ios - Objective-C の CoreLocation で緯度と経度を取得できません

Question

ユーザーの座標を取得したいのですが、ユーザーがアプリを起動したら、GPS 座標を初期化する必要があります。このチュートリアルに従いました: http://www.iosdevnotes.com/2011/10/ios-corelocation-tutorial/

CurrentLocationWithGPS という名前のクラスを作成しました

これはヘッダーです：

#import <Foundation/Foundation.h>
#import <CoreLocation/CoreLocation.h>

@interface CurrentLocationWithGPS : NSObject<CLLocationManagerDelegate>

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation;

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error;

- (void) getLocations;

- (Float32) latitude;


@property (strong, nonatomic) CLLocationManager *locationManager;
@property (strong, nonatomic) CLLocation *currentLocation;

@end

これは実装です：

#import "CurrentLocationWithGPS.h"


@implementation CurrentLocationWithGPS

@synthesize locationManager, currentLocation;

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
    self.currentLocation = newLocation;

    if(newLocation.horizontalAccuracy <= 100.0f) { [locationManager stopUpdatingLocation]; }
}

- (void)locationManager:(CLLocationManager *)manager didFailWithError:(NSError *)error {
    if(error.code == kCLErrorDenied) {
        [locationManager stopUpdatingLocation];
    } else if(error.code == kCLErrorLocationUnknown) {
        // retry
    } else {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Error retrieving location"
                                                        message:[error description]
                                                       delegate:nil
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
    }
}


- (void) getLocations {
    NSLog(@"GPS Location is initialising...");

    locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    [locationManager startUpdatingLocation];
    NSLog(@"GPS Location is initialised...");

}

- (Float32) latitude {

    return currentLocation.coordinate.latitude;
}

- (Float32) longitude {

    return currentLocation.coordinate.longitude;
}

@end

別のスレッドで getLocations 関数を呼び出して、他のものをブロックしないようにします。別のクラスから呼び出す方法は次のとおりです。

- (void)viewDidLoad
{
    [super viewDidLoad];

    NSThread *myThread =[[NSThread alloc]initWithTarget:self selector:@selector(locationSet) object:nil];
    [myThread start];

}

- (void) locationSet {

    CurrentLocationWithGPS *locationFind = [[CurrentLocationWithGPS alloc] init];
    locationFind.getLocations;
    NSLog(@"latitude is %f", locationFind.latitude);
}

問題は両方latitudeであり、longitdute関数は 0.000 を返しています。ここで何が欠けていますか? iOS6.1向けに開発しています。