Programming dynamic abap code

Question

i want to build up a tree with te data of some internal tables.
i have programmed the following coding:
FORM build_node_and_item_table USING pt_node_table TYPE treev_ntab
                                     pt_item_table TYPE item_table_type.
  CLEAR l_index.
  LOOP AT lt_verfasser INTO ls_verfasser.
    l_key = ls_verfasser-key.
    CONCATENATE 'Root' l_key
                INTO ls_text SEPARATED BY '/'.
    CONDENSE ls_text NO-GAPS.
    l_root = ls_text.
    ls_node-node_key = l_root.
    CLEAR ls_node-relatkey.      " Special case: A root node has no parent
    CLEAR ls_node-relatship.                " node.
    ls_node-hidden = ' '.                   " The node is visible,
    ls_node-disabled = ' '.                 " selectable,
    ls_node-isfolder = 'X'.                 " a folder.
    CLEAR ls_node-n_image.       " Folder-/ Leaf-Symbol in state "closed":
    " use default.
    CLEAR ls_node-exp_image.     " Folder-/ Leaf-Symbol in state "open":
    " use default
    CLEAR ls_node-expander.                 " see below.
    " the width of the item is adjusted to its content (text)
    APPEND ls_node TO pt_node_table.
    CLEAR ls_item.
    ls_item-node_key = ls_text.
    ls_item-item_name = '1'.
    ls_item-class = cl_gui_list_tree=>item_class_text. " Text Item
    " the with of the item is adjusted to its content (text)
    ls_item-alignment = cl_gui_list_tree=>align_auto.
    " use proportional font for the item
    ls_item-font = cl_gui_list_tree=>item_font_prop.
    CONCATENATE sy-datum
                ls_verfasser-name
                ls_verfasser-rolle
                INTO ls_text SEPARATED BY space.
    ls_item-text = ls_text.
    APPEND ls_item TO pt_item_table.
* Schmerz
    READ TABLE lt_schmerz INTO ls_schmerz WITH KEY ls_verfasser-key.
    IF sy-subrc = 0.
      CLEAR ls_node.
      l_key = l_index.
      CONCATENATE 'FO_Schmerz' l_key
                  INTO ls_text SEPARATED BY '/'.
      CONDENSE ls_text NO-GAPS.
      l_node_schmerz = ls_text.
* Node with key 'Child1'
      CLEAR ls_node.
* Achtung node_key darf nur 12 Zeichen lang sein!!!
      ls_node-node_key = l_node_schmerz.
      " Key of the node
      " Node is inserted as child of the node with key 'Root'.
      ls_node-relatkey = l_root.
      ls_node-relatship = cl_gui_list_tree=>relat_last_child.
      ls_node-isfolder = 'X'.
      APPEND ls_node TO pt_node_table.
* Node with key 'Child1'
      CLEAR ls_item.
      ls_item-node_key = l_node_schmerz.
      ls_item-item_name = '1'.
      ls_item-class = cl_gui_list_tree=>item_class_text.
      ls_item-alignment = cl_gui_list_tree=>align_auto.
      ls_item-font = cl_gui_list_tree=>item_font_prop.
      ls_item-text = 'Schmerz'(004).
      APPEND ls_item TO pt_item_table.
      LOOP AT lt_schmerz INTO ls_schmerz
        WHERE key = ls_verfasser-key.
        l_tabix = sy-tabix.
        CLEAR ls_node.
        l_key = l_tabix.
        CONCATENATE 'IT_Schmerz' l_key
                    INTO ls_text SEPARATED BY '/'.
        CONDENSE ls_text NO-GAPS.
        ls_node-node_key = ls_text.
        ls_node-relatkey = l_node_schmerz.
        ls_node-relatship = cl_gui_list_tree=>relat_last_child.
        APPEND ls_node TO pt_node_table.
* Items of node with key 'New1'
        CLEAR ls_item.
        ls_item-node_key = ls_text.
        ls_item-item_name = '1'.
        ls_item-class = cl_gui_list_tree=>item_class_text.
        CONCATENATE ls_schmerz-ort
                    ls_schmerz-wo
                    ls_schmerz-art
                    ls_schmerz-kommentar
        INTO ls_text SEPARATED BY space.
        l_length = STRLEN( ls_text ).
        ls_item-length = l_length.
        ls_item-ignoreimag = 'X'.               " see documentation of Structure
        " TREEV_ITEM
*  ls_item-usebgcolor = 'X'.               " item has light grey background
*  ls_item-t_image = '@01@'.               " icon of the item
        ls_item-text = ls_text.
        APPEND ls_item TO pt_item_table.
