RestoreViewState with HTMLB-TREES/TREENODES

Question

Hello,
we want to achieve that our dynamic tree will
be built up in the state it was before we jumped onto another page. When navigating backwards, the tree
does not remember any more it treenodes properties.
Just the root is displayed, not any more the information which node was open and which not.
Also restoreViewState  = "TRUE" did not help.
Any ideas ?
Thanks.

Answer 1

Here is a complete (yet simplistic) example that proves that the serialization idea works.
Stateless Application
Page One called tree.htm
Page Attributes (Auto Flag is NOT set)
h1_isopen     TYPE     STRING
h2_isopen     TYPE     STRING
view_state     TYPE     SHSVALTAB
OnInitialization
* event handler for data retrieval
DATA: istream TYPE string,
         xslt_err TYPE REF TO cx_xslt_exception.
**** Read Server cookie
CALL METHOD cl_bsp_server_side_cookie=>get_server_cookie
   EXPORTING
     name                  = 'view_state'
     application_name      = runtime->application_name
     application_namespace = runtime->application_namespace
     username              = sy-uname
     session_id            = runtime->session_id
     data_name             = 'view_state'
   CHANGING
     data_value            = istream.
**** deserialize the Class
IF istream IS NOT INITIAL.
   TRY.
       CALL TRANSFORMATION id
       SOURCE XML istream
       RESULT view_state = view_state.
     CATCH cx_xslt_exception INTO xslt_err.
   ENDTRY.
ENDIF.
CHECK view_state IS NOT INITIAL.
FIELD-SYMBOLS: <wa_state> LIKE LINE OF view_state.
LOOP AT view_state ASSIGNING <wa_state>.
   IF <wa_state>-key CS 'Header1'.
     IF <wa_state>-value = 'O'.
       h1_isopen = 'TRUE'.
     ENDIF.
   ENDIF.
   IF <wa_state>-key CS 'Header2'.
     IF <wa_state>-value = 'O'.
       h2_isopen = 'TRUE'.
     ENDIF.
   ENDIF.
ENDLOOP.
OnInputProcessing
* event handler for checking and processing user input and
* for defining navigation
DATA: fields TYPE tihttpnvp.
request->get_form_fields( CHANGING fields = fields ).
FIELD-SYMBOLS: <wa_field> LIKE LINE OF fields,
               <wa_state> LIKE LINE OF view_state.
LOOP AT fields ASSIGNING <wa_field>.
  IF <wa_field>-name CS 'test'. "My Tree ID
    APPEND INITIAL LINE TO view_state ASSIGNING <wa_state>.
    <wa_state>-key   = <wa_field>-name.
    <wa_state>-value = <wa_field>-value.
  ENDIF.
ENDLOOP.
DATA: ostream TYPE string,
        xslt_err TYPE REF TO cx_xslt_exception.
***** serialize model class
TRY.
    CALL TRANSFORMATION id
    SOURCE view_state = view_state
    RESULT XML ostream.
****Write cookie it into the Server Cookie
    cl_bsp_server_side_cookie=>set_server_cookie( name = 'view_state'
      application_name = runtime->application_name
      application_namespace = runtime->application_namespace
      username = sy-uname
      session_id = runtime->session_id
      data_name = 'view_state'
      data_value = ostream
      expiry_time_rel = '1200' ).
  CATCH cx_xslt_exception INTO xslt_err.
ENDTRY.
navigation->goto_page( 'Navigate.htm' ).
Layout of tree.htm
<%@page language="abap" %>
<%@extension name="htmlb" prefix="htmlb" %>
<htmlb:content design="design2003" >
  <htmlb:page title=" " >
    <htmlb:form>
      <htmlb:tree id               = "test"
                  restoreViewState = "TRUE" >
        <htmlb:treeNode id     = "Header1"
                        text   = "Header1"
                        isOpen = "<%= h1_isopen %>" >
          <htmlb:treeNode id     = "Header2"
                          text   = "Header2"
                          isOpen = "<%= h2_isopen %>" >
            <htmlb:treeNode id   = "Item1"
                            text = "Item1" />
            <htmlb:treeNode id   = "Item2"
                            text = "Item2" />
          </htmlb:treeNode>
          <htmlb:treeNode id   = "Item3"
                          text = "Item3" />
          <htmlb:button text    = "test"
                        onClick = "TEST" />
        </htmlb:treeNode>
      </htmlb:tree>
    </htmlb:form>
  </htmlb:page>
</htmlb:content>
Second Page Navigate.htm (Just a dummy page to simulate Navigation)
OnInputProcessing
* event handler for checking and processing user input and
* for defining navigation
navigation->goto_page( 'tree.htm' ).
Layout for Navigate.htm
<%@page language="abap"%>
<%@extension name="htmlb" prefix="htmlb"%>
<htmlb:content design="design2003">
  <htmlb:page title = " ">
    <htmlb:form>
      <htmlb:textView     text          = "Hello World!"
                          design        = "EMPHASIZED" />
      <htmlb:button       text          = "Press Me"
                          onClick       = "myClickHandler" />
    </htmlb:form>
  </htmlb:page>
</htmlb:content>