Put a Image over an activity

How I can put an image over an activity (something like the image below) but with the buttons and other widgets under this image receiving the touch events?

image http://images.macworld.com/appguide/images/androi开发者_开发技巧d/558/2908791394402692/5582908791394402692_1.jpg

You can create a transparent Activity like this How do I create a transparent Activity on Android? and make a Layout with a fullscreen ImageView

I solve the problem override the draw function.

public class TutorialLinearLayout extends LinearLayout {

  public TutorialLinearLayout(Context context) {
    super(context);
  }

  @Override
  public void draw(Canvas canvas) {
    super.draw(canvas);
    Bitmap tutorial = BitmapFactory.decodeResource(getResources(), R.drawable.tutorial);
    canvas.drawBitmap(tutorial, 0, 0, null);
    tutorial.recycle();
  }
}