1部分.常识
转载自：http://blog.tianya.cn/blogger/post_show.asp?BlogID=1271361&PostID=14936563
SAP-ABAP SELECT-SCREEN 的几个用法
如下一段程序：
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN POSITION 1.
PARAMETER P_FLEX RADIOBUTTON GROUP ways TYPE c.
SELECTION-SCREEN COMMENT 3(20) text-s30 for field P_FLEX.
SELECTION-SCREEN COMMENT 25(10) text-s31 for field P_PAYM_B.
SELECTION-SCREEN POSITION 38.
PARAMETER P_PAYM_B LIKE PA0015-PABRP MODIF ID wty.
parameters P_PAYY_B LIKE PA0015-pabrj MODIF ID wty.
SELECTION-SCREEN POSITION 57.
SELECTION-SCREEN COMMENT 57(5) text-s32 for field P_PAYM_E.
parameters P_PAYM_E LIKE PA0015-pabrp MODIF ID wty.
parameters P_PAYY_E LIKE PA0015-pabrj MODIF ID wty.
SELECTION-SCREEN END OF LINE.
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN POSITION 25.
SELECTION-SCREEN COMMENT 25(9) text-s18 for field S_LGART.
SELECT-OPTIONS S_LGART FOR p0014-LGART MODIF ID wty.
SELECTION-SCREEN END OF LINE.
SELECTION-SCREEN SKIP 1.
本程序中涉及到几个SELECTION-SCREEN的用法：
1 SELECTION-SCREEN BEGIN OF LINE. ....END OF LINE.
这条语句的作用是让Begin of line 与End of line之间的部分位于同一行。
2 SELECTION-SCREEN POSITION XX.
这条语句的作用是将该语句后面的第一个Screen element定位在这一行的XX位置，最大值为79。值得注意的是，如果同一行中多个Position语句因为空间不够或Element所占空间重叠，将导致Screen创建时的错误，无法激活。此时并无具体的提示。只能仔细观察代码。
3 SELECTION-SCREEN COMMENT XX(Y) TEXT-XXX FOR FIELD XXX.
这条语句的作用是在当前行的指定列位置处输出一段文本，For field则表示文本与某个element 关联，当此语句使用时，可以不必设定屏幕的Text element，系统会自动关联。XX表示位置，Y表示长度，注意，如果长度不足，超常的文字将被截掉。此处似乎还有一个小BUG，当Y小于5时，输出的文字字体会变大一号。不知道为什么。
SELECTION-SCREEN COMMENT /10(30) comm1.
INITIALIZATION.
comm1 ='Auswahlknopfgruppe 1'.
4 SELECTION-SCREEN SKIP 1.
跳过一行。类似于用WRITE写Report时的SKIP 1.也可以跳过多行。
以下是 屏幕上画横线
SELECTION-SCREEN ULINE /1(50).
5.内存记忆 留有上次输入过的记录
parameters test(16) type c memory id rid.
6.检查输入值 如果不在表中 不用做代码检查了
PARAMETERS p_carr TYPE spfli-carrid OBLIGATORY VALUE CHECK.
7.复选框
PARAMETERS: a AS CHECKBOX,
b AS CHECKBOX DEFAULT 'X'.
8.单选框
PARAMETERS: r1 RADIOBUTTON GROUP rad1,
r2 RADIOBUTTON GROUP rad1 DEFAULT 'X',
r3 RADIOBUTTON GROUP rad1,
s1 RADIOBUTTON GROUP rad2,
s2 RADIOBUTTON GROUP rad2,
s3 RADIOBUTTON GROUP rad2 DEFAULT 'X'.
9.屏幕动作变化 引起屏幕变化： modif id 起作用
举例：
report a.
SELECTION-SCREEN BEGIN OF BLOCK BL1 WITH FRAME title TEXT-003.
PARAMETERS:
P_1 TYPE C RADIOBUTTON GROUP DATE
DEFAULT 'X'
USER-COMMAND FLAG, "重要*
P_2 TYPE C RADIOBUTTON GROUP DATE,
P_3 TYPE C RADIOBUTTON GROUP DATE,
P_4 TYPE C RADIOBUTTON GROUP DATE
.
