title: how to use addChildViewController in subview
body: <p>I want to use <code>addChildViewController</code> in <code>View</code> (one view fro subviews array) but I don't know about that. this is my code :</p>
  
  <pre><code>for (UIView *subview in self.view.subviews) {
          if (subview.tag == 1) {
              CartView *cart = [[CartView alloc]init];
  
              [cart willMoveToParentViewController:????];/* (UIViewController*) from subview*/
              [cart.view setFrame:CGRectMake(0.0f,CGRectGetHeight(self.view.frame),CGRectGetWidth(self.view.frame),CGRectGetHeight(self.view.frame))];
              [UIView beginAnimations:nil context:nil];
              [UIView setAnimationDuration:0.3];
              [cart.view setFrame:CGRectMake(0.0f,0,CGRectGetWidth(self.view.frame),CGRectGetHeight(self.view.frame))];
              [UIView commitAnimations];
              [subview addSubview:cart.view];
              [???? addChildViewController:cart];
              [cart didMoveToParentViewController:????];
          }
      }
  </code></pre>
  
  <p>I don't know how to get UIViewController* from subview!!!!</p>