我认为您将错误的post ID值传递给get_post_meta() 作用尝试以下操作：

$ytubeID = get_post_meta(get_the_ID(), \'_youtubeID\', true);
$vimID = get_post_meta(get_the_ID(), \'_vimeoID\', true);

Note:, 由于您正在使用WP\\u Query的新实例，因此不需要wp_reset_query();, 使用wp_reset_postdata(); 相反

在添加用于存储自定义字段值的完整代码之前，我只能说，您再次向update_post_meta() 和delete_post_meta() 函数。。通常，post ID会传递给save函数回调，而$post->ID是错误的（您正在进行的$post->post\\u类型检查也是错误的）。您还将向save回调传递第二个参数，但save回调只接受一个参数。尝试以下操作：

add_action( \'save_post\', \'my_save_postdata\' );
function my_save_postdata($post_id){
    $video_meta[\'_youtubeID\'] = $_POST[\'_youtubeID\'];
    $video_meta[\'_vimeoID\'] = $_POST[\'_vimeoID\'];
    foreach ($video_meta as $key => $value) { // Cycle through the $video_meta array
        if(  $_POST[\'post_type\'] == \'revision\' ) return; // Don\'t store custom data twice
        $value = implode(\',\', (array)$value); // If $value is an array, make it a CSV

        if(get_post_meta($post_id, $key, FALSE)) { // If the custom field already has a value
            update_post_meta($post_id, $key, $value);
        } else { // If the custom field doesn\'t have a value
            add_post_meta($post_id, $key, $value);
        }
        if(!$value) delete_post_meta($post_id, $key); // Delete if blank
    }//endforeach video meta
 }

您可以进行进一步的改进，但它们超出了答案的范围，我举个例子，以下代码：

        if(get_post_meta($post_id, $key, FALSE)) { // If the custom field already has a value
            update_post_meta($post_id, $key, $value);
        } else { // If the custom field doesn\'t have a value
            add_post_meta($post_id, $key, $value);
        }
        if(!$value) delete_post_meta($post_id, $key); // Delete if blank

可以是：

if($value) {
    update_post_meta($post_id, $key, $value);
} else {
    delete_post_meta($post_id, $key); // Delete if blank
}

因为update_post_meta() 将检查自定义字段是否已经有值并将其更新，如果自定义字段没有值（键不存在），则函数将调用add_post_meta().

代码中的所有上述内容：

// Create the Video Information Meta Box by hooking into the admin menu for a post
// Add the meta boxes in the add_meta_boxes action hook, no in admin menu
    add_action(\'add_meta_boxes\', \'video_add_box\');

    //Function call by the "add_action" to tell it what to add, "video_information" and where "post"
    function video_add_box(){
    add_meta_box(\'video_information\', \'Video Information\', \'video_information\', \'videos\', \'normal\', \'high\');
    }

    //function to populate the meta box added above
    function video_information(){
    global $post;

    // Noncename needed to verify where the data originated
    echo \'<input type="hidden" name="video_noncename" id="video_noncename" value="\' .
    wp_create_nonce( plugin_basename(__FILE__) ) . \'" />\';

    //adds the custom field _youtubeID plus some other stuff
    $youtubeID = get_post_meta($post->ID, \'_youtubeID\', true);
    if ( empty($youtubeID) ) {
    $youtubeID = \'\';
    }

    //adds the custom field _vimeoID
    $vimeoID = get_post_meta($post->ID, \'_vimeoID\', true);
    if ( empty($vimeoID) ) {
    $vimeoID = \'\';
    }

    //add the box
    echo \'<br />\';
    echo \'<strong>Youtube ID:</strong>  <input type="text" name="_youtubeID" value="\' . $youtubeID  . \'" size="20" maxlength="30" />\';
    echo \'<br />\';
    echo \'<strong>Vimeo ID:</strong>  <input type="text" name="_vimeoID" value="\' . $vimeoID  . \'" size="20" maxlength="30" />\';
    echo \'<br />\';
    } //end video_information function

    //save_video_meta is called below with the action "save_post" and saves your IDs to the post
    function save_video_meta($post_id) {
    // the $post parameter you wass passing has any effect, the save
    // action only accept one parameter. If you need all the post data beeing saved
    // you can access to the global $post_data; or to the superglobal $_POST

    // verify this came from the our screen and with proper authorization,
    // because save_post can be triggered at other times

    if ( !wp_verify_nonce( $_POST[\'video_noncename\'], plugin_basename(__FILE__) )) {
    return $post->ID;
    }

    // Is the user allowed to edit the post or page?

    if ( !current_user_can( \'edit_post\', $post->ID )){
    return $post->ID;
    }

    $video_meta[\'_youtubeID\'] = $_POST[\'_youtubeID\'];
    $video_meta[\'_vimeoID\'] = $_POST[\'_vimeoID\'];
    foreach ($video_meta as $key => $value) { // Cycle through the $video_meta array
    if( $_POST[\'post_type\'] == \'revision\' ) return; // Don\'t store custom data twice

    $value = implode(\',\', (array)$value); // If $value is an array, make it a CSV

        if($value) {
            update_post_meta($post_id, $key, $value);
        } else {
            delete_post_meta($post_id, $key); // Delete if blank
        } 
    }//endforeach video meta

    } //end save_video_meta

    //save the video custom fields
    add_action(\'save_post\', \'save_video_meta\', 1, 2);

Just a reminder: Wordpress可以处理大量的外部视频提供商，如youtube和vimeo。只需将视频URL粘贴到编辑器框中，它就会自动显示在前端。此外，还有一个内置的分类法“post format”，可以让您通过“视频格式”过滤帖子。简言之，我认为完全不需要用自定义元框注册一个新的帖子类型，只需显示“视频类型”的帖子；使用内置特性，只需很少的额外代码即可实现相同的功能。