add\\u menu\\u页面的第五个参数的类型为callable. 因此，您不能只给它“test.php”并期望它加载。但你可能会这样做：

// Include the fine with some function for example bananaMonday() declared
include_once( __DIR__ . \'/test.php\' );

// And then use it as param for add_menu_page
add_menu_page(\'Test\', \'test\', \'manage_options\', \'test\', \'bananaMonday\', null, 6);

functions.php

function se331925_custom_menu_page() {
    // Include the fine with some function for example bananaMonday() declared
    include_once( __DIR__ . \'/test.php\' );

    // And then use it as param for add_menu_page
    add_menu_page(\'Test\', \'test\', \'manage_options\', \'test\', \'bananaMonday\', null, 6);
}

add_action( \'admin_menu\', \'se331925_custom_menu_page\' );

test.php

function bananaMonday() {
    echo \'<h1>Hello, it\\\'s monday\';
}

这是我的代码，用于将主题文件夹中的文件作为“管理”菜单的页面插入：

// functions.php
add_action(\'admin_menu\', function () {
    add_menu_page(
        \'Custom Admin Page\',
        \'Custom Admin Page\',
        \'manage_options\',
        \'custom-admin-page\',
        function () {
            include dirname(__FILE__) . \'/inc/admin-settings.php\';
        }
    );
});