ios - PFFacebookUtils.logInInBackground 不执行 segue

Question

嘿，下面的代码在某种程度上不适用于 segue。它返回:

警告:尝试呈现不在窗口层次结构中的 View !

代码在 IBAction 按钮中运行。然后我在没有 PFFFacebookUtils 代码的情况下执行 segue，它工作正常。从那我猜 segue 不能从 PFFFacebookUtils 调用，因为它在后台以某种方式工作。

代码:

PFFacebookUtils.logInInBackground(withReadPermissions: permissions) {
            (user: PFUser?, error: Error?) -> Void in
            if let user = user {
                if user.isNew {
                    print("User signed up and logged in through Facebook!")
                    self.performSegue(withIdentifier: "segueSignUpWindow", sender: nil)

                } else {
                    print("User logged in through Facebook!")
                    self.performSegue(withIdentifier: "segueSignUpWindow", sender: self)
            } else {
                print("Uh oh. The user cancelled the Facebook login.")
                self.loginCancelledLabel.alpha = 1
            }
        }

我尝试插入额外的代码，例如:

DispatchQueue.main.async {
                let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let vc = storyboard.instantiateViewController(withIdentifier: "SignUp")
                self.show(vc, sender: self)
                print("Hello")

或者函数:

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
        if (segue.identifier == "segueSignUpWindow") {
            DispatchQueue.main.async {
                let storyboard: UIStoryboard = UIStoryboard(name: "Main", bundle: nil)
                let vc = storyboard.instantiateViewController(withIdentifier: "SignUp")
                self.show(vc, sender: self)
                print("Hello")
            }
        }

没有任何作用。有人有可行的解决方案吗？我的目标是在登录或继续登录后转至另一个 Storyboard。

我查看了 stackoverflow 中的大多数线程。没有找到有效的解决方案。

Answer 1

我能得到的最接近的:

使用初始化值创建触发器 var segueLogin : Bool = false。

当 PFFacebookUtils 获取 segue 所需的值时，将触发器更改为 true:

PFFacebookUtils.logInInBackground(withReadPermissions: permissions) {
            (user: PFUser?, error: Error?) -> Void in
            if let user = user {
                if user.isNew {
                    print("User signed up and logged in through Facebook!")
                    self.segueLogin = true

                } else {
                    print("User logged in through Facebook!")
                    self.segueLogin = true
                }
            } else {
                print("Uh oh. The user cancelled the Facebook login.")
                self.loginCancelledLabel.alpha = 1
            }
        }

然后将代码添加到 viewDidAppear 类。意识到每次 PFFFacebookUtils 完成时它都会启动。因此它检查返回值是否为真并在成功的 PFFFacebookUtils session 后执行 segue:

override func viewDidAppear(_ animated: Bool) {
        if segueLogin == true {
            self.performSegue(withIdentifier: "segueSingup", sender: self)
        }
    }