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我无法以编程方式创建 UINavigationController 工具栏。我以前使用故事板成功地做到了这一点，但想尝试在代码中完成这一切。

我以编程方式创建了 UIBarButtonItems，但它们在按下时应该执行的实际功能或操作不起作用。

澄清一下，我不是试图将 UIBarButtonItems 添加到顶部栏。我见过几十个问题都在问同样的问题。我指的是 UINavigationController 附带的底部工具栏。这意味着没有“rightBarButtonItem”或“leftBarButtonItem”

这是代码：

class ProgOneViewController: UIViewController {
    var chatRoomsButton: UIBarButtonItem = {
        var button = UIBarButtonItem(title: "Chats", style: .plain, target: self, action: #selector(segueToChatRoomController(_:)))
        return button
    }()

    var exploreButton: UIBarButtonItem = {
        var button = UIBarButtonItem(title: "Explore", style: .plain, target: self, action: #selector(segueToExploreController(_:)))
        return button
    }()

    var profileButton: UIBarButtonItem = {
        var button = UIBarButtonItem(title: "Profile", style: .plain, target: self, action: #selector(segueToProfileController(_:)))

        return button
    }()

    // Flexible spaces that are added in between each button.
    var flexibleSpace1: UIBarButtonItem = {
        var flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil)
        return flexibleSpace
    }()

    var flexibleSpace2: UIBarButtonItem = {
        var flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil)
        return flexibleSpace
    }()

    var flexibleSpace3: UIBarButtonItem = {
        var flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil)
        return flexibleSpace
    }()

    var flexibleSpace4: UIBarButtonItem = {
        var flexibleSpace = UIBarButtonItem(barButtonSystemItem: .flexibleSpace, target: self, action: nil)
        return flexibleSpace
    }()

    // These are the functions that are not being called for some mysterious reason. 
    func segueToChatRoomController(_ sender: Any) {
        print("segueing to chat rooms controller")
        let chatRoomsController = ChatRoomsViewController()
        let navController = UINavigationController(rootViewController: chatRoomsController)
        self.present(navController, animated: false, completion: nil)
    }

    func segueToExploreController(_ sender: Any) {
        print("segueing to explore controller")
        let exploreController = ExploreCollectionViewController()
        let navController = UINavigationController(rootViewController: exploreController)
        self.present(navController, animated: false, completion: nil)
    }

    func segueToProfileController(_ sender: Any) {
        print("segueing to profile controller")
        let profileController = ProfileTableViewController()
        let navController = UINavigationController(rootViewController: profileController)
        self.present(navController, animated: false, completion: nil)
    }

    func setUpToolbar() {
        print("setting up toolbar")

        self.navigationController?.setToolbarHidden(false, animated: false)
        self.navigationController?.toolbar.isUserInteractionEnabled = true

        let toolBarItems = [flexibleSpace1, chatRoomsButton, flexibleSpace2, exploreButton, flexibleSpace3, profileButton, flexibleSpace4]

        self.setToolbarItems(toolBarItems, animated: true)
        // For some reason, these two methods leave the toolbar empty.

        //self.navigationController?.setToolbarItems(toolBarItems, animated: true)

        //self.navigationController?.toolbar.items = toolBarItems
    }

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor.white

        setUpToolbar()
    }

 }

编辑* 这是用于在 UINavigationController 中实例化 ProgOneViewController 的代码

 func pushToTestProgrammaticallyCreatedViews() {
    let progOneViewController = ProgOneViewController()
    let navController = UINavigationController(rootViewController: progOneViewController)
    //navController.isToolbarHidden = false
    //progOneViewController.setUpToolbar()

    self.present(navController, animated: false, completion: nil)
}

我在我的故事板创建的视图控制器中单击一个按钮时调用了这个函数。函数签名很长，以便指定哪些视图控制器是测试（以编程方式创建）:)

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1 回答 1

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首先，您必须确保您ProgOneViewController的确实包含在UINavigationController. 如果是这种情况，则会显示工具栏和 barbuttonitems（在我的项目中尝试了您的代码）。

除此之外，您必须将所有 barbuttonitem 声明更改为，lazy var以便声明中的引用self指向 viewcontroller 和 target-action 工作。

如果有任何问题，请随时询问：）

于 2017-01-08T10:14:56.947 回答