I have found this in the GOOGLE MAP website. there are other classes too Like Polygon. I didn't try this but Hope it will work.
// Instantiates a new Polyline object and adds points to define a rectangle
PolylineOptions rectOptions = new PolylineOptions()
.add(new LatLng(37.35, -122.0))
.add(new LatLng(37.45, -122.0))
// North of the previous point, but at the same
longitude.add(new LatLng(37.45, -122.2))
// Same latitude, and 30km to the west
.add(new LatLng(37.35, -122.2))
// Same longitude, and 16km to the south
.add(new LatLng(37.35, -122.0));
// Closes the polyline.
// Get back the mutable Polylineenter code here
Polyline polyline = myMap.addPolyline(rectOptions);