Refresh ALVtree

Declare table to store top leve nodes in top include

types: begin of t_topnodes,
 nodekey type lvc_nkey,
end of t_topnodes.
data: it_topnodes type standard table of t_topnodes,
      wa_topnodes like line of it_topnodes.

Add code to build top level node table
*&----------------------------------------------------------*
*&      Form  CREATE_ALVTREE_HIERARCHY
*&----------------------------------------------------------*
*       text
*-----------------------------------------------------------*
*       Builds ALV tree display, (inserts nodes, subnodes etc)
*-----------------------------------------------------------*
form create_alvtree_hierarchy.
  data: ls_sflight type sflight,
        lt_sflight type sflight occurs 0.
  data: ld_ebeln_key type lvc_nkey,
        ld_ebelp_key type lvc_nkey.
  loop at it_ekko into wa_ekko.
    perform add_ekko_node using      wa_ekko
                                     ''
                            changing ld_ebeln_key.

        wa_topnodes-nodekey = ld_ebeln_key.
        append wa_topnodes to it_topnodes.

    loop at it_ekpo into wa_ekpo where ebeln eq wa_ekko-ebeln.
      perform add_ekpo_line using      wa_ekpo
                                       ld_ebeln_key
                              changing ld_ebelp_key.
    endloop.
  endloop.
* calculate totals
  call method gd_tree->update_calculations.
* this method must be called to send the data to the frontend
  call method gd_tree->frontend_update.
endform.                    " CREATE_ALVTREE_HIERARCHY

Add code to to the ALV Tree user command functionality
*************************************************
*  EXAMPLE CODE used for demonstration purpose **
************************************************* 
*-------------------------------------------------------------------*
*       CLASS lcl_toolbar_event_receiver IMPLEMENTATION
*-------------------------------------------------------------------*
*       ........                                                    *
*-------------------------------------------------------------------*
class lcl_toolbar_event_receiver implementation.
  method on_function_selected.
    data: ls_gmsec type zgmsec,
           ld_answer type c.
    case fcode.
      when 'CHNG'.
        data: ld_uname type zgmuserparam-uname.
        data: lt_selected_node type lvc_t_nkey.
        call method tree1->get_selected_nodes
          CHANGING
            ct_selected_nodes = lt_selected_node.
        call method cl_gui_cfw=>flush.
        data l_selected_node type lvc_nkey.
        check not lt_selected_node[] is initial.
        read table lt_selected_node into l_selected_node index 1.
        call method tree1->get_outtab_line
          EXPORTING
            i_node_key    = l_selected_node
          IMPORTING
            e_outtab_line = ls_gmsec.
        if ls_gmsec-uname is initial.
          message i010(ad) with 'Please choose a valid user'.
        else.

*       Example: i.e calls screen to allow user to make chnage
          call screen 0300.

* AT this point user has returned from a screen (i.e. 300) which
* allowed them to make changes to existing data/node
* The following code deletes all the existing nodes using the top
* node table populated earlier
          loop at it_topnodes into wa_topnodes.
            call method TREE1->DELETE_SUBTREE
              EXPORTING
                i_node_key = wa_topnodes-nodekey.
          endloop.
          call method cl_gui_cfw=>flush.

* Now you need to re-select your data and re-build your hierarchy
* from scratch. for example the code could look somthing like this.
          REFRESH: it_ekko, it_ekpo.
          SELECT ebeln
          UP TO 10 ROWS
            FROM ekko
            INTO corresponding fields of TABLE it_ekko.
          loop at it_ekko into wa_ekko.
            SELECT ebeln ebelp statu aedat matnr menge meins
                   netpr peinh
              FROM ekpo
              appending TABLE it_ekpo
             where ebeln eq wa_ekko-ebeln.
          endloop.
          perform create_alvtree_hierarchy.