iOS app background location access using a timer - ios

Question

I am looking for a solution to access/stop location services while app is in the background. My app takes continuous location when it's sent to background (It has access to continuous location) . It's necessary for the app functionality.
So I would like to know few things:
How long my app can take continuous location while it's still in the background? (before OS kills the background process or something like that)
If I want to add a timer say after 60 minutes app will stop taking the location, what would be the correct approach?

Answer 1

Background location updation can be done using following code:
In Appdelegate class:
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
if ([launchOptions objectForKey:UIApplicationLaunchOptionsLocationKey]) {
// This "afterResume" flag is just to show that he receiving location updates
// are actually from the key "UIApplicationLaunchOptionsLocationKey"
self.shareModel.afterResume = YES;
[self.shareModel startMonitoringLocation];
}
return YES;
}
- (void)applicationDidEnterBackground:(UIApplication *)application {
[self.shareModel stopContinuosLocationUpdate];
[self.shareModel restartMonitoringLocation];
}
- (void)applicationDidBecomeActive:(UIApplication *)application {
//Remove the "afterResume" Flag after the app is active again.
self.shareModel.afterResume = NO;
[self.shareModel startContinuosLocationUpdate];
}
In Location update class, say LocationManager.m:
#import <CoreLocation/CoreLocation.h>
#property (nonatomic) CLLocationManager * anotherLocationManager;
- (void)startContinuosLocationUpdate
{
CLAuthorizationStatus status = [CLLocationManager authorizationStatus];
if (status == kCLAuthorizationStatusDenied)
{
NSLog(#"Location services are disabled in settings.");
}
else
{
// for iOS 8
if ([self.anotherLocationManager respondsToSelector:#selector(requestAlwaysAuthorization)])
{
[self.anotherLocationManager requestAlwaysAuthorization];
}
// for iOS 9
if ([self.anotherLocationManager respondsToSelector:#selector(setAllowsBackgroundLocationUpdates:)])
{
[self.anotherLocationManager setAllowsBackgroundLocationUpdates:YES];
}
[self.anotherLocationManager startUpdatingLocation];
}
}
- (void)stopContinuosLocationUpdate
{
[self.anotherLocationManager stopUpdatingLocation];
}
- (void)startMonitoringLocation
{
if (_anotherLocationManager)
[_anotherLocationManager stopMonitoringSignificantLocationChanges];
self.anotherLocationManager = [[CLLocationManager alloc]init];
_anotherLocationManager.delegate = self;
_anotherLocationManager.desiredAccuracy = kCLLocationAccuracyBestForNavigation;
_anotherLocationManager.activityType = CLActivityTypeOtherNavigation;
if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(#"9.0")) {
[_anotherLocationManager setAllowsBackgroundLocationUpdates:YES];
}
else if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(#"8.0")) {
[_anotherLocationManager requestAlwaysAuthorization];
}
[_anotherLocationManager startMonitoringSignificantLocationChanges];
}
- (void)restartMonitoringLocation
{
[_anotherLocationManager stopMonitoringSignificantLocationChanges];
if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(#"9.0")) {
[_anotherLocationManager setAllowsBackgroundLocationUpdates:YES];
}
else if(SYSTEM_VERSION_GREATER_THAN_OR_EQUAL_TO(#"8.0")) {
[_anotherLocationManager requestAlwaysAuthorization];
}
[_anotherLocationManager startMonitoringSignificantLocationChanges];
}
#pragma mark - CLLocationManager Delegate
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
if(_dictLocation && [_dictLocation isKindOfClass:[NSDictionary class]])
{
float latitudeValue = [[RVCommon validateDataForNumber:_dictLocation[#"lat"]] floatValue];
float longitudeValue = [[RVCommon validateDataForNumber:_dictLocation[#"lng"]] floatValue];
CLLocation *facilityLocation = [[CLLocation alloc] initWithLatitude:latitudeValue longitude:longitudeValue];
CLLocation *mostRecentLocation = locations.lastObject;
CLLocationDistance distanceInMeters = [mostRecentLocation distanceFromLocation:facilityLocation];
if (distanceInMeters <= 500.0)
{
//Here I am informing the server when user is within 500mts of the coordinate.
}
}
NSLog(#"locationManager didUpdateLocations: %#",locations);
}