Display Custom Toxonomy In WordPress and theme Widgets category selection dropdown list

Question

I need help on how to make Custom Toxonomy
or categories for 'Video' CPT to appear in both WordPress native widgets and theme Widget's category dropdown options list. The only categories am getting are for default posts.

Any help would be really appreciated. Am not much familiar with php.

More details.

The Theme is: CoverNews

1. My Custom Post Types

2. Now I need help how to modify the Widget's code to include custom post type categories in the dropdown list.

This is the theme widget code:

    {
    /**
     * Sets up a new widget instance.
     *
     * @since 1.0.0
     */
    function __construct()
    {
        $this->text_fields = array('covernews-posts-slider-title');
        $this->select_fields = array('covernews-select-category');

        $widget_ops = array(
            'classname' => 'covernews_posts_slider_widget',
            'description' => __('Displays posts slider from selected category.', 'covernews'),
            'customize_selective_refresh' => true,
        );

        parent::__construct('covernews_posts_slider', __('CoverNews Posts Slider', 'covernews'), $widget_ops);
    }

    /**
     * Front-end display of widget.
     *
     * @see WP_Widget::widget()
     *
     * @param array $args Widget arguments.
     * @param array $instance Saved values from database.
     */

    public function widget($args, $instance)
    {
        $instance = parent::covernews_sanitize_data($instance, $instance);


        /** This filter is documented in wp-includes/default-widgets.php */
        $title = apply_filters('widget_title', $instance['covernews-posts-slider-title'], $instance, $this->id_base);
        $category = isset($instance['covernews-select-category']) ? $instance['covernews-select-category'] : 0;
        $show_excerpt = 'true';
        $excerpt_length = '25';
        $number_of_posts = 5;

        // open the widget container
        echo $args['before_widget'];
        ?>
        <?php if (!empty($title)): ?>
        <div class="em-title-subtitle-wrap">
            <?php if (!empty($title)): ?>
                <h4 class="widget-title header-after1">
                    <span class="header-after">
                        <?php echo esc_html($title);  ?>
                        </span>
                </h4>
            <?php endif; ?>
        </div>
    <?php endif; ?>
        <?php

        $all_posts = covernews_get_posts($number_of_posts, $category);
        ?>
        <div class="posts-slider">
            <?php
            if ($all_posts->have_posts()) :
                while ($all_posts->have_posts()) : $all_posts->the_post();
                    if (has_post_thumbnail()) {
                        $thumb = wp_get_attachment_image_src(get_post_thumbnail_id(get_the_ID()), 'covernews-slider-full');
                        $url = $thumb['0'];
                    } else {
                        $url = '';
                    }

                    global $post;
                    ?>
                    <figure class="slick-item">

                        <div class="data-bg data-bg-hover data-widget-slide" data-background="<?php echo esc_url($url); ?>">
                            <?php echo covernews_post_format($post->ID); ?>
                            <figcaption class="slider-figcaption slider-figcaption-1">

                                <div class="figure-categories figure-categories-bg">

                                    <?php covernews_post_categories(); ?>
                                </div>
                                <h2 class="slide-title">
                                    <a href="<?php the_permalink(); ?>"><?php the_title(); ?></a>
                                </h2>

                                <div class="grid-item-metadata grid-item-metadata-1">
                                    <?php covernews_post_item_meta(); ?>
                                </div>
                                <?php if ($show_excerpt != 'false'): ?>
                                    <div class="full-item-discription">
                                        <div class="post-description">
                                            <?php if (absint($excerpt_length) > 0) : ?>
                                                <?php
                                                $excerpt = covernews_get_excerpt($excerpt_length, get_the_content());
                                                echo wp_kses_post(wpautop($excerpt));
                                                ?>
                                            <?php endif; ?>
                                        </div>
                                    </div>
                                <?php endif; ?>
                            </figcaption>
                        </div>
                    </figure>
                    <?php
                endwhile;
            endif;
            wp_reset_postdata();
            ?>
        </div>

        <?php
        // close the widget container
        echo $args['after_widget'];
    }

    /**
     * Back-end widget form.
     *
     * @see WP_Widget::form()
     *
     * @param array $instance Previously saved values from database.
     */
    public function form($instance)
    {
        $this->form_instance = $instance;

        $categories = covernews_get_terms();
        if (isset($categories) && !empty($categories)) {
            // generate the text input for the title of the widget. Note that the first parameter matches text_fields array entry
            echo parent::covernews_generate_text_input('covernews-posts-slider-title', __('Title', 'covernews'), 'Posts Slider');
            echo parent::covernews_generate_select_options('covernews-select-category', __('Select category', 'covernews'), $categories);

        }
    }
}

endif;

Answer 1

I took a look at the theme's code. the function covernew_get_terms() function accepts a taxonomy argument, take a look at the source code:

/**
 * Returns all categories.
 *
 * @since CoverNews 1.0.0
 */
if (!function_exists('covernews_get_terms')):
function covernews_get_terms( $category_id = 0, $taxonomy='category', $default='' ){
   #... rest of the code

}
endif;

By default the taxonomy being used is category, so you have to manually specify an array of taxonomies you want included by calling the function this way:

public function form($instance)
{
    $this->form_instance = $instance;

    $categories = covernews_get_terms(0, array('category', 'custom_taxonomy1'));
    #... rest of the code

    }
}

Since you're working with custom post types, you also have to modify the WP_Query because by default it just retrieves the type 'post'.

// widget-posts-carousel.php
// $all_posts = covernews_get_posts($number_of_posts, $category); #line 61. Replace with:

$all_posts = new WP_Query(array(
    'post_type' => array('post', 'cptsample'), # set your CPT here.
    'posts_per_page' => absint($number_of_posts),            
    'post_status' => 'publish',
    'orderby' => 'date',
    'order' => 'DESC',
    'tax_query' =>array(
        array(
            'taxonomy' => get_term(intval($category))->taxonomy,
            'field' => 'term_id',
            'terms' => $category
        )
    ) 
));