Issue with CHECK_CHANGED_DATA method of CL_GUI_ALV_GRID class

Question

HI,
I want to check whether my grid has any changes or not, for that i am using the CHECK_CHANGED_DATA method of CL_GUI_ALV_GRID class,
What i am doing is.... I am doing some changes in my grid data  and clicking on SAVE . This time  CHECK_CHANGED_DATA is saying the grid have changes ,and i am displaying a pop up whether to save the changes or not. And i am saving changes.
Till now Fine.
If i click on SAVE again CHECK_CHANGED_DATA is showing again the Grid has changes. 
So how can i solve this problem.
Thanks in advance.

Answer 1

Hello Narendra
If you do not need to do any validations of the changed ALV list data then you can use a very simple approach which does not even require an event handler for event DATA_CHANGED.
The crucial part of the coding is shown below, followed by the entire sample report ZUS_SDN_ALV_EDITABLE_1A. Basically, the ALV list is stored as a "PBO" image of the data (GT_OUTTAB_PBO). And only if the user changed the data (i.e. GT_OUTTAB_PBO <> GT_OUTTAB) the save option including the popup is executed.
*&      Module  USER_COMMAND_0100  INPUT
*       text
MODULE user_command_0100 INPUT.
  " NOTE: retrieve changed data from frontend (grid control) into
  "       the backend (itab in ABAP)
  go_grid->check_changed_data( ).
  CASE gd_okcode.
    WHEN 'BACK'  OR
         'EXIT'  OR
         'CANC'.
      SET SCREEN 0. LEAVE SCREEN.
    WHEN 'SAVE'.
      IF ( gt_outtab = gt_outtab_pbo ).
        MESSAGE 'No data changed' TYPE 'S'.
      ELSE.
        CLEAR: gd_answer.
        CALL FUNCTION 'POPUP_TO_CONFIRM'
          EXPORTING
*             TITLEBAR                    = ' '
*             DIAGNOSE_OBJECT             = ' '
            text_question               = 'Save data?'
          IMPORTING
            answer                      = gd_answer
*           TABLES
*             PARAMETER                   =
          EXCEPTIONS
            text_not_found              = 1
            OTHERS                      = 2.
        IF sy-subrc <> 0.
*       MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*               WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
        ENDIF.
        IF ( gd_answer = '1' ).  " yes
          MESSAGE 'Data successfully saved' TYPE 'S'.
          gt_outtab_pbo = gt_outtab.  " update PBO data !!!
        ELSE.
          MESSAGE 'Action cancelled by user'  TYPE 'S'.
        ENDIF.
      ENDIF.
    WHEN OTHERS.
  ENDCASE.
  CLEAR: gd_okcode.
ENDMODULE.                 " USER_COMMAND_0100  INPUT
*& Report  ZUS_SDN_ALV_EDITABLE
* Flow logic of screen '100' (no elements, ok-code => gd_okcode ):
**PROCESS BEFORE OUTPUT.
**  MODULE STATUS_0100.
**PROCESS AFTER INPUT.
**  MODULE USER_COMMAND_0100.
REPORT  zus_sdn_alv_editable_1a.
TYPE-POOLS: abap.
CONSTANTS:
  gc_tabname       TYPE tabname  VALUE 'KNB1'.
TYPES: BEGIN OF ty_s_outtab.
INCLUDE TYPE knb1.
TYPES: END OF ty_s_outtab.
TYPES: ty_t_outtab    TYPE STANDARD TABLE OF ty_s_outtab
                      WITH DEFAULT KEY.
DATA:
  gd_okcode        TYPE ui_func,
  gd_repid         TYPE syst-repid,
  gt_fcat          TYPE lvc_t_fcat,
  gs_layout        TYPE lvc_s_layo,
  gs_variant       TYPE disvariant,
  go_docking       TYPE REF TO cl_gui_docking_container,
  go_grid          TYPE REF TO cl_gui_alv_grid.
DATA:
  gs_outtab        TYPE ty_s_outtab,
  gt_outtab        TYPE ty_t_outtab,
  gt_outtab_pbo    TYPE ty_t_outtab.
DATA:
  gd_answer        TYPE c.
START-OF-SELECTION.
  SELECT * FROM  (gc_tabname) INTO TABLE gt_outtab UP TO 99 ROWS.
  gt_outtab_pbo = gt_outtab.  " set PBO data
  PERFORM init_controls.
* ok-code field = GD_OKCODE
  CALL SCREEN '0100'.
END-OF-SELECTION.
*&      Form  INIT_CONTROLS
*       text
*  -->  p1        text
*  <--  p2        text
FORM init_controls .
* Create docking container
  CREATE OBJECT go_docking
    EXPORTING
      parent = cl_gui_container=>screen0
      ratio  = 90
    EXCEPTIONS
      OTHERS = 6.
  IF sy-subrc <> 0.
*   MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*              WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.
* Create ALV grid
  CREATE OBJECT go_grid
    EXPORTING
      i_parent = go_docking
    EXCEPTIONS
      OTHERS   = 5.
  IF sy-subrc <> 0.
*   MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*              WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.
  " NOTE: not required
*  set handler:
*    lcl_eventhandler=>handle_data_changed for go_grid.
* Build fieldcatalog and set hotspot for field KUNNR
  PERFORM build_fieldcatalog.
  PERFORM set_layout_and_variant.
* Display data
  CALL METHOD go_grid->set_table_for_first_display
