在wordpress自定义帖子类型库中添加多个图像

function create_custom_post_type() {
    register_post_type( 'gallery',
        array(
            'labels' => array(
                'name' =>__( 'Galleries' ),
                'singular_name' =>__( 'Gallery' )
            ),
            'public' => true,
            'has_archive' => true,
            'supports' => array( 'title', 'editor', 'thumbnail' ),
        )
    );
}
add_action( 'init', 'create_custom_post_type' );

function add_gallery_images_meta_box() {
    add_meta_box(
        'gallery_images',
        __( 'Gallery Images', 'textdomain' ),
        'gallery_images_callback',
        'gallery',
        'normal',
        'high'
    );
}
add_action( 'add_meta_boxes', 'add_gallery_images_meta_box' );

function gallery_images_callback( $post ) {
    wp_nonce_field( basename( __FILE__ ), 'gallery_images_nonce' );
    $gallery_images = get_post_meta( $post->ID, '_gallery_images', true );
    ?>
    <div id="gallery-images-container">
        <?php if ( $gallery_images ) : ?>
            <?php foreach ( $gallery_images as $image_id ) : ?>
                <img src="<?php echo wp_get_attachment_url( $image_id ); ?>" alt="" />
            <?php endforeach; ?>
        <?php endif; ?>
    </div>
    <button id="add-gallery-image">Add Image</button>
    <?php
}

function save_gallery_images_meta_box( $post_id ) {
    if ( ! isset( $_POST['gallery_images_nonce'] ) || ! wp_verify_nonce( $_POST['gallery_images_nonce'], basename( __FILE__ ) ) ) {
        return;
    }
    if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
        return;
    }
    if ( ! current_user_can( 'edit_post', $post_id ) ) {
        return;
    }
    if ( isset( $_POST['gallery_images'] ) ) {
        update_post_meta( $post_id, '_gallery_images', $_POST['gallery_images'] );
    } else {
        delete_post_meta( 'gallery_images', $post_id );
    }
}
add_action( 'save_post', 'save_gallery_images_meta_box' );

function enqueue_gallery_scripts() {
    wp_enqueue_media();
    wp_enqueue_script(
        'gallery-script',
        plugins_url( '/js/gallery-script.js', __FILE__ ),
        array( 'jquery' ),
        null,
        true
    );
}
add_action( 'admin_enqueue_scripts', 'enqueue_gallery_scripts' );