Question

I have created a MKAnnotationView and do add a UIButton on it. Now I would like that button to remove the pin it is in.

This is how I add the button:

- (MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKPinAnnotationView *pinAnnotation = nil;
    if(annotation != myMapView.userLocation) 
    {
        NSString *defaultPinID = [[NSString alloc] initWithFormat:@"pin%d",pinCount];
        pinAnnotation = (MKPinAnnotationView *)[myMapView dequeueReusableAnnotationViewWithIdentifier:defaultPinID];
        if ( pinAnnotation == nil )
            pinAnnotation = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:defaultPinID] autorelease];
        pinAnnotation.canShowCallout = YES;

    //// ADDING MY BUTTON
        UIButton *deleteButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
        pinAnnotation.rightCalloutAccessoryView = deleteButton;
    //// ADDING IT'S ACTION
        [deleteButton addTarget:self action:@selector(deletePin) forControlEvents:UIControlEventTouchUpInside];
    }
    pinCount++;
    return pinAnnotation;
}

As you can see there, I set the action to call this method:

-(void)deletePin
{
    //What to put here...?
}

How can I make that action delete it’s button’s pin?

I figured maybe sending the id thru or something, but am not sure how.

Answer 1

With annotation callout accessory views, do not use your own target/action method.

Instead, use the map view’s calloutAccessoryControlTapped delegate method which will make this job much easier.

Remove the addTarget line and your custom method. Then implement the delegate method instead:

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view 
            calloutAccessoryControlTapped:(UIControl *)control
{
    [mapView removeAnnotation:view.annotation];
}

Also, unrelated, but the way you are setting the re-use identifier is wrong and defeats re-usability by assigning a different id to every annotation. The following is recommended:

- (MKAnnotationView *)mapView:(MKMapView *)mV viewForAnnotation:(id <MKAnnotation>)annotation
{
    MKPinAnnotationView *pinAnnotationView = nil;
    if (annotation != myMapView.userLocation) 
    {
        NSString *reuseId = @"StandardPin";
        pinAnnotationView = (MKPinAnnotationView *)[myMapView dequeueReusableAnnotationViewWithIdentifier:reuseId];
        if ( pinAnnotationView == nil )
        {
            pinAnnotationView = [[[MKPinAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:reuseId] autorelease];
            pinAnnotationView.canShowCallout = YES;

            UIButton *deleteButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            pinAnnotationView.rightCalloutAccessoryView = deleteButton;
        }
        else
            //update annotation property if view is being re-used...
            pinAnnotationView.annotation = annotation;
    }

    return pinAnnotationView;
}