ABAP 一个隐藏 selection-screen block的实例

以下是一个演示如何通过 selection-screen 中的pushbutton来动态改变屏幕上的字段的显示状态的（即显示或者隐藏）。
      注意：显示 通过本示例可知selection-screen 中的 field 的显示状态都是 的，在程序中修改其属性 active 的值为 '0' 时，该field就回隐藏起来。 但是在下一次屏幕显示前，其默认值又归为显示了。这时候可以在 at selection-screen output 事件或者 PBO中来修改active 值为 '0'即可。
另外，注意使用 modif id *** 来将selection screen 中的 field 指派到 screen-group1 中。 *** 是不超过三个字符的 id 名称，即指定了 screen-group1的值。

 *INCLUDE <icon>.
 TABLES: sscrfields,
         sflight.

 SELECTION-SCREEN: PUSHBUTTON /() pbo1      "open block 1
                   USER-COMMAND ucomm_o1 MODIF ID mo1,
                   PUSHBUTTON /() pbc1      "close block 1
                   USER-COMMAND ucomm_c1 MODIF ID mc1.

 SELECTION-SCREEN BEGIN OF BLOCK b01 WITH FRAME.

 SELECT-OPTIONS: s_car FOR sflight-carrid MODIF ID mc1,
 *                s_con FOR sflight-connid MODIF ID mc1,
 *                s_fld FOR sflight-fldate MODIF ID mc1,
                 s_pri FOR sflight-price MODIF ID mc1.

 SELECTION-SCREEN END OF BLOCK b01.

 SELECTION-SCREEN: PUSHBUTTON /() pbo2      "open block 1
                   USER-COMMAND ucomm_o2 MODIF ID mo2,
                   PUSHBUTTON /() pbc2      "close block 1
                   USER-COMMAND ucomm_c2 MODIF ID mc2.

 SELECTION-SCREEN BEGIN OF BLOCK b02 WITH FRAME.

 SELECT-OPTIONS: s_car2 FOR sflight-carrid MODIF ID mc2,
 *                s_con2 FOR sflight-connid MODIF ID mc2,
 *                s_fld2 FOR sflight-fldate MODIF ID mc2,
                 s_pri2 FOR sflight-price MODIF ID mc2.

 SELECTION-SCREEN END OF BLOCK b02.

 PARAMETERS: par_cb1() TYPE c NO-DISPLAY,
             par_cb2() TYPE c NO-DISPLAY.

 INITIALIZATION.

   CONCATENATE icon_expand: '打开' '' INTO pbo1,
                '打开' '' INTO pbo2.

   CONCATENATE icon_collapse: '关闭' '' INTO pbc1,
                 '关闭' '' INTO pbc2.
   par_cb1 = 'X'.
   par_cb2 = 'X'.

 AT SELECTION-SCREEN.
   CASE sscrfields-ucomm.
     WHEN 'UCOMM_O1'.
       CLEAR par_cb1.
     WHEN 'UCOMM_C1'.
       par_cb1 = 'X'.
     WHEN 'UCOMM_O2'.
       CLEAR par_cb2.
     WHEN 'UCOMM_C2'.
       par_cb2 = 'X'.
   ENDCASE.

 AT SELECTION-SCREEN OUTPUT.
   LOOP AT SCREEN.
     PERFORM close_block USING:  par_cb1 'MO1' 'X',
                                 par_cb1 'MC1' space,
                                 par_cb2 'MO2' 'X',
                                 par_cb2 'MC2' space.

   ENDLOOP.

 START-OF-SELECTION.
   DO.
     IF sy-index = .
       EXIT.
     ENDIF.
   ENDDO.
 *&--------------------------------------------------------------------*
 *&      Form  close_block
 *&--------------------------------------------------------------------*
 *       text
 *---------------------------------------------------------------------*
 *      -->VALUE(U_CLOtextLOCK)
 *      -->U_MODIFY_IDtext
 *      -->U_CONVERT  text
 *---------------------------------------------------------------------*
 FORM close_block USING value(u_close_block) LIKE par_cb1
                        u_modify_id LIKE screen-group1
                        u_convert.

   IF NOT u_convert IS INITIAL.
     IF u_close_block IS INITIAL.
       u_close_block = 'X'.
     ELSE.
       CLEAR u_close_block.
     ENDIF.
   ENDIF.

   IF ( screen-group1 = u_modify_id )
     AND ( NOT u_close_block IS INITIAL ).
     screen-active = ''.
     MODIFY SCREEN.
   ENDIF.

 ENDFORM.                    "close_block