By using meaningful graphics as icons, you can draw your users’ attention
toward important parts of your portlet. Using icons also enhances your portlet’s
design. Think of it as wrapping your portlet up in a nice, user-friendly bow.
You can display icons in your portlets with the
liferay-ui:icon taglib. See
the figure below for an example of icons being used in a portlet.
Now it’s time to go icon crazy! Get started by learning how to use Liferay’s icons in your portlets.
Liferay has a wide variety of icons that you can use in your portlets. They are
located in your
Follow these steps and you’ll be using them in no time:
view.jspof your portlet.
Reference the liferay-ui and portlet taglibs by adding the following taglib declarations to the top of your
<%@ taglib uri="http://liferay.com/tld/ui" prefix="liferay-ui" %> <%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet" %>
Now that you have the proper taglibs referenced, you can use
view.jsp to add icons to your portlet.
To use an icon, declare its name (without file extension) in the image attribute
liferay-ui:icon. The code below uses Liferay’s Add icon in a portlet:
view.jsp that includes the icon would look like this:
<%@ taglib uri="http://liferay.com/tld/ui" prefix="liferay-ui" %> <%@ taglib uri="http://java.sun.com/portlet_2_0" prefix="portlet" %> <portlet:defineObjects /> This is the <b>icon example</b> portlet. <liferay-ui:icon image="add"/>
The figure below illustrates the code above:
Congrats! You have successfully added an icon to a portlet! Note that the icon in
the example appears near the top of the portlet. The position of the icon in the
portlet is dictated by the position of
liferay-ui:icon relative to other items
There are a few more attributes for
liferay-ui:icon that can take your design
to the next level. What if you want to link an icon to a site? No problem! Just
url attribute with the site URL to
liferay-ui:icon. For example, this
code creates a URL to the Liferay home page using the add icon:
<liferay-ui:icon image="add" url="http://www.liferay.com" />
You can also change the tool tip that appears when you hover your mouse over the
icon. By default, the tool tip is just the name of the icon. This can be useful,
but sometimes it isn’t sufficiently descriptive. For example, you might want to
use the tool tip to suggest the user take a specific action. Implementing this is
a piece of cake! Just add a
message attribute to
liferay-ui:icon with the
text you wish to display. The next bit of code defines a message that tells your
user to click the icon.
<liferay-ui:icon image="add" url="http://www.liferay.com" message="click here"/>
Now that you have an understanding of how to use Liferay’s icons in your portlet, it’s time to use some of your own!
The process for adding your own icons in a portlet is similar to the process of using Liferay’s icons. There are just a few minor but important differences.
You should note that
liferay-ui:icon uses sprites that hold multiple icons.
For instance, all of the navigation icons are in one
_sprite.png file. When
you use one of the navigation icons, you are grabbing the icon from a larger
group of icons in a single sprite file.
You may be thinking, “What is all this sprite talk? I’m not thirsty!”. In this case, a sprite refers to an image sprite. An image sprite is a group of images that are combined into one single image. Why do developers do this? To make their sites load faster. Each image loaded by the browser is a separate HTTP request to the server. By combining multiple icons into one larger image, you can turn 12, 20, or even 100 separate HTTP requests into just one. Thus, using sprites greatly decreases load times and increases efficiency.
Lucky for you, Liferay automatically generates sprites of your icons as long as
they are placed in the proper folder. When it comes to portlets, sprites are
only generated for
png files located in the
To put your own icons in your portlet, just add a
src attribute to
liferay-ui:icon that points to the location of your custom icon. For example,
this bit of code puts
/name-of-your-portlet/icons/my-custom-icon.png in your
<liferay-ui:icon image="my-custom-icon" src="/name-of-your-portlet/icons/my-custom-icon.png" />
Deploy your portlet and your new icon appears inside it. Congrats! You have learned how to use your own icons in a portlet!