How to show an urgent message in the WordPress admin area!

When writing custom WordPress theme or plugins, you might want to inform users that something important needs doing, perhaps due to an upgrade. e.g. You need the user to update a setting, or check that their settings have been transposed correctly. This is a very short guide that shows you how to add a error or status message using the correct WordPress hooks.

To do show an urgent message in the WordPress admin area, the following is a snippet of my custom function that shows a message to the user. This be used from anywhere in your theme or plugin if you wanted to give the user a standard message. e.g. “Settings successfully updated” or something similar.

/**
 * Generic function to show a message to the user using WP's 
 * standard CSS classes to make use of the already-defined
 * message colour scheme.
 *
 * @param $message The message you want to tell the user.
 * @param $errormsg If true, the message is an error, so use 
 * the red message style. If false, the message is a status 
  * message, so use the yellow information message style.
 */
function showMessage($message, $errormsg = false)
{
	if ($errormsg) {
		echo '<div id="message">';
	}
	else {
		echo '<div id="message">';
	}

	echo "<p><strong>$message</strong></p></div>";
}

Now we just add a hook to the admin notices function to show our custom message.

/**
 * Just show our message (with possible checking if we only want
 * to show message to certain users.
 */
function showAdminMessages()
{
    // Shows as an error message. You could add a link to the right page if you wanted.
    showMessage("You need to upgrade your database as soon as possible...", true);

    // Only show to admins
    if (user_can('manage_options') {
       showMessage("Hello admins!");
    }
}

/** 
  * Call showAdminMessages() when showing other admin 
  * messages. The message only gets shown in the admin
  * area, but not on the frontend of your WordPress site. 
  */
add_action('admin_notices', 'showAdminMessages');

And that’s all there is to it!

Thanks to Dan Harrison of WordPress Doctors for the tip!