Ios5 用户位置未显示在地图中

我需要在地图上用蓝色圆点显示用户当前位置。我用了CLLocationManager。但仅显示mapview。我寄了定制的lat，long。但这个lat，long不能显示在地图上

代码：

---

使用InterfaceBuilder，将地图视图放到屏幕上，勾选“显示用户位置”旁边的框

此外，您不需要locationmanager来显示用户位置，mapview将负责这一点

- (void)viewDidLoad
{
    UIView *vc=[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)];

    [self.view addSubview:vc];
    MKMapView *map = [[MKMapView alloc] init]; 
    map.frame = CGRectMake(0, 0, 320, 480);

    map.showsUserLocation=YES;
  [self.view addSubview:map];
locationManager = [[CLLocationManager alloc] init];
    locationManager.delegate = self;
    locationManager.distanceFilter = kCLDistanceFilterNone;
    locationManager.desiredAccuracy = kCLLocationAccuracyBest;

    [locationManager startUpdatingLocation];



    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
   // NSLog(@"OldLocation %f %f", oldLocation.coordinate.latitude, oldLocation.coordinate.longitude);
   // NSLog(@"NewLocation %f %f", newLocation.coordinate.latitude, newLocation.coordinate.longitude);

    CLLocationCoordinate2D loc = [newLocation coordinate];

    NSLog(@"current longitude = %f  ,   current latitude = %f",loc.longitude,loc.latitude);
}