雖然當前導航然后顯示視圖控制器欄按鈕不來，為什么在 swift

Question

我的視圖控制器流程如下：

  navigationcontroller -> logoutviewcontroller ->(present) 

                       viewcontroller -> (present) logoutviewcontroller (bar button coming)
                                |
                           loginviewcontroller
                                |
                        (present) logoutviewcontroller (bar button not coming)   

注銷VC代碼：

  override func viewDidLoad() {
    super.viewDidLoad()        
    navigationItem.leftBarButtonItem = UIBarButtonItem(title: "logout", style: .plain, target: self, action: #selector(handleLogout))
    }


  @objc func handleLogout(){

let vc = self.storyboard?.instantiateViewController(withIdentifier: "ViewController") as! ViewController
self.present(vc, animated: true, completion: nil)

 }

loginVC 代碼：當出現 logoutVC 來但條形按鈕不來時.. 為什么

 @IBAction func loginButn(_ sender: Any) {

guard  let email = emailTf.text, let password = passwordTf.text
else {
    print("form is not valid")
    return
}
Auth.auth().signIn(withEmail: email, password: password, completion: { (user, error) in
    
    if error != nil{
        print("login adding error: \(String(describing: error))" as Any)
        return
    }
    print("login sucessfully")
    let vc = self.storyboard?.instantiateViewController(withIdentifier: "LogOutViewController") as! LogOutViewController
        
    self.present(vc, animated: true, completion: nil)
    
})
}

請在這里用代碼建議

Answer 1

如果 bar 按鈕是指navigationController的navigationBar ，則不需要顯示ViewController但需要使用

self.navigationController?.pushViewController(vc, animated: true)