ios - 注销用户会使应用程序崩溃

Question

在我的 SettingsVC 中，我发送了一个 NSNotification.Name(rawValue: "LogOut") 的通知，AppDelegate 的 didFinishLaunchingWithOptions 函数会观察到它。

收到通知后，我调用 User.logout 清除所有用户数据，然后应用程序在 DispatchQueue block 中崩溃。

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

    window = UIWindow(frame: UIScreen.main.bounds)
    window?.backgroundColor = .white

    NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: "LogOut"), object: nil, queue: nil) { _ in
        User.logout()

        DispatchQueue.main.sync {
            self.navigationController?.setViewControllers([WelcomeViewController()], animated: false)
        }
    }

    if let _ = UserDefaults.standard.string(forKey: "loggedIn") {
        self.navigationController = UINavigationController(rootViewController: HomeViewController())
    } else {
        self.navigationController = UINavigationController(rootViewController: WelcomeViewController())
    }

    window?.rootViewController = navigationController
    window?.makeKeyAndVisible()

    return true
}

崩溃发生时没有任何附加信息。知道如何使它不崩溃吗？谢谢!

Answer 1

我认为你应该在调用 setViewControllers 之前“清除”导航堆栈，此外:

launch the main thread synchronously from a background thread before it exits

在逻辑上是错误的，最好以这种方式使用async:

NotificationCenter.default.addObserver(forName: NSNotification.Name(rawValue: "LogOut"), object: nil, queue: nil) { _ in
  User.logout()
  DispatchQueue.main.async {
    self.navigationController?.popToRootViewController(animated: false)
    self.navigationController?.setViewControllers([WelcomeViewController()], animated: false)
  }
}