REUSE_ALV_FIELDCATALOG_MERGE函数可根据内表结构返回FIELDCAT字段结构信息，具体的参数等信息请查看ALV调用的几个标准函数里相关的介绍，好的，那么让我们开始学习如何使用此函数。
REPORT ZZWEI_ALV_DEMO.
*ALV START
TYPE-POOLS:SLIS. "调用该类型池
*定义FIELDCAT与LAYOUT
DATA:fieldCat TYPE SLIS_T_FIELDCAT_ALV WITH HEADER LINE,
layout TYPE SLIS_LAYOUT_ALV,
w_repid LIKE SY-REPID.
TABLES:SPFLI.
DATA:LSPFLI LIKE STANDARD TABLE OF SPFLI WITH HEADER LINE.
*屏幕开始事件
START-OF-SELECTION.
PERFORM GETDATA.
PERFORM CATALOG.
PERFORM ALVSHOW.
*The Function Of GETDATA
FORM GETDATA.
SELECT * FROM SPFLI INTO CORRESPONDING FIELDS OF TABLE LSPFLI.
ENDFORM.
*FORM CATALOG 根据结构体获取FIELDCAT
FORM CATALOG.
w_repid = SY-REPID.
CLEAR fieldCat.
CALL FUNCTION 'REUSE_ALV_FIELDCATALOG_MERGE'
EXPORTING
I_PROGRAM_NAME = w_repid
*I_INTERNAL_TABNAME =
I_STRUCTURE_NAME = 'SPFLI'
*I_CLIENT_NEVER_DISPLAY = 'X'
*I_INCLNAME =
*I_BYPASSING_BUFFER =
*I_BUFFER_ACTIVE =
CHANGING
CT_FIELDCAT = fieldCat[] "导出FIELDCAT内表数据
EXCEPTIONS
INCONSISTENT_INTERFACE = 1
PROGRAM_ERROR = 2
OTHERS = 3
.
IF SY-SUBRC <> 0.
MESSAGE ID SY-MSGID TYPE SY-MSGTY NUMBER SY-MSGNO
WITH SY-MSGV1 SY-MSGV2 SY-MSGV3 SY-MSGV4.
ENDIF.
"对fieldcat属性的修改
*READ TABLE fieldCat INDEX 2. "将第二列设为热点显示
*fieldCat-HOTSPOT = 'X'.
*MODIFY fieldCat INDEX 2.
*
*READ TABLE fieldCat INDEX 4. "将第四列设为KEY值字段
*fieldCat-KEY = 'X'.
*MODIFY fieldCat INDEX 4.
*
*READ TABLE fieldCat INDEX 5. "将第五列设为CHECKBOX
*fieldCat-CHECKBOX = 'X'.
*MODIFY fieldCat INDEX 5.
layout-COLWIDTH_OPTIMIZE = 'X'. "设置LAYOUT输出格式最优化
ENDFORM.
*The Function Of Show ALV
FORM ALVSHOW.
CALL FUNCTION 'REUSE_ALV_GRID_DISPLAY'
EXPORTING
I_CALLBACK_PROGRAM = w_repid
I_GRID_TITLE = 'ALV REPORT TEST' "ALV显示标题
IS_LAYOUT = layout
IT_FIELDCAT = fieldCat[]
TABLES
T_OUTTAB = LSPFLI
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.
最终运行结果如下：
错误排查：
有的时候写好代码调用 REUSE_ALV_FIELDCATALOG_MERGE 时会莫名的出错提示为 READ_REPORT_LINE_TOO_LONG 下面列出的错误信息有这么一句.
The internal table "/FUNCTION=K_KKB_FIELDCAT_MERGE/DATA=L_ABAP_SOURCE[]" is 72
characters wide. The program line is 99 characters wide.
该FM会把整个程序代码拷贝至其内表中，如果程序的行超过72个字符，即报如上错误。可以做以下设置。
