title: When to use Categories Objective-C?
body: <p>If I have a method to attach an animation to an <code>UI Element</code>, instead of <strong>copy/pasting</strong> the code for this method into many <code>viewcontrollers</code>, can I just create one <code>class</code> to hold the method and then import it? </p>
  
  <p>I assume it doesn't make sense to use a <code>category</code> in this instance because I need this method in multiple <code>viewcontrollers</code>, and a <code>category</code> is an extension of a single <code>viewcontroller</code>.</p>