The data in personalized Meta Box is not saved

I have a problem with my custom meta box where the data is not saved. When creating this, I followed a tutorial, I checked the codex and other examples: I could not identify the culprit.

Here is my code:

ID, & # 39; project_fields & # 39 ;, true); ?>

<input type = "hidden" name = "projects_meta_box_nonce" value = "">

    
    


<input type = "text" name = "project_fields[text]"id =" project_fields[text]"class =" regular text "value ="">


<? php} / * Save meta in the database * / function save_project_fields_meta ($ post_id) { // verify nonce yes (! wp_verify_nonce ($ _POST['project_meta_box_nonce'], base name (__ ARCHIVE__))) { returns $ post_id; } // check autoguard if (defined (& # 39; DOING_AUTOSAVE & # 39;) && DOING_AUTOSAVE) { returns $ post_id; } // check permissions yes (isset ($ _ POST['post_type'])) {// Arrangement 2 yes (& # 39; page & # 39; === $ _POST['post_type'] ) { if (! current_user_can (& # 39; edit_page & # 39 ;, $ post_id)) { returns $ post_id; } elseif (! current_user_can (& # 39; edit_post & # 39 ;, $ post_id)) { returns $ post_id; } } } $ old = get_post_meta ($ post_id, & # 39; project_fields & # 39 ;, true); yes (isset ($ _ POST['project_fields'])) {// Arrangement 3 $ new = $ _POST['project_fields']; if ($ new && $ new! == $ old) { update_post_meta ($ post_id, & # 39; project_fields & # 39 ;, $ new); } elseif (& # 39; & # 39; === $ new && $ old) { delete_post_meta ($ post_id, & # 39; project_fields & # 39 ;, $ old); } } } add_action (& # 39; save_post & # 39 ;, & # 39; save_project_fields_meta & # 39;);