title: Objective C Communicating to one view controller that another has changed
body: <p>I have two view controllers - one "main" view controller which displays the main content and one "settings" table view controller which is held in a container within a slide-out view. The concept is this:</p>
  
  <ol>
  <li>User taps an item on settings panel.</li>
  <li>Settings TVC creates a "Button States" dictionary object with all of the button settings.</li>
  <li>Button States dictionary is passed to a class that converts the button states to a dictionary of settings that the main model object can understand.</li>
  <li><em><strong></em>__<em>_</em>__<em>_</em>_</strong>???</li>
  </ol>
  
  <p>At this point, I need to inform the main view controller (which holds the instance of my main model object) that the settings have been updated and it needs to update the settings on its model object. How do I go about doing this? Should I have a class method on the main view controller and include the header file in my settings conversion class?</p>