Android - Expand And Shrink Circle On Google Map

I'm trying to draw a resizable circle on google map, which the user will be able to expand or shrink using touch gestures and also want it to work like zooming in/out option in the

Solution 1:

draw a circle with a radius or diameter of some size. Then allow the user to zoom in and out on the map. Once the user has finished zooming in or out to include areas in the circle, you can get the distance between the points on the circle.

You can either control the circle with pinch or control the map with pinch. It is much easier to draw a static circle and get the area than try to control both the map and the circle with gestures. There are only certain actions that are exposed by the map:

https://developers.google.com/android/reference/com/google/android/gms/maps/GoogleMap