title: MKMapView not updating with calls to setRegion:animated
body: <p>I'm trying to learn how to use MKMapView and have created a sample application to do so; however, in my code I'm making a call to <code>setRegion:animated</code> to change the center point and the span, but the map never updates.  I've run through a few threads on StackOverflow (SO) where others have mentioned similar problems and tried implementing their solutions to no avail.</p>
  
  <p>Things I made sure to try in my code based on other's SO threads I found:</p>
  
  <ul>
  <li>Ensure I initialized the MKMapView with a frame</li>
  <li>Tried running the <code>setRegion:animated</code> method call on the main thread</li>
  </ul>
  
  <p>My included my code below, can anyone shed some light on why my MKMapView instance will not update it's view?</p>
  
  <p>EDIT: Correct code shown below:
  <strong>MK_ViewController.h</strong>:</p>
  
  <pre><code>#import &lt;UIKit/UIKit.h&gt;
  #import &lt;MapKit/MapKit.h&gt;
  
  @interface MV_ViewController : UIViewController {
      IBOutlet MKMapView *myMapView;
      MKCoordinateRegion defaultRegion;
      CLLocationCoordinate2D defaultCenter;
      MKCoordinateSpan defaultSpan;
  }
  
  @end
  </code></pre>
  
  <p><strong>MK_ViewController.m</strong>:</p>
  
  <pre><code>#import "MV_ViewController.h"
  
  @interface MV_ViewController ()
  
  @end
  
  @implementation MV_ViewController
  
  - (void)viewDidLoad {
  
      [super viewDidLoad];
  
      // initialize default map view properties
      defaultCenter = CLLocationCoordinate2DMake(33.732894,-118.091718);
      defaultSpan = MKCoordinateSpanMake(0.028270, 0.0465364);
  
      // Setup MapView's inital region
      defaultRegion = MKCoordinateRegionMake(defaultCenter, defaultSpan);
  
      // create the map view
      CGRect screenRect = [[UIScreen mainScreen] bounds];
      myMapView = [[MKMapView alloc] initWithFrame:screenRect];
  
  }
  
  - (void)viewWillAppear:(BOOL)animated {
  
      [super viewWillAppear:animated];
  
      // update map's initial view
      [myMapView setRegion:defaultRegion animated:YES];
  
  }
  
  - (void)didReceiveMemoryWarning
  {
      [super didReceiveMemoryWarning];
      // Dispose of any resources that can be recreated.
  }
  
  @end
  </code></pre>
  
  <p><strong>MK_ViewController+MKMapViewDelegate.m</strong>:</p>
  
  <pre><code>#import "MV_ViewController.h"
  
  @implementation MV_ViewController (MKMapViewDelegate)
  
  - (void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated {
      MKCoordinateRegion region = mapView.region;
      CLLocationCoordinate2D center = region.center;
      MKCoordinateSpan span = region.span;
  
      NSLog(@"Center (lat,lon): (%f,%f)",center.latitude,center.longitude);
      NSLog(@"Span (lat,lon): (%f,%f)",span.latitudeDelta,span.longitudeDelta);
  }
  
  @end
  </code></pre>