PrimeFaces AccordionPanel - onTabChange and onTabShow Events

This tutorial explains the event change listeners used along with the AccordionPanel component. The onTabChange is called before a tab is displayed to the user and onTabShow is called after displayed to the user. Both receive container element of the tab to show as a parameter.

At the other hand tabChange is the one and only ajax behavior event for accordion panel that’s executed when a tab is toggled. It is used inside the sub-element p:ajax. Your listener (if defined) will be invoked with an org.primefaces.event.TabChangeEvent instance that contains a reference to a new active tab and the accordion panel itself.

Read : PrimeFaces Tutorials

Look at the below sample code to understand how to use the tab change listener in AccordionPanel.

1. Managed Bean

AccordionPanel.java

package net.javabeat.primefaces;

import javax.faces.bean.ManagedBean;
import javax.faces.bean.SessionScoped;

import org.primefaces.event.TabChangeEvent;

@ManagedBean
@SessionScoped
public class AccordionPanel {
	private String messageOne = "Hello JavaBeat One";
	private String messageTwo = "Hello JavaBeat Two";
	private String messageThree = "Hello JavaBeat Three";

	public String getMessageOne() {
		System.out.println("Message One Loaded");
		return messageOne;
	}
	public void setMessageOne(String messageOne) {
		this.messageOne = messageOne;
	}
	public String getMessageTwo() {
		System.out.println("Message Two Loaded");
		return messageTwo;
	}
	public void setMessageTwo(String messageTwo) {
		this.messageTwo = messageTwo;
	}
	public String getMessageThree() {
		System.out.println("Message Three Loaded");
		return messageThree;
	}
	public void setMessageThree(String messageThree) {
		this.messageThree = messageThree;
	}
	public void changeListener(TabChangeEvent e){
		System.out.println("TabChangeEvent Has Fired By ::"+e.getSource());
		System.out.println("The next Tab Title is :: "+e.getTab().getTitle());
	}
}

2. The View

index.xhtml

<html xmlns="http://www.w3.org/1999/xhtml"
	xmlns:ui="http://java.sun.com/jsf/facelets"
	xmlns:h="http://java.sun.com/jsf/html"
	xmlns:f="http://java.sun.com/jsf/core"
	xmlns:p="http://primefaces.org/ui">
	<h:head>
		<script name="jquery/jquery.js" library="primefaces"></script>
		<script>
			function onTabChange(panel){
				alert('Client Callback : Before Tab Being Changed');
			}

			function onTabShow(panel){
				alert('Client Callback : After Tab Been changed');
			}
		</script>
	</h:head>
	<f:view>
		<h:form prependId="false">
			<h1>JavaBeat Primefaces Example</h1>
			<h2>Primefaces AccordionPanel</h2>
			<br/>
			<p:accordionPanel onTabShow="onTabShow(panel)" onTabChange="onTabChange(panel)">
				<p:ajax event="tabChange" listener="#{accordionPanel.changeListener}"></p:ajax>
				<p:tab title="First Tab Title">
					<h:outputText value="#{accordionPanel.messageOne}"></h:outputText>
				</p:tab>
				<p:tab title="Second Tab Title">
					<h:outputText value="#{accordionPanel.messageTwo}"></h:outputText>
				</p:tab>
				<p:tab title="Third Tab Title">
					<h:outputText value="#{accordionPanel.messageThree}"></h:outputText>
				</p:tab>
			</p:accordionPanel>
		</h:form>
	</f:view>
</html>

3. AccordionPanel onTabChange and onTabShow Events Demo

The below snapshots show you the application behavior once you’ve used the client side callbacks and the Ajax event of the p:accordionPanel component in your application.

This client side callback has been invoked once the user has activated the second Tab.
The callback JavaScript method does define a parameter for the accordionPanel itself.

The client side callback has been invoked after the user has activated the second Tab.
The callback JavaScript method does define a parameter for the accordionPanel itself.

The listener of the TabChange event has been invoked.
The TabChangeEvent provides references for the accordion panel itself and for the tab being activated.

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1. Managed Bean

2. The View

3. AccordionPanel onTabChange and onTabShow Events Demo

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