title: Is calling updateViewConstraints manually a good idea?
body: <p>I'm creating my constraints mainly in <code>viewDidLoad</code>. In <code>updateViewConstraints</code> I'm adding or removing some subviews and additionally adding and removing constraints. As a side note I'm using a container with child view controllers and I'm reusing the same view for different orientations (full in landscape, in a popover in portrait).</p>
  
  <p>Because I have my complete setup in <code>updateViewConstraints</code> I have to call it in some situations manually to adapt the visual changes and not to brake the constraints (e.g. when presenting the same view in a popover, or on iOS 7 it is not called on rotation). I also tried to use <code>setNeedsUpdateConstraints</code> and so on but that always broke my constraints.</p>
  
  <p>My question now is am I allowed to call <code>updateViewConstraints</code> manually? Does it has some negative side effects? Or is the flow of my application wrong?</p>