iOS Location Services - App is checking for location before allowed

Question

Just trying to determine a user's location. Here's the code:

self.locationManager = [[CLLocationManager alloc] init];
//self.locationManager.delegate = self;
self.locationManager.distanceFilter = 80.0;
[self.locationManager startUpdatingLocation];

self.geoCoder = [[CLGeocoder alloc] init];
[self.geoCoder reverseGeocodeLocation: self.locationManager.location completionHandler:

 ^(NSArray *placemarks, NSError *error) {

     CLPlacemark *placemark = [placemarks objectAtIndex:0];

     UIAlertView *locationAlert = [[UIAlertView alloc] initWithTitle:@"Location" message:[NSString stringWithFormat:@"The app has determined that your country is: %@ (%@)", placemark.country, placemark.ISOcountryCode] delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil];
     [alert show];


 }];

The first time I run the app, I get a double alert popup. The locationAlert pops up first, informing the user of a (null) country, then the default popup that says the app would like to use my location pops up pretty much simultaneously. If I click YES, the next time I run the app I will get the single popup of the user's correct country.

So my question is, how can I first gain permission to access the user's location, THEN run this code to find their location, without getting a null response because I've queried their location without permission?

Answer 1

The reverse geolocation code is trying to use the location property from the locationManager but it is not valid until the CLLocationManager delegate method locationManager:didUpdateToLocation:fromLocation: is called.

You should have a delegate method like this one to handle location updates.