输出ALV完整流程

1.定义一个SAP标准类型库
TYPE-POOLS: SLIS.
2.定义一个LAYOUT式样，和一个FIELDCAT字段格式，

DATA: G_F TYPE SLIS_T_FIELDCAT_ALV , "字段目录内表
       W_L TYPE SLIS_LAYOUT_ALV. "用于定义ALV表单的相关格式、属性

3.如果选择屏幕复选框参考了表
TABLES : EKKO, EKPO.
4.定义一个结构

TYPES: BEGIN OF G_TY,
   BOX TYPE C,
   EKORG TYPE EKKO-EKORG,
   BSART TYPE EKKO-BSART,
   LIFNR TYPE EKKO-LIFNR,
   EBELN TYPE EKKO-EBELN,
 END OF G_TY.

5.定义表和工作区

DATA: G_TAB TYPE TABLE OF G_TY,
       W_TAB LIKE LINE OF G_TAB.   或者 
       W_TAB TYPEG_TY.

6.定义屏幕

SELECTION-SCREEN BEGIN OF BLOCK XYY WITH FRAME TITLE TEXT-001.
PARAMETERS P_VKORG TYPE VBAK-VKORG OBLIGATORY.
  SELECT-OPTIONS: S_VBELN FOR VBAK-VBELN,
                  S_AUART FOR  VBAK-AUART.
SELECTION-SCREEN END OF BLOCK XYY.

这里只定义了单选框(PARAMETERS)和复选框(SELECT-OPTIONS)。一个用TYPE,一个用FOR。表查询会依照屏幕条件筛选数据。

7.初始化屏幕
INITIALIZATION.
加这个条件是告诉系统在这屏幕展示完，要查数据，展示报表了。

8.按顺序执行

START-OF-SELECTION.
  PERFORM FRM_SELDATA.
  PERFORM FRM_WRITE .
END-OF-SELECTION.  

9.数据查询实现PERFORM 方法

FORM FRM_SELDATA .
SELECT:
  EKKO~EKORG
  EKKO~BSART
  EKKO~LIFNR
  INTO CORRESPONDING FIELDS OF TABLE G_TAB
  FROM EKKO INNER JOIN EKPO ON EKKO~EBELN = EKPO~EBELN
  WHERE EKKO~EKORG IN P_EKORG
  AND EKKO~BSART IN P_BSART
  AND EKKO~LIFNR IN P_LIFNR
  AND EKKO~EBELN IN P_EBELN.
ENDFORM. "FRM_SELDATA

查询的时候三个表以下可以用 INNER JOIN，否则就用内表传递，一个表一个表的查，再传递。

10.实现ALV输出

FORM FRM_WRITE .
   PERFORM LAYOUT.              "输出样式
   PERFORM INIT_FIELDCA.       "输出属性
   PERFORM LISTADO.                "展示
ENDFORM. " FRM_WRITE

（1）实现ALV输出具体的方法：定义ALV样式

FORM LAYOUT .
   W_L-BOX_FIELDNAME = 'BOX'.
   W_L-ZEBRA = 'X'.         "颜色间隔
  W_L-COLWIDTH_OPTIMIZE = 'X'.       "自适应宽度
ENDFORM. " LAYOUT_19

（2）

FORM INIT_FIELDCA .
   CLEAR G_F.
  G_F-FIELDNAME = 'EKORG'. "必须为大写
  G_F-SELTEXT_S  = '采购组织'.
  G_F-SELTEXT_M  = G_F-SELTEXT_S.
  G_F-SELTEXT_L  = G_F-SELTEXT_S.
   APPEND G_F.

CLEAR G_F.
G_F-FIELDNAME = 'TXZ01'.
G_F-SELTEXT_S  = '行文本'.
G_F-SELTEXT_M  = G_F-SELTEXT_S.
G_F-SELTEXT_L  = G_F-SELTEXT_S.
G_F-EDIT  = 'X' .
G_F-REF_FIELDNAME  = 'TXZ01'.  "参考字段名
G_F-REF_TABNAME    = 'EKPO'.   "参考表名
APPEND G_F.
ENDFORM. " INIT_FIELDCAT_19  

（3）输出

FORM LISTADO .
   CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
    EXPORTING
      I_CALLBACK_PROGRAM = SY-REPID   "当前程序名
     I_CALLBACK_USER_COMMAND    = 'USER_COMMAND' "自定义按钮响应事件
     I_CALLBACK_PF_STATUS_SET   = 'SET_PF_STATUS' "设置ALV的自定义按钮
     IS_LAYOUT          = W_L "输出样式
     IT_FIELDCAT        = G_F[]  "字段定义描述表
"     I_CALLBACK_TOP_OF_PAGE = 'F_TOP_OF_PAGE'
     I_SAVE             = 'A'
       " I_SAVE有4个可选值： I_SAVE= '' --- 不能保存格式；
      " I_SAVE = 'X' --- 保存标准格式；
      " I_SAVE = 'U' --- 保存特定用户格式；
      " I_SAVE = 'A' --- 保存标准格式和特定用户格式。
   TABLES
      T_OUTTAB           = G_TAB   "内表输出名称
   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.
 ENDFORM. " LISTADO
 FORM SET_PF_STATUS USING RT_EXTAB TYPE SLIS_T_EXTAB.
   SET PF-STATUS 'STATUS' .
 ENDFORM.

11.写USER_COMMAND的一个事件（这个作业要求实现更改数据，点击按钮且保存成功）

FORM USER_COMMAND USING R_UCOMM LIKE SY-UCOMM
                         RS_SELFIELD TYPE SLIS_SELFIELD.
   DATA: GV_GRID TYPE REF TO CL_GUI_ALV_GRID.
   "刷新
  CALL FUNCTION 'GET_GLOBALS_FROM_SLVC_FULLSCR'
     IMPORTING
       E_GRID = GV_GRID.
   CALL METHOD GV_GRID->CHECK_CHANGED_DATA.
    CASE R_UCOMM.
       WHEN 'SKIP'.
         IF SY-SUBRC = 0.
         ENDIF.
     ENDCASE.
 ENDFORM. "LISTADO