Hierarchical ALV

On selecting the header record, corresponding item record is shown. This has been done using hierarchical ALV:

*&---------------------------------------------------------------------*
*& Report  YHIERARCHY
*&
*&---------------------------------------------------------------------*
*& HIERARCHICAL ALV
*& Help: http://sapabap-4.blogspot.in/2015/11/alv-hierarchical-report.html
*&---------------------------------------------------------------------*
*
REPORT yhierarchy.

TYPE-POOLS: slis.

TYPES: BEGIN OF gty_ekko.
        INCLUDE STRUCTURE ekko.
TYPES: expand.
TYPES: END OF gty_ekko.

DATA: gt_ekko    TYPE TABLE OF gty_ekko,
      gt_ekpo    TYPE TABLE OF ekpo,
      gt_fcat    TYPE slis_t_fieldcat_alv,
      gt_tmp     TYPE slis_t_fieldcat_alv,
      gs_fcat    TYPE slis_fieldcat_alv,
      gs_layout  TYPE slis_layout_alv,
      gs_key     TYPE slis_keyinfo_alv "FOR HIERARCHICAL ALV
      .

START-OF-SELECTION.
  SELECT * FROM ekko INTO TABLE gt_ekko UP TO 10 ROWS.

  SELECT *
  FROM ekpo
  INTO TABLE gt_ekpo
  FOR ALL ENTRIES IN gt_ekko
  WHERE ebeln = gt_ekko-ebeln
  .

  DATA lv_col TYPE i VALUE 0.

  IF gt_ekko IS NOT INITIAL.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'EBELN'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Purchase Order'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'BUKRS'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Company Code'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'AEDAT'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Creation Date'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'ERNAM'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Created By'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'LIFNR'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Vendor'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'BEDAT'.
    gs_fcat-tabname   = 'IT_EKKO'.
    gs_fcat-seltext_l = 'Purchasing Document Date'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.
  ENDIF.

  IF gt_ekpo IS NOT INITIAL.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'EBELN'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Purchase Order'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'EBELP'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Item'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'MATKL'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Material Group'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'AEDAT'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Creation Date'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'MENGE'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'PO Quantity'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'MEINS'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Unit'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'NETPR'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Net Price'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.

    lv_col            = lv_col + 1.
    gs_fcat-col_pos   = lv_col.
    gs_fcat-fieldname = 'PEINH'.
    gs_fcat-tabname   = 'IT_EKPO'.
    gs_fcat-seltext_l = 'Price Unit'.
    APPEND gs_fcat TO gt_fcat.
    CLEAR gs_fcat.
  ENDIF.

  CONSTANTS: lc_expand TYPE slis_fieldname VALUE 'EXPAND'.

  gs_layout-zebra             = 'X'. "Zebra looks
  gs_layout-colwidth_optimize = 'X'. "Column width optimized
  gs_layout-expand_fieldname  = 'EXPAND'. "Expand operation
  gs_layout-window_titlebar   = 'Hierarchical PO Header & Item Display'.

  gs_key-header01 = 'EBELN'. "Purchase Order number
  gs_key-item01   = 'EBELN'. "is the key for header & item table

  CALL FUNCTION 'REUSE_ALV_HIERSEQ_LIST_DISPLAY'
    EXPORTING
      i_callback_program = sy-repid
      is_layout          = gs_layout
      it_fieldcat        = gt_fcat
      i_tabname_header   = 'IT_EKKO'
      i_tabname_item     = 'IT_EKPO'
      is_keyinfo         = gs_key
    TABLES
      t_outtab_header    = gt_ekko
      t_outtab_item      = gt_ekpo
    EXCEPTIONS
      program_error      = 1
      OTHERS             = 2.
  IF sy-subrc <> 0.
*   Implement suitable error handling here
  ENDIF.