title: iOS refresh annotations on mapview
body: <p>I have a mapview where the annotation's coordinates are constantly being updated but when I use setCoordinate, the annotation does not move. How do I refresh the annotations to reflect their coordinates?</p>
  
  <pre><code>- (void)updateUnits {
  
      PFQuery *query = [PFQuery queryWithClassName:@"devices"];
      [query whereKeyExists:@"location"];
      [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
  
          if (!error) {
  
              for (PFObject *row in objects) {
  
                  PFGeoPoint *geoPoint = [row objectForKey:@"location"];
                  CLLocationCoordinate2D coord = { geoPoint.latitude, geoPoint.longitude };
  
                  for (id&lt;MKAnnotation&gt; ann in mapView.annotations) {
  
                      if ([ann.title isEqualToString:[row objectForKey:@"deviceid"]]) {
  
                          [ann setCoordinate:coord];
  
                          NSLog(@"latitude is: %f" , coord.latitude);
                          NSLog(@"Is called");
                          break;
                      }
                      else {
  
                          //[self.mapView removeAnnotation:ann];
                      }
                  }
              }
          }
          else {
  
          }
      }];
  }
  </code></pre>