      ENDLOOP.
    ENDIF.
** Ernährung
*    READ TABLE lt_ernaehrung INTO ls_ernaehrung WITH KEY ls_verfasser-key.
*    IF sy-subrc = 0.
*      CLEAR ls_node.
*      l_key = l_index.
*      CONCATENATE 'FO_Ern' l_key
*                  INTO ls_text SEPARATED BY '/'.
*      CONDENSE ls_text NO-GAPS.
*      l_node_ern = ls_text.
** Node with key 'Child1'
*      CLEAR ls_node.
** Achtung node_key darf nur 12 Zeichen lang sein!!!
*      ls_node-node_key = l_node_ern.
*      " Key of the node
*      " Node is inserted as child of the node with key 'Root'.
*      ls_node-relatkey = l_root.
*      ls_node-relatship = cl_gui_list_tree=>relat_last_child.
*      ls_node-isfolder = 'X'.
*      APPEND ls_node TO pt_node_table.
** Node with key 'Child1'
*      CLEAR ls_item.
*      ls_item-node_key = l_node_ern.
*      ls_item-item_name = '1'.
*      ls_item-class = cl_gui_list_tree=>item_class_text.
*      ls_item-alignment = cl_gui_list_tree=>align_auto.
*      ls_item-font = cl_gui_list_tree=>item_font_prop.
*      ls_item-text = 'Ernährung'(004).
*      APPEND ls_item TO pt_item_table.
*      LOOP AT lt_ernaehrung INTO ls_ernaehrung
*        WHERE key = ls_verfasser-key.
*        l_tabix = sy-tabix.
*        CLEAR ls_node.
*        l_key = l_tabix.
*        CONCATENATE 'IT_Ern' l_key
*                    INTO ls_text SEPARATED BY '/'.
*        CONDENSE ls_text NO-GAPS.
*        ls_node-node_key = ls_text.
*        ls_node-relatkey = l_node_ern.
*        ls_node-relatship = cl_gui_list_tree=>relat_last_child.
*        APPEND ls_node TO pt_node_table.
** Items of node with key 'New1'
*        CLEAR ls_item.
*        ls_item-node_key = ls_text.
*        ls_item-item_name = '1'.
*        ls_item-class = cl_gui_list_tree=>item_class_text.
*        CONCATENATE ls_ernaehrung-art
*                    ls_ernaehrung-kommentar
*                    ls_ernaehrung-hilfsmittel
*                    ls_ernaehrung-bericht
*        INTO ls_text SEPARATED BY space.
*        l_length = STRLEN( ls_text ).
*        ls_item-length = l_length.
*        ls_item-ignoreimag = 'X'.               " see documentation of Structure
*        " TREEV_ITEM
**  ls_item-usebgcolor = 'X'.               " item has light grey background
**  ls_item-t_image = '@01@'.               " icon of the item
*        ls_item-text = ls_text.
*        APPEND ls_item TO pt_item_table.
*      ENDLOOP.
*    ENDIF.
* Index vor dem nächsten Durchlauf um 1 erhöhen
    l_index = l_index + 1.
  ENDLOOP.
ENDFORM.   
This works fine and the data is displayed in the alv-tree. I would like to programm this a little more dynamic because of lines of code. As you see, I commented the data filling of the tree with the data of the second internal table.
I'd like to programm the coding so dynamic, that i would only use the coding i have posted, without copying the code for each internal table.
Could you please help me how to do this.
I thought about a internal table, where i collect the names of the tables which should be displayed in the alv tree.
but how do i create the internal tables dynamicly. i would also use a work area for the loop of the internal tables. how could i create the work area dynamicly?
I hope anyone could help my to spare some lines of code and make my posted coding dynamicly.
Thanks very much!
Greetings!

Answer 1

You could try researching the way SAPLink works to import that kind of objects, it creates those (and other) kinds of objects based on data in XML files (nuggets and slinkees). You could adapt it to create them based on your kind of input instead.
A word of caution though, I'm not sure it uses only SAP approved methods / APIs to achieve that. For instance, I know (from Thomas Jung's comments in other threads) that the APIs used in SAPLink to import Web Dynpro components are SAP internal and not intended to be used by customer developers; however to date there was no public API to do that.
SAPLink's site: http://saplink.org/
Regards
Edited by: Alejandro Bindi on Aug 11, 2009 6:54 PM