我正在做类似的事情。这是一个播客上传元框。返回文件的url。以下是我目前掌握的情况：

//Add Metabox
add_action(\'add_meta_boxes\', \'add_upload_file_metaboxes\');

function add_upload_file_metaboxes() {
    add_meta_box(\'swp_file_upload\', \'File Upload\', \'swp_file_upload\', \'podcasts\', \'normal\', \'default\');
}


function swp_file_upload() {
    global $post;
    // Noncename needed to verify where the data originated
    echo \'<input type="hidden" name="podcastmeta_noncename" id="podcastmeta_noncename" value="\'.
    wp_create_nonce(plugin_basename(__FILE__)).
    \'" />\';
    global $wpdb;
    $strFile = get_post_meta($post -> ID, $key = \'podcast_file\', true);
    $media_file = get_post_meta($post -> ID, $key = \'_wp_attached_file\', true);
    if (!empty($media_file)) {
        $strFile = $media_file;
    } ?>


    <script type = "text/javascript">

        // Uploading files
        var file_frame;
    jQuery(\'#upload_image_button\').live(\'click\', function(podcast) {

        podcast.preventDefault();

        // If the media frame already exists, reopen it.
        if (file_frame) {
            file_frame.open();
            return;
        }

        // Create the media frame.
        file_frame = wp.media.frames.file_frame = wp.media({
            title: jQuery(this).data(\'uploader_title\'),
            button: {
                text: jQuery(this).data(\'uploader_button_text\'),
            },
            multiple: false // Set to true to allow multiple files to be selected
        });

        // When a file is selected, run a callback.
        file_frame.on(\'select\', function(){
            // We set multiple to false so only get one image from the uploader
            attachment = file_frame.state().get(\'selection\').first().toJSON();

            // here are some of the variables you could use for the attachment;
            //var all = JSON.stringify( attachment );      
            //var id = attachment.id;
            //var title = attachment.title;
            //var filename = attachment.filename;
            var url = attachment.url;
            //var link = attachment.link;
            //var alt = attachment.alt;
            //var author = attachment.author;
            //var description = attachment.description;
            //var caption = attachment.caption;
            //var name = attachment.name;
            //var status = attachment.status;
            //var uploadedTo = attachment.uploadedTo;
            //var date = attachment.date;
            //var modified = attachment.modified;
            //var type = attachment.type;
            //var subtype = attachment.subtype;
            //var icon = attachment.icon;
            //var dateFormatted = attachment.dateFormatted;
            //var editLink = attachment.editLink;
            //var fileLength = attachment.fileLength;

            var field = document.getElementById("podcast_file");

            field.value = url; //set which variable you want the field to have
        });

        // Finally, open the modal
        file_frame.open();
    });

    </script>



    <div>

        <table>
        <tr valign = "top">
        <td>
        <input type = "text"
    name = "podcast_file"
    id = "podcast_file"
    size = "70"
    value = "<?php echo $strFile; ?>" />
        <input id = "upload_image_button"
    type = "button"
    value = "Upload">
        </td> </tr> </table> <input type = "hidden"
    name = "img_txt_id"
    id = "img_txt_id"
    value = "" />
        </div>     <?php
    function admin_scripts() {
        wp_enqueue_script(\'media-upload\');
        wp_enqueue_script(\'thickbox\');
    }

    function admin_styles() {
        wp_enqueue_style(\'thickbox\');
    }
    add_action(\'admin_print_scripts\', \'admin_scripts\');
    add_action(\'admin_print_styles\', \'admin_styles\');
}


//Saving the file
function save_podcasts_meta($post_id, $post) {
    // verify this came from the our screen and with proper authorization,
    // because save_post can be triggered at other times
    if (!wp_verify_nonce($_POST[\'podcastmeta_noncename\'], plugin_basename(__FILE__))) {
        return $post -> ID;
    }
    // Is the user allowed to edit the post?
    if (!current_user_can(\'edit_post\', $post -> ID))
        return $post -> ID;
    // We need to find and save the data
    // We\'ll put it into an array to make it easier to loop though.
    $podcasts_meta[\'podcast_file\'] = $_POST[\'podcast_file\'];
    // Add values of $podcasts_meta as custom fields

    foreach($podcasts_meta as $key => $value) {
        if ($post -> post_type == \'revision\') return;
        $value = implode(\',\', (array) $value);
        if (get_post_meta($post -> ID, $key, FALSE)) { // If the custom field already has a value it will update
            update_post_meta($post -> ID, $key, $value);
        } else { // If the custom field doesn\'t have a value it will add
            add_post_meta($post -> ID, $key, $value);
        }
        if (!$value) delete_post_meta($post -> ID, $key); // Delete if blank value
    }
}
add_action(\'save_post\', \'save_podcasts_meta\', 1, 2); // save the custom fields