title: ngOnInit not called when coming back
body: <p>I noticed that the <code>ngOnInit()</code> method gets not called when I come back to the page which is already instanced. I have to use any other method for this? I need a method which is called everytime when he is visiting the specific page. </p>
  
  <p><strong>EDIT</strong>
  Tested already <code>onPageWillEnter()</code> but it gets not fired in Ionic 2</p>