Is it possible to send information about the location of the iPhone to a separate service, though the application is running in the background or as a background service?
You need to call webservice in CLLocationManagerDelegate Method see this e.g. below
- (void)locationManager:(CLLocationManager *)manager
didUpdateToLocation:(CLLocation *)newLocation
fromLocation:(CLLocation *)oldLocation
{
CLLocationCoordinate2D coordinate = [newLocation coordinate];
CLLocationCoordinate2D oldCoordinate = [oldLocation coordinate];
CLLocation *newlocation = [[CLLocation alloc] initWithLatitude:coordinate.latitude longitude:coordinate.longitude];
CLLocation *oldlocation = [[CLLocation alloc] initWithLatitude:oldCoordinate.latitude longitude:oldCoordinate.longitude];
latitude =coordinate.latitude;
longitude =coordinate.longitude;
CLLocationDistance distDifference = [newlocation distanceFromLocation:oldlocation];
int distance = distDifference;
if (distance>0.5) {
if (isInternetReachable==TRUE) {
[self callWebserviceSetlocationInBackground:newLocation];
}
}
[newlocation release];
[oldlocation release];
}
Also you need to set "Required background modes" Flag to "App registers for location updates" to use core location updated in background.
http://i.stack.imgur.com/WtcCm.png
This may help you.
Just change calling web service code method by below method. I hope it will work:-
-(void) callWebserviceSetlocationInBackground:(CLLocation *)location
{
// REMEMBER. We are running in the background if this is being executed.
// We can't assume normal network access.
// bgTask is defined as an instance variable of type UIBackgroundTaskIdentifier
// Note that the expiration handler block simply ends the task. It is important that we always
// end tasks that we have started.
UIApplication *app = [UIApplication sharedApplication];
UIBackgroundTaskIdentifier bgTask = [app beginBackgroundTaskWithExpirationHandler:^{ [app endBackgroundTask:bgTask];}];
NSLog(#"call web service in background lati = %f and long =%f",location.coordinate.latitude,location.coordinate.longitude);
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
}
Thanks.
Related
Currently I am working in a project , its requirement is to get the current location information specially latitude and longitude value in every 200m interval using wifi network or Cellular network without using gps as it is consuming more battery life.
Is this possible in ios latest version .
If any one having any idea ,please share with me ,
Thank you.
Have a look in to CLLocationManager, That will be able to tell you where the user is located.
.h
#import <CoreLocation/CoreLocation.h>
#property(nonatomic,retain) CLLocationManager *locationManager;
.m
- (void)viewDidLoad
{
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
//let the user know the purpose
locationManager.purpose = #"Enable location services";
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
NSLog(#"User latitude: %f",locationManager.location.coordinate.latitude);
NSLog(#"User longitude: %f",locationManager.location.coordinate.longitude);
[locationManager startUpdatingLocation];
}
It only way to get your location info in every 200m that is CLLocationManager's startUpdatingLocation. But it is comsuming a lot of battery.
But there is a little different way to get your location when it is changed.
CLLocationManager's startMonitoringSignificantLocationChanges.
Here is a Link
The location manager protocol reference
https://developer.apple.com/library/mac/#documentation/CoreLocation/Reference/CLLocationManagerDelegate_Protocol/CLLocationManagerDelegate/CLLocationManagerDelegate.html
1.In Appdelegate
#import <CoreLocation/CoreLocation.h>
In #interface file
CLLocationManager *locationManager;
#property (nonatomic, retain) CLLocationManager *locationManager;
and add protocol CLLocationManagerDelegate protocol.
2.Impliment these functions in .m.
#synthesize locationManager;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.locationManager = [[[CLLocationManager alloc] init] autorelease];
self.locationManager.delegate = self;
self.locationManager.desiredAccuracy = kCLLocationAccuracyBest;
self.locationManager.distanceFilter = 1.0;
[self.locationManager startUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager didEnterRegion:(CLRegion *)region
{
// Show an alert or otherwise notify the user
}
- (void)locationManager:(CLLocationManager *)manager didExitRegion:(CLRegion *)region
{
}
- (void)locationManager:(CLLocationManager *)manager monitoringDidFailForRegion:(CLRegion *)region withError:(NSError *)error
{
}
Note:If you want to debug first set current location in simulator
At Debug--->Location--->Custom Location.
its requirement is to get the current location information specially latitude and longitude value in every 200m interval using wifi network or Cellular network without using gps as it is consuming more battery life
The documentation for CLLocationManager has this to say about distance and the GPS hardware:
... setting the desired accuracy for location events to one kilometer gives the location manager the flexibility to turn off GPS hardware and rely solely on the WiFi or cell radios.
For less than 200 meters you'll probably need to roll-your-own solution here.