    EXPORTING
      is_layout       = gs_layout
      is_variant      = gs_variant
      i_save          = 'A'
    CHANGING
      it_outtab       = gt_outtab
      it_fieldcatalog = gt_fcat
    EXCEPTIONS
      OTHERS          = 4.
  IF sy-subrc <> 0.
*   MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*              WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.
* NOTE:
* Documenation of I_SAVE ("An Easy Reference for ALV Grid Control")
*I_SAVE
*Determines the options available to the user for saving a layout:
*? 'X': global saving only
*? 'U': user-specific saving only
*? 'A': corresponds to 'X' and 'U'
*? SPACE: no saving
* Link the docking container to the target dynpro
  gd_repid = syst-repid.
  CALL METHOD go_docking->link
    EXPORTING
      repid                       = gd_repid
      dynnr                       = '0100'
*      CONTAINER                   =
    EXCEPTIONS
      OTHERS                      = 4.
  IF sy-subrc <> 0.
*   MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*              WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.
ENDFORM.                    " INIT_CONTROLS
*&      Module  STATUS_0100  OUTPUT
*       text
MODULE status_0100 OUTPUT.
  SET PF-STATUS 'STATUS_0100'.
*  SET TITLEBAR 'xxx'.
ENDMODULE.                 " STATUS_0100  OUTPUT
*&      Module  USER_COMMAND_0100  INPUT
*       text
MODULE user_command_0100 INPUT.
  " NOTE: retrieve changed data from frontend (grid control) into
  "       the backend (itab in ABAP)
  go_grid->check_changed_data( ).
  CASE gd_okcode.
    WHEN 'BACK'  OR
         'EXIT'  OR
         'CANC'.
      SET SCREEN 0. LEAVE SCREEN.
    WHEN 'SAVE'.
      IF ( gt_outtab = gt_outtab_pbo ).
        MESSAGE 'No data changed' TYPE 'S'.
      ELSE.
        CLEAR: gd_answer.
        CALL FUNCTION 'POPUP_TO_CONFIRM'
          EXPORTING
*             TITLEBAR                    = ' '
*             DIAGNOSE_OBJECT             = ' '
            text_question               = 'Save data?'
*             TEXT_BUTTON_1               = 'Ja'(001)
*             ICON_BUTTON_1               = ' '
*             TEXT_BUTTON_2               = 'Nein'(002)
*             ICON_BUTTON_2               = ' '
*             DEFAULT_BUTTON              = '1'
*             DISPLAY_CANCEL_BUTTON       = 'X'
*             USERDEFINED_F1_HELP         = ' '
*             START_COLUMN                = 25
*             START_ROW                   = 6
*             POPUP_TYPE                  =
*             IV_QUICKINFO_BUTTON_1       = ' '
*             IV_QUICKINFO_BUTTON_2       = ' '
          IMPORTING
            answer                      = gd_answer
*           TABLES
*             PARAMETER                   =
          EXCEPTIONS
            text_not_found              = 1
            OTHERS                      = 2.
        IF sy-subrc <> 0.
*       MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*               WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
        ENDIF.
*         Triggers PAI of the dynpro with the specified ok-code
        IF ( gd_answer = '1' ).  " yes
          MESSAGE 'Data successfully saved' TYPE 'S'.
          gt_outtab_pbo = gt_outtab.  " update PBO data !!!
        ELSE.
          MESSAGE 'Action cancelled by user'  TYPE 'S'.
        ENDIF.
      ENDIF.
    WHEN OTHERS.
  ENDCASE.
  CLEAR: gd_okcode.
ENDMODULE.                 " USER_COMMAND_0100  INPUT
*&      Form  BUILD_FIELDCATALOG
*       text
*  -->  p1        text
*  <--  p2        text
FORM build_fieldcatalog .
* define local data
  DATA:
    ls_fcat        TYPE lvc_s_fcat.
  CALL FUNCTION 'LVC_FIELDCATALOG_MERGE'
    EXPORTING
*     I_BUFFER_ACTIVE              =
      i_structure_name             = gc_tabname
*     I_CLIENT_NEVER_DISPLAY       = 'X'
*     I_BYPASSING_BUFFER           =
*     I_INTERNAL_TABNAME           =
    CHANGING
      ct_fieldcat                  = gt_fcat
    EXCEPTIONS
      inconsistent_interface       = 1
      program_error                = 2
      OTHERS                       = 3.
  IF sy-subrc <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
  ENDIF.
  ls_fcat-edit = abap_true.
  MODIFY gt_fcat FROM ls_fcat
      TRANSPORTING edit
    WHERE ( key NE abap_true ).
ENDFORM.                    " BUILD_FIELDCATALOG
*&      Form  SET_LAYOUT_AND_VARIANT
*       text
*  -->  p1        text
*  <--  p2        text
FORM set_layout_and_variant .
  CLEAR: gs_layout,
         gs_variant.
  gs_layout-cwidth_opt = abap_true.
  gs_layout-zebra      = abap_true.
  gs_variant-report = syst-repid.
  gs_variant-handle = 'GRID'.
ENDFORM.                    " SET_LAYOUT_AND_VARIANT
Regards
  Uwe