SELECTION-SCREEN END OF BLOCK BL1.
SELECTION-SCREEN BEGIN OF BLOCK BL2 WITH FRAME title TEXT-004.
SELECTION-SCREEN: BEGIN OF LINE,
COMMENT 6(10) TEXT-001.
PARAMETERS: GP_IPDAT TYPE SY-DATUM MODIF ID BL1, "重要*
GP_2 TYPE SY-DATUM MODIF ID BL2 . "重要*
SELECTION-SCREEN END OF LINE.
SELECTION-SCREEN SKIP 2.
SELECTION-SCREEN: BEGIN OF LINE,
COMMENT 8(60) TEXT-005,
END OF LINE,
BEGIN OF LINE,
COMMENT 8(60) TEXT-006,
END OF LINE.
SELECTION-SCREEN END OF BLOCK BL2.
"在AT SELECTION-SCREEN中循环SCREEN系统变量，把需要修改的画面元素的属性进行相应的修改
*----------------------------------------------------------------------*
*AT SELECTION-SCREEN
*----------------------------------------------------------------------*
AT SELECTION-SCREEN OUTPUT.
LOOP AT SCREEN.
IF P_1 = 'X' AND SCREEN-GROUP1 = 'BL1'.
SCREEN-INPUT = '0'.
CLEAR GP_IPDAT.
ENDIF.
IF P_2 = 'X' AND SCREEN-GROUP1 = 'BL1'.
SCREEN-INPUT = '1'.
ENDIF.
IF P_3 = 'X' AND SCREEN-GROUP1 = 'BL2'.
SCREEN-ACTIVE = '0'.
CLEAR GP_IPDAT.
ENDIF.
IF P_4 = 'X' AND SCREEN-GROUP1 = 'BL2'.
SCREEN-ACTIVE = '1'.
ENDIF.
MODIFY SCREEN.
ENDLOOP.
10.ranges 使用方法
ranges s_carrid1 for spfli-carrid.
s_carrid1-sign = 'I'.
s_carrid1-option = 'EQ'.
s_carrid1-low = 'LH'.
append s_carrid1.
11. options限制 输入
SELECT-OPTIONS airline FOR wa_spfli-carrid NO INTERVALS
NO-EXTENSION default g obligatory.”
12. 一行中的若干元素
DATA wa_spfli TYPE spfli.
SELECT-OPTIONS airline FOR wa_spfli-carrid.
SELECTION-SCREEN BEGIN OF LINE.
SELECTION-SCREEN POSITION pos_high.
PARAMETERS field(5) TYPE c.
SELECTION-SCREEN END OF LINE.
13 屏幕元素事件 按钮 及 new window USER-COMMAND
TABLES sscrfields.
DATA flag(1) TYPE c.
SELECTION-SCREEN:
BEGIN OF SCREEN 500 AS WINDOW TITLE tit,
BEGIN OF LINE,
PUSHBUTTON 2(10) but1 USER-COMMAND cli1,
PUSHBUTTON 12(10) text-020 USER-COMMAND cli2,
END OF LINE,
BEGIN OF LINE,
PUSHBUTTON 2(10) but3 USER-COMMAND cli3,
PUSHBUTTON 12(10) text-040 USER-COMMAND cli4,
END OF LINE,
END OF SCREEN 500.
AT SELECTION-SCREEN.
MESSAGE i888(sabapdocu) WITH text-001 sscrfields-ucomm.
CASE sscrfields-ucomm.
WHEN 'CLI1'.
flag = '1'.
WHEN 'CLI2'.
flag = '2'.
WHEN 'CLI3'.
flag = '3'.
WHEN 'CLI4'.
flag = '4'.
ENDCASE.
START-OF-SELECTION.
tit = 'Four Buttons'.
but1 = 'Button 1'.
but3 = 'Button 3'.
CALL SELECTION-SCREEN 500 STARTING AT 10 10.
CASE flag.
WHEN '1'.
WRITE / 'Button 1 was clicked'.
WHEN '2'.
WRITE / 'Button 2 was clicked'.
WHEN '3'.
WRITE / 'Button 3 was clicked'.
