How to Display an Admin Notice For Required Theme Plugins

I typically build all the functionality needed directly into each theme I release, but sometimes it makes sense to refer to a 3rd party plugin to achieve what you are looking to do. For instance, most of my video-centric themes require the Press75.com “Simple Video Embedder” plugin for embedding videos within each post. In my opinion, it makes sense to maintain that functionality separately within a plugin (1 source) rather than duplicating and maintaining multiple versions of the same functionality within each theme. The problem is that when you require 3rd party plugins for your themes to function properly, you will run into several end users who simply do not read the setup or usage instructions. In those cases, don’t be surprised if you get overwhelmed with support related questions regarding the installation of 3rd party plugins.

To eliminate this potential hassle for both you and your users, I would recommend that you implement a very simple “plugin check” that is triggered upon theme activation. Use the code below (2 parts) within your theme “functions.php” file to check and generate an admin notice for any required plugins that you may be using with your theme. Also… major props to James Lao who originally provided this code to use with my themes on Press75.com.

Part 1 – Check for the Required Plugin

The first part simply checks to see if the required plugin is available and activated within the users WordPress installation. Even if the plugin is available, this piece of code will return true until the plugin is actually activated.

// Check for Simple Video Embedder Plugin
sve_check();

function sve_check()
{
  if ( !function_exists('p75GetVideo') )
  {
    add_thickbox(); // Required for the plugin install dialog.
    add_action('admin_notices', 'sve_check_notice');
  }
}

The key to this portion of code is the function reference. Basically, we are looking to see if the “p75GetVideo” function is available. If not, the Simple Video Embedder plugin is most likely not installed and activated as required by the theme. When you apply this check for a different plugin, you will need to replace the “p75GetVideo” with a key function that is provided by the plugin you require for your theme to function properly.

Part 2 – Display an Admin Notice

Checking if the plugin is available really doesn’t do you any good unless you can actually display some sort of notice to your users. The code below will generate an admin notice if the required plugin is not available. It will even provide a link for your users to auto-intall the required plugin making things even easier.

// The Admin Notice
function sve_check_notice()
{
?>
  <div class='updated fade'>
    <p>The Simple Video Embedder plugin is required for this theme to function properly. <a href="<?php echo admin_url('plugin-install.php?tab=plugin-information&plugin=simple-video-embedder&TB_iframe=true&width=640&height=517'); ?>" class="thickbox onclick">Install now</a>.</p>
  </div>
<?php
}

Of course you will want to replace the admin notice text with something that is relevant to the plugin you require for your theme to function properly. You will also want to replace “simple-video-embedder” within the “Install Now” link with the plugin you are referring to. For example, if you require the BuddyPress plugin for your theme to function properly, you would replace “simple-video-embedder” with “buddypress”. This comes from the actual link within the WordPress.org plugin directory (e.g. “http://wordpress.org/extend/plugins/buddypress/”).