我正在编写一个插件，将一组自定义字段添加到“编辑页面”管理屏幕，使用Custom Meta Boxes 2 plugin.这就是我目前写的：

<?php
/**
 * Plugin Name:     foo Page Banner
 * Plugin URI:      http://www.foo.eu
 * Description:     foo custom widget to display a media element banner with custom text, title and links
 * Text Domain:     foo
 * Domain Path:     /languages
 * Version:         0.0.1
 *
 * @package         foo_Page_Banner
 * @version         0.0.1
 */

if ( ! defined( \'ABSPATH\' ) ) {
    exit;
}

add_action( \'cmb2_init\', \'add_foo_page_cmb2_metaboxes\' );
function add_foo_page_cmb2_metaboxes() {

    $prefix = \'_foo_page_\';

    $cmb = new_cmb2_box( array(
        \'id\'           => $prefix . \'banner_media\',
        \'title\'        => __( \'Banner media\', \'foo\' ),
        \'object_types\' => array( \'page\' ),
        \'context\'      => \'advanced\',
        \'priority\'     => \'default\',
    ) );

    $cmb->add_field( array(
        \'name\' => __( \'Banner Title\', \'foo\' ),
        \'id\' => $prefix . \'banner_title\',
        \'type\' => \'text_small\',
        \'default\' => \'page title\',
        \'desc\' => __( \'Banner Title\', \'foo\' ),
    ) );

    $cmb->add_field( array(
        \'name\' => __( \'Banner media\', \'foo\' ),
        \'id\' => $prefix . \'banner_media\',
        \'type\' => \'file\',
    ) );

    $cmb->add_field( array(
        \'name\' => __( \'Banner Description\', \'foo\' ),
        \'id\' => $prefix . \'banner_description\',
        \'type\' => \'text_medium\',
        \'default\' => \'page description\',
    ) );

    $cmb->add_field( array(
        \'name\' => __( \'Banner Links\', \'foo\' ),
        \'id\' => $prefix . \'banner_links\',
        \'type\' => \'text_url\',
        \'default\' => \'http://www.example.com\',
        \'repeatable\' => true,
    ) );

}

我感觉需要添加特定操作来加载add_foo_page_cmb2_metaboxes 仅当当前管理屏幕是页面编辑屏幕时才起作用。我错了吗？我如何做到这一点？

$cmb = new_cmb2_box( array(
        \'id\'           => $prefix . \'banner_media\',
        \'title\'        => __( \'Banner media\', \'foo\' ),
        \'object_types\' => array( \'post\' , \'page\' ),
        \'context\'      => \'advanced\',
        \'priority\'     => \'default\',
    ) );