Ios 当我以编程方式切换时，UIBarButtonim将不显示

我正在构建一个应用程序，其中我以编程方式从ViewControllerA中分离，因为它是一个菜单项列表，每个菜单项都指向不同的VC，所以我没有使用多个分段，而是在代码中实例化了view controller。我的问题是，即使我的故事板上有一个条形按钮项目，它也不会显示在应用程序中

查看控制器A菜单型号代码：

class PlayerMenu: Hashable {
       let title: String
       let numberOfItems: String
       let menuItemViewController: UIViewController.Type?

       init(title: String, numberOfItems: String, viewController: UIViewController.Type? = nil) {
           self.title = title
           self.numberOfItems = numberOfItems
           self.menuItemViewController = viewController
       }

       func hash(into hasher: inout Hasher) {
           hasher.combine(identifier)
       }

       static func == (lhs: PlayerMenu, rhs: PlayerMenu) -> Bool {
           return lhs.identifier == rhs.identifier
       }
       private let identifier = UUID()

   }

查看控制器A代码

 private lazy var menuItems: [PlayerMenu] = {
        return [
            PlayerMenu(title: "Status", numberOfItems: "Available.", viewController: nil),
            PlayerMenu(title: "Pertinent Medical History", numberOfItems: "", viewController: nil),
            PlayerMenu(title: "Injury / Illness", numberOfItems: "There are no injuries.", viewController: nil),
            PlayerMenu(title: "Allergy", numberOfItems: "There are no allergies.", viewController: AllergyTableViewController.self),
            PlayerMenu(title: "Neurocognitive", numberOfItems: "Unavailable.", viewController: nil),
            PlayerMenu(title: "Medication", numberOfItems: "There are no medications.", viewController: nil),
            PlayerMenu(title: "Immunization", numberOfItems: "There are no immunizations", viewController: nil),
            PlayerMenu(title: "Dictations", numberOfItems: "There are no dictations.", viewController: nil),
            PlayerMenu(title: "Imaging",  numberOfItems: "There is no imaging.", viewController: nil),
            PlayerMenu(title: "Participation", numberOfItems: "Unavailable.", viewController: nil),
            PlayerMenu(title: "Away Game Injury", numberOfItems: "Unavailable.", viewController: nil),

        ]
    }()

extension PlayerDashboardViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let menuItem = self.dataSource.itemIdentifier(for: indexPath) else { return }
        if let viewController = menuItem.menuItemViewController {
            let navController = UINavigationController(rootViewController: viewController.init())
            present(navController, animated: true)
        }
    }
}

ViewControllerA Segue

 private lazy var menuItems: [PlayerMenu] = {
        return [
            PlayerMenu(title: "Status", numberOfItems: "Available.", viewController: nil),
            PlayerMenu(title: "Pertinent Medical History", numberOfItems: "", viewController: nil),
            PlayerMenu(title: "Injury / Illness", numberOfItems: "There are no injuries.", viewController: nil),
            PlayerMenu(title: "Allergy", numberOfItems: "There are no allergies.", viewController: AllergyTableViewController.self),
            PlayerMenu(title: "Neurocognitive", numberOfItems: "Unavailable.", viewController: nil),
            PlayerMenu(title: "Medication", numberOfItems: "There are no medications.", viewController: nil),
            PlayerMenu(title: "Immunization", numberOfItems: "There are no immunizations", viewController: nil),
            PlayerMenu(title: "Dictations", numberOfItems: "There are no dictations.", viewController: nil),
            PlayerMenu(title: "Imaging",  numberOfItems: "There is no imaging.", viewController: nil),
            PlayerMenu(title: "Participation", numberOfItems: "Unavailable.", viewController: nil),
            PlayerMenu(title: "Away Game Injury", numberOfItems: "Unavailable.", viewController: nil),

        ]
    }()

extension PlayerDashboardViewController: UITableViewDelegate {
    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
        guard let menuItem = self.dataSource.itemIdentifier(for: indexPath) else { return }
        if let viewController = menuItem.menuItemViewController {
            let navController = UINavigationController(rootViewController: viewController.init())
            present(navController, animated: true)
        }
    }
}

故事板截图

---

在情节提要中设计视图控制器时，您没有看到它的原因是调用

viewController.init（）

不会从情节提要中实例化视图控制器。您需要拨打：

或者（仅适用于iOS 13+）：

我建议不要将视图控制器类型存储在

playermunu

类中，而是存储视图控制器的脚本标识符，如下所示：

class player菜单：可散列{
标题：字符串
让numberOfItems:字符串
let menuItemViewControllerStoryboardIdentifier:字符串？
init（标题：String，numberOfItems:String，viewControllerStoryboardIdentifier:String？=nil）{
self.title=标题
self.numberOfItems=numberOfItems
self.menuItemViewControllerStoryboardIdentifier=viewControllerStoryboardIdentifier
}
[...]
}

然后，当您想要实例化视图控制器时，获取对情节提要的引用（如果它与当前视图控制器的情节提要相同，那么您可以只说

self.storyboard

，否则直接使用创建情节提要）：

扩展播放器DashboardViewController:UITableViewDelegate{
func tableView（tableView:UITableView，didSelectRowAt indexPath:indexPath）{
guard let menuItem=self.dataSource.itemIdentifier（for:indexPath），
让viewControllerStoryboardIdentifier=menuItem.menuItemViewControllerStoryboardIdentifier，
让viewController=self.storyboard？.instanceeviewcontroller（标识符：viewControllerStoryboardIdentifier）else{
返回
}
让navController=UINavigationController（rootViewController:viewController）
存在（导航控制器，动画：真）
}
}

然后确保在情节提要中提供视图控制器标识符，并创建

PlayerMenu

项，如下所示：

PlayerMenu（标题：“过敏”，numberOfItems：“没有过敏”，viewControllerStoryboardIdentifier：“过敏表ViewController（或您在故事板中给出的任何标识符）”）