使用startUpdatingLocation更新位置时显示多个注释

Question

当用户移动时，我的mapView显示用户位置更新时的使用注释数。我想知道userAnnotion如何在用户位置更改时仅显示一次。

[self.myMapview removeAnnotation：userAnnotation];不工作

    -(void) viewDidLoad
    {

        [super viewDidLoad];
     [locationManager startUpdatingLocation];

    }





    -(void) checkLongLatitudeAgain {
        [locationManager startUpdatingLocation];
    }




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

        userlat=self.lastLocation.coordinate.latitude;
        userlong=self.lastLocation.coordinate.longitude;
        CLLocationCoordinate2D userCord =
        {userlat, userlong};
        Pins *userAnnotation =
        [[Pins alloc] initWithCoordinate:userCord];
        [userAnnotation setTypeOfAnnotation:CUR_ANNOTATION];

        if (newLocation.coordinate.latitude != self.lastLocation.coordinate.latitude &&
            newLocation.coordinate.longitude != self.lastLocation.coordinate.longitude) {
            [self.myMapView removeAnnotation:userAnnotation];
            self.lastLocation = newLocation;

            userlat=self.lastLocation.coordinate.latitude;
            userlong=self.lastLocation.coordinate.longitude;
            CLLocationCoordinate2D userCord =
            {userlat, userlong};
            Pins *userAnnotation =
            [[Pins alloc] initWithCoordinate:userCord];
            [userAnnotation setTypeOfAnnotation:CUR_ANNOTATION];

            [self.myMapView addAnnotation:userAnnotation];

    }

    }        

Answer 1

将annotation设为全局变量，并在didUpdateLocation:

中更新其坐标