带光环的iPhone MKMapView针

Question

On an MKMapView, you can show the user location. Around the blue user location dot is a sort of 'blue halo' to represent the accuracy. How would one go about adding this into my own app, but around a pin? The location of the pin comes from a Mac that used CoreLocation there, and I already know the accuracy. Thanks!

Answer 1

You could simply draw an MKCircle around that pin. Assuming you have the center coordinate and the accuracy (the radius of the circle), you could just add an overlay to the map with a call [map addOverlay: [MKCircle circleWithCenterCoordinate: coordinate radius: accuracy]]

You can then customize the appearance of the circle in MKMapViewDelegate method mapView:viewForOverlay: , where you can create a MKCircleView and return that.

This wouldn't allow animating, but it would be quite similar to the circle used around the user location.

Answer 2

You would need to either implement a custom MKAnnotationView subclass, or assign appropriate images to the image property of an existing MKAnnotationView object. The fancy animated indicator used for the user location is a private class, so you cannot access it directly as a base for your custom behavior.