTimerWithTimeInterval(5.0, target: self, selector: Selector("getLocationUpdate"), userInfo: nil, repeats: false)
}
func getLocationUpdate() {
finalTimer?.invalidate()
mapView?.canReportLocation = true
}
In the mapView (locationManager points to the object in the AppDelegate)
override func viewDidLoad() {
super.viewDidLoad()
var appDelegate = UIApplication.sharedApplication().delegate! as AppDelegate
locationManager = appDelegate.locationManager!
locationManager.delegate = self
canReportLocation = true
}
func locationManager(manager: CLLocationManager!, didUpdateLocations locations: [AnyObject]!) {
if canReportLocation! {
canReportLocation = false
locationManager.desiredAccuracy = kCLLocationAccuracyThreeKilometers
} else {
//println("Ignore location update")
}
}
I recently started testing my app on an iPhone 5, and to my alarm, it seems that the CLLocationManager doesn't really work! Although [CLLocationManager headingAvailable] is YES, I don't receive any heading updates at all. Strangely, on an iPhone 4, after 30 or so heading updates, locationManager:didUpdateToHeading: is no longer called. This issue is entirely new. The location manager also returns negative numbers for verticalAccuracy, so I'm assuming the altitude it is invalid. Here's how I'm creating the location manager:
CLLocationManager* locationManager = [[CLLocationManager alloc] init];
if([locationManager respondsToSelector:#selector(disallowDeferredLocationUpdates)]) {
[locationManager disallowDeferredLocationUpdates];
[locationManager setPausesLocationUpdatesAutomatically:NO];
}
locationManager.headingOrientation = CLDeviceOrientationFaceUp;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.headingFilter = -1;
locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
[sharedSingleton setLocationManager:locationManager];
sharedSingleton is just my singleton class that handles some odds and ends, including holding onto a reference to the location manager.
If I need to post any more code let me know. I just don't know what might be causing this strange issue. Thanks!
You need to retain "locationManager" in memory somewhere, either as a property of your object or as an instance variable.
What I belive is happening is that you're creating your location manager, and then your method exits and "locationManager" falls out of scope and is magically released by ARC.
So, instead, do something like this:
in your #implementation:
#property (strong) CLLocationManager * locationManager;
and in your #interface:
self.locationManager = [[CLLocationManager alloc] init];
if([self.locationManager respondsToSelector:#selector(disallowDeferredLocationUpdates)]) {
[self.locationManager disallowDeferredLocationUpdates];
[self.locationManager setPausesLocationUpdatesAutomatically:NO];
}
self.locationManager.headingOrientation = CLDeviceOrientationFaceUp;
self.locationManager.distanceFilter = kCLDistanceFilterNone;
self.locationManager.headingFilter = -1;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
You could try a few things. First of all, I don't see a startUpdatingHeading call. Maybe you're doing it somewhere else. You should add the locationManager:didFailWithError: method to the delegate to check for errors, and try returning YES in locationManagerShouldDisplayHeadingCalibration: in case it's a calibration issue.
Seems the solution was obvious and I overlooked it. The delegate was being set to nil just moments after the location manager was started, which explains why on a slower device like the iPhone 4 a few updates were able to come through before the code setting the delegate to nil was run, but on the iPhone 5 it was instantaneous.
I'm trying a lot of things to stop the location update of my app but nothing seems work…
What I do (regard of the post : StopUpdatingLocation method not working for iOS5) :
// Initialise my locationManager and start monitoring :
locationManager = [[CLLocationManager alloc] init];
[locationManager startUpdatingLocation];
// .. Some code to use the coordinates that locationManager gives me.
// To stop monitoring :
locationManager = nil;
You have to know I placed [locationManager stopUpdatingLocation]; in the method :
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
So the location is updated only 1 time (btw tell me if it's a good idea…).
I also tried to place [locationManager stopUpdatingLocation]; just before locationManager = nil; in the main code, but the blue dot that gives me my location is still moving on my map in both cases…
I also set a timer which print the locationManager object in the console, and it gives me (null) meanwhile the blue dot is still moving on my iPhone 5 so I don't understand that…
Or maybe the dot is still moving because of another thing, but not because of locationManager update ?
I'm certainly missing something but I don't get what :/.
Thanks for ideas and help.
One possibility: The blue dot moving on your map is because you set the MKMapView's showsUserLocation to YES. It will track until you set it to NO.
Another possibility: This line is wrong:
locationManager = nil;
That does not stop monitoring, but it does cause you to be unable to refer to the location manager, so now you can't stop monitoring! Cut that line.
I faced the same problem that even after I placed the code
[locationManager stopUpdatingLocation];
locationManager=nil;
my application was using GPS service which was un-necessarily consuming battery power. the solution for this problem is to turn off the showUserLocation property of MKMapView .
[self.mapView setShowsUserLocation:NO];
Since the MKMapView keeps on using your GPS service even if the LocationManager is nil.
Hope it will help you
Use this lines of code
[self.locationManager stopUpdatingLocation];
self.locationManager.delegate = nil;
self.locationManager = nil;
Thanks!
Here is my code:
- (void) viewWillAppear:(BOOL)animated
{
// SETUP THE LOCATION MANAGER.
self.locManager = [[CLLocationManager alloc] init];
self.locManager.delegate = self;
[self.locManager startUpdatingLocation];
}
- (void) viewWillDisappear:(BOOL)animated
{
[self.locManager stopUpdatingLocation];
[self.locManager.delegate release];
}
When the View Controller exits the CLLocationManager arrow logo in the top right corner is still showing. This is both on iOS 4.3 and 5.0. Any explanation?
I believe the system indicates the location badge on any app that has used Core Location in last hour or so.
The purple arrow should disappear as soon as you call:
[self.locManager stopUpdatingLocation];
While allocating your locManager, you need not call self.locManager. That will bump up the retain count to 2. Instead use:
locManager = [[CLLocationManager alloc] init];
Also, put a breakpoint in your viewWillDisappear: method and make sure it does get called. Also, set the delegate to nil at the end.
After following these points, your code shall work.
The purple arrow is for Location Services and consumes battery heavily. Make sure the arrow disappears as soon as you call stopUpdatingLocation:
I have a MKMapView whereby I drop an annotation everytime the view loads, or when showLocation custom class method is called.
I need the accuracy to be the best
-(void)viewDidLoad {
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
[locationManager startUpdatingLocation];
}
-(IBAction) showLocation:(id) sender{
[locationManager startUpdatingLocation];
}
- (void) locationManager:(CLLocationManager *) manager
didUpdateToLocation:(CLLocation *) newLocation
fromLocation:(CLLocation *) oldLocation {
// start geocoding with newLocation coordinate which will automatically set annotation.
SVGeocoder *geocodeRequest = [[SVGeocoder alloc]
initWithCoordinate:CLLocationCoordinate2DMake(newLocation.coordinate.latitude, newLocation.coordinate.longitude)];
[geocodeRequest setDelegate:self];
[geocodeRequest startAsynchronous];
[geocodeRequest release];
[locationManager stopUpdatingLocation];
}
My question is when will the didUpdateToLocation method be called? Only after a new location is found when I perform [locationManager startUpdatingLocation]?
I am facing some weird issue when the user is travelling and on stationary.
Say the user is travelling from point A->B->C->D with 1 min intervals between points. When I call my method at point C, sometime it returns the coordinates of point A, sometimes point B and sometimes C. It's just random.
It's even more weird when I am on stationary. I get different coordinates when I calls showLocation method even though I am hooked up on my house WiFi.
I was thinking of implementing the didUpdateToLocation to get the best result it can within 5secs. If within the 5secs, it finds a particular location of an accuracy I had defined, then use the coordinate. If not, use the best it has found within the 5sec time frame. But as I am new I am not sure how to code something like that. I read up NSTimer and it seems like it might work.
Any advices guys?
Thanks a lot in advance!
One of the reasons you are receiving the location from point A is that CoreLocation is returning the last valid location it had first until it can obtain a more accurate location. When you call [locationManager startUpdatingLocation]; it will return the -didUpdateToLocation over and over until you are statisfied and finally call -stopUpdatingLocation.
I think you just need to allow a bit of time for it to get a better location fix before you stop updating your location. I would consider moving the stop updating location from your -didUpdateToLocation to a different method.
Remove [locationManager stopUpdatingLocation]; from your code and try .