原文：Small Fire · ABAP 动态内表 · ABAP 子专栏 · Small Fire 技术笔记

ABAP动态内表操作

动态内表的列是可以跟随数据的变化而变化，可以使报表显示更简洁漂亮。

REPORT  zdyn_test.
DATA: dyn_table TYPE REF TO data,
      dyn_line  TYPE REF TO data,
FIELD-SYMBOLS: <dyn_table> TYPE STANDARD TABLE.
FIELD-SYMBOLS: <dyn_wa> TYPE ANY.
FIELD-SYMBOLS: <dyn_field> TYPE ANY.
DATA: layout TYPE LVC_S_LAYO,
      structures TYPE lvc_t_fcat,
      structure TYPE lvc_s_fcat.
START-OF-SELECTION.
PERFORM create_structure.       "定义内表的结构"
PERFORM create_dynamic_table.   "按照定义的内表结构，产生一个内表"
PERFORM write_data_to_dyntable. "向动态内表中写数"
PERFORM output_dyntable_data.   "从动态内表中取数，并写到屏幕"

Step1：创建动态内表

动态内表的结构的定义.

动态内表表结构的定义必须使用表结构与 lvc_t_fcat 一样的内表。一般情况下，我们都内表的所有列定义成字符型.

*&-----------------------------------------------------------*
*&      Form  create_structure
*&-----------------------------------------------------------*
FORM create_structure .
  structure-fieldname = 'COL1'.  " 第一列列名 "
  structure-col_pos   = 1.
  structure-inttype = 'C'.       " 数据类型 "
  structure-intlen = 6.          " 长度 "
  APPEND structure TO structures.
  structure-fieldname = 'COL2'.  " 第二列列名 "
  structure-col_pos   = 2.
  structure-inttype = 'C'.       " 数据类型 "
  structure-intlen = 6.          " 长度 "
  APPEND wa_structure TO structures.
  structure-fieldname = 'COL3'.  " 第三列名 "
  structure-col_pos   = 3.
  structure-inttype = 'C'.       " 数据类型 "
  structure-intlen = 6.          " 长度 "
  APPEND structure TO structures.
ENDFORM.                    " create_structure "

根据表结构生成内表.

系统提供了一个标准的 method 来产生动态表，使用方法如下:

*&-----------------------------------------------------------*
*&      Form  create_dynamic_table
*&-----------------------------------------------------------*
FORM create_dynamic_table .
  CALL METHOD cl_alv_table_create=>create_dynamic_table
    EXPORTING
      it_fieldcatalog = structures
    IMPORTING
      ep_table        = dyn_table.
  "用表类型指针<dyn_table>指向数据对象的内容. "
  ASSIGN dyn_table->* TO <dyn_table>.
ENDFORM.                    " create_dynamic_table "

Step2：动态内表的赋值

获取指定的字段并给指定的字段赋值

*&-----------------------------------------------------------*
*&      Form  write_data_to_dyntable
*&-----------------------------------------------------------*
FORM write_data_to_dyntable .
  DATA:i TYPE n.
  DATA:j TYPE n.
  " 建立一个与动态内表结构相同的数据对象，且数据对象为是一个结构 "
  CREATE DATA dyn_line LIKE LINE OF <dyn_table>.
  ASSIGN dyn_line->* TO <dyn_wa>. " 用<dyn_wa>指针指向该结构 "
  DO 3 TIMES.
    i = i + 1.
    CLEAR j.
    LOOP AT structures INTO structure.
      j = j + 1.
      " 用指针<dyn_field>指向工作区<dyn_wa>中的一个字段，字段名为structure-fieldname. "
      ASSIGN COMPONENT structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
      CONCATENATE i j INTO <dyn_field>.  " 给指针指向的字段赋值 "
    ENDLOOP.
    APPEND <dyn_wa> TO <dyn_table>.
    CLEAR <dyn_wa>.
  ENDDO.
ENDFORM.                    " write_data_to_dyntable "
*&-----------------------------------------------------------*

Step3：读取动态内表的值

获取指定的字段并读取指定的字段值

*&-----------------------------------------------------------*
*&      Form  output_dyntable_data
*&-----------------------------------------------------------*
FORM output_dyntable_data .
  LOOP AT structures INTO structure.
    WRITE: structure-fieldname(5).
  ENDLOOP.
  LOOP AT <dyn_table> INTO <dyn_wa>.
    WRITE: / .
    CLEAR structure.
    LOOP AT structures INTO structure.
    " 用指针<dyn_field>指向工作区<dyn_wa>中的一个字段，字段名为structure-fieldname. "
      ASSIGN COMPONENT structure-fieldname OF STRUCTURE <dyn_wa> TO <dyn_field>.
     WRITE: <dyn_field>.
    ENDLOOP.
  ENDLOOP.
ENDFORM.                    " output_dyntable_data "