Swift 3中的其他視圖控制器無法編輯Label Outlet

Question

我想更改登錄屏幕的用戶名出口，但無法正常工作，我找不到解決方案

    let loginVC = storyboard?.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
    if self.emailTextField.text == "" {
        loginVC.userName?.text = "Hello"
    } else {
        loginVC.userName?.text = self.emailTextField.text!
    }
    navigationController?.pushViewController(loginVC, animated: true)

Answer 1

嘗試這個：

let loginVC = storyboard?.instantiateViewController(withIdentifier: "LoginViewController") as! LoginViewController
if self.emailTextField.text == "" 
{
    loginVC.str = "Hello"
} 
else 
{
    loginVC.str = self.emailTextField.text!
}
navigationController?.pushViewController(loginVC, animated: true)

LoginViewController

class LoginViewController: UIViewController 
{
    var str:String! = nil
    override func viewDidLoad() 
    {
       super.viewDidLoad()
       self.userName.text = str
    }
}