ios - 未执行 Segue

Question

在我的第一个 ViewController 中，我正在检查用户是否已经使用 Firebase 登录，如果他/她已经登录，则重定向到主切换面板，如果没有，则重定向到登录 View 。但是，欢迎 View 仅保留在 View 中，不会发生重定向。

import UIKit
import Firebase

class WelcomeVC: UIViewController {

    @IBOutlet weak var btnLogin: RoundedShadowButton!

    override func viewDidLoad() {
        super.viewDidLoad()

        if(Auth.auth().currentUser?.uid != nil) {
            //user is logged in
            performSegue(withIdentifier: "goToSwitchboardVC", sender: self)
        }
        else {
            //user in not logged in
            performSegue(withIdentifier: "goToLoginVC", sender: self)
        }
    }

    @IBAction func btnLoginWasPressed(_ sender: Any) {
        performSegue(withIdentifier: "goToLoginVC", sender: self)
    }

}

代码已更改

import UIKit
import Firebase

class WelcomeVC: UIViewController {

    @IBOutlet weak var btnLogin: RoundedShadowButton!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear(_ animated: Bool) {
        print("AUTH USER")
        print(Auth.auth().currentUser)
        print(Auth.auth().currentUser?.uid)

        if(Auth.auth().currentUser?.uid != nil) {
            //user is logged in
            performSegue(withIdentifier: "goToSwitchboardVC", sender: self)
        }
        else {
            //user in not logged in
            performSegue(withIdentifier: "goToLoginVC", sender: self)
        }
    }

    @IBAction func btnLoginWasPressed(_ sender: Any) {
        performSegue(withIdentifier: "goToLoginVC", sender: self)
    }

}

Answer 1

您的代码不会重定向到任何 View ，因为您已经在 viewWillAppear 中编写了它。在 View 出现之前无法执行 Segue所以你必须在 viewDidAppear 中执行 segue。如果其他一切都正确(segue 名称和连接)那么它肯定会工作。

试试这个-

override func viewDidAppear(_ animated: Bool) {
    print("AUTH USER")
    print(Auth.auth().currentUser)
    print(Auth.auth().currentUser?.uid)

    if(Auth.auth().currentUser?.uid != nil) {
        //user is logged in
        performSegue(withIdentifier: "goToSwitchboardVC", sender: self)
    }
    else {
        //user in not logged in
        performSegue(withIdentifier: "goToLoginVC", sender: self)
    }
}