ME5xN(x:1-2): custom column is editable in Subscreen Item but not in ALV grid

FM

MEMFS_BUILD_MAPPING_PO_VIEWS->LMEMFSF0Z

enhancement 14  zenhance_alvg_rid_editable.    "active version
  map 'ZZ_NOT_INPUT' mmmfd_cust_01.
endenhancement.

BADI

IF_EX_ME_PROCESS_REQ_CUST~FIELDSELECTION_ITEM

method IF_EX_ME_PROCESS_REQ_CUST~FIELDSELECTION_ITEM.
* To control 'ZZ_NOT-INPUT' field editable in ALV grid of ME5xN x=1.2
  CHECK sy-tcode eq 'ME51N' or sy-tcode eq 'ME52N'.
  TYPE-POOLS:mmmfd.
  data: f_document  type mepo_document.
  FIELD-SYMBOLS: <fs> LIKE LINE OF ch_fieldselection.
* In ME52N change mode,it's editable,but in view mode,it's not.
     CALL METHOD im_header->GET_TRANSACTION_STATE( IMPORTING EX_DOCUMENT = f_document ).
     IF f_document-TRTYP eq 'V'.
      READ TABLE ch_fieldselection ASSIGNING <fs> WITH TABLE KEY metafield = mmmfd_cust_01.
      IF sy-subrc IS INITIAL.
        <fs>-fieldstatus = '.'.
      ENDIF.
     ENDIF.
endmethod.