ALV - Field Name change

Question

Hi all,
I need to change my field name.
data : begin of it_output,
      vbeln type vbak-vbeln,
      date type sy-datum,
      field2 type string,
endof it_output.
in case like this, when the pass the internal table to ALV FM,
and the field2 will be appear blank in the output screen. My question, how can I set the field name before passing to ALV FM?
    CALL METHOD CL_SALV_TABLE=>FACTORY
      IMPORTING
        R_SALV_TABLE = GR_TABLE
      CHANGING
        T_TABLE      = IT_OUTPUT_ALL[].
    GR_FUNCTIONS = GR_TABLE->GET_FUNCTIONS( ).
    GR_FUNCTIONS->SET_ALL( ABAP_TRUE ).
    GR_TABLE->DISPLAY( ).

Answer 1

data:   r_columns TYPE REF TO cl_salv_columns_table,
          r_column  TYPE REF TO cl_salv_column_table.
PERFORM process_columns.   "<-- after cl_salv_table=>factory
*&      check all options that you can change
FORM process_columns RAISING cx_salv_not_found.
  r_columns = r_alvtab->get_columns( ).
  r_columns->set_optimize( ).
  r_column ?= r_columns->get_column( columnname = 'MANDT' ).
  r_column->set_technical( ).
  r_columns->set_column_position( columnname = 'CITYTO'
                                  position = 5 ).
  r_column ?= r_columns->get_column( columnname = 'CITYTO' ).
r_column->set_cell_type( if_salv_c_cell_type=>text ).
  r_column->set_long_text( 'Desde ciudad' ).
  MOVE: cl_gui_resources=>list_col_group TO color-col,
        '1'   TO color-int.                                 "<-- 0 & 1
  r_column->set_color( value = color ).
ENDFORM.