Plugin: How to get logged in userdata inside a class

I am building my first plugin in OOP, for a couple of things I need to get the users ID(roles etc) so I need the users data inside the whole class, I dont want to include the puggable.php file so I need some help on this.

the code(basic overview)

<?php

	class WP_PM{

		public $mainnuser;

		public function __construct(){

			//the idea
			global $current_user;
			$this->mainnuser = $current_user->ID;

			$this->addActions();
			$this->someUserStuff();
		}

		private function addActions(){
			add_action('wp_loaded', array($this, 'getCid'));
			add_action('admin_menu', array($this, 'setPages'));

		}

		public function getCid(){
			global $current_user;

			echo $current_user->ID;//working

			$this->mainuser = $current_user->ID;// settings but no value outside this function
			//$this->mainuser = 100;// this will return an value of 100

		}

		public function setPages() {

			echo $current_user->ID;//NOT working
			echo $this->mainuser;//NOT working

			// the idea on how to use
			if($mainnuser == 'administrator'){
				add_menu_page();//dummy
			}else{
				// do nothing
			}
		}

		public function someUserStuff() {

			echo $current_user->ID;//NOT working
			echo $this->mainuser;//NOT working

			// the idea on how to use
			if($mainnuser == 'administrator'){
				echo 'adminnininistratoooor';
			}else{
				// do nothing
			}
		}
	}

	$wppm = new WP_PM();

?>