下面是完整的代码：如果有人可以尝试，我可能会做错什么，但我找不到什么。（整个代码都在小部件页面中）

/*
 *
 * add meta box : habillage
 *
 */
add_action( \'add_meta_boxes\', \'myplugin_add_custom_box\' );
add_action( \'save_post\', \'myplugin_save_postdata\' );

/* Adds a box to the main column on the Post and Page edit screens */
function myplugin_add_custom_box() {
add_meta_box(
    \'test1\',
    __( \'My test1\', \'myplugin_textdomain\' ),
    \'myplugin_inner_custom_box\',
    \'post\'
);
add_meta_box(
    \'test2\',
    __( \'My test2\', \'myplugin_textdomain\' ),
    \'myplugin_inner_custom_box\',
    \'movies\'
);
}


/* Prints the box content */
function myplugin_inner_custom_box() {
global $post;
// Use nonce for verification
wp_nonce_field( plugin_basename( __FILE__ ), \'myplugin_noncename\' );
$met = get_post_meta($post->ID, \'champ\', true)? get_post_meta($post->ID, \'champ\', true) : \'empty meta\';

    /* input */
echo \'<label for="myplugin_new_field">\';
_e("Description field : ", \'myplugin_textdomain\' );
echo \'</label> \';
echo \'<input type="text" id="champ" name="champ" value="\'.$met.\'" />\';




/* select list */
echo \'<label for="my_list_field">\';
_e("Description for this field", \'myplugin_textdomain\' );
echo \'</label> \';
echo \'<select name="my_list_field" id="my_list_field">\';

print_r ($post->ID);

global $post;

$s_query = new WP_Query( array(
\'suppress_filters\' => false,
\'post_type\' => \'movies\'));
while($s_query->have_posts()):$s_query->the_post();

    $sname = $post->post_title;
    $s_output2 =\'\';
    $s_output2 .= \'<option value="\'.$post->ID.\'" >\';
    $s_output2 .= $post->post_title.\' : allo\';
    $s_output2 .= \'</option>\';
    echo $s_output2;

endwhile ;
echo \'</select>\';
wp_reset_query();
}


/* When the post is saved, saves our custom data */
function myplugin_save_postdata( $post_id ) {
  // verify if this is an auto save routine.
  // If it is our form has not been submitted, so we dont want to do anything
  if ( defined( \'DOING_AUTOSAVE\' ) && DOING_AUTOSAVE )
      return;

  // 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[\'myplugin_noncename\'], plugin_basename( __FILE__ ) ) )
  return;

  // Check permissions
  if ( \'page\' == $_POST[\'post_type\'] )
  {
    if ( !current_user_can( \'edit_page\', $post_id ) )
    return;
  }
  else
  {
    if ( !current_user_can( \'edit_post\', $post_id ) )
        return;
  }
  // OK, we\'re authenticated: we need to find and save the data
  //$mydata = $_POST[\'myplugin_new_field\'];
  // Do something with $mydata
  // probably using add_post_meta(), update_post_meta()
  add_post_meta($post->ID, "champ_key", \'banana\');

return $post_id;
//return $mydata;
}
?>

尝试并添加global $post; 直接进入你的功能。

编辑：答案已从注释移至此处：

请尝试以下代码：

    add_post_meta($post_id, "champ", $_POST[\'champ\'], true); 
update_post_meta($post_id, "champ", $_POST[\'champ\']);

好吧，这里有几个问题。

首先，在元框回调中(myplugin_inner_custom_box), 你不需要把帖子全球化。WordPress将post对象作为第一个参数传递给该函数。所以你可以稍微改变一下：

<?php
function myplugin_inner_custom_box( $post ) {
// blah blah blah
}

$met = get_post_meta($post->ID, \'champ\', true);

此外，您将使用$post_id, 这是您在新更新的post meta中传递到saving函数的，而不是$post->ID。

所以

<?php
function myplugin_save_postdata( $post_id ) {
    if ( defined( \'DOING_AUTOSAVE\' ) && DOING_AUTOSAVE ) 
        return;

    if ( ! isset( $_POST[\'myplugin_noncename\'] ) || ! wp_verify_nonce( $_POST[\'myplugin_noncename\'], plugin_basename( __FILE__ ) ) ) 
        return;

    if ( \'page\' == $_POST[\'post_type\'] )
    {
     if ( !current_user_can( \'edit_page\' ) )
     return;
    }
    else
    {
     if ( !current_user_can( \'edit_post\' ) )
         return;
    }

    if( isset( $_POST[\'champ\'] ) )
        update_post_meta( $post_id, "champ", $_POST[\'champ\'] );
}

您的代码，修订版：http://pastie.org/2438831 （我拿出add\\u meta\\u box to movie call和select box，因为我没有电影帖子类型）。