iOS：iOS 4.3和5.0之间的不同addSubview行为 [英] iOS: different addSubview behavior between iOS 4.3 and 5.0

问题描述

在iOS 4.3编码之前，我发现在使用 [superview addSubView：controller.view] 将视图控制器的视图添加到另一个视图时，控制器实例将不会收到 -viewWillAppear / viewDidAppear 消息，比我在堆栈溢出中的某个线程中发现了同样的问题。之后，我根据需要手动调用 -viewWillAppear / -viewDidAppear 。

while coding in iOS 4.3 before, I found while add a view controller's view to another view with [superview addSubView:controller.view], the controller instance will not receive the -viewWillAppear/viewDidAppear message, than I found same issue in some thread in stack overflow. After that, I manually call -viewWillAppear/-viewDidAppear as needed.

但是，升级到 iOS 5.0 后，一些活泼的 UIView 行为发生了。最后我发现在iOS 5中， [superview addSubView：controller.view] ，将发送 -viewWillAppear / -viewDidAppear 自动向控制器实例发送消息，加上我的手动调用，每次控制器执行其行为时都会有两条重复的消息。

but, after upgrade to iOS 5.0, some frisky UIView behavior happened. Finally I found that in iOS 5, the [superview addSubView:controller.view] , will send a -viewWillAppear/-viewDidAppear message to the controller instance automatically, plus my manually calls, there are two duplicated message each time the controller action its behavior.

我也发现了类似的问题： iOS 5：-viewWillAppear未被调用在解雇iPad中的模式后

and I also found a similar issue: iOS 5 : -viewWillAppear is not called after dismissing the modal in iPad

现在，问题是，在搜索苹果的文档之后，我没有找到关于这些问题的任何明确的文档。我甚至怀疑这是否是iOS 5.0中保证的视图生命周期行为。

Now, the problem is, after search apple's documents, I didn't find any explicitly doc for diff about these issues. I even wonder if this is a guaranteed view life cycle behavior in iOS 5.0 .

是否有人解决类似问题或找到有关这些差异的指导原则。因为我想在 4.x&中运行我的应用程序5.x iOS 。

Does anyone fix similar issues or find some guidelines about these difference. cause I want to run my app both in 4.x & 5.x iOS.

推荐答案

在iOS 4中你必须手动调用 -viewWillAppear ， -viewWillDisappear 等。如果在窗口层次结构中添加或删除视图，则会在iOS 5中自动调用它们。幸运的是，iOS 5在 UIViewController 中有一个方法可以覆盖以将行为恢复为与iOS 4一起工作的方式。只需将其添加到 UIViewController ：

In iOS 4 you had to manually call -viewWillAppear, -viewWillDisappear, etc. when adding or removing a view from your view hierarchy. These are called automatically in iOS 5 if the view is being added or removed from the window hierarchy. Fortunately, iOS 5 has a method in UIViewController that you can override to revert the behaviour back to how it worked with iOS 4. Just add this to your UIViewController:

-(BOOL)automaticallyForwardAppearanceAndRotationMethodsToChildViewControllers {
   return NO;
}

这可能是最简单的解决方案，只要你支持iOS 4 5.一旦您放弃对iOS 4的支持，您可以考虑修改代码以在交换视图时使用更新的方法。

This is probably the easiest solution as long as you're supporting both iOS 4 and iOS 5. Once you drop support for iOS 4 you might consider modifying your code to use the newer approach when swapping views.

编辑2012年2月5日

显然这个函数需要使用 addChildViewController：方法将子视图控制器添加到主视图控制器中。 iOS4中不存在此方法，因此您需要执行以下操作：

Apparently this function requires the child view controller be added to the main view controller using the addChildViewController: method. This method doesn't exist in iOS4, so you need to do something like this:

  if ([self respondsToSelector:@selector(addChildViewController:)] ) {
     [self addChildViewController:childViewController];
  }

感谢所有纠正我的人。

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