code: public void setPromptView(View prompt) {
          boolean showing = isShowing();
          if (showing) {
              removePromptView();
          }
          mPromptView = prompt;
          if (showing) {
              show();
          }
      }
docs: Set a view to act as a user prompt for this popup window. Where the prompt view will appear
  is controlled by {@link #setPromptPosition(int)}.
  
  @param prompt View to use as an informational prompt.