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POTurning user location annotation with heading
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copied!<p>I'm trying to change the User Annotation in my app so that it shows the usual blue dot, but with a triangle coming off of it to show which direction the user is facing (I'd rather rotate the user annotation than the entire map, which is what MKUserTrackingModeFollowWithHeading does). I've got a rudimentary version working, but it has some weird behavior.</p> <p>First, some code:</p> <pre><code>-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation { if ([annotation isKindOfClass:[MKUserLocation class]]) { _userLocationView = [[MKAnnotationView alloc] initWithAnnotation:annotation reuseIdentifier:@"userLocationIdentifier"]; //use a custom image for the user annotation _userLocationView.image = [UIImage imageNamed:@"userLocationCompass.png"]; return _userLocationView; } else { return nil; } } -(void)locationManager:(CLLocationManager *)manager didUpdateHeading:(CLHeading *)newHeading { //rotate user location annotation based on heading from location manager. if (!_locatorButton.hidden) { CLLocationDirection direction = newHeading.magneticHeading; CGAffineTransform transform = CGAffineTransformMakeRotation(degreesToRadians(direction)); _userLocationView.transform = transform; } } -(void)GPSButtonPressed:(id)sender { if (self.GPSEnabled) { //if GPS is already on, disable it. _mapview.showsUserLocation = NO; [_mapview removeAnnotation:_mapview.userLocation]; self.GPSEnabled = NO; [_locationManager stopUpdatingHeading]; } else { //enable GPS. _mapview.showsUserLocation = YES; self.GPSEnabled = YES; if ([CLLocationManager headingAvailable]) { [_locationManager startUpdatingHeading]; } } } </code></pre> <p>The user location annotation image shows up fine, and rotates based on the heading, but here are the funny behaviors:</p> <p>1- The annotation does not follow my location-- it only stays in one place, but rotates with the correct heading. If I turn off the GPS with the "GPS Button", then turn it back on, the annotation shows up in the correct place, but still won't follow as I walk.</p> <p>2- If I scroll the map, the annotation pops back to due north, then quickly rotates to the correct heading, causing an annoying flickering effect.</p> <p>3- If I turn off the GPS and remove the user location, the annotation is removed as intended, but if I then scroll the map, the annotation pops back to the screen rather than staying hidden.</p> <p>What am I doing wrong? Thanks for any helpful hints!</p>

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