Swift中的自定义Segue [英] Custom Segue in Swift

问题描述

@objc(SEPushNoAnimationSegue)
class SEPushNoAnimationSegue: UIStoryboardSegue {
    override func perform () {
      self.sourceViewController.navigationController.pushViewController(self.destinationViewController, animated:false)
    }
}

在上面的代码中，我有两个问题：
1）。它有一个编译错误：
'UINavigationController！'没有名为'pushViewController'的成员

In the above code, I have 2 questions: 1). it has a compile error: 'UINavigationController!' does not have a member named 'pushViewController'

但在该类中，它确实有一个pushViewController方法。

But in that class, it did has a pushViewController method.

2）。我必须添加注释：@objc（SEPushNoAnimationSegue），否则
，在storyboard中，它只识别随机生成的名称，如_tcxxxxSEPushNoAnimationSegue。

2). I have to add the annotation: @objc(SEPushNoAnimationSegue), otherwise, in storyboard, it only recognize the random generated name, like, _tcxxxxSEPushNoAnimationSegue.

为什么这两个问题发生在这里？

why these 2 issues happen here?

推荐答案

问题＃1

UIStoryboardSegue有一个恼人的缺陷：它的sourceViewController和destinationViewController属性被输入为 AnyObject！（即使在Objective-C（Id类型）中也是如此）而不是 UIViewController ，应该是。

Issue #1

UIStoryboardSegue has an irritating flaw: its sourceViewController and destinationViewController properties are typed as AnyObject! (that's the case even in Objective-C (Id type)) and not as UIViewController, as it should be.

同样的缺陷会在你完美而简单的代码中造成破坏。以下是如何重写它以修复编译错误：

That same flaw creates havoc in your perfect and simple code. Here's how to rewrite it in order to fix the compile errors:

@objc(SEPushNoAnimationSegue)
class SEPushNoAnimationSegue: UIStoryboardSegue {
    override func perform () {
        let src = self.sourceViewController as UIViewController
        let dst = self.destinationViewController as UIViewController
        src.navigationController.pushViewController(dst, animated:false)
    }
}

注意：Apple在iOS 9中解决了这个问题。 sourceViewController 和 destinationViewController 现在已正确声明为 UIViewController 。

NOTE: Apple fixed this thing in iOS 9. sourceViewController and destinationViewController are now correctly declared as UIViewController.

Swift编译器使用自己的名称错误，并且好的'Objective-C在Xcode中无法识别它。使用显式的 @obj（）解决了这个问题。

The Swift compiler stores its symbols using its own name mangling, and good ol' Objective-C does not recognize it in Xcode. Using an explicit @obj() solves the issue.

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