Web Dynpro Tree expanding

Question

Hi there!
I am using the tree element in web dynpro.
Not the tree in the table.
I need to expand a part of the tree during loading
I do not find an example.
Any help is warmly appreciated.
Thanks in advance, Frank

Answer 1

Hi,
the "dynamic" tree expansion depends on who you populate the tree content e.g. how you load the data to your tree.
In my application, I have choosen to load the root nodes, first - all over sub-nodes (including items) are loaded "on demand" that means the user clicks on the node. This click will trigger the the action onLoadChildren which pulls the data from a data provider and binds the retrieved data to the corresponding
context node.
This expansion can be perfomed automatically by a recursive method which is called when a user pushes a button called "Expand all"....
I don't have much time to explain the details, but I will provided the source code..., hope it helps!
Darko
Source Code -
Import to the Method:
i_node_ref type IF_WD_CONTEXT_NODE = Reference to the context node
METHOD nav_tree_expand_all.
Data declaration
  DATA node_elements TYPE wdr_context_element_set.
  DATA node_element  LIKE LINE OF node_elements.
  DATA child_node    TYPE REF TO if_wd_context_node.
  DATA ls_tree_attr  TYPE zlm_str_tree_gen.
  DATA lt_tree       TYPE zlm_tty_tree_gen.
Get all node elements
  node_elements = i_node_ref->get_elements( ).
Loop over each element
  LOOP AT node_elements INTO node_element.
    " Get Static attributes
    node_element->get_static_attributes( IMPORTING static_attributes = ls_tree_attr ).
    " Check if data has already been loaded
    IF ls_tree_attr-children_loaded = abap_true.
      " now we know that the data has been loaded, only the elements have to be declared as expanded
      ls_tree_attr-is_expanded = abap_true.
      node_element->set_static_attributes( EXPORTING static_attributes = ls_tree_attr ).
      " get possible other nodes recursively
      child_node = node_element->get_child_node( 'SUBTREE' ).
      me->nav_tree_expand_all( EXPORTING i_node_ref      = child_node
                                         i_screen_id     = i_screen_id
                                         i_component_id  = i_component_id ).
    ELSE.
      " data has not been loaded yet...
      " First load the nodes...
     clear lt_tree.
      me->get_nav_tree_nodes( .....importing lt_tree.). Custom specific data retrieval
      IF lt_tree IS NOT INITIAL.
        child_node = node_element->get_child_node( 'SUBTREE' ).
        child_node->bind_table( lt_tree ).
        " Update Attributes of the node
        ls_tree_attr-is_expanded     = abap_true.
        ls_tree_attr-children_loaded = abap_true.
        node_element->set_static_attributes( EXPORTING static_attributes = ls_tree_attr ).
        " Call the method again recursively...
        me->nav_tree_expand_all( EXPORTING i_node_ref      = child_node
                                           i_screen_id     = i_screen_id
                                           i_component_id  = i_component_id ).
      ENDIF.
      " ... then load the items
      CLEAR lt_tree.
      me->get_nav_tree_items( .....importing lt_tree.).  Custom specific data retrieval
      IF lt_tree IS NOT INITIAL.
        " Update Attributes of the node
        ls_tree_attr-is_expanded     = abap_true.
        ls_tree_attr-children_loaded = abap_true.
        node_element->set_static_attributes( EXPORTING static_attributes = ls_tree_attr ).
        child_node = node_element->get_child_node( 'ITEM' ).
        child_node->bind_table( lt_tree ).
      ENDIF.
    ENDIF.
  ENDLOOP.
  RETURN.
Edited by: Darko Mocelj on May 7, 2008 8:57 PM