Android MenuItem Toggle Button

Answer 1

It's looks like this menu item is implemented as a custom view.

In the android source code you can take a look at com.android.phone.InCallMenuView.java to see how this is implemented.

It doesn't look like it is part of the public API, but it looks pretty self-contained. If your project has a compatible license, you may be able to copy it into your project and use and modify it as you see fit.

Answer 2

You could do something like the snippet below as well, originally sourced from anddev.org

public boolean onPrepareOptionsMenu(final Menu menu) {       
      if(super.mMapView.isTraffic()) 
           menu.findItem(MENU_TRAFFIC_ID).setIcon(R.drawable.traffic_off_48); 
      else 
           menu.findItem(MENU_TRAFFIC_ID).setIcon(R.drawable.traffic_on_48); 

      return super.onPrepareOptionsMenu(menu); 
 }