Automattic

Widgetizing Themes

This page contains technical instructions on updating a theme for use with widgets. Many themes can be updated in five to ten minutes. Others will take an hour or two to get all of the kinks worked out. Some will look awful no matter what you do. This document assumes basic PHP editing skills, though you probably won’t have to write any code of your own.

I’m a theme author. What’s with all this email asking me to update my theme?

You should be happy they like your theme well enough to contact you rather than switch to somebody else’s themes. Well done on making users happy! We’re making this plugin available now to see how the WordPress community likes it and to give people a chance to write widgets. If all goes well, this feature will be integrated into the standard WordPress distribution and any themes that don’t support widgets will, if you believe our crystal ball, become very unpopular very fast.

We’re sorry if that seems threatening. It hurt us more than it hurt you. Please fix up your theme.

I give in. How do I fix up my theme?

First you have to ask yourself, “Do I know anything about my theme? Does it use an unordered list to create the sidebar?” (If you can’t answer that, you’ll need in-depth help on this task and that usually means paying somebody a lot of money or asking very nicely at the forums. Better yet, you can learn HTML. Sorry, we don’t teach that here.)

Here is an example of good sidebar markup:

<ul id="sidebar">
 <li id="about">
  <h2>About</h2>
  <p>This is my blog.</p>
 </li>
 <li id="links">
  <h2>Links</h2>
  <ul>
   <li><a href="http://example.com">Example</a></li>
  </ul>
 </li>
</ul>

Notice that the entire sidebar is an unordered list and the titles are in <h2> tags. Not every theme is built this way and it’s not necessary to do so, but it’s currently the most common sidebar markup in the themes we surveyed so we adopted it. The element with id=”links” is the equivalent of one basic widget.

When activated, the Dynamic Sidebar plugin gives you a few functions to use in your template just like template tags. These functions let WordPress replace your theme’s sidebar with a dynamic one while still falling back on the old sidebar in case you deactivate the plugin or remove all the widgets.

Here is an example of a basic sidebar upgrade using the same markup as above:

<ul id="sidebar">
<?php if ( !function_exists('dynamic_sidebar')
        || !dynamic_sidebar() ) : ?>
 <li id="about">
  <h2>About</h2>
  <p>This is my blog.</p>
 </li>
 <li id="links">
  <h2>Links</h2>
  <ul>
   <li><a href="http://example.com">Example</a></li>
  </ul>
 </li>
<?php endif; ?>
</ul>

See? We just added two lines to the template and now it’ll display a dynamic sidebar if possible, otherwise display the old sidebar. Disabling the plugin or removing all the widgets from the sidebar in the admin interface will cause the old sidebar to be displayed.

Now there is one more thing to be done to the theme. Assuming you are using WordPress 2.0 or higher, this change will be made within functions.php in your theme’s directory. (WordPress 1.5 users: we don’t encourage people to use WordPress 1.5 anymore, so you won’t find any help here. We don’t even know if it’s possible because it hasn’t been tested.)

Here is an example of functions.php for a theme that does not yet have such a file (no blank lines at the beginning or end of the file, please):

<?php
if ( function_exists('register_sidebar') )
    register_sidebar();
?>

That’s it, just four lines. This code tells the plugin that your theme will need exactly one dynamic sidebar. At this point, your admin interface should have an extra item in the Presentation menu: Sidebar Widgets. Try dragging some widgets from the palette on the left into the box marked Sidebar 1 and saving your changes. Got it working? Fantastic.

My sidebar isn’t a list. What do I do?

We knew you’d ask that. You’ll have to discover your sidebar’s design pattern, then use some extra parameters to tell the plugin how to format them to work with your theme. We’ll work through one example.

