Having trouble running the app.
As soon as I typed the following code:
- (void)mapView:(MKMapView *)mapView didAddAnnotationViews:(NSArray *)views
MKAnnotationView *annotationView = [views objectAtIndex:0];
id <MKAnnotation> mp = [annotationView annotation];
MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance([mp coordinate], 250, 250);
[mv setRegion: region animated:YES];
Got the “Use of undeclared identifier 'mv” What is the “mv”, and how can I fix this error?