Building a WordPress Carousel Plugin: Part 1

This tutorial details creating a WordPress carousel plugin leveraging the WordPress Links Manager API – the most efficient method for managing link lists within WordPress. The carousel will showcase a series of items, each featuring a background image and linking to a custom URL. Users navigate using "previous" and "next" arrows.

The carousel, essentially a link list stored in the WordPress Links Manager, uses JavaScript and jQuery for animation. A plugin facilitates its display. Adding items requires specifying a name, URL, description, and a correctly sized image. A dedicated carousel category is created; target and rel attributes are optional.

This three-part series explores the plugin's construction. The Links Manager, as previously discussed, is ideal for link management. While its API is concise, it offers sufficient functionality for useful applications. wp_list_bookmarks() won't be used; other functions from previous articles will be employed.

Prior familiarity with the WordPress Links Manager and its API is recommended before proceeding.

Carousel Design:

Our carousel displays items, each with a background image (size customizable) and a custom URL. The image name appears above, the description below. Navigation arrows facilitate browsing.

Development Requirements:

The WordPress Links Manager stores the carousel's link data. get_bookmarks() retrieves these links. JavaScript and jQuery handle animation. A plugin ensures clean, maintainable code.

Adding Carousel Items:

Item addition involves selecting a name, URL, description, and a correctly sized image. A dedicated category (e.g., "Carousel") is created for organization. target and rel attributes are optional.

Plugin Creation:

The plugin uses multiple files, residing in the wp-content/plugins directory (or as a mu-plugin). The main file (carousel.php, or a chosen name) declares plugin information and defines the carousel display function.

/*
Plugin Name: Carousel
Plugin URI:
Description: Creates a simple carousel
Version: 0
Author: Jérémy Heleine
Author URI: http://jeremyheleine.me
License: MIT
*/

Carousel Display Function (display_carousel()):

This function retrieves items using get_bookmarks(). An empty array results in no display.

function display_carousel() {
    $args = array(
        'category_name' => 'carousel',
        'orderby' => 'link_id',
        'order' => 'DESC',
        'limit' => 5
    );

    $links = get_bookmarks($args);
    $n = count($links);

    if (!empty($links)) {
        ?>
        <div id="carousel">
            <ul>
                <?php foreach ($links as $i => $link) {
                    // Background image
                    $background = !empty($link->link_image) ? 'url(' . $link->link_image . ')' : 'rgb(' . rand(0, 255) . ', ' . rand(0, 255) . ', ' . rand(0, 255) . ')';

                    // Target attribute
                    $target = !empty($link->link_target) ? ' target="' . $link->link_target . '"' : '';

                    // Rel attribute
                    $rel = !empty($link->link_rel) ? ' rel="' . $link->link_rel . '"' : '';
                    ?>
                    <li style="background: <?php echo $background; ?>">
                        <a class="carousel-link" href="https://www.php.cn/link/67b3d697f52f61a5aae9588726d18edc" title="<?php echo $link->link_name; ?>"<?php echo $target . $rel; ?>>
                            <strong><?php echo $link->link_name; ?></strong>
                            <?php if (!empty($link->link_description)) { ?>
                                <em><?php echo $link->link_description; ?></em>
                            <?php } ?>
                        </a>
                        <?php if ($i > 0) { ?>
                            <a href="https://www.php.cn/link/5e83596334400305514565ee16b9106d" class="carousel-prev"><</a>
                        <?php } ?>
                        <?php if ($i < $n - 1) { ?>
                            <a href="https://www.php.cn/link/6349ccd8e98a367ae2eba1acfa755850" class="carousel-next">></a>
                        <?php } ?>
                    </li>
                <?php } ?>
            </ul>
        </div>
        <?php
    }
}

Next Steps:

Subsequent parts will cover CSS styling and JavaScript animation to create a fully functional slider. FAQs on WordPress carousel plugins are also included in the original text and can be incorporated here if desired.

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