MKAnnotationView is losing reference to MKAnnotation - ios

Question

In an app I'm working on, users are directed to push a button to drop MKAnnotations onto the map. They will drop 2 or 3 pins, each of which is saved to an #property when the pin is added in didAddAnnotationViews because I need a reference to it later, and I need to know which pin it is - pin 1, 2, or 3 (the order in which they are dropped).
I'm using a custom MKAnnotation and MKAnnotationView class to add a few NSStrings to each annotation, I'm not sure if that's important or not.
I'm creating 3 properties like this:
#property (nonatomic, strong) CustomAnnotationView *ann1;
#property (nonatomic, strong) CustomAnnotationView *ann2;
#property (nonatomic, strong) CustomAnnotationView *ann3;
Here is my didAddAnnotationViews:
- (void)mapView:(MKMapView *)aMapView didAddAnnotationViews:(NSArray *)views
{
for(MKAnnotationView *view in views)
{
if(![view.annotation isKindOfClass:[MKUserLocation class]])
{
CustomAnnotationView *newAnnView = (CustomAnnotationView*)view;
if(newAnnView.type == CustomType1)
{
ann1 = newAnnView;
}
else if(newAnnView.type == CustomType2)
{
ann2 = newAnnView;
}
else if(newAnnView.type == CustomType3)
{
ann3 = newAnnView;
}
}
}
}
Also, here's my viewForAnnotation method:
- (MKAnnotationView *)mapView:(MKMapView *)pMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
if([annotation class] == MKUserLocation.class)
{
return nil;
}
CustomAnnotationView *annotationView = [[CustomAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:#"WayPoint"];
annotationView.canShowCallout = YES;
annotationView.draggable = YES;
[annotationView setSelected:YES animated:YES];
[annotationView setRightCalloutAccessoryView:customCalloutButton];
return annotationView;
}
Now, eventually, I need to save the coordinates of these annotations, and here's where things go wrong. Sometimes, but only once in a while, ann1.annotation.coordinate.latitude and ann1.annotation.coordinate.longitude are both 0.0 (this happens with ann1, ann2, or ann3, just using ann1 for example purposes)! Why is this happening? I have a feeling it has something to do with an object reference issue since the MKAnnotationView is still intact, but the annotation is cleared out. Maybe it's bad that I'm assigning the reference with ann1 = newAnnView? Am I supposed to use viewForAnnotation?
Does anyone see something I'm doing wrong?
UPDATE
I looked over my MKAnnotation subclass and I noticed that while I am defining a coordinate property according to the docs, I was not #synthesizing it in my implementation file. I have now added that and I haven't been able to replicate the issue yet...if this ends up being the "fix", I'm still very confused why my code would have worked most of the time without the #synthesize. Maybe I didn't actually fix it, and I'm setting myself up for disappointment later.

Answer 1

I don't think you;re supposed to use didAddAnnotationViews like that. Usually the flow is as follows:
Create an MKAnnotation, or an instance of your subclass of it
Assign the strings you mentioned
Call [mapView addAnnotation:myAnnotation]
In viewForAnnotation create an MKAnnotationView (or CustomAnnotationView( based on the annotation provided as a parameter
When you need to save the coordinates you can either loop through the mapView.annotations array, or if you have kept thre3 variables called ann1, ann2, ann3 could save them one by one.
Of course if you've found a better way or this doesn't fit something else in your app you don't need to use it, but this is the only flow I have seen thus far.