Custom MKAnnotationView intermittently recognize touch

Question

I have a custom MKAnnotationView that I am loading from an XIB. When I first load the mapview, I have several standard MKAnnotationView.

When a user selects one, the custom MKAnnotationView is presented. I would like for the user to be able to tap anywhere inside the custom annotation view to present a new view controller.

What I've tried (all of these were suggestions I found here on StackOverflow):

• Overriding hit test is the custom MKAnnotationView class. The issue here is that CGPoint would return as nil most of the time. (How do I make a MKAnnotationView touch sensitive?)
• Adding a tap gesture to a UIButton and adding that button to the custom annotation view in the viewForAnnotation delegate method. (How to get click event from a button added over MKAnnotationView). This never really worked and it didn't make much sense to me. Adding a tap gesture to a button seems redundant.
• Adding KVO to the annotation view. (http://www.jakeri.net/2009/12/custom-callout-bubble-in-mkmapview-final-solution/). This caused an issue because the annotationView that was added to the map seemed to get deallocated before sending the notification.
• Adding a clear button in the XIB that is the size of the custom view and adding a target/selector to it. I also make sure to bring it to the front of the parent view.

What is strange is that if I drag the map while the annotation is present, the button works fine. The issue only shows up when I first show the custom view.

Any ideas would be appreciated.

Answer 1

You should checkout out the MKMapKit Delegate documentation it has lots of good methods you can use to do exactly what you're trying to do. I would absolutely not try and add a UIButton to a annotation view.

Managing Annotation Views – mapView:viewForAnnotation: – mapView:didAddAnnotationViews: – mapView:annotationView:calloutAccessoryControlTapped: Dragging an Annotation View – mapView:annotationView:didChangeDragState:fromOldState: Selecting Annotation Views – mapView:didSelectAnnotationView:
– mapView:didDeselectAnnotationView:

- (MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation  {
if([annotation isKindOfClass: [MKUserLocation class]])
{
    return nil;
}
else if([annotation isKindOfClass:[MYCLASS class]])
{
    static NSString *annotationViewReuseIdentifier = @"annotationViewReuseIdentifier";
    MKAnnotationView *annotationView = (MKAnnotationView *)[self.mapView dequeueReusableAnnotationViewWithIdentifier:annotationViewReuseIdentifier];
    if (annotationView == nil)
    {
        annotationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:annotationViewReuseIdentifier];
    }

    //Add an Image!
    annotationView.image = [UIImage imageNamed:@"trashMarker.png"];

    //Move the Frame Around!
    [annotationView setFrame:CGRectMake(annotationView.frame.origin.x, annotationView.frame.origin.y - annotationView.frame.size.height, annotationView.frame.size.height, annotationView.frame.size.width)];

    //Finally Set it as the annotation!
    annotationView.annotation = annotation;

    //Return the annotationView so the MKMapKit can display it!
    return annotationView;
}}

Your subclass of the MKAnnotation (IE conforms to protocol) should contain a tag by default (I think) but if it doesn't just add one yourself with a property so you can distinguish between the different markers on the map. Your method should look something like this,

-(void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view  {
MYCLASS *selectedMapPin = view.annotation;
if(selectedMapPin.tag == MY_PIN_TAG)
{
    //SHOW VIEW CONTROLLER
}}

For more examples you can refer to our open source project for Green Up Vermont

Green Up Vermont iOS App