ios - UINavigationBar 滑开而不是停留在原地

Question

我创建了演示项目来展示问题。

我们在 UINavigationController 中有两个 View Controller 。

MainViewController 是根。

class MainViewController: UIViewController {

    lazy var button: UIButton = {
        let button = UIButton()
        button.setTitle("Detail", for: .normal)
        return button
    }()

    override func viewDidLoad() {
        super.viewDidLoad()
        navigationItem.title = "Main"
        view.backgroundColor = .blue
        view.addSubview(button)
        button.translatesAutoresizingMaskIntoConstraints = false
        button.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
        button.centerYAnchor.constraint(equalTo: view.centerYAnchor).isActive = true
        button.widthAnchor.constraint(equalToConstant: 150).isActive = true
        button.heightAnchor.constraint(equalToConstant: 42).isActive = true
        button.addTarget(self, action: #selector(buttonTapped(_:)), for: .touchUpInside)
    }

    @objc func buttonTapped(_ sender: UIButton) {
        navigationController?.pushViewController(DetailViewController(), animated: true)
    }
}

和被推送的DetailViewController。

class DetailViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        view.backgroundColor = .white
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)
        navigationController?.setNavigationBarHidden(true, animated: animated)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)
        navigationController?.setNavigationBarHidden(false, animated: animated)
    }
}

如您所见，我想在 DetailViewController 中隐藏 UINavigationBar:

问题

问题是，UINavigationBar 会滑走，而不是与整个 MainViewController 一起留在原处。我怎样才能改变这种行为并保持弹出手势？

Answer 1

在您的 MainViewController 中添加该方法

override func viewDidAppear(_ animated: Bool) {        
        UIView.animate(withDuration: 0) {
            self.navigationController?.setNavigationBarHidden(false, animated: false)
        }
    }

并在 DetailViewController 中用以下方法替换您的方法

 override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    navigationController?.setNavigationBarHidden(true, animated: animated)
}