Iphone UIView在旋转前未正确初始化

我使用的代码与下面非常相似：

- (void)flipToViewController:(UIViewController*)targetViewController
              transition:(UIViewAnimationTransition)transition

{ if（targetViewController） { [[[self-activeViewController]视图]setUserInteractionEnabled:否]

  // force the view to be instantiated (loadView/layoutSubviews)
  [[targetViewController view] setHidden:NO];

  [UIView beginAnimations:nil context:NULL];
  [UIView setAnimationDuration:0.8f];
  [UIView setAnimationTransition:transition forView:self.view cache:YES];

  [targetViewController viewWillAppear:YES];
  [[self activeViewController] viewWillDisappear:YES];

  [[[self activeViewController] view] removeFromSuperview];

  [[self view] addSubview:[targetViewController view]];

  [[self activeViewController] viewDidDisappear:YES];
  [targetViewController viewDidAppear:YES];

  [[targetViewController view] setUserInteractionEnabled:YES];

  [UIView commitAnimations];

  [self setActiveViewController:targetViewController];
  }

}

我正在使用翻转转换，但是，当我的targetViewController翻转到视图时，视图没有正确初始化。UISegmentedControl看起来很奇怪，一个子视图位置错误

只有在动画完成后，所有内容才会进入正确的位置

我在ViewWillDisplay（而不是ViewDidDisplay）中执行所有子视图设置，因此我不明白为什么它没有及时初始化

有什么建议吗

---

我还注意到（调试后）在viewDidLoad方法之前调用了ViewWillDisplay？为什么要这样做？

移动以下行：

[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.8f];
[UIView setAnimationTransition:transition forView:self.view cache:YES];

…就在这条线下面：

[[self view] addSubview:[targetViewController view]];

显然，addSubView/insertSubView不能在动画中