ios performSegueWithIdentifier 没有带标识符的 segue
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performSegueWithIdentifier has no segue with identifier
提问by Ian
I encountered a crash while testing my app. The following image is my storyboard:
我在测试我的应用程序时遇到了崩溃。下图是我的故事板：
I have the code in View Controller:
我在视图控制器中有代码：
@IBAction func unwindToHomeScreen(segue:UIStoryboardSegue) {
}
The view of "Add new Item" have a "Cancel" button, I controlled-drag it to the "Exit" icon at the top and link to unwindToHomeScreen, it works fine.
“添加新项目”的视图有一个“取消”按钮，我控制拖动它到顶部的“退出”图标并链接到unwindToHomeScreen，它工作正常。
The "Add new Item" has a class AddTableViewControllerand the code I wrote inside:
“添加新项目”有一个类AddTableViewController和我在里面写的代码：
@IBAction func save() {
// Execute the unwind segue and go back to the home screen
performSegueWithIdentifier("unwindToHomeScreen", sender: self)
}
I controlled-drag the "Save" button to the func, but the app crash when I click the button
我控制拖动“保存”按钮到 func，但当我点击按钮时应用程序崩溃
I can use dismissViewControllerAnimated(true, completion: nil)instead, but I just wonder why performSegueWithIdentifiercan't work?
我可以使用dismissViewControllerAnimated(true, completion: nil)，但我只是想知道为什么performSegueWithIdentifier不能工作？
I read the code at dropbox.com/s/hpybgg9x67rtqng/foodpinstatictable.zip?dl=0and try to make one and using performSegueWithIdentifierlike this example for practicing, I didn't see the segue identifier at her, what is the difference?
我在dropbox.com/s/hpybgg9x67rtqng/foodpinstatictable.zip?dl=0 上阅读了代码并尝试制作一个并使用performSegueWithIdentifier此示例进行练习，我没有在她身上看到 segue 标识符，有什么区别？
回答by AstroCB
You haven't actually given that segue an identifier. unwindToHomeScreenis a function that you can call; what you're looking for is your segue identifier, which is set in Interface Builder like this:
你实际上还没有给那个 segue 一个标识符。unwindToHomeScreen是一个可以调用的函数；您正在寻找的是您的 segue 标识符，它在 Interface Builder 中设置如下：
In this example, I have a button wired to the next view via Interface Builder like you describe ("Interface Builder") and a button that is wired to this IBActionin my view controller ("Programmatically"):
在这个例子中，我有一个按钮通过 Interface Builder 连接到下一个视图，就像你描述的一样（“Interface Builder”）和一个IBAction在我的视图控制器中连接到这个的按钮（“Programmatically”）：
@IBAction func goToNextView(sender: UIButton!) {
self.performSegueWithIdentifier:("go", sender: self)
}
In any case, what you're missing is the actual identifier, which can be set in the attributes of a segue created in Interface Builder.
无论如何，您缺少的是实际标识符，它可以在 Interface Builder 中创建的 segue 的属性中设置。
回答by Phil Hudson
I found that because I renamed my view controller, I needed to delete and recreate the segue.
我发现因为我重命名了我的视图控制器，所以我需要删除并重新创建 segue。
回答by Kristian
Swift 4:
斯威夫特 4：
Sometimes we must cleanthe build folder and then try again.
有时我们必须清理构建文件夹，然后再试一次。
Worked for me after ctrl-dragging the new segue and giving it a name, then using it programatically as:
在 ctrl 拖动新 segue 并为其命名后为我工作，然后以编程方式使用它：
performSegue(withIdentifier: "goToMyNewViewController" , sender: self)
回答by Stéphane de Luca
A possible issue with iOS?12 and earlier (iOS?13 seems not to suffer from the same issue) might come from the fact that performSegue(withIdentifier:,sender:) is called from the view controller viewdidLoad() callback.
iOS?12 和更早版本（iOS?13 似乎没有遇到同样的问题）可能存在的问题可能来自于从视图控制器 viewdidLoad() 回调调用 performSegue(withIdentifier:,sender:)的事实。
You absolutely must invoke it from the viewDidAppear(_ animated: Bool)callbackin order to avoid the question-mentioned crash.
您绝对必须从viewDidAppear(_animated: Bool)回调中调用它，以避免出现问题提到的崩溃。
That will certainly save hours of hair-puling…
这肯定会节省数小时的拔毛时间……
回答by Espacucho
in my case reorder the Embed in
在我的情况下重新排序嵌入
Tab bar controller Navigation controller vc (contains button - tapping button initiates a "show, e.g. push" segue)
标签栏控制器导航控制器 vc（包含按钮 - 点击按钮启动“显示，例如推”segue）
Too fix the title in the navigationBar
太固定导航栏中的标题
回答by Sumit
for me --> click on the relation-arrow between view controllers and then select attribute inspector, there is identifier give name and select push class done...
对我来说 --> 单击视图控制器之间的关系箭头，然后选择属性检查器，有标识符给出名称并选择推送类完成...
