如何将视图添加为某些控制器的子视图

Question

我的应用中有多个故事板。我想在某些控制器的导航栏下方的顶部始终添加一个视图。我怎样才能做到这一点？

我已经使用了导航委托并在窗口中添加了一个视图，但没有运气。在附加图像中显示灰色视图的步骤是。 1.单击该视图控制器上的按钮；灰色视图应显示并保留在控制器的顶部，直到未完成设备的所有扫描，无论用户是否应该转到任何视图控制器。

Answer 1

您可以创建一个 UINavigationController 子类并在其中添加视图。

class NavigationController: UINavigationController {

    let customView = UIView()
    let iconImgView = UIImageView()
    let msgLbl = UILabel()

    override func viewDidLoad() {
        super.viewDidLoad()

        customView.isHidden = true
        customView.translatesAutoresizingMaskIntoConstraints = false
        customView.backgroundColor = .gray
        view.addSubview(customView)

        iconImgView.contentMode = .scaleAspectFit
        iconImgView.translatesAutoresizingMaskIntoConstraints = false
        customView.addSubview(iconImgView)

        msgLbl.numberOfLines = 0
        msgLbl.lineBreakMode = .byWordWrapping
        msgLbl.textColor = .white
        msgLbl.translatesAutoresizingMaskIntoConstraints = false
        customView.addSubview(msgLbl)

        customView.topAnchor.constraint(equalTo: self.view.safeAreaLayoutGuide.topAnchor).isActive = true
        customView.leadingAnchor.constraint(equalTo: view.leadingAnchor).isActive = true
        customView.trailingAnchor.constraint(equalTo: view.trailingAnchor).isActive = true

        iconImgView.widthAnchor.constraint(equalToConstant: 40).isActive = true
        iconImgView.heightAnchor.constraint(equalToConstant: 40).isActive = true
        iconImgView.centerYAnchor.constraint(equalTo: customView.centerYAnchor).isActive = true
        iconImgView.leadingAnchor.constraint(equalTo: customView.leadingAnchor, constant: 15).isActive = true
        iconImgView.trailingAnchor.constraint(equalTo: msgLbl.leadingAnchor, constant: 15).isActive = true

        msgLbl.topAnchor.constraint(equalTo: customView.topAnchor, constant: 10).isActive = true
        msgLbl.bottomAnchor.constraint(equalTo: customView.bottomAnchor, constant: 10).isActive = true
        msgLbl.trailingAnchor.constraint(equalTo: customView.trailingAnchor, constant: -15).isActive = true
        msgLbl.heightAnchor.constraint(greaterThanOrEqualToConstant: 30).isActive = true
    }

    func showCustomView(message: String, icon: UIImage) {
        msgLbl.text = message
        iconImgView.image = icon
        customView.isHidden = false
    }
    func hideCustomView() {
        customView.isHidden = true
    }
}

在此导航控制器中嵌入所有视图控制器。当您想在视图控制器中显示/隐藏灰色视图时，请使用

显示

(self.navigationController as? NavigationController)?.showCustomView(message: "Any Message", icon: UIImage(named: "anyImage")!)

隐藏

(self.navigationController as? NavigationController)?.hideCustomView()

当你从同一个导航控制器推送另一个视图控制器时，视图不会被隐藏，直到你调用 hide 方法

Answer 2

您可以简单地使用相关的frame 创建一个自定义UIView，然后在要添加它的view 上调用addSubview()。

lazy var customView: UIView = {
    let customView = UIView(frame: CGRect.init(x: 0, y: self.view.safeAreaInsets.top, width: UIScreen.main.bounds.width, height: 100))
    customView.backgroundColor = .gray
    return customView
}()

@IBAction func onTapButton(_ sender: UIButton) {
    self.view.addSubview(customView)
}

override func viewWillDisappear(_ animated: Bool) {
    super.viewWillDisappear(animated)
    self.customView.removeFromSuperview()
}

要将其添加到navigationBar 下方，请将frame 的y 位置用作self.view.safeAreaInsets.top。这样您的customView 将始终在navigationBar 下方对齐。

您可以根据您的要求使用height 创建视图。我用过height = 100。

提供正确的frame，您可以将任何视图作为subView 添加到另一个视图。