WHEN '4'.
WRITE / 'Button 4 was clicked'.
WHEN OTHERS.
WRITE / 'No Button was clicked'.
ENDCASE.
14 执行按钮旁边加触点 点击改变屏幕
REPORT demo_sel_screen_function_key.
TABLES sscrfields.
PARAMETERS: p_carrid TYPE s_carr_id,
p_cityfr TYPE s_from_cit.
SELECTION-SCREEN: FUNCTION KEY 1,
FUNCTION KEY 2. “此为两个触点定义
INITIALIZATION.
sscrfields-functxt_01 = 'LH'.
sscrfields-functxt_02 = 'UA'. ”此为两个触点的文本
AT SELECTION-SCREEN.
CASE sscrfields-ucomm.
WHEN'FC01'. “默认的 返回key
p_carrid = 'LH'.
p_cityfr = 'Frankfurt'.
WHEN 'FC02'.
p_carrid = 'UA'.
p_cityfr = 'Chicago'.
ENDCASE.
START-OF-SELECTION.
WRITE / 'START-OF-SELECTION'.
15.关于修改 标准status （有待研究）
REPORT demo_sel_screen_status .
DATA itab TYPE TABLE OF sy-ucomm.
PARAMETERS test(10) TYPE c.
AT SELECTION-SCREEN OUTPUT.
APPEND: 'PRIN' TO itab,
'SPOS' TO itab.
CALL FUNCTION 'RS_SET_SELSCREEN_STATUS'
EXPORTING
p_status = sy-pfkey
TABLES
p_exclude = itab.
16.选择屏幕 事件何时触发（有待研究）
REPORT demo_selection_screen_events MESSAGE-ID sabapdocu.
DATA field1(10) TYPE c.
SELECT-OPTIONS sel_opt1 FOR field1.
SELECTION-SCREEN BEGIN OF BLOCK block1.
PARAMETERS: test1(10) TYPE c,
test2(10) TYPE c.
SELECTION-SCREEN END OF BLOCK block1.
PARAMETERS: r1 RADIOBUTTON GROUP rad1 DEFAULT 'X',
r2 RADIOBUTTON GROUP rad1.
AT SELECTION-SCREEN.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'.
AT SELECTION-SCREEN OUTPUT.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'OUTPUT'.
AT SELECTION-SCREEN ON sel_opt1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON SEL_OPT1'.
AT SELECTION-SCREEN ON test1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON TEST1'.
AT SELECTION-SCREEN ON test2.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON TEST2'.
AT SELECTION-SCREEN ON END OF sel_opt1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON END OF SEL_OPT1'.
AT SELECTION-SCREEN ON HELP-REQUEST FOR sel_opt1-low.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON HELP-REQUEST FOR SEL_OPT1-LOW'.
AT SELECTION-SCREEN ON HELP-REQUEST FOR sel_opt1-high.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON HELP-REQUEST FOR SEL_OPT1-HIGH'.
AT SELECTION-SCREEN ON HELP-REQUEST FOR test1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON HELP-REQUEST FOR TEST1'.
AT SELECTION-SCREEN ON HELP-REQUEST FOR test2.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON HELP-REQUEST FOR TEST2'.
AT SELECTION-SCREEN ON VALUE-REQUEST FOR sel_opt1-low.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON VALUE-REQUEST FOR SEL_OPT1-LOW'.
AT SELECTION-SCREEN ON VALUE-REQUEST FOR sel_opt1-high.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON VALUE-REQUEST FOR SEL_OPT1-HIGH'.
AT SELECTION-SCREEN ON VALUE-REQUEST FOR test1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON VALUE-REQUEST FOR TEST1'.
AT SELECTION-SCREEN ON VALUE-REQUEST FOR test2.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON VALUE-REQUEST FOR TEST2'.
AT SELECTION-SCREEN ON BLOCK block1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON BLOCK BLOCK1'.
AT SELECTION-SCREEN ON RADIOBUTTON GROUP rad1.
MESSAGE i888 WITH 'AT SELECTION-SCREEN'
'ON RADIOBUTTON GROUP RAD1'.
17.