Using selectedIndex of UIX choice element?

Question

I'm a bit embarrased that I can't figure this out - it's probably very simple.
I have a messageChoice element on a UIX page, and I'd like to render the page differently based on which option is currently selected. To do this, I figure I can just use an event handler to maintain a value in the page state, tie the event handler to the messageChoice element, and use a switcher referencing that value on the page state to choose between the different sets of elements I want to render.
I added a <primaryClientAction> element to the messageChoice element, a <fireAction> element to that, and tied the event to an event handler. All of this is correct, and I can verify that the event handler runs via a breakpoint and the debugger.
I just can't figure out how to pass the selected index to the event handler! I assume you just add a parameter to the event, but I haven't the slightest clue how to reference the selectedIndex attribute of the messageChoice element from within the UIX page.
I've been searching for hours! Not sure what's wrong with me, but I can't find the solution.
A little help would be hugely appreciated =]
-Matt

Answer 1

Here are some examples that should help you. I have to go fix a high priority bug right now, so I can't mock up a choice example:
<lovChoice name="lovChoiceName" prompt="hello" tip="this is a tip"
                                        destination="lovChoice_DemoDlg.uix" selectedValue="${sessionScope.userDataForLovChoice.favoriteVacation.location}">
  <contents   childData="${sessionScope.userDataForLovChoice.vacationSpots}">
  <option text="${uix.current.location}" value="${uix.current.location}"/>
  </contents>
<primaryClientAction>
<firePartialAction targets="selectedValueTextID selectedValueTextID2 selectedValueTextID3 lovChoiceID"
                                                         event="lovChoiceUpdate"/>
</primaryClientAction>
</lovChoice>and the event handler calls a java method:
    <event name="lovChoiceUpdate">
      <method class="oracle.cabo.servlet.demo.lovchoice.LovChoiceEvents"
              method="handleLovChoiceUpdateEvent"/>
    </event>and this method gets the parameter:
   * handleLovChoiceUpdateEvent
   * @param context the current baja context
   * @param Page the current page
   * @param event the event that got us here
   * @return The event result containing all the parameters
  public static EventResult handleLovChoiceUpdateEvent(
    BajaContext bc,
    Page page,
    PageEvent event)
    HttpSession sess = bc.getServletRequest().getSession();
    UserData uData = _getUserData(sess);
    String selectedLocation = (String)event.getParameter("lovChoiceName");
    if (uData != null && selectedLocation != null)
      VacationSpot favVacation =  uData.findVacationSpot(selectedLocation);
      uData.setFavoriteVacation(favVacation);
    return null;
  }  To do it simpler, you can do something like this:
In the following example the page property named "disclosed" is updated to the event source. Notice that data binding is supported.
<set target="${uix.pageProp}"
property="disclosed"
value="${param.source}" />
In the following example the session attribute identified by the event source is updated to the event name.
<set target="${sessionScope}"
property="${param.source}"
value="${param.event}" />
(I got this information from the UIX Element Reference).
Here's an example I found for hide/show:
             <hideShow id="hideShow-2" >
              <boundAttribute name="disclosed" >
               <comparison type="equals" >
                <defaulting>
                 <dataObject select="hideShow-2"
                             source="${uix.pageState}" />
                 <fixed text="hide" />
                </defaulting>
                <fixed text="show" />
               </comparison>
              </boundAttribute>
              <contents>
               <header text="Other Header">
                <contents>
                 <header text="Other SubHeader"/>
                </contents>
               </header>
              </contents>
             </hideShow>
    <event name="hide show">
      <set
             property="${param.source}" target="${uix.pageState}" value="${param.event}"/>
    </event>Jeanne