为sap的alv的最左侧添加【选中】按钮用于同时选中多行

abap编程中alv的显示代码如下：

CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
      EXPORTING
        I_CALLBACK_PROGRAM       = SY-REPID
        I_CALLBACK_PF_STATUS_SET = 'SET_PF_STATUS'   "GUI状态
        I_CALLBACK_USER_COMMAND  = 'USER_COMMAND'  "回调方法
        IS_LAYOUT                = GS_LAYOUT       "布局
        IT_FIELDCAT              = GT_FIELDCAT[] "字段
        I_SAVE                   = 'A'
      TABLES
        T_OUTTAB                 = GT_DATA[]  "被alv显示的内表
      EXCEPTIONS
        PROGRAM_ERROR            = 1
        OTHERS                   = 2.
    IF SY-SUBRC <> 0.
      MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
      WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
    ENDIF.

我们最终要的效果是如下所示：

如何做到呢？

TYPES:BEGIN OF ITAB_DATA,
      MATNR TYPE MARC-MATNR,"物料编码
      MAKTX TYPE MAKT-MAKTX,"物料描述
      SEL(1),   "被显示的内表，添加一个专用字段
END OF ITAB_DATA.
DATA: GT_DATA  TYPE STANDARD TABLE OF ITAB_DATA.

FORM FRM_GET_LAYOUT .

  CLEAR GS_LAYOUT.
  GS_LAYOUT-ZEBRA = 'X'.
  GS_LAYOUT-DETAIL_POPUP = 'X'.
  GS_LAYOUT-NO_SUBTOTALS = ''.
  GS_LAYOUT-BOX_FIELDNAME = 'SEL'.  "指定这个字段为【选择块】

ENDFORM.