Tracking User Location in the Background in iOS 7 - ios

I am trying to track's user location when the application moves to background. I just need to track once. So, I am not using background location services. In the code below this works when I uncomment 1 but it doesn't work when I uncomment 2.
- (void)applicationDidEnterBackground:(UIApplication *)application
{
// 1 works here [self startStandardUpdates];
self.bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
[application endBackgroundTask:self.bgTask];
self.bgTask = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT,0), ^{
// 2 doesn't work here [self startStandardUpdates];
});
}
In second case this delegate function is not called.
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
NSLog(#"Updated\n%#",locations);
[self.manager stopUpdatingLocation];
[[UIApplication sharedApplication] endBackgroundTask:self.bgTask];
self.bgTask = UIBackgroundTaskInvalid;
}
Can someone tell me why this is not working in 2nd case. Also, is it fine using [self startStandardUpdates] in the first position ?

Try this
By default, this is YES for applications linked against iOS 6.0 or later.
if ([self.manager respondsToSelector:#selector(pausesLocationUpdatesAutomatically)]) {
self.manager.pausesLocationUpdatesAutomatically = NO;
}

Related

Error to get location after push notification iOS 9

After receive a push notification I am trying to get the current localization.
However when I start the code bellow the corelocation fails (didFailWithError) when the app is at background :(
Only works in foreground.
Why?
I already did the .plist for background configuration
-(void)application:(UIApplication *)application didReceiveRemoteNotification:(nonnull NSDictionary *)userInfo fetchCompletionHandler:(nonnull void (^)(UIBackgroundFetchResult))completionHandler{
__block UIBackgroundTaskIdentifier bgTask = [application beginBackgroundTaskWithExpirationHandler:^{
[application endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
NSLog(#" Finalizado background...");
}];
[self handleStartMonitoringLocation];
NSLog(#"Main Thread proceeding...");
}
-(void)handleStartMonitoringLocation{
// location
if (!self.shareModel) {
self.shareModel = [LocationManager sharedManager];
self.shareModel.afterResume = NO;
[self.shareModel addApplicationStatusToPList:#"didFinishLaunchingWithOptions"];
}
[self.shareModel addApplicationStatusToPList:#"applicationDidBecomeActive"];
//Remove the "afterResume" Flag after the app is active again.
self.shareModel.afterResume = NO;
// [self.shareModel startMonitoringLocation];
[self.shareModel startBackgroundLocationUpdates];
}
-(void)startBackgroundLocationUpdates {
// Create a location manager object
self.anotherLocationManager = [[CLLocationManager alloc] init];
// Set the delegate
self.anotherLocationManager.delegate = self;
// Request location authorization
[self.anotherLocationManager requestWhenInUseAuthorization];
// Set an accuracy level. The higher, the better for energy.
self.anotherLocationManager.desiredAccuracy = kCLLocationAccuracyBest;
// Enable automatic pausing
self.anotherLocationManager.pausesLocationUpdatesAutomatically = YES;
// Specify the type of activity your app is currently performing
self.anotherLocationManager.activityType = CLActivityTypeFitness;
if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(#"9.0")){
// Enable background location updates
self.anotherLocationManager.allowsBackgroundLocationUpdates = YES;
[self.anotherLocationManager requestLocation];
}
else{
// Start location updates
[self.anotherLocationManager startUpdatingLocation];
}
}
#pragma mark - CLLocationManager Delegate
-(void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
NSLog(#"locationManager error: %#",error);
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations{
NSLog(#"locationManager didUpdateLocations: %#",locations);
}

ios, get location every hour (ios7)

