第四个论点add_meta_box() 是上下文，在这种情况下teams, 不latest discussion 或next fixture 就像你在这里一样。此外，由于您希望这些元盒仅显示在您的CPT的新建和编辑屏幕上，因此最简单的方法是为您的特定CPT注册元盒回调，并取消对admin_init. 将其添加到$args数组中，例如。\'register_meta_box_cb\' => \'prefix_teams_cpt_add_metaboxes\'. 因此，您的代码的修改版本：

// Register Teams
add_action(\'init\', \'register_teams\');

function register_teams() {

    $labels = array(
        \'name\' => _x(\'Teams\', \'post type general name\'),
        \'singular_name\' => _x(\'Team\', \'post type singular name\'),
        \'add_new\' => _x(\'Add New\', \'team item\'),
        \'add_new_item\' => __(\'Add New Team\'),
        \'edit_item\' => __(\'Edit Team\'),
        \'new_item\' => __(\'New Team\'),
        \'view_item\' => __(\'View Team\'),
        \'search_items\' => __(\'Search Teams\'),
        \'not_found\' =>  __(\'Nothing found\'),
        \'not_found_in_trash\' => __(\'Nothing found in Trash\'),
        \'parent_item_colon\' => \'\'
    );

    $args = array(
        \'labels\' => $labels,
        \'public\' => true,
        \'publicly_queryable\' => true,
        \'show_ui\' => true,
        \'query_var\' => true,
        \'rewrite\' => true,
        \'capability_type\' => \'post\',
        \'hierarchical\' => false,
        \'menu_position\' => null,
        \'menu_icon\' => get_stylesheet_directory_uri() . \'/images/menu-teams.png\',
        \'supports\' => array( \'title\', \'editor\', \'thumbnail\' ),
        \'has_archive\' => true,
        \'register_meta_box_cb\' => \'prefix_teams_cpt_add_metaboxes\'
      );

    register_post_type( \'teams\' , $args );
}

// Add Metaboxes
function prefix_teams_cpt_add_metaboxes(){
    add_meta_box("latest_discussion", "Latest Discussion", "prefix_latest_discussion_metabox", "teams", "side", "low");
    add_meta_box("next_fixture", "Next Fixture", "prefix_next_fixture_metabox", "teams", "side", "low");
}

function prefix_latest_discussion_metabox(){
    global $post;
    $custom = get_post_custom($post->ID);
    $latest_discussion = $custom["latest_discussion"][0];
    ?>
    <label>Latest Discussion URL:</label><br /><br />
    <input size="40" name="latest_discussion" value="<?php echo $latest_discussion; ?>" />
    <?php
}

function prefix_next_fixture_metabox(){
    global $post;
    $custom = get_post_custom($post->ID);
    $next_fixture = $custom["next_fixture"][0];
    ?>
    <label>Next Fixture:</label><br /><br />
    <input size="40" name="next_fixture" value="<?php echo $next_fixture; ?>" />
    <?php
}

// Save Fields
add_action(\'save_post\', \'prefix_save_teams_details\');

function prefix_save_teams_details(){
    global $post;
    update_post_meta($post->ID, "latest_discussion", $_POST["latest_discussion"]);
    update_post_meta($post->ID, "next_fixture", $_POST["next_fixture"]);
}