title: Detect when UITextFiled is being drawn
body: <p>I have subclassed <code>UIViewController</code> to enable my theming strategy.</p>
  
  <p>That is to say, all of my <code>UIViewControllers</code> extend my version called <code>MyUIViewController</code> which has an <code>override</code> on <code>viewWillLayoutSubviews</code>. Therefore, when a page is loaded, I can call my <code>setupView</code> method which will properly set my background and other styles and animations for me.  </p>
  
  <p>I have done the same thing for my <code>UITextField</code>. The problem Im running into however, is that I cannot find a method in the <code>UITextField</code> class that gets called every time the view appears. </p>
  
  <p>The basic question is, what is <code>UITextFields</code> <code>viewWillLayoutSubviews</code> or <code>viewDidLoad</code>.</p>
  
  <p><strong>Some Solutions:</strong> </p>
  
  <p>In the event that there is nothing that gets called I have the following solutions whihc I dont really like.</p>
  
  <ol>
  <li><p>Using the <code>ViewController</code>, iterate through all of the subviews that a view controller has and if a given view is type <code>UITextField</code>, call a static method in my extension of it to set its style</p></li>
  <li><p>Register my subclass <code>UITextField</code> with notification center and when I change the theme, send out a notification.</p></li>
  </ol>
  
  <p>I have tested both of the methods from the above and they do work, however they are not as nice as having the class itself do what it needs to do when it comes in the view.</p>
  
  <p>To recap, I would like to know if there is a method that I can override in the <code>UITextField</code> class that will notify me every time the view comes alive.</p>