A Tip for the Fade Effect in Primefaces Components

I was trying to fade in a Primefaces panel component that was initially hidden and found it to be somewhat of a struggle. After a bit of googling, the only thing I found out was that I wasn’t the first to come across the problem. Here’s the basic JSF code to use an effect on a panel in response to the button click.

<p:button id="showme" value="Show Me" onclick="return false">
	<p:effect type="fade" event="click" for="myPanel"/>
</p:button>

<h:panelGroup layout="block" id="myPanel" style="display:none">Show Me</h:panelGroup>

This code does nothing because by default the fade effect fades out the component. Looking at the options for the fade gives us no clues either since it claims there are no parameters. The solution is to provide a mode parameter that can be either show or hide which is used for most of the effects. In our case, we want to show the component.

<p:button id="showme" value="Show Me" onclick="return false">
	<p:effect type="fade" event="click" for="myPanel">
		<f:param name="mode" value="'show'"/>
	</p:effect>
</p:button>

<h:panelGroup layout="block" id="myPanel" style="display:none">Show Me</h:panelGroup>

This will show the panel that was initially hidden when you click the button. The only nagging problem is that the button retains its hover style until you click elsewhere in the page.

From http://www.andygibson.net/blog/quickbyte/fading-in-primefaces-components/