iOS SDK Mapview Annotation callout redraw error - ios

Question

I'm trying to add the distance from the user's position to a selected annotation's subtitle in a mapview. The mechanics of it are working, but the actual callout gets messed up the first time it's displayed. There appears to be a redraw problem.
Subsequent taps on the pin show the correct layout.
Here's the relevant code:
// called when selecting annotations
- (void)mapView:(MKMapView *)mapView didSelectAnnotationView:(MKAnnotationView *)view{
MKPointAnnotation *selectedAnnotation = view.annotation;
//attempt to add distance on annotation
CLLocation *pointALocation = [[CLLocation alloc]
initWithLatitude:selectedAnnotation.coordinate.latitude
longitude:selectedAnnotation.coordinate.longitude];
float distanceMeters = [pointALocation distanceFromLocation:locationManager.location];
//for sending info to detail
myPinTitle = selectedAnnotation.title;
[selectedAnnotation setSubtitle:[NSString stringWithFormat:#"%.2f miles away", (distanceMeters / 1609.344)]];
}
I've tried calling [view setNeedsDisplay], but to no avail.
Thanks in advance for your help.
The Solution that Worked
Here's the solution I finally came up with. It seems to work.
I edited out the duplicate code from the didSelectAnnotationView method, above, and came up with:
//called when user location changes
- (void)updatePinsDistance
{
for (int x=0; x< [[mapView annotations]count]; x++) {
MKPointAnnotation *thisPin =[[mapView annotations] objectAtIndex:x];
//attempt to add distance on annotation
CLLocation *pointALocation = [[CLLocation alloc]
initWithLatitude:thisPin.coordinate.latitude
longitude:thisPin.coordinate.longitude];
float distanceMeters = [pointALocation distanceFromLocation:locationManager.location];
NSString *distanceMiles = [NSString stringWithFormat:#"%.2f miles from you",
(distanceMeters / 1609.344)];
[thisPin setSubtitle:distanceMiles];
}
}

Answer 1

You should set your subtitle in another place than didSelectAnnotationView. Actually all annotationViews should have their title and subtitle set before they are returned by the mapView:viewForAnnotation: method.
The fact that you set a long subtitle certainly explains that the callout is not the right size. The size must be calculated before the didSelectAnnotationView is called.