Removing selection image on user location annotation

Question

I have the following code:

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)annotation{
    annotation.image = [UIImage imageNamed:@"pinIconOn.png"];
}

- (void)mapView:(MKMapView *)mapView didDeselectAnnotationView:(MKAnnotationView *)annotation{
    annotation.image = [UIImage imageNamed:@"pinIconOff.png"];
}

However, when I select the user location, the pin icon appears. How can I set the select annotation as void for the user location, but enabled for all the other annotations?

Answer 1

In the delegate methods, you can check if the selected annotation is of type MKUserLocation and, if it is, do not change the image.

MKUserLocation is the documented class of the user location annotation.

In these delegate methods, the second parameter is the MKAnnotationView.
That class has the property annotation which points to the underlying annotation model object that the view is for. Check the type of the annotation property.

For example:

- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)annotation{
    
    if ([annotation.annotation isKindOfClass:[MKUserLocation class]])
    {
        //it's the user location, do nothing
        return;
    }
    
    annotation.image = [UIImage imageNamed:@"pinIconOn.png"];
}

- (void)mapView:(MKMapView *)mapView didDeselectAnnotationView:(MKAnnotationView *)annotation{

    if ([annotation.annotation isKindOfClass:[MKUserLocation class]])
    {
        //it's the user location, do nothing
        return;
    }
    
    annotation.image = [UIImage imageNamed:@"pinIconOff.png"];
}

Two additional suggestions:

1. Don't name the parameter annotation in these delegate methods. Use the same name as suggested in the documentation which is view because that is what the parameter really is. It is the view object for the annotation -- not the annotation model object itself. This will make the code in the delegate method less confusing.

   So change (MKAnnotationView *)annotation to (MKAnnotationView *)view and the check becomes if ([view.annotation isKindOfClass:[MKUserLocation class]]).

2. Ideally, you should be storing the "selected" state in the annotation model object when these delegate methods are called as well as changing the image on the view. Then, in viewForAnnotation, the code should check the annotation's state and set the image there using the same logic as the delegate methods (different image based on whether it's "selected" or not) Otherwise, what may happen is that after selecting an annotation, if the user zooms/pans the map, the image may revert back to the value specified in viewForAnnotation.

Answer 2

If I understand correctly your question, you need to use an annotationArray of type (NSMutableArray) that will hold all your pins every time you drop a pin. Ex: something like this :

MKPointAnnotation *annotationPoint = [[MKPointAnnotation alloc]init];
annotationPoint.coordinate = annotationCoord;
annotationPoint.title = yourPinName;//add more things...

[annotationArray addObject:annotationPoint];
[self addAnnotation:annotationPoint];//self is your mapView

is this helping at all?