ios - 标签栏 Controller : Show Login Controller + Stop Double Tap on Tab Button

Question

我有一个以 UITabBarController 作为 Root View 的应用程序。我不希望我的用户必须登录才能查看该应用程序，因此所有用户都可以看到第一个选项卡(选项卡 1)。现在其他选项卡应该锁定在 LoginViewController 后面。

我在锁定 View 上有以下内容:

ActivityViewController.swift

override func viewWillAppear(_ animated: Bool) {
   super.viewWillAppear(animated)
   if AccessToken.current != nil {
   // Do Stuff
   }
   else {
       let vc = UIStoryboard(name:"Main", bundle:nil).instantiateViewController(withIdentifier: "UserLoginViewController")
       self.navigationController?.pushViewController(vc, animated:false)
   }
}

UserLoginViewController.swift

override func viewDidLoad() {
    super.viewDidLoad()

    // Do any additional setup after loading the view.
    navigationItem.hidesBackButton = true
    self.navigationController?.setNavigationBarHidden(true, animated: true)
}

override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)

    if AccessToken.current != nil {
        _ = self.navigationController?.popViewController(animated: true)
    }
}

// Functions to handle login omitted
// I do the following once login is successful
_ = self.navigationController?.popViewController(animated: true)

// Close button to return to first no login required tab (Tab 1)
@IBAction func closeButtonPressed(_ sender: AnyObject) {
    // Send back to the first index in the tab bar controller
    self.navigationController?.tabBarController?.selectedIndex = 0
}

我有以下问题:

1. 在锁定的标签上按一次，正确显示登录屏幕。再次按下相同的选项卡，将关闭登录屏幕，动画显示登录屏幕隐藏的 View ，然后再次弹出登录屏幕。有什么办法可以阻止这种情况吗？

Answer 1

通常的做法是显示您的登录 Controller UserLoginViewController，因此它将显示在 UITabBarController 的前面。然后在登录 Controller 内部，添加登录成功时的关闭 Action

if AccessToken.current != nil {
    // Do Stuff
}
else {
    let vc = UIStoryboard(name:"Main", bundle:nil).instantiateViewController(withIdentifier: "UserLoginViewController")
    presentViewController(vc, animated: true, completion: nil)
}