ABAP屏幕元素的創建

SAP的基本屏幕元素定義語句包括： SELECT-OPTIONS, PARAMETERS, SELECTION-SCREEN.

SELECT-OPTIONS:

SELECT-OPTIONS:DATA FOR SY-DATUM.

出現以下是樣的提示（效果）

PARAMETERS:可以參照數據字典具體字段或自定義數據類型創建文本輸入域以及單選框/複選框。

PARAMETERS:MATNR LIKE MARA-MATNR.
PARAMETERS:TYPE AS CHECKBOX.
PARAMETERS:P1 RADIOBUTTON GROUP GRP1 DEFAULT'X',
           P2 RADIOBUTTON GROUP GRP1,
           P3 RADIOBUTTON GROUP GRP1.

SELECTION-SCREEN
用於創建屏幕的框架結構，主要包括屏幕元素的創建，子屏幕的創建等。

CALL SCREEN 123
            STARTING AT 10 10
            ENDING AT  80 10.
SELECTION-SCREEN BEGIN OF SCREEN 123 AS WINDOW TITLE TEXT-A01.
PARAMETERS:MATNR LIKE MARA-MATNR.
PARAMETERS:TYPE AS CHECKBOX.
SELECTION-SCREEN END OF SCREEN 123.          

INITIALIZATION事件
這個是對於所定義屏幕元素進行初始化賦值。

REPORT Z_HELLOWORLD.

PARAMETERS QUAL_DAY TYPE D DEFAULT SY-DATUM.
INITIALIZATION.
  QUAL_DAY+6(2) ='01'.
  QUAL_DAY   = QUAL_DAY - 1.

START-OF-SELECTION
在單擊執行按鈕後觸發該事件。

REPORT Z_HELLOWORLD.

PARAMETERS QUAL_DAY TYPE D DEFAULT SY-DATUM.
INITIALIZATION.
  QUAL_DAY+6(2) ='01'.
  QUAL_DAY   = QUAL_DAY - 1.
  START-OF-SELECTION.
  WRITE:'DATE:',QUAL_DAY.

END-OF-SELECTION
該事件應用於所有數據處理完成，即START-OF-SELECTION相關事件執行完成，但輸出屏幕還未顯示之前。

PARAMETERS QUAL_DAY TYPE D DEFAULT SY-DATUM.
INITIALIZATION.
  QUAL_DAY+6(2) ='01'.
  QUAL_DAY   = QUAL_DAY - 1.
  START-OF-SELECTION.
  WRITE:'DATE:',QUAL_DAY.
  END-OF-SELECTION.
  IF QUAL_DAY <> SYST-DATUM.
    WRITE:'Today:',SYST-DATUM.
  ENDIF.