public function database_name_check($input){
//debug
add_settings_error('notice', 'lol', 'lol');
if($this->wpdb->get_var($this->wpdb->prepare('SHOW DATABASES LIKE %s', $input)) == $input)
return $input;
else{
add_settings_error('notice', 'lol', 'lol');
return FALSE;
}
}
I can not understand why the error does not exceed, any suggestions?
Take a look at the add_settings_error prototype.
add_settings_error( $setting, $code, $message, $type );
The first argument is your settings name/key -- or if your setting is on another page (eg general) it should be the page key. The second is whatever you'd like to add to the ID attribute, then error/updated message, and finally type. It doesn't work because you're using it incorrectly.
So you probably want...
<?php
add_settings_error(
'your_setting_key', // whatever you registered in `register_setting
'a_code_here', // doesn't really mater
__('This is the message itself', 'wpse'),
'error', // error or notice works to make things pretty
);
You also need to tell WordPress to display your settings errors. If it's on a custom page, you'll need to include settings_errors in the callback.
settings_errors('your_setting_key');
die().
settings_errors in your admin page callback.