无法将自定义导航小部件提交到菜单

Question

我创建了一个自定义元素，例如＆＃39;自定义链接＆＃39;来自functions.php中的WordPress，用户可以在其中添加名称，网址和图片。它还有一个CSS的自定义类。

但是点击“添加到菜单”按钮＆＃39;没有任何反应，任何想法为什么？

这是我的functions.php的副本：

class logo_custom_element {
 public function add_nav_menu_meta_boxes() {

 /**
 * Adds the meta box container
 */
 add_meta_box(
   'add-custom-logo',
   __( 'Logo' ),
   array( $this, 'render_meta_box_content'),
   'nav-menus',
   'side',
   'low'
  );
 }

 /**
 * Render Meta Box content
 */
 public function render_meta_box_content() {
  global $_nav_menu_placeholder, $nav_menu_selected_id;
 ?>

<div class="customlinkdiv" id="customlogodiv">

  <input type="hidden" value="custom" name="menu-item[<?php echo $_nav_menu_placeholder; ?>][menu-item-type]" />
  <input type="hidden" class="menu-item-classes" name="menu-item[<?php echo $_nav_menu_placeholder; ?>][menu-item-classes]" value="nav-product-image">

  <p id="menu-item-url-wrap" class="wp-clearfix">
    <label class="howto" for="menu-item-url"><?php _e( 'URL' ); ?></label>
    <input id="menu-item-url" name="menu-item[<?php echo $_nav_menu_placeholder; ?>][menu-item-url]" type="text" class="code menu-item-textbox" value="http://" />
  </p>

  <p id="menu-item-name-wrap" class="wp-clearfix">
    <label class="howto" for="menu-item-name"><?php _e( 'Link Text' ); ?></label>
    <input id="menu-item-name" name="menu-item[<?php echo $_nav_menu_placeholder; ?>][menu-item-title]" type="text" class="regular-text menu-item-textbox" />
  </p>

  <p id="menu-item-img-wrap" class="wp-clearfix">
    <label class="howto" for="menu-item[<?php echo $_nav_menu_placeholder; ?>][image]"><?php _e( 'Logo URL' ); ?></label>
    <input type="button" class="button right image-upload" value="Zoeken in media..."><br>
    <input type="text" class="regular-text menu-item-textbox meta-image" name="menu-item[<?php echo $_nav_menu_placeholder; ?>][image]" id="menu-item[<?php echo $_nav_menu_placeholder; ?>][image]" value="<?php echo $meta['image']; ?>">

    <div class="image-preview" style="background-color: #f1f1f1;">
      <img src="<?php echo $meta['image']; ?>" style="max-width: 100%;">
    </div>
  </p>

  <script>
    jQuery(document).ready(function ($) {
      var meta_image_frame;
      $('.image-upload').click(function (e) {
        var meta_image_preview = $(this).parent().parent().children('.image-preview');
        e.preventDefault();
        var meta_image = $(this).parent().children('.meta-image');
        if (meta_image_frame) {
          meta_image_frame.open();
          return;
        }
        meta_image_frame = wp.media.frames.meta_image_frame = wp.media({
          title: meta_image.title,
          button: {
            text: meta_image.button
          }
        });
        meta_image_frame.on('select', function () {
          var media_attachment = meta_image_frame.state().get('selection').first().toJSON();
          meta_image.val(media_attachment.url);
          meta_image_preview.children('img').attr('src', media_attachment.url);
        });
        meta_image_frame.open();
      });
    });
  </script>

  <p class="button-controls wp-clearfix">
    <span class="add-to-menu">
      <input type="submit"<?php wp_nav_menu_disabled_check( $nav_menu_selected_id ); ?> class="button submit-add-to-menu right" value="<?php esc_attr_e('Toevoegen'); ?>" name="add-custom-menu-item" id="customlogodiv" />
      <span class="spinner"></span>
    </span>
  </p>
</div>
<?php }
 }
 $custom_nav = new logo_custom_element;
 add_action( 'admin_init', array( $custom_nav, 'add_nav_menu_meta_boxes' ));

保存的值我想用自定义助行器加载，谢谢！