To change the GUI status while executing the program

  PERFORM show_progress_indicator USING text-i02.
  PERFORM process_report_data.

*&---------------------------------------------------------------------*
*&      Form  show_progress_indicator
*&---------------------------------------------------------------------*
*       text
*----------------------------------------------------------------------*
FORM show_progress_indicator USING prf_text. "Processing report data...
                                             "Data selection in progress...
  CALL FUNCTION 'SAPGUI_PROGRESS_INDICATOR'
    EXPORTING
      text = prf_text.

ENDFORM.