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
[locationManager stopUpdatingLocation];
[locationManager stopMonitoringSignificantLocationChanges];
[self performSelector:#selector(stopUpadateLocation)];
CLLocation *location = [locationManager location];
CLLocationCoordinate2D coord;
coord=[location coordinate];
NSLog(#"coord %f %f", coord.latitude, coord.longitude);
NSString *urlString = [NSString stringWithFormat:#"http://maps.google.com/maps/geo?q=%f,%f&output=json", newLocation.coordinate.latitude, newLocation.coordinate.longitude];
NSURL *url = [NSURL URLWithString:urlString];
NSString *locationString = [NSString stringWithContentsOfURL:url encoding:NSUTF8StringEncoding error:nil];
NSDictionary *dic=[locationString JSONValue];
NSLog(#"locationString:%#",locationString );
[strAddr setString:[AppUtility removeNull:[NSString stringWithFormat:#"%#",[[[dic valueForKey:#"Placemark"] objectAtIndex:0] valueForKey:#"address"]]]];
[txtNear setText:strAddr];
}
- (void)startUpdateLocation{
[locationManager startUpdatingLocation];
}
- (void)stopUpadateLocation{
[locationManager stopUpdatingLocation];
[locationManager stopMonitoringSignificantLocationChanges];
}
You have to use the Core Location method startMonitoringSignificantLocationChanges which uses only the wifi or cellular networks!
I am trying to post data on background and I want to receive response from in regular interval that so that I am trying to use CLLocation Manager . But didUpdateToLocation method calling only once.
Please suggest me !
enter code here
- (void)applicationDidEnterBackgroundUIApplication *)application
{
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyBest; // 100 m
[locationManager startUpdatingLocation];
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
// code for Posting Data Here
NSLog(#"backgroundTimeRemaining: %f", [[UIApplication sharedApplication] backgroundTimeRemaining]);
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
- (void)locationManagerCLLocationManager *)manager
didUpdateToLocationCLLocation *)newLocation
fromLocationCLLocation *)oldLocation
{
NSLog(#"Location Change");
}
This Method Call Only Once.
Of course, and you should be happy what delegate received message at least once. There is no code which will delay application suspending in your background execution code. Also this kind of code can work about 10 minutes and will be killed by system.
If you need to track user location in background, than maybe you just set this mode for application background operation in Info.plist (UIBackgroundModes and add option location) and your app won't be suspended (only in case of heavy memory usage)
I am trying to post data on background and I want to receive response from in regular interval that so that I am trying to use CLLocation Manager . But didUpdateToLocation method calling only once.
Please suggest me !
enter code here
- (void)applicationDidEnterBackgroundUIApplication *)application
{
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
locationManager.desiredAccuracy = kCLLocationAccuracyBest; // 100 m
[locationManager startUpdatingLocation];
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
// code for Posting Data Here
NSLog(#"backgroundTimeRemaining: %f", [[UIApplication sharedApplication] backgroundTimeRemaining]);
[app endBackgroundTask:bgTask];
bgTask = UIBackgroundTaskInvalid;
});
}
- (void)locationManagerCLLocationManager *)manager
didUpdateToLocationCLLocation *)newLocation
fromLocationCLLocation *)oldLocation
{
NSLog(#"Location Change");
}
This Method Call Only Once.
Make sure you are not testing this in simulator.
You don't get location updates on the iphone simulator.
In order to run location services in the background, you need to modify your plist such that the UIBackgroundModes key contains location.
the call should be
[locationManager startMonitoringSignificantLocationChanges];
(BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
// Override point for customization after application launch.
locmanager = [[CLLocationManager alloc] init];
[locmanager setDelegate:self];
[locmanager setDesiredAccuracy:kCLLocationAccuracyHundredMeters];
[locmanager setDistanceFilter:10];
[locmanager startUpdatingLocation];
[window makeKeyAndVisible];
return YES;
}
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
CLLocationCoordinate2D loc = [newLocation coordinate];
latitude = [NSString stringWithFormat: #"%f", loc.latitude];
longitude= [NSString stringWithFormat: #"%f", loc.longitude];
//Call to the web service for sending data
}
Will it be possible to start this application automatically when the phone starts.I don't want users to start this.
No, the only way for your application to start is for a user to start it, either by tapping on it on the home screen, or by opening it through a push notification.
CoreLocation runs in the background as part of iOS, but your app can only access that data when it is open. If it is running in multitasking mode, I imagine that you'd be able to access location data through a background task.
Note that a "Location" indicator will appear in the status bar on the right whenever you use Core Location. This is done for privacy reasons.
No. Not unless it's jailbroken.
Is there a way to return the users location as a string from a model?
I have a model thats job is to download same JSON data from a web service. When sending in my request I need to add ?lat=LAT_HERE&lng=LNG_HERE to the end of the string.
I have seen tons of examples using the map or constantly updating a label. But I cant find out how to explicitly return the lat and lng values.
Im only 2 days into iPhone dev so go easy on me :)
You need to leverage Core Location, specifically CLLocationManager. Apple doesn't provide any CL programming guide, so just look at one of the samples like LocateMe to see how to do it.
You need to use CLLocationManager like this:
- (void)viewDidLoad
{
// this creates the CCLocationManager that will find your current location
CLLocationManager *locationManager = [[[CLLocationManager alloc] init] autorelease];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyNearestTenMeters;
[locationManager startUpdatingLocation];
}
// this delegate is called when the app successfully finds your current location
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
// retrieve lat and lng in a string from newLocation.coordinate
NSString *lat = [NSString stringWithFormat:#"%d", newLocation.coordinate.latitude];
NSString *lng = [NSString stringWithFormat:#"%d", newLocation.coordinate.longitude];
}
// this delegate method is called if an error occurs in locating your current location
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error
{
NSLog(#"locationManager:%# didFailWithError:%#", manager, error);
}