ABAP FUNCTION ALV中如何在状态栏添加下拉框按钮

在 ABAP FUNCTION ALV 中添加状态栏下拉框按钮，可以使用函数模块 `REUSE_ALV_HIERSEQ_LIST_DISPLAY`。该函数模块可以在状态栏中添加下拉框按钮，用于切换不同的层次结构。

以下是添加下拉框按钮的代码示例：

REPORT ztest.

DATA: it_list TYPE STANDARD TABLE OF sflight,
      wa_list TYPE sflight.

DATA: it_fieldcat TYPE slis_t_fieldcat_alv.

FIELD-SYMBOLS: <fs_fieldcat> TYPE slis_fieldcat_alv.

* 初始化 ALV 数据
SELECT * FROM sflight INTO TABLE it_list.

* 初始化字段目录
CLEAR: it_fieldcat.
wa_fieldcat-fieldname = 'CARRID'.
wa_fieldcat-ref_table = 'SCARR'.
wa_fieldcat-ref_field = 'CARRID'.
APPEND wa_fieldcat TO it_fieldcat.

wa_fieldcat-fieldname = 'CONNID'.
APPEND wa_fieldcat TO it_fieldcat.

wa_fieldcat-fieldname = 'FLDATE'.
APPEND wa_fieldcat TO it_fieldcat.

wa_fieldcat-fieldname = 'SEATSMAX'.
APPEND wa_fieldcat TO it_fieldcat.

wa_fieldcat-fieldname = 'SEATSOCC'.
APPEND wa_fieldcat TO it_fieldcat.

CALL FUNCTION 'REUSE_ALV_HIERSEQ_LIST_DISPLAY'
  EXPORTING
    i_callback_program       = sy-repid
    i_callback_pf_status_set = 'PF_STATUS'
    is_layout                = VALUE #( ( hierarchy_seq = 'CARRID' ) )
  TABLES
    t_fieldcat               = it_fieldcat
    t_outtab                 = it_list.
    
    
* 定义层次结构下拉框的值集合
DATA: it_hier TYPE STANDARD TABLE OF lvc_s_layo WITH HEADER LINE.
it_hier-fieldname = 'HIERARCHY_SEQ'.
it_hier-seltext_l = '层次结构'.
it_hier-selopt   = 'O'.
it_hier-no_out   = 'X'.
APPEND it_hier.

it_hier-fieldname = 'CARRID'.
it_hier-seltext_l = '按航空公司'.
it_hier-selopt   = 'C'.
it_hier-no_out   = ' '.
APPEND it_hier.

it_hier-fieldname = 'FLDATE'.
it_hier-seltext_l = '按航班日期'.
it_hier-selopt   = 'D'.
it_hier-no_out   = ' '.
APPEND it_hier.

it_hier-fieldname = 'SEATSMAX'.
it_hier-seltext_l = '按最大座位数'.
it_hier-selopt   = 'S'.
it_hier-no_out   = ' '.
APPEND it_hier.

it_hier-fieldname = 'SEATSOCC'.
it_hier-seltext_l = '按已占用座位数'.
it_hier-selopt   = 'O'.
it_hier-no_out   = ' '.
APPEND it_hier.

* 设置层次结构下拉框
SET PF-STATUS 'PF_STATUS' EXCLUDING it_hier.

* PF-STATUS 事件处理程序
MODULE pf_status OUTPUT.
  SET PF-STATUS 'PF_STATUS'.
  SET TITLEBAR 'TITLE'.
ENDMODULE.

* AT SELECTION-SCREEN 事件处理程序
AT SELECTION-SCREEN ON HIERARCHY_SEQ.
  LOOP AT it_hier ASSIGNING FIELD-SYMBOL(<fs_hier>).
    IF <fs_hier>-fieldname = 'HIERARCHY_SEQ'.
      CONTINUE.
    ENDIF.
    IF <fs_hier>-selopt = 'X'.
      CLEAR: it_list.
      SELECT * FROM sflight INTO TABLE it_list ORDER BY carrid.
    ELSE.
      CLEAR: it_list.
      SELECT * FROM sflight INTO TABLE it_list ORDER BY ( <fs_hier>-fieldname ).
    ENDIF.
    CALL FUNCTION 'REUSE_ALV_HIERSEQ_LIST_DISPLAY'
      EXPORTING
        i_callback_program       = sy-repid
        i_callback_pf_status_set = 'PF_STATUS'
        is_layout                = VALUE #( ( hierarchy_seq = <fs_hier>-fieldname ) )
      TABLES
        t_fieldcat               = it_fieldcat
        t_hierarchy              = it_list.
  ENDLOOP.

在代码中，使用了 `REUSE_ALV_HIERSEQ_LIST_DISPLAY` 函数模块来显示 ALV 报表，并在 `is_layout` 参数中指定默认的层次结构。在 `pf_status` 事件处理程序中设置状态栏的标题，并在 `AT SELECTION-SCREEN` 事件处理程序中根据用户选择的层次结构重新查询数据并刷新 ALV 报表。

通过在 `it_hier` 中定义层次结构下拉框的值集合，并在 `SET PF-STATUS` 语句中排除该值集合，即可在状态栏中添加下拉框按钮。在 `AT SELECTION-SCREEN` 事件处理程序中，根据用户选择的层次结构重新查询数据，并使用 `REUSE_ALV_HIERSEQ_LIST_DISPLAY` 函数模块刷新 ALV 报表显示。