Help needed regarding ALV

Question

hi All,
I am very new to ABAP.
I got a requirement to modify already existing program like , I need to display 5 columns in the ALV Grid basing on a condition i.e., there will be a checkbox on the selection screen. When the cehckbox is checked, hten i should display the 5 columns o n the ALV Grid.
The existing program has a code which is calling the ALV_GRID_DISPLAY function module and  the parameters passed are the program and then the structure in se11. The structure contains 30 fields and in the  ALV grid , all the 30 fields are displayed.
Now, I need to write the code to add my 5  fields to the already existing ALV Grid display.
when i asked my frnds, they told me to add the 5 fields in the structure taht the program is already using. But , there is a problem. Even though the checkbox is not checked, the empty 5 columns are displayed on the grid as they are already added in the structure. But, we want the 5 columns only when the checkbox on the selction screen is checked.
Please help me out in provding me the code. The program is not using any fieldcatalog. Do i need to addit?
How can i proceedfurther? I am already stuck with it. Please help me out as it  is a v urgent requirement.
Regards,
Mohan.
Edited by: Julius Bussche on Jul 19, 2008 8:43 PM

Answer 1

Hi,
Follow these steps:
1. Add ur 5 fields in the structure (in DDIC level)
2. Instead of passing the structure name directly to the FM REUSE_ALV_GRID_DISPLAY pass it to FM REUSE_ALV_FIELDCATALOG_MERGE
  CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
       EXPORTING
            I_STRUCTURE_NAME     = < ur structure name>
       CHANGING
            ct_fieldcat        = fieldcat[].
3. As in ur case if the check box is checked only then u need to display ur 5 fields..so to do that u need to modify the filed v=catalog table returned by the above FM like:
if check_box = 'X'.
loop at fieldcat into w_cat.
if w_cat-fieldname = 'MYFLD1' or
   w_cat-fieldname = 'MYFLD2' or
   w_cat-fieldname = 'MYFLD3' or
   w_cat-fieldname = 'MYFLD4' or
   w_cat-fieldname = 'MYFLD5'.
w_cat-no_out = 'X'.
modify fieldcat from w_cat transporting no_out index sy-tabix.
ENDIF.
endloop.
endif.
4. pass this field catalog table to Fm REUSE_ALV_GRID_DISPLAY instead of the structure name.
  CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
       EXPORTING
I_STRUCTURE_NAME     = << Comment out this parameter
         I_CALLBACK_PROGRAM                = g_REPID
         iS_LAYOUT   = is_layout
         it_SORT     = It_SORT
         it_fieldcat = fieldcat[]
         I_SAVE                            = 'A' "
         IS_VARIANT                        = VARIANT
       I_CALLBACK_TOP_OF_PAGE            = 'TOP_OF_PAGE'
       I_GRID_TITLE                      = 'Special ALV'
       TABLES
            t_outtab    = t_daten.
Hope it will solve ur problem
Regards,
JOy.