title: Where should I be setting autolayout constraints when creating views programmatically
body: <p>I see different examples where constraints are set. Some set them in <code>viewDidLoad</code> / <code>loadView</code> (after the subview was added). Others set them in the method <code>updateViewConstraints</code>, which gets called by <code>viewDidAppear</code>.</p>
  
  <p>When I try setting constraints in <code>updateViewContraints</code> there can be a jumpiness to the layout, e.g. slight delay before the view appears.  Also, if I use this method, should I clear out existing constraints first i.e. <code>[self.view [removeConstraints:self.view.constraints]</code>?</p>