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Hi I am using p:layout component.

p:layout style="min-width:400px;min-height:200px;" id="layout">  
    <p:layoutUnit position="west" resizable="true" size="100" minSize="40" maxSize="200">  

        <p:panel id="pnl" header="Help" toggleable="true"  toggleSpeed="500" 
        closeSpeed="500" widgetVar="panel" style="width:265px" rendered="#{backBean.renderPanel}">  
</p:panel>
<p:dataGrid var="sample" value="#{backBean.list}"
                            columns="1" style="margin-left: -5px;width: 275px; border:none;"
                            rows="7" >

                            //displaying some values from list here

</p:dataGrid>
        <p:poll interval="3"   
            listener="#{backBean.check}" update="pnl" />  
    </p:layoutUnit>  

    <p:layoutUnit position="center">  
        Center  
    </p:layoutUnit>

Now I want to render panel as shown above when list is empty,if its empty then panel will not get rendered. So I as we know we have p:poll component which automaticallly updates any particular panel or any else component after specified interval. So I have applied poll listener and checking list size in this way.

public void check(){

    if(list.size>0){
    renderPanel=false;
    }
    else{
    renderPanel=true;
    }
    }
which is working fine . I am getting value of renderPanel flag as true when list is empty , but still my panel is not rendering.
why is it so? what I am missing?

My backing bean code for renderPanel flag :



@ManagedBean
@ViewScoped
    class BackBean implements Serializable{

    private  boolean renderPanel=false;
        public boolean isRenderPanel() {
        return renderPanel;
    }


    public void setRenderPanel(boolean renderPanel) {
        this.renderPanel = renderPanel;
    }



    }

How should I render my panel ?

4

1 回答 1

1

您需要更新面板的父级，因为它在第一次不存在时无法重新渲染：

<h:panelGroup id="pnl">
    <p:panel header="Help" toggleable="true"  toggleSpeed="500" closeSpeed="500" widgetVar="panel" style="width:265px" rendered="#{backBean.renderPanel}">  
    </p:panel>
</h:panelGroup>

现在pnl将永远存在rendered="#{}"，而不是它的孩子的属性。

于 2013-04-30T17:01:07.910 回答