I'm looking into Android APIs in order to understand how to add an overlay widget to Andoid Auto but to no avail. I'm not willing to add the widget on the main phone's screen but on the car display/head unit: my purpose is to write a simple widget which overlays the android auto bottom bar and adds a very readable clock (since the embedded one is really small!!!). I've looked into existing tools for this to no avail and can't even find any hint if this is even possible using the APIs to target specifically the second screen used by AndroidAuto.
The reasonable starting point might be the WindowManager with appropriate LayoutParameters but this does not seem to be the right way.
Any hint?