画面遷移ができない。 whose view is not in the window hierarchy!

Question

前提・実現したいこと

whose view is not in the window hierarchy!というエラーが発生しており、viewDidLoadで画面遷移を行うことで発生する様なのですが、遷移の処理はmainthreadで行っており、エラーの原因が特定できず困っています。

ConversationControllerのProfileControllerDelgateのhandleLogoutメソッド内でpresentLoginScreen()を呼ぶとエラーが発生し、呼ばなければ遷移せず、エラーは発生しませんでした。

profileControllerDelegate

発生している問題・エラーメッセージ

 Warning: Attempt to present <UINavigationController: 0x10b867a00> on <FirebaseChat.conversationsViewController: 0x10a520990> whose view is not in the window hierarchy!

該当のソースコード

##問題のController

import Firebase
import UIKit

private let reuseIdentifier = "ConversationCell"

class conversationsViewController: UIViewController {
    
    //MARK: - Property
    
    private let tableView = UITableView()
    private var conversations = [Conversation]()
    
    private let newMessageButton: UIButton = {
        
        let button = UIButton(type: .system)
        button.setImage(UIImage(systemName: "plus"), for: .normal)
        button.backgroundColor = .systemPurple
        button.tintColor = .white
        button.imageView?.setDimensions(height: 24, width: 24)
        button.addTarget(self, action: #selector(showNewMessage), for: .touchUpInside)
        
        return button
    }()
    
    //MARK: - View LifeCycle
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        configureUI()
        authenticateUser()
    }
    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        
        fetchConversations()
        configureNavigationBar(Title: "Message", prefersLargeTitle: true)
        
        navigationController?.navigationBar.isHidden = false
    }
    //MARK: - Selector's
    
    @objc func showProfile() {
        
        let controller = ProfileController(style: .insetGrouped) //MARK: - Point TableViewに余白ができる。
        controller.delegate = self
        let nav = UINavigationController(rootViewController: controller)
        
        nav.modalPresentationStyle = .fullScreen
        present(nav, animated: true, completion: nil)
    }
    
    @objc func showNewMessage() {
        
        //navigationBarを付与してから遷移
        let controller = NewMessageController()
        controller.delegate = self
        let nav = UINavigationController(rootViewController: controller)
        
        nav.modalPresentationStyle = .fullScreen
        present(nav, animated: true, completion: nil)
    }
    
    //MARK: - API
    
    func fetchConversations() {
        
        Service.fetchConversation { (conversations) in
            
            self.conversations = conversations
            self.tableView.reloadData()
        }
    }
    
    func authenticateUser() {
        
        if Auth.auth().currentUser?.uid == nil {
            
            presentLoginScreen()
        }else{
            print("DEBUG : current userId =>(Auth.auth().currentUser!.uid)")
        }
    }
    
    //MARK: - User Interface's
    
    private func configureUI() {
        
        // Style Property
        let bgColor: UIColor = .white
        
        view.backgroundColor = bgColor
        
        configureGradientLayer()
        configureNavigationBar(Title: "Message", prefersLargeTitle: true)
        configureTableView()
        
        navigationItem.leftBarButtonItem = UIBarButtonItem(image: UIImage(systemName: "person.circle.fill"), style: .plain, target: self, action: #selector(self.showProfile))
        
        
        view.addSubview(newMessageButton)
        newMessageButton.setDimensions(height: 56 ,width: 56)
        newMessageButton.layer.cornerRadius = 56/2 //この時点でbuttonのheightは0 ×：newMessageButton.frame.height
        newMessageButton.anchor(bottom: view.safeAreaLayoutGuide.bottomAnchor, right: view.rightAnchor,
                                 paddingBottom: 16, paddingRight: 24)
    }
    
    private func configureTableView() {
        
        //Style Property
        let tableViewBgColor: UIColor = .white
        
        tableView.register(ConversationCell.self, forCellReuseIdentifier: reuseIdentifier)
        tableView.backgroundColor = tableViewBgColor
        tableView.rowHeight = 80
        tableView.tableFooterView = UIView()
        
        tableView.delegate = self
        tableView.dataSource = self
        
        tableView.frame = self.view.frame
        self.view.addSubview(self.tableView)
    }
    
    //MARK: - Helpers
    
    private func presentLoginScreen() {
        
        DispatchQueue.main.async {
            
            let controller = LoginController()
            let nav = UINavigationController(rootViewController: controller)
            
            nav.modalPresentationStyle = .fullScreen
            self.present(nav, animated: true, completion: nil)
        }
    }
    
    private func showChatController(foruser user: User) {
        
        let chatController = ChatController(user: user)
        self.navigationController?.pushViewController(chatController, animated: true)
    }
}

//MARK: - UITableviewDatasource

extension conversationsViewController: UITableViewDataSource {
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        
        return conversations.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        
        let cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier, for: indexPath) as! ConversationCell
         
        cell.conversation = conversations[indexPath.row]
        return cell
    }
}

//MARK: - UITableView Delegate

extension conversationsViewController: UITableViewDelegate {
    
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        
        tableView.deselectRow(at: indexPath, animated: true)
        showChatController(foruser: conversations[indexPath.row].user)
    }
}

extension conversationsViewController: NewMessageControllerDelegate {
    
    func controller(_ controller: NewMessageController, wantsToStartWith user: User) {
        
        controller.dismiss(animated: true, completion: nil)// Point : NewMessageControllerからConvaseationsControllerに戻ってきてからpushViewController。
        showChatController(foruser: user)
    }
    
}

//MARK: - ProfileController Delegate
extension conversationsViewController: ProfileControllerDelegate {
    
    func handleLogout() {
        
        AuthService.shared.logout { (error) in
            
            if let error = error {
                self.showHud(error: true, title: "Logout Error", Description: error.localizedDescription)
                return
            }
            self.presentLoginScreen()//このメソッドを呼ぶとエラーが発生、遷移しない
        }
    }
}

##AuthService Logout()

func logout(completion: @escaping(_ error: Error?) -> Void) {
        
        do{
            try Auth.auth().signOut()
            completion(nil)
        }catch{
            let error = CustomError.logout
            completion(error)
        }
    }

##ProfileDelegate HandleLogout()

protocol ProfileControllerDelegate: class {
    
    func handleLogout()
}

//profileFooterViewのDelegateMethod名もhandleLogout ボタンが押された時に呼ばれるだけ。
extension ProfileController: ProfileFooterDelegate{

    func handleLogout() {
        
        let alert = UIAlertController(title: nil, message: "Are you sure you want to logout ??", preferredStyle: .actionSheet)
        
        alert.addAction(UIAlertAction(title: "Log Out", style: .default, handler: { (_) in
            
            self.delegate?.handleLogout() // ProfileControllerDelegateのhandleLogout()
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
        
        present(alert, animated: true, completion: nil)
    }
}

試したこと

ConversationControllerのauthenticateUser()をViewdidappear()に変えたりしましたが、関係ありませんでした。

補足情報（FW/ツールのバージョンなど）

swift5
xcode 11

Answer 1

    
    func handleLogout() {
        
        let alert = UIAlertController(title: nil, message: "Are you sure you want to logout ??", preferredStyle: .actionSheet)
        
        alert.addAction(UIAlertAction(title: "Log Out", style: .default, handler: { (_) in
            self.dismiss(animated: true) {
                self.delegate?.handleLogout()
            }
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: nil))
        
        present(alert, animated: true, completion: nil)
    }
}

delegateを委譲する前に,dismissを呼ぶと正常に動きました。