title: How to get UITextView height according to content in iOS 9
body: <p>I'm using a <code>UITextView</code> to display some data. I need to calculate the height of the <code>UITextView</code> depending on its content. I have tried <code>contentSize.height</code>, but it doesn't work for me.
  Does anyone have a solution for this?
  Here is my code with AutoLayout. I have set the height constraint with outlet</p>
  
  <pre><code>CGFloat height= _myTextView.contentSize.height;
  _heightConstraint.constant = height;
  </code></pre>