Navigation menu and layouts

<?page title="ZK Web Flow Sample Application" contentType="text/html;charset=UTF-8"?>
<?variable-resolver class="org.zkoss.zkplus.spring.DelegatingVariableResolver" ?>

<zk xmlns="http://www.zkoss.org/2005/zul">
	<window id="pantallaLogin" visible="pantallaLoginVisible">
		<include src="/login.zul"/>
	</window>
	<borderlayout id="main" forward="onCreate=onMainCreate"
		apply="${menu}">
		<north id="cabecera">
			<include style="padding:3px;" src="/cabecera.zul"/>
		</north>
		<west title="Menu" maxsize="300" size="15%">
			<panel>
				<panelchildren>
					<listbox id="itemList" oddRowSclass="non-odd"
						itemRenderer="${main$Menu.itemRenderer}"
						model="${main$Menu.selectedModel}" fixedLayout="true"
						vflex="true">
					</listbox>
				</panelchildren>
			</panel>
		</west>
		<center>
			<include style="padding:3px;" id="xcontents" />
		</center>
	</borderlayout>
</zk>

[...]
public class Menu extends GenericForwardComposer {
	private final int NUMERO_ITEMS_MENU = 3;
	
	private final String URI_PRINCIPAL="/index1.zul";

	Listbox itemList;

	Include xcontents;
	
	Listitem selected;
	
	private boolean pantallaLoginVisible;
	
	

	private static final ListitemRenderer _defRend = new ItemRender();

	public void onMainCreate(Event event) {
		final Execution exec = Executions.getCurrent();
		final String loginParam = exec.getParameter("login");
		Window pantallaLogin=(Window)self.getFellow("pantallaLogin");
		if(loginParam!=null){
			try {
				pantallaLogin.doModal();
			} catch (SuspendNotAllowedException e) {
				e.printStackTrace();
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
			pantallaLoginVisible=true;
		}else{
			pantallaLoginVisible=false;
		}
		
		Listitem item = null;
		final LinkedList list = new LinkedList();
		final MenuItem[] items = getMenuItems();
		for (int i = 0; i < items.length; i++) {
			list.add(items<i >);
		}
		if(selected==null)
			xcontents.setSrc(URI_PRINCIPAL);
		
		if (!list.isEmpty()) {
			itemList.setModel(new ListModelList(list));
			itemList.renderAll();

		}
		


	}
	
	public ListModel getSelectedModel() {
		return new ListModelList(getMenuItems());
	}
	

	
	private static class ItemRender implements ListitemRenderer, java.io.Serializable {
		public void render(Listitem item, Object data) {
			MenuItem di = (MenuItem) data;
			Listcell lc = new Listcell();
			item.setValue(di);
			lc.setHeight("30px");			
			lc.setLabel(di.getNombre());
			lc.setParent(item);
		}
	};
	
	public void onSelect$itemList(SelectEvent event) {
		Listitem item = itemList.getSelectedItem();
		selected=item;
		if (item != null) {
			
			// sometimes the item is unloaded.
			if (!item.isLoaded()) {
				itemList.renderItem(item);
			}
			
			
			xcontents.setSrc(((MenuItem) item.getValue()).getUri());
		}
	}

	public Menu() {

	}
	
	public void setContenido(String uri){
		Include contenido=(Include)self.getFellow("xcontents");
		contenido.setSrc(uri);
		Executions.sendRedirect("");
	}
	
	public void onSetContenido(Event event){
		String label=event.getTarget().getId();
		setContenido("/"+label+".zul");
	}
	
	public ListitemRenderer getItemRenderer() {
		return _defRend;
	}

	//Aqui relleno los elementos del menu
	public MenuItem[] getMenuItems() {
		MenuItem[] menuItems = new MenuItem;
		menuItems[0] = new MenuItem("Campings", "", "/campings.zul");
		menuItems[1] = new MenuItem("Camping2", "", "/camping1.zul");
		menuItems[2] = new MenuItem("Camping3", "", "/camping3.zul");
		return menuItems;
	}
	
	public boolean isPantallaLoginVisible() {
		return pantallaLoginVisible;
	}

	public void setPantallaLoginVisible(boolean pantallaLoginVisible) {
		this.pantallaLoginVisible = pantallaLoginVisible;
	}

}

<?page title="new page title" contentType="text/html;charset=UTF-8"?>
<hbox apply="${campingBean}">
CAmpings
<button id="btn_prueba" label="prueba"/>
</hbox>

[...]
public class CampingBean extends GenericForwardComposer{
	private CampingBusiness campingBusiness;
	private Menu menu;
	
	
	public void onClick$btn_prueba(Event event){
		menu.setContenido("/prueba.zul");
	}
	
	//getter and setters
}