显示没有导航视图控制器的后退按钮

Question

我有方案：UITabBarViewController（带有 3 个标签）。
在所有这些选项卡中，我不想在顶部显示导航菜单。 从第一个选项卡中，我想通过按钮单击推送另一个视图控制器，该控制器将具有“返回”按钮（以及带有“取消”的顶部工具栏）

我尝试了一些方法 - 在 storyboard 中使用 push segue - 没有后退按钮。 可能是因为我没有导航视图控制器，所以我的导航堆栈是空的。

以编程方式：

let storyBoard : UIStoryboard = UIStoryboard(name: "Main", bundle:nil)

let nextViewController = storyBoard.instantiateViewController(withIdentifier: "AddCoinTableViewController") as! AddCoinTableViewController
self.present(nextViewController, animated:true, completion:nil)

如果我在导航控制器中嵌入标签，那么我有顶部工具栏（我不想要）。

有什么制作方法吗？

Answer 1

如果不使用UINavigationController，您将无法实现导航功能。我的意思是你必须自己做所有动画类型的东西，我认为这不是一个好主意。而不是这样，您可以使用UINavigationController，如果您不想在某些视图控制器上显示navigationBar，请对这些视图控制器执行以下操作。

override func viewWillApear() {
    super.viewDidLoad()
    self.navigationController?.isNavigationBarHidden = true
}

override func viewWillDisappear(animated: Bool) {
    self.navigationController?.isNavigationBarHidden = false
}

Answer 2

您可以将导航控制器嵌入到您的第一个选项卡控制器（或任何您想要的）中，并将其隐藏在您不想要的控制器中 viewDidLoad 中，如下所示：

self.navigationController?.isNavigationBarHidden = true

这样做，您将能够在您按下的控制器上看到返回按钮，并且没有隐藏导航栏。

确保使用导航控制器推送控制器，如下所示：

self.navigationController?.pushViewController(YOUR VIEW CONTROLLER, animated: true)

Answer 3

下面的代码将允许您创建自己的导航处理类，并拥有UINavigationController 具有的“推送”“弹出”动画。您可以创建一个新项目，将下面的内容复制粘贴到ViewController.swift 并查看为自己..

现在你可以赋予任何UIViewController 导航控制器能力..

import UIKit

class NavigationHandler : NSObject, UIViewControllerTransitioningDelegate, UIViewControllerAnimatedTransitioning, UINavigationBarDelegate {
    private var isPresenting: Bool = false
    private weak var controller: UIViewController?

    init(controller: UIViewController) {
        super.init()

        self.controller = controller
        controller.transitioningDelegate = self

        let navigationBar = UINavigationBar()
        controller.view.addSubview(navigationBar)
        NSLayoutConstraint.activate([
            navigationBar.leftAnchor.constraint(equalTo: controller.view.leftAnchor),
            navigationBar.rightAnchor.constraint(equalTo: controller.view.rightAnchor),
            navigationBar.topAnchor.constraint(equalTo: controller.view.safeAreaLayoutGuide.topAnchor)
        ])
        navigationBar.translatesAutoresizingMaskIntoConstraints = false
        navigationBar.delegate = self

        let item = UINavigationItem(title: controller.title ?? "")
        let barButton = UIBarButtonItem(title: "Back", style: .done, target: self, action: #selector(onBackButton(button:)))

        item.leftBarButtonItems = [barButton]
        navigationBar.setItems([item], animated: true)
    }

    func position(for bar: UIBarPositioning) -> UIBarPosition {
        return .topAttached
    }

    @objc
    private func onBackButton(button: UIBarButtonItem) {
        self.controller?.dismiss(animated: true, completion: nil)
    }

    func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        self.isPresenting = true;
        return self;
    }

    func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        self.isPresenting = false;
        return self;
    }

    func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
        return 0.25;
    }

    func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
        let duration = self.transitionDuration(using: transitionContext)
        let fromController = transitionContext.viewController(forKey: .from)
        let toController = transitionContext.viewController(forKey: .to)
        let containerView = transitionContext.containerView

        if self.isPresenting {
            let frame = fromController!.view.frame
            containerView.addSubview(toController!.view)
            toController?.view.frame = CGRect(x: frame.origin.x + frame.width, y: frame.origin.y, width: frame.width, height: frame.height)

            UIView.animate(withDuration: duration, animations: {

                fromController?.view.frame = CGRect(x: frame.origin.x - frame.size.width, y: frame.origin.y, width: frame.size.width, height: frame.size.height)

                toController?.view.frame = frame

            }, completion: { (completed) in
                transitionContext.completeTransition(true)
            })
        }
        else {
            let frame = fromController!.view.frame
            containerView.insertSubview(toController!.view, at: 0)
            toController?.view.frame = CGRect(x: frame.origin.x - frame.size.width, y: frame.origin.y, width: frame.size.width, height: frame.size.height)

            UIView.animate(withDuration: duration, animations: {

                fromController?.view.frame = CGRect(x: frame.origin.x + frame.width, y: frame.origin.y, width: frame.width, height: frame.height)

                toController?.view.frame = frame

            }, completion: { (completed) in
                transitionContext.completeTransition(true)
            })
        }
    }
}

查看控制器进行测试：

class ViewController : UIViewController {

    private var navigationHandler: NavigationHandler?

    override func viewDidLoad() {
        super.viewDidLoad()

        let button = UIButton(type: .custom)
        button.setTitle("Push Controller", for: .normal)
        button.setTitleColor(UIColor.red, for: .normal)
        button.layer.borderColor = UIColor.black.cgColor
        button.layer.borderWidth = 1.0
        button.layer.cornerRadius = 5.0
        button.translatesAutoresizingMaskIntoConstraints = false
        self.view.addSubview(button)
        NSLayoutConstraint.activate([
            button.centerXAnchor.constraint(equalTo: self.view.centerXAnchor),
            button.centerYAnchor.constraint(equalTo: self.view.centerYAnchor),
            button.heightAnchor.constraint(equalToConstant: 45.0),
            button.widthAnchor.constraint(equalToConstant: 150.0)
        ])

        button.addTarget(self, action: #selector(onPush(button:)), for: .touchUpInside)
    }

    @objc
    private func onPush(button: UIButton) {
        let child = ChildViewController()
        self.navigationHandler = NavigationHandler(controller: child)
        self.present(child, animated: true, completion: nil)
    }
}

class ChildViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()

        self.view.backgroundColor = UIColor.blue
    }
}