code: private void drawThumb(float screenCoord, boolean pressed, Canvas canvas, boolean areSelectedValuesDefault) {
          Bitmap buttonToDraw;
          if (!activateOnDefaultValues && areSelectedValuesDefault) {
              buttonToDraw = thumbDisabledImage;
          } else {
              buttonToDraw = pressed ? thumbPressedImage : thumbImage;
          }
  
          canvas.drawBitmap(buttonToDraw, screenCoord - thumbHalfWidth,
                  textOffset,
                  paint);
      }
docs: Draws the "normal" resp. "pressed" thumb image on specified x-coordinate.
  
  @param screenCoord The x-coordinate in screen space where to draw the image.
  @param pressed     Is the thumb currently in "pressed" state?
  @param canvas      The canvas to draw upon.