In my project I need to get location evry hour. My code looks like this:
#import "AppDelegate.h"
#implementation AppDelegate {
UIBackgroundTaskIdentifier bgTask;
CLLocationManager *locationManager;
}
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.pausesLocationUpdatesAutomatically = NO;
locationManager.activityType = CLActivityTypeOther;
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
locationManager.distanceFilter = kCLDistanceFilterNone;
return YES;
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
__block UIBackgroundTaskIdentifier background_task;
background_task = [application beginBackgroundTaskWithExpirationHandler:^ {
[application endBackgroundTask: background_task];
background_task = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[locationManager startUpdatingLocation];
while(TRUE)
{
NSLog(#"Background time Remaining: %f",[[UIApplication sharedApplication] backgroundTimeRemaining]);
[NSThread sleepForTimeInterval:200]; //wait for x sec
[locationManager startUpdatingLocation];
}
[application endBackgroundTask: background_task];
background_task = UIBackgroundTaskInvalid;
});
}
- (void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations {
CLLocation *location = [locations lastObject];
NSDate* eventDate = location.timestamp;
NSTimeInterval time = [eventDate timeIntervalSinceNow];
if (abs(time) < 15.0) {
if (location != nil) {
NSString *lat = [NSString stringWithFormat:#"%.8f", location.coordinate.latitude];
NSString *lng = [NSString stringWithFormat:#"%.8f", location.coordinate.longitude];
NSLog(#"location update ...");
//[APIConnection SaveMyPositionWitLat:lat withLng:lng];
//[locationManager stopUpdatingLocation];
}
}
}
This works, but battery im my phone is drained very fast and location is checking every second. If I enable:
[locationManager stopUpdatingLocation];
then location service is stoped permanently. How to change this code for saving battery power ?
Your idea about getting the location is not really possible in iOS since your app needs a active location monitoring to keep running in the background.
For this Apple has the methods to check only major changes, startMonitoringSignificantLocationChanges.
This will inform you app of any major changes in location. Then what you could do to get a more accurate location is start the normal startUpdatingLocation.
This way you save battery and only grab the location when needed.
can you set locationManager.pausesLocationUpdatesAutomatically to YES this should help

how to call a method by using nstimer in background state

I want to fetch service for every 15 mins,so i am using NSTimer.It is working fine.But how to call same service while app is in background state by using nstimer.Nstimer is not working in background state.Please suggest me.
//when the application is about to move from active to inactive state.
- (void)applicationWillResignActive:(UIApplication *)application
{
[self sendBackgroundLocationToServer];
}
- (void) sendBackgroundLocationToServer
{
UIBackgroundTaskIdentifier bgTask = UIBackgroundTaskInvalid;
bgTask = [[UIApplication sharedApplication]
beginBackgroundTaskWithExpirationHandler:^{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
}];
//Start Timer
[self startTimer];
//Close the task
if (bgTask != UIBackgroundTaskInvalid)
{
[[UIApplication sharedApplication] endBackgroundTask:bgTask];
}
}

How to reinitialize app after backgrounding

-(void) closeUpShopBeforeBackgrounding {
// this listen to the UIApplicationDidEnterBackgroundNotification
[self beginBackgroundUpdateTask];
// do some closing stuff
[self endBackgroundUpdateTask]; }
- (void) beginBackgroundUpdateTask {
self.backgroundTask = [[UIApplication sharedApplication] beginBackgroundTaskWithExpirationHandler:^{
[self endBackgroundUpdateTask];
}]; }
- (void) endBackgroundUpdateTask {
[[UIApplication sharedApplication] endBackgroundTask: self.backgroundTask];
self.backgroundTask = UIBackgroundTaskInvalid; }
This code is working fine for me, but when I foreground the app again, its dead in the water. Its as if the viewDidLoads are not firing, and nothing is happening.
Is there anything I need to do when the app foregrounds to kick it back into life?

