How show circle around annotation how in google maps

Question

I use MKMapView. How to show circle around annotation how in google maps ( when show current user location). This circle moving with animation to new location and radius of circle dependent from current zoom level.

Answer 1

The annotations themselves don't have a property for showing a circle but you can use a circle overlay with the same center as the coordinate of the annotation to achieve this effect, just like the image below (from one of my projects).

Note: the property for the center of the circle is called "coordinate", just as for the annotations.

The second part is animating the movement. You achieve this by animating the coordinate property of the circle overlay at the same time as the coordinate property of the annotation. This way they will both move together to the new location.

This question can help you with how to move and animate the position of an annotation. If you need the radius of the circle to change at the same time (e.g. when animating the coordinate) you just use Core Animation to animate it together with the coordinate.

Concerning changing the size depending on the zoom level, Map Kit will always handle this for you automatically with Overlays and Annotations so that they always cover the same area of the map, even as the map resizes. (The second image is the same annotations and overlays as below, just zoomed in on the ones to the left (closer to Stockholm in the first image)).