needs to calculate distance between two location [duplicate] - ios

Question

This question already has answers here:
Calculate distance between two place using latitude-longitude in gmap for iPhone [duplicate]
(2 answers)
Closed 8 years ago.
I tried to calculate the distance between two locations but something is wrong because the distance is 0 every time.
float oldLatitude = [gInfo.latitude floatValue];
float oldLongitude = [gInfo.longitude floatValue];
CLLocation *oldLocation = [[CLLocation alloc] initWithLatitude:oldLatitude longitude:oldLongitude];
CLLocation *newLocation = [[CLLocation alloc] initWithLatitude:newLatitude longitude:newLongitude];
if (newLatitude == 0 && newLongitude == 0) {
[self showAlarm2];
return;
}
float distance = [newLocation distanceFromLocation:oldLocation];
// distance 0 ????????
int result = (int)roundf(distance );
if (result < 0) {
result = -result;
}
// long result = (long)distance;
NSLog(gInfo.name );
NSLog(#"Distance i meters: %i", result);
//**************** filter group by check distance *************
if (result <= 10) {
[viewArray addObject:gInfo];
}

Answer 1

Use this
CLLocationManager *locationManager = [[CLLocationManager alloc] init];
locationManager.delegate = self;
locationManager.desiredAccuracy = kCLLocationAccuracyBest;
locationManager.distanceFilter = kCLDistanceFilterNone;
[locationManager startUpdatingLocation];
CLLocation *location = [locationManager location];
// Configure the new event with information from the location
CLLocationCoordinate2D coordinate = [location coordinate];
latitude = coordinate.latitude;
longitude = coordinate.longitude;
MKCoordinateRegion myRegion;
MKCoordinateSpan mySpan;
mySpan.latitudeDelta = 1.0f;
mySpan.longitudeDelta = 1.0f;
myRegion.center = coordinate;
myRegion.span = mySpan;
//-----------------------------------------------
NSDictionary *dict = (NSDictionary*)[arrayJsonData objectAtIndex:indexPath.row];
CLLocation *locA = [[CLLocation alloc] initWithLatitude:latitude longitude:longitude];
CLLocation *locB = [[CLLocation alloc] initWithLatitude:[[dict1 valueForKey:#"Latitude"] doubleValue] longitude:[[dict1 valueForKey:#"Longitude"] doubleValue]];
CLLocationDistance distance = [locA distanceFromLocation:locB];
double distanceInMiles = (distance/CONVERSION_TO_MILES);
// CONVERSION_TO_MILES 1609.344