Dynamic ui include and commandButton

问题:

I have a page which includes content from another page dynamically (this is done by a method in the bean)

firstPage.xhtml

<ui:include src="#{managedBean.pageView}">
    <ui:param name="method" value="#{managedBean.someAction}"/>
</ui:include>

This redirects to a secondPage which is within <ui:composition> which has commandButton.

secondPage.xhtml

<ui:composition>
..
..
<p:commandButton actionListener=#{method} value="Submit"/>
</ui:composition>

ManagedBean

public String pageView(){
return "secondPage.xhtml";
}

public void someAction(){
*someAction*
}

The commandButton in the secondPage.xhtml is not working.

Any help shall be much appreciated.

回答1:

You can't pass method expressions via <ui:param>. They're interpreted as value expression.

You've basically 3 options:

1. Split the bean instance and the method name over 2 parameters:

   <ui:param name="bean" value="#{managedBean}" />
   <ui:param name="method" value="someAction" />
   

   And couple them in the tag file using brace notation [] as follows:

   <p:commandButton action="#{bean[method]}" value="Submit" />
   

   ---

2. Create a tag handler which converts a value expression to a method expression. The JSF utility library OmniFaces has a <o:methodParam> which does that. Use it as follows in the tag file:

   <o:methodParam name="action" value="#{method}" />
   <p:commandButton action="#{action}" value="Submit" />
   

   ---

3. Use a composite component instead. You can use <cc:attribute method-signature> to define action methods as attributes.

   <cc:interface>
       <cc:attribute name="method" method-signature="void method()"/>
   </cc:interface>
   <cc:implementation>
       <p:commandButton action="#{cc.attrs.method}" value="Submit"/>
   </cc:implementation>
   

   Which is used as follows:

   <my:button method="#{managedBean.someAction}" />