NSLocationWhenInUseUsageDescription

requestAlwaysAuthorization

/*
So the first thing you need to do is to add one or both of the following keys to your Info.plist file:

    NSLocationWhenInUseUsageDescription
    NSLocationAlwaysUsageDescription

Both of these keys take a string which is a description of why you need location services. You can enter a string like “Location is required to find out where you are” which, as in iOS 7,
can be localized in the InfoPlist.strings file.
*/


- (void)requestAlwaysAuthorization
{
    CLAuthorizationStatus status = [CLLocationManager authorizationStatus];

    // If the status is denied or only granted for when in use, display an alert
    if (status == kCLAuthorizationStatusAuthorizedWhenInUse || status == kCLAuthorizationStatusDenied) {
        NSString *title;
        title = (status == kCLAuthorizationStatusDenied) ? @"Location services are off" : @"Background location is not enabled";
        NSString *message = @"To use background location you must turn on 'Always' in the Location Services Settings";

        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:title
                                                            message:message
                                                           delegate:self
                                                  cancelButtonTitle:@"Cancel"
                                                  otherButtonTitles:@"Settings", nil];
        [alertView show];
    }
    // The user has not enabled any location services. Request background authorization.
    else if (status == kCLAuthorizationStatusNotDetermined) {
        [self.locationManager requestAlwaysAuthorization];
    }
}

- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{
    if (buttonIndex == 1) {
        // Send the user to the Settings for this app
        NSURL *settingsURL = [NSURL URLWithString:UIApplicationOpenSettingsURLString];
        [[UIApplication sharedApplication] openURL:settingsURL];
    }
}