Google Maps itself can sort of Highlight areas, when you are searching for example for a city. 
Since i haven´t found very much via the search function and google….
Is there an intended way to highlight an area (circle or rectangle) on an android mapview Or do i have to go the long way of calculating the necessary size of an picture (for example circle) (which is depending on the zoomlevel) and place it as a mapoverlay, which has to be replaced, whenever the zoom-level changes?
Extend
Overlayand override thedrawmethod.For example:
Then add it to your mapView by calling
mapView.getOverlays().add(new HighlightedAreaOverlay());