地理位置仅显示全球地图

Question

我尝试按照本教程中所示对我的 iPhone 应用程序进行精确定位： http://www. youtube.com/watch?v=qNMNRAbIDoU 我的问题是，当我构建并运行时，我看到了地图，但地理定位服务没有跟踪我的位置，所以我只看到了全局地图:( 这是我的代码，我希望你能帮助我找出问题：

appdelegate.h

    @interface WhereAmIAppDelegate : NSObject <UIApplicationDelegate,CLLocationManagerDelegate> {
    UIWindow *window;
    WhereAmIViewController *viewController;
    CLLocationManager *locationManager;
}

@property (nonatomic, retain) IBOutlet UIWindow *window;
@property (nonatomic, retain) CLLocationManager *locationManager; 
@property (nonatomic, retain) IBOutlet WhereAmIViewController *viewController;

appdelegate.m：

@implementation WhereAmIAppDelegate

@synthesize window;
@synthesize viewController;
@synthesize locationManager;

#pragma mark -
#pragma mark Application lifecycle

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    

    // Override point for customization after application launch.



    self.locationManager=[[[CLLocationManager alloc] init] autorelease];

    if([CLLocationManager locationServicesEnabled]) {
        self.locationManager.delegate=self;
        self.locationManager.distanceFilter=100;
        [self.locationManager startUpdatingLocation];

    }



    // Add the view controller's view to the window and display.
    [window addSubview:viewController.view];
    [window makeKeyAndVisible];

    return YES;
}

- (void)dealloc {
    [viewController release];
    [window release];
    [super dealloc];
}


#pragma mark CLLocationManagerDelegate Methods


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

    MKCoordinateSpan span;
    span.latitudeDelta=0.2;
    span.longitudeDelta=0.2;


    MKCoordinateRegion region;
    region.span=span;
    region.center=newLocation.coordinate;
    [viewController.mapView setRegion:region animated:YES];

    viewController.mapView.showsUserLocation=YES;
    viewController.latitude.text=[NSString stringWithFormat:@"%f",newLocation.coordinate.latitude];

    viewController.longitude.text=[NSString stringWithFormat:@"%f",newLocation.coordinate.longitude];
}
@end

MyViewController.h

@interface WhereAmIViewController : UIViewController {

    MKMapView  *mapView;
    UILabel    *latitude;
    UILabel    *longitude;


}

@property (nonatomic,retain)IBOutlet MKMapView *mapView;
@property (nonatomic,retain)IBOutlet UILabel *latitude;
@property (nonatomic,retain)IBOutlet UILabel *longitude;

myViewController.m：

@implementation WhereAmIViewController



@synthesize mapView;
@synthesize latitude;
@synthesize longitude;

- (void)dealloc {


    [mapView release];
    [latitude release];
    [longitude release];
    [super dealloc];
}

@end

Answer 1

有两件事需要检查：
1）模拟器没有位置，它总是显示苹果加州总部的经纬度
2）确定位置需要一点时间，所以如果你立即询问位置，你不会得到。

此外，您还需要在 WhereAmI 视图控制器中添加更多代码。通常您会在 viewWillAppear 中看到一些内容。 此处是有关视图控制器和地图视图的 Big Nerd Ranch 教程的链接。也许它会对你有所帮助。

Answer 2

这里有一些事情需要注意：

1) iPhone 模拟器没有 GPS 功能，但它有一个默认位置 1 Infinite Loop, Cupertino, CA (USA)

2) 您的委托方法应该是 didUpdateFromLocation< /code>，而不是 didUpdateToLocation。