how to add delay to mkannotation pin drop - ios6

Question

In my map view I set the map to open, then with a delay of 2 seconds the map zooms in to show my mkannotation, what I have been trying to do is to animate the pin dropping once the view is fully zoomed in, but haven't been able to achieve this.
So basically I want to add a delay to the annotation+pin being dropped at my location.
How do I do this?
Code what I have in place currently in ViewDidLoad, the code for the mkannotation is in void - showDetails:
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view.
[mapView setMapType:MKMapTypeStandard];
[mapView setZoomEnabled:YES];
[mapView setScrollEnabled:YES];
MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = 54.5;
region.center.longitude = -3.5;
region.span.longitudeDelta = 10.0f;
region.span.latitudeDelta = 10.0f;
[mapView setRegion:region animated:NO];
[self performSelector:#selector(zoomInToMyLocation)
withObject:nil
afterDelay:2]; //will zoom in after 2 seconds
}
-(void)zoomInToMyLocation
{
MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = 51.502729 ;
region.center.longitude = -0.071948;
region.span.longitudeDelta = 0.19f;
region.span.latitudeDelta = 0.19f;
[mapView setRegion:region animated:YES];
[mapView setDelegate:self];
DisplayMap *ann = [[DisplayMap alloc] init];
ann.title = #"Design Museum";
ann.subtitle = #"Camberwell, London";
ann.coordinate = region.center;
[mapView addAnnotation:ann];
}

Answer 1

If you set the delegate before you set the region your delegate will receive a call to mapView:regionDidChangeAnimated. That is called many times while scrolling so what you could do is check the map's current center point and when it is close enough to your target center point you add the annotation.
- (void)viewDidLoad
{
[super viewDidLoad];
[mapView setDelegate:self];
............
haveAddedPin = false;
}
-(void)zoomInToMyLocation
{
MKCoordinateRegion region = { {0.0, 0.0 }, { 0.0, 0.0 } };
region.center.latitude = 51.502729 ;
region.center.longitude = -0.071948;
region.span.longitudeDelta = 0.19f;
region.span.latitudeDelta = 0.19f;
[mapView setRegion:region animated:YES];
}
-(void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(Boolean) animated)
{
if (haveAddedPin == false && mapView.center == the coordinates of the target you are zooming to)
{
DisplayMap *ann = [[DisplayMap alloc] init];
ann.title = #"Design Museum";
ann.subtitle = #"Camberwell, London";
ann.coordinate = region.center;
[mapView addAnnotation:ann];
haveAddedPin = true;
}
}