Display header for excel output using FM GUI_DOWNLOAD

Question

Good morning experts,
                 I've been exporting my output in excel using the FM GUI_DOWNLOAD.  The problem is, my header is not displaying.  Kindly check what I've done wrong.  Below is how I declared my header.
DATA: BEGIN OF header OCCURS 0,
        head1(15),
        head2(15),
      END OF header.
*&      FORM USER_COMMAND
      COMMAND for ALV Grid Buttons
FORM user_command USING r_ucomm LIKE sy-ucomm
                  rs_selfield TYPE slis_selfield.
PERFORM write_header.
CASE r_ucomm.
  WHEN 'XCEL'.
    CONCATENATE: 'C:\' fname sy-datum INTO fname.
    CONCATENATE: fname '.XLS' INTO FILENAME.
    CALL FUNCTION 'GUI_DOWNLOAD'
      EXPORTING
        FILENAME = FILENAME
        WRITE_FIELD_SEPARATOR = 'X'
      TABLES
        DATA_TAB = jtab
        FIELDNAMES = header
      EXCEPTIONS
        FILE_WRITE_ERROR        = 1
        NO_BATCH                = 2
        GUI_REFUSE_FILETRANSFER = 3
        INVALID_TYPE            = 4
        NO_AUTHORITY            = 5
        UNKNOWN_ERROR           = 6
        HEADER_NOT_ALLOWED      = 7
        SEPARATOR_NOT_ALLOWED   = 8
        FILESIZE_NOT_ALLOWED    = 9
        HEADER_TOO_LONG         = 10
        DP_ERROR_CREATE         = 11
        DP_ERROR_SEND           = 12
        DP_ERROR_WRITE          = 13
        UNKNOWN_DP_ERROR        = 14
        ACCESS_DENIED           = 15
        DP_OUT_OF_MEMORY        = 16
        DISK_FULL               = 17
        DP_TIMEOUT              = 18
        FILE_NOT_FOUND          = 19
        DATAPROVIDER_EXCEPTION = 20
        CONTROL_FLUSH_ERROR = 21
        OTHERS = 22.
      IF sy-subrc <> 0.
        MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
        WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
      ELSEIF sy-subrc = 0.
        MESSAGE S000(38) WITH 'File ' fname 'saved in Drive C.'.
      ENDIF.
ENDCASE.
ENDFORM.
*&      Form  write_header
      text
-->  p1        text
<--  p2        text
FORM write_header.
DATA: ctr(2) TYPE p.
DO 6 TIMES.
  ADD 1 TO ctr.
  CASE ctr.
    WHEN 1. header-head1 = 'EMPLOYEE'.
            header-head2 = '   NO   '.
    WHEN 2. header-head1 = 'EMPLOYEE'.
            header-head2 = '  NAME  '.
    WHEN 3. header-head1 = 'LOAN'.
            header-head2 = 'TYPE'.
    WHEN 4. header-head1 = 'APPROVAL'.
            header-head2 = '  DATE  '.
    WHEN 5. header-head1 = 'LOAN'.
            header-head2 = 'CODE'.
    WHEN 6. header-head1 = '   MONTHLY  '.
            header-head2 = 'AMORTIZATION'.
  ENDCASE.
  APPEND header.
  CLEAR: header.
Please help me.  All helpful advice will be rewarded points.  Thanks a lot.

Answer 1

Follow this Example. You can do it in the below manner
You need not add HEADER1 HEADER2 to the internal table. You can just declare one field like below and append all the header columns to the internal table HEADER
data : begin of IT_HEADING occurs 0,
         TEXT(15),
       end of IT_HEADING.
    IT_HEADING-TEXT = 'Company Code'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Number'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Line Item'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Number'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Line Item'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Quantity'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Unit'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Amount'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'PO Currency'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'Job Number'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Quantity'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Unit'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Amount'.
    append IT_HEADING.
    IT_HEADING-TEXT = 'SO Currency'.
    append IT_HEADING.
    move P_FNAME to L_FNAME.
    call function 'GUI_DOWNLOAD'
      exporting
        FILENAME                = L_FNAME
        FILETYPE                = 'DAT'
      tables
        DATA_TAB                = IT_FINAL
        FIELDNAMES              = IT_HEADING
      exceptions
        FILE_WRITE_ERROR        = 1
        NO_BATCH                = 2
        GUI_REFUSE_FILETRANSFER = 3
        INVALID_TYPE            = 4
        NO_AUTHORITY            = 5
        UNKNOWN_ERROR           = 6
        HEADER_NOT_ALLOWED      = 7
        SEPARATOR_NOT_ALLOWED   = 8
        FILESIZE_NOT_ALLOWED    = 9
        HEADER_TOO_LONG         = 10
        DP_ERROR_CREATE         = 11
        DP_ERROR_SEND           = 12
        DP_ERROR_WRITE          = 13
        UNKNOWN_DP_ERROR        = 14
        ACCESS_DENIED           = 15
        DP_OUT_OF_MEMORY        = 16
        DISK_FULL               = 17
        DP_TIMEOUT              = 18
        FILE_NOT_FOUND          = 19
        DATAPROVIDER_EXCEPTION  = 20
        CONTROL_FLUSH_ERROR     = 21
        others                  = 22.
    if SY-SUBRC <> 0.
* MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
*         WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    endif.
Regards
Gopi