popViewController 的完成块 [英] Completion block for popViewController

问题描述

当使用 dismissViewController 关闭模态视图控制器时，可以选择提供一个完成块.popViewController 是否有类似的等价物?

When dismissing a modal view controller using dismissViewController, there is the option to provide a completion block. Is there a similar equivalent for popViewController?

完成参数非常方便.例如，我可以使用它来推迟从 tableview 中删除一行，直到模态离开屏幕，让用户看到行动画.从推送的视图控制器返回时，我希望有同样的机会.

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.

我尝试将 popViewController 放在 UIView 动画块中，在那里我可以访问完成块.但是，这会对弹出的视图产生一些不需要的副作用.

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.

如果没有这样的方法可用，有哪些解决方法?

If there is no such method available, what are some workarounds?

推荐答案

我知道一个答案已经在两年多前被接受了，但是这个答案是不完整的.

I know an answer has been accepted over two years ago, however this answer is incomplete.

没有办法做你想做的开箱即用

There is no way to do what you're wanting out-of-the-box

这在技术上是正确的，因为 UINavigationController API 没有为此提供任何选项.但是，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];

一旦 popViewControllerAnimated: 使用的动画结束，将立即调用完成块.此功能从 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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