Getting user location every n minutes after app goes to background

I am trying to implement the suggestions given in this post.
Unfortunately the steps are not clear to me. I tried implementing those suggestions, but the backgroundTimeRemaining continues to decrease even after I start and stop locationServices. This is how I developed it:
- (void)applicationDidEnterBackground:(UIApplication *)application {
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[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.
self.timer = nil;
[self initTimer];
});
}
initTimer:
- (void)initTimer {
// Create the location manager if this object does not
// already have one.
if (nil == self.locationManager)
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
[self.locationManager startMonitoringSignificantLocationChanges];
if (self.timer == nil) {
self.timer = [NSTimer scheduledTimerWithTimeInterval:0.3
target:self
selector:#selector(checkUpdates:)
userInfo:nil
repeats:YES];
}
}
checkUpdates:
- (void)checkUpdates:(NSTimer *)timer{
UIApplication* app = [UIApplication sharedApplication];
double remaining = app.backgroundTimeRemaining;
if(remaining < 580.0) {
[self.locationManager startUpdatingLocation];
[self.locationManager stopUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges];
}
DbgLog(#"Reminaing %f", app.backgroundTimeRemaining);
}
Does anyone have a suggestion on what might be wrong in my code? Both initTimer and checkUpdates are being called, but only during for the background execution time (+- 10 Mins). I want the app to update the location every n minutes "forever".
My app's UIBackgroundModes is set to location.
UPDATE:
I am now resetting the timer on didUpdateToLocation and didFailWithError. But still the backgroundTimeRemaining keeps decreasing:
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
NSLog(#"Did Update Location = %f / %f", [newLocation coordinate].latitude, [newLocation coordinate].longitude);
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[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.
[self initTimer];
});
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
[self.locationManager stopUpdatingLocation];
UIApplication* app = [UIApplication sharedApplication];
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
// Start the long-running task and return immediately.
[self initTimer];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task.
});
}
I am also invalidating the timer:
- (void)checkUpdates:(NSTimer *)timer{
UIApplication* app = [UIApplication sharedApplication];
double remaining = app.backgroundTimeRemaining;
if(remaining < 580.0 && remaining > 570.0) {
[self.timer invalidate];
self.timer = nil;
[self.locationManager startUpdatingLocation];
[self.locationManager stopUpdatingLocation];
}
DbgLog(#"*************************Checking for updates!!!!!!!!!!! Reminaing %f", app.backgroundTimeRemaining);
}
To anyone else having a nightmare of a time trying to figure this one out, I have a simple solution.
Study the example from raywenderlich.com. The sample code works perfectly, but unfortunately there's no timer during background location. This will run indefinitely.
Add timer by using this code snippet:
-(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.
After some days trying all possible solutions I was finally able to make it work. Here is what was wrong in my solution:
I need to setup 2 UIBackgroundTaskIdentifiers, one for the timer, and another one for the locationManager
On my solution, just add:
UIApplication *app = [UIApplication sharedApplication];
bgTask2 = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask2];
bgTask2 = UIBackgroundTaskInvalid; }];
self.locationManager.delegate = self;
[self.locationManager startUpdatingLocation];
Once you're in the background you can only have 10 minutes of additional time. There is no way to extend that. You should use the location background services instead.
Working Code(Entire Stepwise Code)
Modified scurioni's code
Step 1
Go to project -> Capabilities -> Background Modes -> select Location updates.
Go to Project -> Info -> add a key NSLocationAlwaysUsageDescription with an optional string.
Step 2
Add this code to AppDelegate.m
#interface AppDelegate ()<CLLocationManagerDelegate>
#property (strong, nonatomic) CLLocationManager *locationManager;
#property (strong, nonatomic) NSTimer *timer;
#end
Step 3
Add This Code in to applicationDidEnterBackground method in AppDelegate.m
- (void)applicationDidEnterBackground:(UIApplication *)application {
UIApplication *app = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTaskId =
[app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTaskId];
bgTaskId = UIBackgroundTaskInvalid;
}];
dispatch_async( dispatch_get_main_queue(), ^{
self.timer = nil;
[self initTimer];
[app endBackgroundTask:bgTaskId];
bgTaskId = UIBackgroundTaskInvalid;
});
}
- (void)initTimer {
if (nil == self.locationManager)
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.delegate = self;
[self.locationManager requestAlwaysAuthorization];
[self.locationManager startMonitoringSignificantLocationChanges];
if (self.timer == nil) {
self.timer = [NSTimer scheduledTimerWithTimeInterval:0.3
target:self
selector:#selector(checkUpdates:)
userInfo:nil
repeats:YES];
}
}
- (void)checkUpdates:(NSTimer *)timer{
UIApplication *app = [UIApplication sharedApplication];
double remaining = app.backgroundTimeRemaining;
if(remaining < 580.0) {
[self.locationManager startUpdatingLocation];
[self.locationManager stopUpdatingLocation];
[self.locationManager startMonitoringSignificantLocationChanges];
}
}
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation {
NSLog(#"Did Update Location = %f / %f", [newLocation coordinate].latitude, [newLocation coordinate].longitude);
[self updateLocationWithLatitude:[newLocation coordinate].latitude andLongitude:[newLocation coordinate].longitude];
UIApplication* app = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTask =
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
[self initTimer];
});
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
[self.locationManager stopUpdatingLocation];
UIApplication *app = [UIApplication sharedApplication];
__block UIBackgroundTaskIdentifier bgTask =
bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}];
[self initTimer];
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
// Do the work associated with the task
});
}
-(void)updateLocationWithLatitude:(CLLocationDegrees)latitude
andLongitude:(CLLocationDegrees)longitude{
//Here you can update your web service or back end with new latitude and longitude
}

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