如何在mapkit中显示用户位置？

Question

I'd like to display the blue pulsing dot for a user's location. I'm doing this:

- (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation    *)newLocation fromLocation:(CLLocation *)oldLocation{
//some other stuff here
[self.mapView setShowsUserLocation:YES];
}

But I eventually get

-[MKUserLocation establishment]: unrecognized selector sent to instance 0x125e90

Should I be doing this some other way?

-- EDIT --

I'm also doing this, which is where I eventually get the above exception:

- (MKAnnotationView *) mapView:(MKMapView *)_mapView viewForAnnotation:(AddressNote *) annotation{

if(annotation.establishment != nil){
//do something}

establishment is a custom class I have on AddressNote. When establishment has a value, the exception occurs. If I don't set ShowsUserLocation, everything works fine but of course, I don't see the user location.

Answer 1

When the viewForAnnotation is requested, you need to check wether or not the given annotation corresponds to the current user location. If yes, return nil, otherwise return your own normal annoationView.

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id )annotation {
    if (annotation==self.mapView.userLocation)
        return nil;
    //then the rest of your code for all your 'classic' annotations.

[EDIT] an alternative way is to check the kind of the class of the annotation :

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id )annotation {
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;
    //then the rest of your code for all your 'classic' annotations.

Answer 2

Not sure what the actual problem is, but you don't need to do this on every update. Set it once after creating the mapView , and you should be in business.

mapView.showsUserLocation = YES;

You might need to zoom the map to the region where the user actually is, for the dot to be visible.

Answer 3

You're using the wrong delegate method. For mapview, you should use this delegate method to catch the user location:

- (void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
{
}