title: objective-c ios: override implementation method of class
body: <p>I'm new to iOS development and a bit stucked with such problem. </p>
  
  <p>In my iphone app I'm using this awesome dropdown view controller <a href="https://github.com/nmattisson/DropdownMenu" rel="nofollow">https://github.com/nmattisson/DropdownMenu</a> <strong>via Cocoapods</strong>. </p>
  
  <p>I'm extending <code>DropdownMenuController</code> in my own <code>MyDropdownMenuController</code>:</p>
  
  <p><strong>MyDropdownMenuController.h</strong></p>
  
  <pre><code>#import "DropdownMenuController.h"
  
  @interface MyDropdownMenuController : DropdownMenuController
  
  @end
  </code></pre>
  
  <p>I would like to override this <code>drawOpenLayer</code> (<a href="https://github.com/nmattisson/DropdownMenu/blob/master/DropdownMenu/DropdownMenuController.m#L126" rel="nofollow">https://github.com/nmattisson/DropdownMenu/blob/master/DropdownMenu/DropdownMenuController.m#L126</a>) method inside my controller instance, but unfortunately compiler says it's not possible:</p>
  
  <p><strong>MyDropdownMenuController.m</strong></p>
  
  <pre><code>- (void)drawOpenLayer {
     // compiler says 
     // "No visible @interface for "DropdownMenuController" declares the selector "drawOpenLayer"
     [super drawOpenLayer];
  }
  </code></pre>
  
  <p>Is it possible to override this method without actually updating external interface etc.?</p>