iOS CoreLocation not getting GPS coordinates - ios

Question

So I am new to iOS development, and I am just trying to get a label updated with my current GPS Coordinates. I am not having an issue compiling, but my coordinates are coming up as 0.00000, 0.00000.
Here is the code for my .h file:
#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>
#import <CoreLocation/CoreLocation.h>
#interface ViewController : UIViewController{
IBOutlet CLLocationManager *locationManager;
IBOutlet UILabel *location;
}
//#property (nonatomic, retain) IBOutlet CLLocationManager *locationManager;
//#property (weak, nonatomic) IBOutlet UILabel *location;
#end
Here is the code for my .m file:
#implementation ViewController
- (void) updateLabel
{
NSObject *latitude = [NSString stringWithFormat:#"%f", locationManager.location.coordinate.latitude];
NSObject *longitude = [NSString stringWithFormat:#"%f", locationManager.location.coordinate.longitude];
location.text = [NSString stringWithFormat: #"%#,%#", latitude, longitude];
}
- (void)viewDidLoad
{
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
[self updateLabel];
[super viewDidLoad];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end

Answer 1

Fixed it:
I wasn't implementing any delegate methods, and I was not implementing [locationManager startUpdatingLocation]. Now I know better.
.h File:
#interface MapViewController : UIViewController <CLLocationManagerDelegate>
#property (nonatomic, retain) IBOutlet CLLocationManager *locationManager;
#property (strong, nonatomic) IBOutlet UILabel *location;
#end
.m File:
- (void) updateCurrentLabel
{
NSObject *latitude = [NSString stringWithFormat:#"%f", locationManager.location.coordinate.latitude];
NSObject *longitude = [NSString stringWithFormat:#"%f", locationManager.location.coordinate.longitude];
self.location.text = [NSString stringWithFormat: #"Current Location: %#,%#", latitude, longitude];
}
- (void)viewDidLoad
{
[self getCurrentLocation];
[super viewDidLoad];
}
-(void) locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
[self updateCurrentLabel];
}
-(void) getCurrentLocation
{
self.locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];
}
Thanks for pointing out how nooby I was. Figured it out. Thanks guys!

Answer 2

once try like this,in ViewDidLoad:
locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = (id)self;
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
[locationManager startUpdatingLocation];
[self updateLabel];
Use this Delegate Method otherwise you will get 0 values:
- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation
{
//No need to do any code...
// NSLog(#"Got location %f,%f", newLocation.coordinate.latitude, newLocation.coordinate.longitude);
}
In Updating Label Method :
- (void) updateLabel
{
//Getting Current Latitude and longitude..
CLLocation *location = [locationManager location];
float longitude=location.coordinate.longitude;
float latitude=location.coordinate.latitude;
NSLog(#"latitude,longitudes are >> %f,%f",latitude,longitude);
locationlabel.text = [NSString stringWithFormat:#"%f,%f",longitude,latitude];
}

Answer 3

Instead of using locationManager.location.coordinate.latitude, keep an instance variable of type CLLocationCoordinate2D. You can call it something like currentLocation. Then when you get a value in the delegate method locationManager:didUpdateLocations:, set the value of currentLocation.
You'll have to call [locationManager startUpdatingLocation] and set its delegate too (as well as implementing that delegate method).
The way you're using the location manager at the moment is wrong and I think you'd be better off following a tutorial to get the basics down.

Answer 4

I find this is fascinating to use location as singleton, and save the values into default user . I am young programmer and am trying to code all in oop. I use this as follow ( this code still need to be refactored and alertUserWithTitle: is a class method of NYMessageToUser to alert user):
//##Header file:
#interface NYLocationManager : NSObject<CLLocationManagerDelegate>
{
CLLocationManager *locationManager;
float lonngitude;
float latitude;
float altitude;
}
#property(nonatomic,retain)CLLocationManager *locationManager;
#property(nonatomic,readwrite)float longitude;
#property(nonatomic,readwrite)float latitude;
#property(nonatomic,readwrite)float altitude;
+(NYLocationManager *) getInstance;
-(void)startUpdatingLocation;
-(void)stopUpdatingLocation;
-(double)getDistanceFromUserLocationToCordinatesLatitude:(float)lat Longitude:(float)lon;
#end
//### implementation file:
#implementation NYLocationManager
#synthesize locationManager;
#synthesize latitude;
#synthesize longitude;
#synthesize altitude;
+ (id)getInstance
{
static NYLocationManager *Instance = nil;
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
Instance = [[self alloc] init];
});
[Instance startUpdatingLocation];
return Instance;
}
- (id)init
{
if (self = [super init])
{
latitude =0.0;
longitude =0.0;
altitude =0.0;
if([[NSUserDefaults standardUserDefaults] objectForKey:#"locationLongitude"] != nil)
{
NSUserDefaults *savedLocation=[NSUserDefaults standardUserDefaults];
latitude =[[savedLocation objectForKey:#"locationLatitude"] floatValue];
longitude =[[savedLocation objectForKey:#"locationLongitude"] floatValue];
altitude =[[savedLocation objectForKey:#"locationAltitude"] floatValue];
}
locationManager = [[CLLocationManager alloc] init];
locationManager.distanceFilter = kCLDistanceFilterNone;
locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters;
locationManager.delegate = self;
if ([CLLocationManager locationServicesEnabled])
{
[locationManager startUpdatingLocation];
} else
{
[NYMessageToUser alertUserWithTitle:#"Location Services is Disabled!!!" withMessage:#"This app is designed to share images with location, Please enable location for this app and relucnh the app"];
}
}
return self;
}
- (void)dealloc
{
// Should never be called, but just here for clarity really.
}
- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
CLLocation *loc =[locations lastObject];
self.longitude =loc.coordinate.longitude;
self.latitude =loc.coordinate.latitude;
self.altitude =loc.altitude;
NSUserDefaults *savedLocation=[NSUserDefaults standardUserDefaults];
[savedLocation setObject: [NSString stringWithFormat:#"%f", self.longitude] forKey:#"locationLongitude"];
[savedLocation setObject: [NSString stringWithFormat:#"%f", self.latitude] forKey:#"locationLatitude"];
[savedLocation setObject: [NSString stringWithFormat:#"%f", self.altitude ] forKey:#"locationAltitude"];
[savedLocation synchronize];
[locationManager stopUpdatingLocation];
}
- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
[locationManager stopUpdatingLocation];
[NYMessageToUser alertUserWithTitle:#"Location Error!!!" withMessage:#"This app is designed to use with valid location, Please enable location for this app and relucnh the app"];
}
-(void)startUpdatingLocation
{
if ([CLLocationManager locationServicesEnabled])
{
[locationManager startUpdatingLocation];
} else
{
[NYMessageToUser alertUserWithTitle:#"Location Services is Disabled!!!" withMessage:#"This app is designed to share images with location, Please enable location for this app and relucnh the app"];
}
}
-(void)stopUpdatingLocation
{
[locationManager stopUpdatingLocation];
}
-(double)getDistanceFromUserLocationToCordinatesLatitude:(float)lat Longitude:(float)lon
{
CLLocation *locA = [[CLLocation alloc] initWithLatitude:self.latitude longitude:self.longitude];
CLLocation *locB = [[CLLocation alloc] initWithLatitude:lat longitude:lon];
CLLocationDistance distance = [locA distanceFromLocation:locB];
return distance;
}
#end
//### How to use
NYLocationManager *loc =[NYLocationManager getInstance];
NSLog(#"longitude: %f, latitude: %f, altitude: %f",loc.longitude,loc.latitude,loc.altitude);