如何检查视图控制器是否已在 Swift 中被关闭

Question

如果我像这样呈现 ViewController：

let authViewController = authUI!.authViewController()
authViewController.modalPresentationStyle = .overCurrentContext
self.present(authViewController, animated: true, completion: nil)

我想知道 ViewController 何时被解雇。我尝试了以下方法：

let authViewController = authUI!.authViewController()
authViewController.modalPresentationStyle = .overCurrentContext
self.present(authViewController, animated: true, completion: {
   print("View Dismissed")
})

但这只会让我知道视图是否已成功呈现。此 ViewController 不是我创建的，因此我无法更改 viewWillDissapear 方法。

Answer 1

整个答案基于 OP 无法访问 authViewController 代码的假设

如果您无权访问 authViewController 代码，糟糕的解决方案是使用视图控制器的 viewWillAppear 来查找何时取消授权视图控制器。

基本上，当您 present/push 任何 viewController 覆盖现有的视图控制器时，当 presented/pushed 视图控制器被关闭或弹出时，您的视图控制器的 viewWillDisappear 将被类似地调用out viewWillAppear 将被调用。

因为 viewWillAppear 也可能因其他原因被调用，您不想将其混淆为 authViewController 解雇，请使用布尔值

private var shouldMonitorAuthViewControllerDismiss = false //declared a instance property

当您实际呈现 authViewController

时，将布尔值设置为 true

let authViewController = authUI!.authViewController()
authViewController.modalPresentationStyle = .overCurrentContext
self.present(authViewController, animated: true, completion: {
    shouldMonitorAuthViewControllerDismiss = true
})

终于在你的 viewWillAppear

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(true)
        if shouldMonitorAuthViewControllerDismiss {
            //auth view controller is dismissed
        }
        shouldMonitorAuthViewControllerDismiss = false
    }

如何检查视图控制器是否已在 Swift 中被关闭

How to check if a view controller has been dismissed in Swift

ios

swift

viewcontroller