sap longon abap选择屏幕代码

以下是 ABAP 中的 SAP 登录屏幕代码示例：

REPORT zlogin_screen.

TABLES: dd02l.

PARAMETERS: p_uname TYPE sy-uname,
            p_pass TYPE char10.

DATA: lpass TYPE string,
      l_exit TYPE sy-subrc,
      wa_usr02 TYPE usr02.

AT SELECTION-SCREEN OUTPUT.
  LOOP AT SCREEN.
    IF screen-name = 'P_PASS'.
      screen-input = 1.
      MODIFY SCREEN.
    ENDIF.
  ENDLOOP.

START-OF-SELECTION.
  CONCATENATE p_pass cl_abap_char_utilities=>cr_lf INTO lpass.
  CALL FUNCTION 'RSAQ_REMOTE_LOGIN'
    EXPORTING
      client         = sy-mandt
      userid         = p_uname
      password       = lpass
    EXCEPTIONS
      communication  = 1
      system_failure = 2
      internal_error = 3
      OTHERS         = 4.
  IF sy-subrc = 0.
    SELECT SINGLE bname name lname
      INTO wa_usr02
      FROM usr02
      WHERE bname = p_uname.
    IF sy-subrc = 0.
      WRITE: / 'Welcome', wa_usr02-lname.
    ENDIF.
  ELSEIF sy-subrc = 4.
    MESSAGE 'Invalid User ID or Password' TYPE 'E'.
  ELSE.
    MESSAGE 'Logon Error' TYPE 'E'.
  ENDIF.

以上代码中，PARAMETERS 语句用于定义输入参数，AT SELECTION-SCREEN OUTPUT 语句用于修改输入屏幕，START-OF-SELECTION 语句用于执行登录操作，使用 CALL FUNCTION 调用函数 RSAQ_REMOTE_LOGIN 实现登录。