Here’s the original markup:

<div id="sidebar">
 <div class="title">About</div>
 <p>This is my blog.</p>
 <div class="title">Links</div>
 <ul>
  <li><a href="http://example.com">Example</a></li>
 </ul>
</div>

Yes, we’ve seen markup like this. It’s the second most common sidebar design pattern, which is why we chose it for the example. The first difference is that the sidebar is not built inside a <ul> tag. That means we should not be wrapping any of our widgets in <li> tags. The second difference is that our titles are wrapped in <div class=”title”> instead of <h2> tags.

We prefer to change the markup to our ul/li/h2 standard, but the API is powerful enough that we don’t have to. Instead, we fix these issues by adding some parameters to the code in functions.php:

<?php
if ( function_exists('register_sidebar') )
    register_sidebar(array(
        'before_widget' => '',
        'after_widget' => '',
        'before_title' => '<div class="title">',
        'after_title' => '</div>',
    ));
?>

And here is the sidebar.php markup with our special template tags inserted:

<div id="sidebar">
<?php if ( !function_exists('dynamic_sidebar')
        || !dynamic_sidebar() ) : ?>
 <div class="title">About</div>
 <p>This is my blog.</p>
 <div class="title">Links</div>
 <ul>
  <li><a href="http://example.com">Example</a></li>
 </ul>
<?php endif; ?>
</div>

That’s it. Your HTML markup is taken care of.

Well, mostly taken care of. The default before_widget is a little bit more than just <li>. It includes an id and class. Well, sort of, but this is where it gets complicated. The default before_widget includes sprintf directives %1$s and %2$s, which are replaced by the id and class, respectively. The id is generated by sanitizing the widget name (which is why you should name your widget carefully: you don’t want duplicate id’s in one HTML document!) and the class is generated from the widget’s callback. This ensures all Text and RSS widgets, for
instance, have unique id’s and similar classnames. Additionally, there is a “widget” class for each widget.

So, if you want your theme to be most flexible you should use this instead of
the empty strings shown above:

    'before_widget' => '<div id="%1$s" class="widget %2$s">',
    'after_widget' => '</div>',

Now your HTML markup is REALLY taken care of.

The HTML looks good but the page looks awful in the browser!

Yeah, we knew that would happen. Your theme was probably written before widgets were born so the author didn’t know she should make the stylesheet flexible enough to handle new markup in the sidebar. If you know some CSS, you should be able to handle the problems with a few new rules at the end of your stylesheet. Look in your blog’s markup for the selectors (id and/or class) belonging to each widget you want to style.

If CSS is a mystery to you, we regret that we can’t offer you any help. As much as we’d like to help you with this, it just isn’t possible due to the wild variations of themes. Contact your theme’s author and ask her to update the theme for better compatibility with widgets.

The search widget is still ugly. I want my theme’s original search box as a widget.

The widgets are CSS-selectable so that you can style them very specifically. However, the markup might not be to your liking. Many themes will look better if they supply their own widgets to replace some of the basic widgets, such as Search and Meta. It’s usually best to copy the existing markup from sidebar.php into a new widget in functions.php, then use the registration functions to replace the standard widget with the custom one.

You can do this with any part of the theme’s sidebar, or all of them. Here’s an example of how to do this:

function widget_mytheme_search() {
?>
    << PASTE YOUR SEARCH FORM HERE >>
<?php
}
if ( function_exists('register_sidebar_widget') )
    register_sidebar_widget(__('Search'), 'widget_mytheme_search');

I have a theme with more than one sidebar. How do I make them all dynamic?

Oh, that’s easy. Instead of register_sidebar() you should use register_sidebars(n) where n is the number of sidebars. Then place the appropriate number in the dynamic_sidebar() function, starting with 1. (There are several other ways to use these function. See the API).

You can even give your sidebars names rather than numbers, which lets you maintain a different set of saved sidebars for each theme. But if you need to know so much about the plugin, why aren’t you reading the API or the source code?

More information, please!

Go read our other exciting documentation, Widgetizing Plug-ins and the Widget API. If they don’t satisfy your hunger, go read the source code!

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