Adding a custom taxonomy using plug-in ensures that the classification structure remains after topic switching and is easy to reuse. 1. Create plug-in folders and PHP files and add plug-in header information; 2. Write a registration taxonomy function, set tags and parameters and mount them to init actions; 3. Use taxonomy in the article editing interface after enabling the plug-in; 4. Get and display the classification through get_the_terms in the front desk; 5. Pay attention to refreshing the fixed link, unique naming, enabling debugging, and keeping the plug-in lightweight.

In WordPress development, if you want to add a classification system (such as a tag or category) to custom content types, you can do it by creating a custom taxonomy. If you want this feature to be portable or retained with topic switching, using plug-ins to register custom taxonomy is a good choice.

Why add it in plug-in?

Although it is simple to write directly in functions.php or other files of the theme, it will fail once the theme is changed. Adding a custom classification method through plug-in can ensure that no matter how you change the topic, your classification structure will not be lost, and it also makes it easier for you to package this set of logic and reuse it in other projects.

Create a basic plugin

First you need to create a basic WordPress plugin. The steps are as follows:

• Create a new folder in the /wp-content/plugins/ directory, such as custom-taxonomy-addon
• Create a PHP file in this folder, such as custom-taxonomy-addon.php
• Open the file and enter the following header information:

 <?php
/*
Plugin Name: Custom Taxonomy Addon
Description: Adds a custom taxonomy for posts.
Version: 1.0
Author: Your Name
*/

// Add the subsequent code here

In this way, you have an available empty plug-in, and you can add custom taxonomy code to it.

Register custom classification method

Now you want to register a taxonomy called Project Type and attach it to post (can also be a custom post type of course). The sample code is as follows:

 function create_custom_taxonomy() {
    $labels = array(
        'name' => _x( 'item type', 'taxonomy general name' ),
        'singular_name' => _x( 'project type', 'taxonomy singular name' ),
        'search_items' => __( 'Search item type' ),
        'all_items' => __( 'all item types' ),
        'edit_item' => __( 'Edit project type' ),
        'update_item' => __( 'Update project type'),
        'add_new_item' => __( 'Add new project type'),
        'new_item_name' => __( 'New project type name' ),
        'menu_name' => __( 'Project Type' ),
    );

    $args = array(
        'hierarchical' => true, // Whether to support hierarchical relationships (similar to directory)
        'labels' => $labels,
        'show_ui' => true,
        'show_admin_column' => true,
        'query_var' => true,
        'rewrite' => array( 'slug' => 'project-type' ), // URL alias for the classification page);

    register_taxonomy( 'project_type', array( 'post' ), $args );
}
add_action( 'init', 'create_custom_taxonomy', 0 );

This code registers a new taxonomy when WordPress is initialized and displays on the background article editing page.

Note: If you want to bind this taxonomy to a custom post type, replace 'post' with your post type slug.

Check and use classification

After completing the plug-in installation and enabling, you should see the newly added "Project Type" classification panel in the article editing interface. You can add, edit, and select categories.

In terms of front desk display, you can obtain the category of the current article through the following methods:

 $terms = get_the_terms( get_the_ID(), 'project_type' );
if ( $terms && ! is_wp_error( $terms ) ) {
    foreach ( $terms as $term ) {
        echo &#39;<span class="project-type">&#39; . $term->name . &#39;</span>&#39;;
    }
}

You can also filter content based on this category in the archive page or loop to build a more flexible way of organizing content.

Common precautions

• Don't forget to refresh the permalink settings : After adding or modifying the taxonomy, go to the background "Settings → Permalink" and click "Save Changes" to refresh the rewrite rules.
• Naming should be unique : avoid conflicts with other plugins or topics. It is recommended to use prefixes, such as myplugin_project_type
• Turn on WP_DEBUG during debugging : Helps discover potential syntax or call errors
• Plugins should be kept as light as possible : if you are just registering a taxonomy, no additional dependencies or complex configurations are required

Basically these are the operations. The entire process is not complicated, but a slight negligence may affect the normal operation of the website, especially the naming and mounting timing.

The above is the detailed content of How to add a custom taxonomy with a plugin. For more information, please follow other related articles on the PHP Chinese website!