Ios 如何在ViewController中显示弹出窗口

我想在我的视图控制器中显示这个弹出窗口，当我按下按钮时返回

这是我想显示弹出窗口的部分：

@IBAction func entrarAction(_ sender: UIButton) {
    sender.isEnabled = false
    let l = showLoader()
    let user = userTextField.text!
    let passwd = passwordTextField.text!
    if !validaEntrada(user: user, password: passwd){
        // TODO: show errors!
        // Show popup here

        return

    }
    let login = VenLogin(usuario: user, contrasenia: passwd)
    try! RequestManager.fcReq(url: .login, req: login, res: VenLoginResponse.self) { loginResp, err in
        sender.isEnabled = true
        l.dismiss(animated: true, completion: {
            if let r:VenLoginResponse = loginResp as? VenLoginResponse {
                if r.code0 {
                    let c = self.getAppDelegateContainer()
                    c.register(from: .loginResponse, value: r)
                    c.register(from: .tokenJwt, value: r.tokenJwt!)
                    self.pushServicios()
                }
            }
        })
    }
}

---

您可以使用警报视图，而不是弹出窗口的自定义视图控制器

 @IBAction func entrarAction(_ sender: UIButton) {
    sender.isEnabled = false
    let l = showLoader()
    let user = userTextField.text!
    let passwd = passwordTextField.text!
    if !validaEntrada(user: user, password: passwd){
        // Show popup here

          showErrorAlert()
        return

         // the rest of your code
    }


  func showErrorAlert() {
      let alert = UIAlertController(title: "Usuario o contraseña no válido", message: "", preferredStyle: UIAlertController.Style.alert)
      alert.addAction(UIAlertAction(title: "Aceptar", style: UIAlertAction.Style.cancel, handler: nil))
      self.present(alert, animated: true, completion: nil)
  }

但如果您仍要使用自定义视图控制器，请使用此选项显示弹出窗口：

   let storyboard = UIStoryboard(name: "Main", bundle: nil)
   let popupErrorLogin = storyboard.instantiateViewController(withIdentifier: "PopupErrorLogin") as! PopupErrorLogin
   self.present(popupErrorLogin, animated: true, completion: nil)

要关闭它，请执行以下操作：

 @IBAction func aceptarAction(_ sender: Any) {
    self.dismiss(animated: true, completion: nil)
  }

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你到底有什么问题？复制/粘贴代码，不仅仅是截图。好的，我编辑我的问题