title: UITextView will get down when i click textField
body: <p>I have a <code>TextView</code> &amp; a <code>textFile</code> in My <code>ViewController</code> 
  When I click my <code>textFile</code> , my iPhone doesn't have any problem
  but my simulator will get down ,
  and ,if i click "Tab" it will get down again,
  It was over I set navigation controller,
  does anyone know what happened?</p>
  
  <p>Just like this, the black area is my question</p>
  
  <p><a href="https://i.stack.imgur.com/hGzlG.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/hGzlG.png" alt="enter image description here"></a> </p>