ALV grid control, Adding the push Button in the Toolbar

Question

Hello All,
I am facing a problem when trying to do calculation based on the button added at the toolbar of interactive ALV list.
When I click on the toolbar button Compute, the ALV should calculate the
multiplication of the Qty (manually entered by a user) & price per unit already available in the ALV & show it the Column Total value.
Presently when I try to do this using
  Method handle_user_command.
   modifying the inetrnal table GT_FINAL_OUTPUT
   with the Total price value .
   & updating the column Total price (Qty * price) in the Internal table
After doing this  I am agin calling the below function
    CALL METHOD g_grid->set_table_for_first_display
    EXPORTING
    i_structure_name = 'GT_FINAL_OUTPUT'
    is_layout = gs_layout
    CHANGING
    it_fieldcatalog = gt_fieldcat
     it_outtab = GT_FINAL_OUTPUT[].
At above function it gives  short dump or sometimes it does not update the  ALV screen with the new updated value of Total price .
The short dump comes states  the error of unassigned field symbol.
Kindly suggest a program where we can do manipulation at the editable ALV.
Or solution to above issue .
Regards,
Anurag

Answer 1

You should only be calling the SET_TABLE_FOR_FIRST_DISPLAY one time in the PBO of your screen,  otherwise you should be using the REFRESH_TABLE_DISPLAY method.  IN your PBO, check that the instance of the alv_container is alive, if so, do not call the SET method, rather call the REFRESH method.
if alv_container is initial.
    create object......
    create object g_grid.....
    call method g_grid->set_table_for_first_display......
else.
call method   g_grid->refresh_table_display( ).
endif.
Regards,
Rich HEilman