Insert blank line into ALV

Hey gurus,

I have the following code, but the ALV is showed up without any lines.

DATA: tabname TYPE REF TO data,

         wa_tab TYPE REF TO data.

   FIELD-SYMBOLS: <table> TYPE table,

                  <wa_tab> TYPE data.

 

   CREATE DATA tabname TYPE TABLE OF (if_table_name).

   CREATE DATA wa_tab TYPE (if_table_name).

 

   ASSIGN tabname->* TO <table>.

   ASSIGN wa_tab->* TO <wa_tab>.

 

   clear <wa_tab>.

   APPEND <wa_tab> TO <table>.

 

   IF r_grid IS INITIAL.

     CALL METHOD r_grid->set_table_for_first_display

       EXPORTING

         i_structure_name = if_table_name

       CHANGING

         it_outtab        = <table>.

   ELSE.

     IF ok_code EQ 'SAVE'.

       CALL METHOD r_grid->refresh_table_display.

     ENDIF.

ENDIF.

if_table_name contains the table's name.

How could I put a blank line or lines into ALV?

I want to make it because of the new entries to the table, like it is working in SM30.

Regards,

Robert