title: Combining animations on UIView and subiview's CALayer?
body: <p>I'm animating a UIView transition like so:</p>
  
  <pre><code>UIView *areaView = areaController.view;
  [areaController viewWillAppear:YES];
  
  UIView *subView = self.customView.subView;
  UIButton *button = customView.button; // button is a subview of customView.subView
  
  [UIView beginAnimations:nil context:NULL];
  [UIView setAnimationDuration:1];
  
  [UIView setAnimationTransition:UIViewAnimationTransitionFlipFromRight forView:subView cache:YES];
  
  [button removeFromSuperview];
  [subView addSubview:areaView];
  [areaController viewDidAppear:YES];
  
  
  [UIView commitAnimations];
  
  [self.areaController start];  // areaController starts the animation of the CALayer, see below
  </code></pre>
  
  <p>This flips the new view, areaView from "behind" the button just fine, but in areaView there's another subview which is animating it's CALayer:</p>
  
  <pre><code>CATransform3D rotate = CATransform3DMakeRotation(angle, 1, 0, 0);
  
  CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"transform"];
  
  animation.toValue = [NSValue valueWithCATransform3D:rotate];
  animation.duration = .08;
  animation.delegate = self;
  animation.fillMode = kCAFillModeForwards;
  animation.removedOnCompletion = NO;   
  
  [layer addAnimation:animation forKey:@"transform"];
  </code></pre>
  
  <p>My question is:</p>
  
  <p>How do I make both these animations animate in parallell? </p>
  
  <p>Currently, the animation on the CALayer starts when calling <code>[self.areaController start];</code>, but the result is not visible until the transition on the superview is finished. Should I somehow use an animation group with the UIView's layer?</p>