MKMapView and setRegion:animated: not updating the map visuals

Question

Greetings! I'm attempting to use MKMapView without any Apple code samples, though there are a few others out there of varying clarity. (I know, "Read the friendly manual." I've done that but it's not 100% clear, so please bear with me on this one.)

Here's the situation. I have a MKMapView object, wherein I have added a set of about ten MKPinAnnotation objects. So far, so good. Everything is alloced/released sanely and there doesn't appear to be any complaints from Instruments.

Upon initial display, I set up a MKCoordinateRegion object with the centerpoint at our first pin location, and a (arbitrary) span of 0.2 x 0.2. I then call:

[mapView setRegion:region animated:YES];
[mapView regionThatFits:region];

Wow! That worked well.

Meanwhile ... I also have a segmented control to allow for movement to each pin location. So as I tap through the list, the map animates to each new pin location with a new pair of calls to setRegion:animated: and regionThatFits: ... or at least that's the idea.

While the map does "travel" to the new pin location, the map itself doesn't update underneath. Instead, I see my pin on a gray/blank-map background ... until I nudge the map in any direction, however slightly. Then the map shows through! (If I'm only moving within a short distance of the previous pin location, I'll usually see whatever part of the map was already loaded.)

I suspect I'm doing something dumb here, but I haven't been able to figure out what, at least not from the MapKit docs. Perhaps I'm using the wrong calls? (Well, I do need to set the region at least once, yes? Moving that around doesn't seem to help though.) I have also tried using setCenterCoordinate:animated: - same problem.

I'm assuming nothing at this point (no pun intended). Just trying to find my way.

Clues welcome/appreciated!

UPDATE: Calling setRegion:animated: and regionThatFits: the first time, followed by setCenterCoordinate:animated: while traversing the list, has no effect. Interesting finding though: If I change animated to NO in both cases, the map updates!!! Only when it's set to YES. (Wha happen?! Is animated: broken? That can't be ... ???)

Answer 1

It turns out that the map update doesn't work when using the SIMULATOR. When I try setCenterCoordinate:animated: on the device, I do get the map update underneath.

Bottom line: I was trusting the simulator to match the device in terms of map updating behavior. Alas, I was mistaken! Lesson learned. "Don't let this happen to you." :)