呈现一个视图控制器，将其关闭，然后在Swift中呈现一个不同的视图控制器 [英] Present a view controller, dismiss it and present a different one in Swift

问题描述

因此，我有一个根视图控制器，该控制器具有一个按钮，当用户按下该按钮时，将显示另一个视图控制器.第二个控制器具有一个关闭选项，该选项仅返回到根视图控制器，还有一个按钮，当用户触摸它时，该按钮将关闭当前视图控制器，因此它又回到了根视图控制器，并显示另一个按钮.转到我使用的第一个控制器:

So I have a root view controller that has a button that when the user pushes it, another view controller is presented. This second controller has a dismiss option that just comes back to the root view controller and a button that when the user touches it dismisses the current view controller so it goes back to the root view controller for a second and presents another one. Going to the first controller I use:

let vc = FirstController()
self.present(vc, animated: true, completion: nil)

然后在另一个视图控制器中，我选择仅关闭的按钮，然后执行此操作.

And when in the other view controller I select the button that only dismisses I do this.

self.dismiss(animated: true, completion: nil)

因此，对于需要关闭并显示另一个控制器的第二个控制器，我尝试了以下操作:

So for the second controller that needs to dismiss and present another one I have tried the following:

self.dismiss(animated: true, completion: {
            let vc = SecondController()
            self.present(vc, animated: true, completion: nil)
        })

但是我得到一个错误:

Warning: Attempt to present <UINavigationController: 0xa40c790> on <IIViewDeckController: 0xa843000> whose view is not in the window hierarchy!

推荐答案

发生此错误是因为您在关闭FirstController之后尝试从FirstController中显示SecondController.这不起作用:

The error occurs because you are trying to present SecondController from FirstController after you have dismissed FirstController. This doesn't work:

self.dismiss(animated: true, completion: {
    let vc = SecondController()

    // 'self' refers to FirstController, but you have just dismissed
    //  FirstController! It's no longer in the view hierarchy!
    self.present(vc, animated: true, completion: nil)
})

此问题与我昨天回答.

针对您的情况进行了修改，我建议这样做:

Modified for your scenario, I would suggest this:

weak var pvc = self.presentingViewController

self.dismiss(animated: true, completion: {
    let vc = SecondController()
    pvc?.present(vc, animated: true, completion: nil)
})

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