Question

我无法以编程方式创建UINavigationController工具栏。我之前使用故事板成功完成了这项工作，但我想尝试在代码中完成所有操作。

我已经以编程方式创建了UIBarButtonItems，但是按下它们时应该执行的实际函数或操作不起作用。

为了澄清，我不是试图将UIBarButtonItems添加到顶部栏。我已经看过几十个问题都在问同样的问题。我指的是UINavigationController附带底部的工具栏。这意味着没有＆＃34; rightBarButtonItem＆＃34;或＆＃34; leftBarButtonItem＆＃34;

以下是代码：

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)
}

我在单击故事板创建的视图控制器中的按钮时调用了此函数。函数签名很长，以指定哪些viewControllers是测试（以编程方式创建）：）

Answer 1

首先，您必须确保ProgOneViewController真正包含在UINavigationController中。如果是这种情况，则会显示工具栏以及barbuttonitems（在我的项目中尝试过您的代码）。

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

随时询问是否有任何问题：）

IOS Swift以编程方式创建了无法正常工作的navigationController TOOLBAR（底栏）项操作

1 个答案: