从TabBarController>NavigationController>ViewController > ViewController传递数据

Question

我有一个登录屏幕，它转到选项卡栏，然后转换为导航控制器。我需要将用户名传递给导航控制器的第一个视图控制器。所以它是这样的：

登录屏幕-> TabBarController -> NavigationController -> CustomerMainViewController

我已经遍历了堆栈溢出，并实现了以下代码，这似乎是大家的共识：

//From my login View Controller
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {

    let tabVC = segue.destination as! UITabBarController
    let navVC = tabVC.viewControllers!.first as! UINavigationController
    let destVC = navVC.viewControllers.first as! CustomerMainViewController
    destVC.tempName = self.emailTextField.text!
}

@IBAction func loginButtonPresssed(_ sender: Any) {

    self.performSegue(withIdentifier: "GoToTabBar", sender: self)
}
//From my View Controller (CustomerMainView Controller)
override func viewDidLoad() {
    super.viewDidLoad()
    username.text = self.tempName
}

我希望我的视图控制器上的username字段被填充，但它是空的。

Answer 1

您的代码应该可以工作。当您定义了多个segue时，检查segue标识符和/或安全地展开视图控制器可能会有所帮助：

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if segue.identifier == "GoToTabBar" {
        if let tabVC = segue.destination as? UITabBarController, 
            let navVC = tabVC.viewControllers?.first as? UINavigationController,
            let destVC = navVC.viewControllers.first as? CustomerMainViewController {
          destVC.tempName = self.emailTextField.text!
        }
    }
}