Handling error messages in OOPs ALV

Question

The question below is foolish.But I am a beginner so please excuse.
I have successfully displayed an OOPs ALV which displays the material, batch and plant.
A custom toolbar button(delete batches) has been appended to the standard toolbar.
Now when I do not select any rows from the ALV  and click the button(delete batches) I have ensured that an error message flahes at the bottom of the screen.
If I repeat the same procedure without coming out of the program it exits from the program itself. i want to avoid this.
I want to flash the error message continually without coming out of the program till the user commits the mistake. Please note that I have not used any leave screen commands etc.
Can someone please help me..
Thanks in advance

Answer 1

I assume you have the ON TOOLBAR event regiistered and the ENTER event for example.
method constructor .
create object grid_container1
        exporting
*           container_name = 'CCONTAINER1'.
    container_name = cfname.
    create object  grid1
       exporting
          i_parent = grid_container1.
    set handler z_object->on_user_command for grid1.
    set handler z_object->on_toolbar for grid1.
    set handler z_object->handle_data_changed for grid1.
    set handler z_object->handle_data_changed_finished for grid1.
    set handler z_object->on_dubbelklik for grid1.
    set handler z_object->on_hotspot for grid1.
    call method grid1->register_edit_event
        exporting
           i_event_id = cl_gui_alv_grid=>mc_evt_enter.
  endmethod.
So the easy way to do this is in your ON USER COMMAND routine when you can check to see if you selected any rows and the issue a popup warnimg message with the standard SAP MESSAGE statement.
For example in my TEST function here I call a method to get the selected cell.
If none are selected you can then issue your message and you will then be returned back to your GRID display after the user presses the OK button on the message popup.
the grid1 object refers to the class cl_gui_alv_grid.
in your case call a method that gets selected cells rather than selected cell. Use the standard method in cl_gui_alv_grid.
If nothing selected then issue your message.
(Note that your method ON DATA CHANGE / ON DATA CHANGED FINISHED might also be entered as well  so insure that you haven't got any coding in these methods that will interfere with processing flow).
method on_user_command .
*        FOR EVENT before_user_command OF cl_gui_alv_grid
*        IMPORTING
*          e_ucomm
*          sender
case e_ucomm.
      when 'EXIT'.
        leave program.
      when 'EXCEL'.
       call method me->download_to_excel.
      when 'SAVE'.
      when 'PROC'.
        call method me->process.
      when 'REFR'.
        call method me->refresh.
        when 'SWITCH'.
        call method me->switch.
       when 'TEST'.
        call method me->get_cell.
       endcase.
method get_cell .
break-point 1.
call method grid1->get_current_cell
importing
e_row     = ls_row
e_value   = ls_value
e_col     = ls_col
es_row_id = ls_row_id
es_col_id = ls_col_id
es_row_no = ls_row_no.
endmethod.
cheers
jimbo