如何通过cl_dd_document来实现在ALV中输出标题头

样例代码:
REPORT ZTEST4.

TABLES : t001.
TYPE-POOLS: slis.

DATA : w_repid LIKE sy-repid.
TYPES : BEGIN OF ty_comp.
INCLUDE STRUCTURE t001.
TYPES : END OF ty_comp.

DATA: wa_layout TYPE slis_layout_alv.

DATA: it_fieldcat TYPE slis_t_fieldcat_alv,
wa_fieldcat TYPE slis_fieldcat_alv.

DATA : it_comp TYPE TABLE OF ty_comp.

INITIALIZATION.
w_repid = sy-repid.

START-OF-SELECTION.

SELECT * FROM t001 INTO TABLE it_comp.

END-OF-SELECTION.

CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
    EXPORTING
      i_program_name         = w_repid
      i_internal_tabname     = 'IT_COMP'
      I_STRUCTURE_NAME       = 'T001'
      i_inclname             = w_repid
    CHANGING
      ct_fieldcat            = it_fieldcat[]
    EXCEPTIONS
      inconsistent_interface = 1
      program_error          = 2
      OTHERS                 = 3.

CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
    EXPORTING
      i_callback_program          = w_repid
      i_callback_html_top_of_page = 'HTML_TOP_OF_PAGE'
      is_layout                   = wa_layout
      it_fieldcat                 = it_fieldcat
    TABLES
      t_outtab                    = it_comp
    EXCEPTIONS
      program_error               = 1
      OTHERS                      = 2.

*&---------------------------------------------------------------------*
*& Form html_top_of_page
*&---------------------------------------------------------------------*

FORM html_top_of_page USING document TYPE REF TO cl_dd_document.

DATA: text TYPE sdydo_text_element.
text = 'Company Code Data'.
CALL METHOD document->add_text
    EXPORTING
      text      = text
      sap_style = 'HEADING'.

CALL METHOD document->new_line.
CALL METHOD document->new_line.

text = 'User Name : '.
CALL METHOD document->add_text
    EXPORTING
      text         = text
      sap_emphasis = 'Strong'.

CALL METHOD document->add_gap
EXPORTING
width = 2.

text = sy-uname.
CALL METHOD document->add_text
    EXPORTING
      text      = text
      sap_style = 'Key'.

CALL METHOD document->add_gap
EXPORTING
width = 10.

CALL METHOD document->add_icon
    exporting
      sap_icon = 'ICON_DATE'.

text = 'Date : '.
CALL METHOD document->add_text
    EXPORTING
      text         = text
      sap_emphasis = 'Strong'.

CALL METHOD document->add_gap
EXPORTING
width = 2.

text = sy-datum.
CALL METHOD document->add_text
    EXPORTING
      text      = text
      sap_style = 'Key'.

CALL METHOD document->add_gap
EXPORTING
width = 10.

text = 'Time : '.
CALL METHOD document->add_text
    EXPORTING
      text         = text
      sap_emphasis = 'Strong'.

CALL METHOD document->add_gap
EXPORTING
width = 2.

text = sy-uzeit.
CALL METHOD document->add_text
    EXPORTING
      text      = text
      sap_style = 'Key'.

CALL METHOD document->new_line.

CALL METHOD document->underline. "Draw an underLine
ENDFORM. "HTML_TOP_OF_PAGE

效果图如下: