code: private int getCustomMessageId() {
          switch (progressBarPosition) {
              case LEFT:
                  return R.layout.progress_dialog_left;
              case TOP:
                  return R.layout.progress_dialog_top;
              case RIGHT:
                  return R.layout.progress_dialog_right;
              case BOTTOM:
                  return R.layout.progress_dialog_bottom;
              default:
                  return R.layout.progress_dialog_left;
          }
      }
docs: Returns the resource id of the layout, which should be used as the dialog's custom message,
  depending on the position of the dialog's progress bar.
  
  @return The resource id of the layout, which should be used as the diaog's custom message, as
  an {@link Integer} value