primefaces p:ajax return value

问题

I have a JSF 2.2 app with primefaces 4.0. I have a page with some checklboxes. What I want to acomplish is that when I click on one checkbox an ajax request to be fired to my managed bean. That request will hit a method that will return a string. So i do no need to update an element, but to get back the string in js, because if i achieve that then I can return an JSON.
I have this piece of code :

<p:selectManyCheckbox  id="queues" value="#{viewAssignUsersMB.queueIds}" layout="grid" columns="3" converter="javax.faces.Long" converterMessage="Error."> 
<f:selectItems  value="#{viewAssignUsersMB.queues}" 
                var="queue" 
                itemValue="#{queue.id}" 
                itemLabel="#{queue.application.name}"/>
<p:ajax  process="@this" partialSubmit="true" event="change" listener="#{viewAssignUsersMB.xxx()}" async="true" oncomplete="handleSaveRequest(xhr, status, args)"/>

and this method in backing bean :

public void xxx(){  
  RequestContext.getCurrentInstance().addCallbackParam("stringToBePassed","TriluLilu");
}

and my js callback method:

function handleSaveRequest(xhr, status, args) { 
    alert('User with username ' +args.stringToBePassed+ ' is saved successfully');
}

My main problem now is that I do not know how to detect what checkbox was last pressed as in my backing bean I have all the checked checkboxes (#{viewAssignUsersMB.queueIds})...
Is there a better approach for that, as this is a pretty common scenario/ What is the "classic" way to achieve that ... ?

回答1:

You can achieve this by using a remoteCommand.

First: Hook onchange event on all the checkboxes inputs.
Second: In the event function handler, get the element value, and pass the value to the remoteCommand.
Third: Read the value in the backing bean, as a request parameter.

xhtml

 <p:selectCheckboxMenu id="selectCheckboxMenuId" widgetVar="selectCheckWV">  
    <f:selectItems value="#{mainBean.map}" />                              
 </p:selectCheckboxMenu>  
 <p:remoteCommand name="submitNewCheckBoxValue" 
                  process="@this selectCheckboxMenuId"
                  actionListener="#{mainBean.sendLastCheckedBox()}" />

javascript

<script>
   $(document).ready(function() {
      PF('selectCheckWV').inputs.change(function() {
         if($(this).prop('checked'))
            submitNewCheckBoxValue([{name: 'submitedValue', value: $(this).val()}]);
      });
   });
</script>

managedBean

public void sendLastCheckedBox() {
    FacesContext facesContext = FacesContext.getCurrentInstance();
    Map map = facesContext.getExternalContext().getRequestParameterMap();
    String submitedValue = (String) map.get("submitedValue");
    FacesMessage facesMessage = new FacesMessage(submitedValue);
    facesContext.addMessage(null, facesMessage);
}

Here's a working Demo, and a small example on github [1][2]

Hope this helps.

来源：https://stackoverflow.com/questions/24165066/primefaces-pajax-return-value

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jsf-2

primefaces