Question

Would really love an answer to this question https://devforums.apple.com/message/723468. I can’t post the details because its about iOS 6 and is Confidential per Apple.

Please post the answers/comments to the Apple Dev forums post and let me know about it here.

EDIT: Since iOS6 is officially released:

In my pre-ios6 code I’m doing this to rotate the map when the user location moves:

//this is in my MKMapViewDelegate
-(void) rotateMap:(MKMapView *)mapViewTmp forLocation:(MKUserLocation *) userLocation {
     ...
     //calculate needed rotation
     ...
     [mapViewTmp setTransform:CGAffineTransformMakeRotation(lastRotation)]; //rotate the MKMapView

     for (id<MKAnnotation> annotation in mapViewTmp.annotations) {
           MKAnnotationView* annotationView =[mapViewTmp viewForAnnotation:annotation];

                    [annotationView setTransform:CGAffineTransformMakeRotation(-lastRotation)];      //counter rotate the Annotation Views

                    [annotationView setNeedsDisplay];  //ios6
     }

}

And this worked fine (1000s of users).

In ios6 however (I updated Xcode/sdk on 9/4/2012), the annotation views do not maintain this rotation (for example if map is panned). They flip back to their non rotated state (which, since my map is rotated means they show text at an angle instead of horizontal).

The code does temporarily rotate the annotations so their text appears horizontal, but if map is panned (and their seem to be other causes as well) then the annotations flip to their non-rotated state and my annotation text appears at an angle relative to the rotated map.

What is the correct way to rotate an MKAnnotationView so that it stays rotated in IOS6? What has changed in MKMapView that caused the change?

Answer 1

The fix for this is to do the following in the viewForAnnotation method:

// iOS6 BUG WORKAROUND !!!!!!!
if (is6orMore) {
     [annotationView setTransform:CGAffineTransformMakeRotation(.001)]; //any small positive rotation
}

This was posted as a comment by me in the original question and then posted by cristis as an answer (referencing my comment), but I’m posting and accepting my own answer since it was me that came up with it. Did that make sense?