这是MKMapKitDelegate mapView:didUpdateUserLocation的错误吗？

Question

我创建了一个测试应用程序,只有一个包含MKMapView的视图和一个充当MapView委托的控制器.

当我进行全新构建(在重新安装之前完全从设备中删除)并记录回调时,我可以看到mapView:didUpdateUserLocation在用户指示是否希望显示其当前位置之前调用两次.

传递给回调的MKUserLocation对象无效:

2012-03-13 08:20:17.518 MapTest[3325:707] Did update user location: 0.000000,0.000000
2012-03-13 08:20:17.581 MapTest[3325:707] Did update user location: 0.000000,0.000000

这是MKMapKit或bug的预期行为吗？

更新

我在我的iPhone 4上运行它,而不是模拟器.这是控制器代码:

#import "ViewController.h"

@implementation ViewController

@synthesize mapView;

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.mapView.showsUserLocation = YES;
    self.mapView.delegate = self;
}

- (void)viewDidUnload
{
    [super viewDidUnload];
    // Release any retained subviews of the main view.
}

-(IBAction)trackButtonTapped:(id)sender
{
    self.mapView.showsUserLocation = !self.mapView.showsUserLocation;
}

#pragma mark - MKMapKitDelegate

-(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    NSLog(@"Did update user location: %f,%f", userLocation.coordinate.latitude, userLocation.coordinate.longitude);
}

-(void)mapViewWillStartLoadingMap:(MKMapView *)mapView
{
    NSLog(@"Will start loading map");
}

-(void)mapViewDidFinishLoadingMap:(MKMapView *)mapView
{
    NSLog(@"Did finish loading map");    
}

-(void)mapViewWillStartLocatingUser:(MKMapView *)mapView
{
    NSLog(@"Will start locating user");
}

-(void)mapViewDidStopLocatingUser:(MKMapView *)mapView
{
    NSLog(@"Did stop locating user");
}

-(void)mapViewDidFailLoadingMap:(MKMapView *)mapView withError:(NSError *)error
{
    NSLog(@"Did fail loading map");
}

-(void)mapView:(MKMapView *)mapView didFailToLocateUserWithError:(NSError *)error
{
    if (error.code == kCLErrorDenied){
        NSLog(@"User refused location services");
    } else {
        NSLog(@"Did fail to locate user with error: %@", error.description);    
    }    
}

@end

Answer 1

我的观点是,这是一个错误.

当用户甚至没有授予权限时,地图视图如何说用户位置已更新？

我使用的解决方法是检查是否userLocation.location是nil:

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
    if (userLocation.location == nil)
        return;

    //do something with userLocation...
}

Answer 2

而是检查nil userlocation(其中0,0坐标实际上可以有效),你应该使用:

if([CLLocationManager authorizationStatus] == kCLAuthorizationStatusAuthorized) {
  // do something with the coords
} else {
  // the coords are invalid
}