Sub menu in admin panel wordpress

Question

I'm new in wordpress hooks and i can not create a sub_menu like it

i'm tryed the code below but's dont work crud.php

 add_action('admin_menu', 'addAdminPageContent');

    function addAdminPageContent() {
      add_menu_page('CADASTRO', 'CADASTRO', 'manage_options', __FILE__, 'crudAdminPage', 'dashicons-edit-page');
      add_submenu_page( 'crud.php',  'CURSOS', 'manage_options', __FILE__, 'cursos', null );
    }

    function crudAdminPage(){ ....///
    function cursos(){....///

where is the error?

Answer 1

I think you are misleading the usage of add_menu_page() and add_submenu_page() please refer their params. check below code.

add_action('admin_menu', 'addAdminPageContent');
function addAdminPageContent() {
    add_menu_page('CADASTRO', 'CADASTRO', 'manage_options', 'cadastro', 'crudAdminPage', 'dashicons-edit-page');
    add_submenu_page( 'cadastro',  'CURSOS', 'CURSOS', 'manage_options', 'cursos', 'crudAdmiSubnPage' );
}

function crudAdminPage(){

}

function crudAdmiSubnPage(){
    
}