admin_notices not displaying in plugin

I know I’m probably doing something dumb here but I just can’t get this to run. I’m trying to set up a little API for my plugin and to create a class to display admin notices a little easier. Here’s what I have:

// Send data to class to get HTML for admin notice
$efpd=Efpdd::getInstance();
$plugin_update = $efpd->efpd_admin_notice(
    $notice_info = array(
        'type' => 'update',
        'message' => 'The plugin has just been updated.',
        'button' => 'Click for details'
    )
);
//wp_die(var_dump($plugin_update)); // Testing output of admin notice HTML code
add_action('admin_notices',function(){echo $plugin_update;});

And in my class, there is this function:

public function efpd_admin_notice($data=array()){
    extract($data); // Extracts $message, $type, and $button from $data array
    if(empty($message) && !empty($type)){ // If no message was passed through the $data array, create one based on the type of notice passed, also begin the HTML output here
        switch($type){
            case 'error':
                $message="There\"s been an error!';
                $return = "<div id=\"message\" class=\"error\">\n";
            break;
            case 'update':
                $message="There\"s been an update!';
                $return = "<div id=\"message\" class=\"updated\">\n";
            break;
            default:
                $message="There\"s something wrong with your code...';
                $return = "<div id=\"message\" class=\"error\">\n";
            break;
        }
    }
    if(empty($button)) $button = 'Click Here';
    $return .= "    <p style=\"float: left;\">{$message}</p>\n";
    $return .= "    <p style=\"float: left;\"><a href=\"{$settings_url}&amp;clear_cache=y\">{$button}</a></p>\n";
    $return .= "</div>\n";
    return $return;
}

So I guess I’m asking, what am I doing wrong to get this admin notice to not show? Is there a workaround to get this to work? Thanks.

Try this. I cleaned up your arg array and placed everything in a function. Also, why are you using the getInstance method when your efpd_admin_notice is public? See the code below for accessing this method properly.

function plugin_update(){
    $plugin_update = Efpdd::efpd_admin_notice(array(
        'type' => 'update',
        'message' => 'The plugin has just been updated.',
        'button' => 'Click for details'
    );
    echo $plugin_update;
);
add_action('admin_notices', 'plugin_update');