title: How to use NSLayoutConstraint in iOS 6?
body: <p>My app should support both iPhone resolutions (5 and older) using iOS 5 and iOS 6. When I use autolayouts in IB, on iOS 5 app crashes like this: <a href="https://stackoverflow.com/questions/11198981/presentviewcontroller-crash">link</a></p>
  
  <p>So, I am trying to use NSLayoutConstraint in code, but unsuccessfully yet.</p>
  
  <p>Subquestions:</p>
  
  <ol>
  <li>I am adding constraints in viewDidLoad method, but is it correct?</li>
  <li>Does updateViewConstraints invoke by framework? I have never seen that it was invoked.</li>
  <li>I tried to use examples from apple's docs, but it was without effect to view.</li>
  </ol>
  
  <p>Anybody knows how to do it?</p>
  
  <p>PS: I know it's possible to make it manually by setting frames, but I would like to use NSLayoutConstraints.</p>
  
  <p>UDP: Yes, I know, that's why i use NSLayoutConstraint in code. I can make condition for determining iOS version. The question is about iOS6.</p>