导航栏第一次无法正确充电

Question

我正在开发一个包含登录名的应用程序，当首次登录时，登录后进入的视图无法很好地加载导航栏，而当第二次打开该应用程序且已经使用先前输入的凭据时，这一次，如果他们加载导航栏。 有谁知道为什么会这样吗？ 我的viewWillAppear就是这样

override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        let imageView = UIImageView(frame: CGRect(x: 0, y: 0, width: 38, height: 38))
        imageView.contentMode = .scaleAspectFit
        let image = UIImage(named: "img_header")
        imageView.image = image
        navigationItem.titleView = imageView

        //let image_home = UIImage(named: "ic_home")
        //let homeButton = UIBarButtonItem(image: image_home, style: UIBarButtonItemStyle.done, target: self, action: #selector(self.cancelMetod2))
        // navigationItem.leftBarButtonItem = homeButton

        let color_primary: UIColor = val_colores.hexStringToUIColor(val_colores.colorPrimary)
        let color_background_primary: UIColor = val_colores.hexStringToUIColor(val_colores.ColorGrisClaro2)

        //icono more
        let imagen_more = UIImage (named: "ic_more_menu")!
        let buttonMore: UIBarButtonItem = UIBarButtonItem(image: imagen_more, style: UIBarButtonItemStyle.done,target: self, action: #selector(self.moreMetod))
        self.navigationItem.rightBarButtonItem = buttonMore

        //background color
        self.navigationController?.navigationBar.barTintColor = color_primary
        //back button color
        UIBarButtonItem.appearance().tintColor = color_background_primary
        //Since iOS 7.0 UITextAttributeTextColor was replaced by NSForegroundColorAttributeName
        //title color
        UINavigationBar.appearance().titleTextAttributes = [NSAttributedStringKey.foregroundColor: color_background_primary]
        //color in carrier, hour, battery
        UINavigationBar.appearance().barStyle = UIBarStyle.black

        self.navigationController!.navigationBar.titleTextAttributes = [NSAttributedStringKey.foregroundColor: color_background_primary]
        self.navigationController!.navigationBar.barStyle = UIBarStyle.black
        self.navigationController!.navigationBar.tintColor = color_background_primary
    }