code: public void setMenuButtonText(MenuButton button, String text) {
          switch (button) {
              case MID:
                  mMidText.setText(text);
                  break;
              case LEFT:
                  mLeftText.setText(text);
                  break;
              case RIGHT:
                  mRightText.setText(text);
                  break;
          }
      }
docs: Set text displayed under a menu button
  
  @param button
  @param text