Auto save title as custom meta field value

Well because your code seems like to be bugy/not full – i wrote my code. This will add one meta box with one text field in post (you can change it to be added in your custom post_type)- Post title. Also i had to use QUERY to update/add title, because i can not find any other way, $post->post_title="some title" do not work.

If you happy with this code – please mark as good answer, good luck 🙂

EDIT:

 // Save post with your title
function save_the_title($post_id) {
global $wpdb;


if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) 
  return;

if ( !current_user_can( 'edit_post', $post_id ))
    return $post_id;

 $newtitle="";  // SET YOUR TITLE HERE 
 $old_title = get_post_meta($post_id, '_title', true);
 if($newtitle != '' && $newtitle != $old_title) {
 update_post_meta($post_id, '_title', $newtitle);
 $wpdb->query( $wpdb->prepare("UPDATE $wpdb->posts SET post_title = %s WHERE ID = %d ",$title1,$post_id) );

} 

 }

 add_action('save_post', 'save_the_title'); // save the custom fields