title: autolayout set view to screen size
body: <p>I have read tutorials about the auto layout but i just couldn't understand the basic things, where they all deals with technical ways to handle Xcode, i couldn't find a simple, clear , explanation to it .</p>
  
  <p>So I will ask 2 basic questions, for 1 problem, a simple problem. </p>
  
  <p>Problem: I have created <code>UIImageView</code> in <code>storyboard</code>, inside a view controller .
  I would like this view, to <strong>always be in the screen size, no matter what iPhone it is</strong> .</p>
  
  <ol>
  <li>One way i was thinking about, is just to set it with code, to be in the screen size, this does not works, and in simulator(Xcode 6 - iPhone 6) i see its cover part of the screen.</li>
  </ol>
  
  <blockquote>
  <pre><code>float width= [UIScreen mainScreen].bounds.size.width;
  float height=[UIScreen mainScreen].bounds.size.height;
   self.backImage.frame=CGRectMake( 0,
                                    0
                                       , width, height) ;
  </code></pre>
  </blockquote>
  
  <p>Why is this not working(because the image view is checked for auto layout ? ) </p>
  
  <ol start="2">
  <li><p>How to define layouts  in <code>storyboard</code>, for this view, to always cover the screen size exactly ?</p></li>
  <li><p>What if after i set constrains, i would like to set some effect for this view- to move, in code, for example setting the image view size to be 1.5 screen size and centered ?</p></li>
  </ol>