There is an even easier solution.
Create a custom UIView
(for your callout).
Then create a subclass of MKAnnotationView
and override setSelected
as follows:
- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
[super setSelected:selected animated:animated];
if(selected)
{
//Add your custom view to self...
}
else
{
//Remove your custom view...
}
}
Boom, job done.