Get Drawables out of RelativeLayout or Group Drawables

what I want to do is as following: I have a set of Drawables (eg. 16) that I have to combine in different ways (Icon with 1, 2, 3 or 4 Drawables), depending on buisness logic. My idea was to define RelativeLayouts with ImageViews inside. Unfortunately I planned to take these Layouts as an OverlayItem (needs a Drawable) to show them on a MapView. I thought that any Layout is Drawable, but it isn't. I don't find a way to convert this RelativeLayout to a drawable. I really don't get the main difference. Isn't it right that any VIEW can be DRAWN? Can I group multiple Drawables into one? I'm really a beginner on 2D Graphics and got no clue how to solve this. Any idea appreciated

ADD: Code Sample based on the first answer:

public class MapViewActivity extends MapActivity {

MapView mMapView;

@Override
public void onCreate(Bundle savedInstanceState){
    super.onCrea开发者_StackOverflow社区te(savedInstanceState);
    setContentView(R.layout.map_view);

    mMapView = (MapView)findViewById(R.id.mapview);
    mMapView.setBuiltInZoomControls(true);

    List<Overlay> mapOverlays = mMapView.getOverlays();
    Drawable drawable = this.getResources().getDrawable(R.drawable.one_drawable);
    //this is where exception is thrown
    }
}

and the file one_drawable.xml looks like this:

<?xml version="1.0" encoding="utf-8"?>
<layer-list
  xmlns:android="http://schemas.android.com/apk/res/android">
  <item 
      android:id="@+id/item_one"
      android:top="0dip"
      android:right="0dip"
      android:bottom="0dip"
      android:left="0dip"/>
</layer-list>

So I cannot see any mistake (I set the drawables programatically in my Program)

EDIT 2: OK I'm not allowed to do that. I have to set up a drawable, which can be exchanged later

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in spite of any View could be drawn, it is not a drawable. You should use Layer List to operate several pictures as one drawable.