popViewController的完成块
问题说明
当使用 dismissViewController 关闭模态视图控制器时，可以选择提供完成块。是否有类似的等价物 popViewController ？
When dismissing a modal view controller using dismissViewController, there is the option to provide a completion block. Is there a similar equivalent for popViewController?
完成参数相当方便。例如，我可以使用它来阻止从表格视图中删除一行，直到模态在屏幕外，让用户看到行动画。
The completion argument is quite handy. For instance, I can use it to hold off removing a row from a tableview until the modal is off screen, letting the user see the row animation. When returning from a pushed view controller, I would like the same opportunity.
我已经尝试将 popViewController 放在 UIView 动画块，我可以访问完成块。但是，这会对弹出的视图产生一些不必要的副作用。
I have tried placing popViewController in an UIView animation block, where I do have access to a completion block. However, this produces some unwanted side effects on the view being popped to.
如果没有可用的方法，有什么解决方法？
If there is no such method available, what are some workarounds?
正确答案
我知道两年前已经接受了一个答案，但这个答案不完整。
I know an answer has been accepted over two years ago, however this answer is incomplete.
没有办法做你想要的开箱即用的
There is no way to do what you're wanting out-of-the-box
在技术上是正确的，因为 UINavigationController API不提供任何选项。然而，通过使用CoreAnimation框架，可以向底层动画添加完成块：
This is technically correct because the UINavigationController API doesn't offer any options for this. However by using the CoreAnimation framework it's possible to add a completion block to the underlying animation:
[CATransaction begin];
[CATransaction setCompletionBlock:^{
// handle completion here
}];
[self.navigationController popViewControllerAnimated:YES];
[CATransaction commit];
完成块将在 popViewControllerAnimated： 结束。此功能自iOS 4开始可用。
The completion block will be called as soon as the animation used by popViewControllerAnimated: ends. This functionality has been available since iOS 4.
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