Swift3如何设置在扩展

Question

我在UIViewControllers中有一个函数来设置UINavigationBar，它在许多函数中重复。我想在扩展中创建导航栏，但我想在每个函数中设置标题文本和购物车标签。我怎样才能做到这一点？我认为答案是使用协议，但我不知道如何。

这是我的扩展

extension UIViewController {

func shoppingBagButtonTouched(button: UIButton) {
    -----        
}

func closeView() {
    dismiss(animated: true, completion: nil)
}

func setupNavigationHeader(showCart: Bool? = true) {

    let navigationBar: UINavigationBar = {
        let navBar = UINavigationBar(frame: CGRect(0, 0, self.view.frame.size.width, Constants.HEADER_HEIGHT))
        return navBar
    }()

    let navigationItem = UINavigationItem()

    self.automaticallyAdjustsScrollViewInsets = false

    UINavigationBar.appearance().barTintColor = .red

    UINavigationBar.appearance().tintColor = .white

    let titleLabel: UILabel = {
        let label = UILabel()
        label.textAlignment = .center
        label.translatesAutoresizingMaskIntoConstraints = false
        label.backgroundColor = .clear
        label.layer.masksToBounds = true
        label.minimumScaleFactor = 10/UIFont.labelFontSize
        label.adjustsFontSizeToFitWidth = true
        label.numberOfLines = 1
        label.text = "not set"
        label.textColor = .white
        return label
    }()

    let fixedSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)

    let menuBtn = UIBarButtonItem(image: UIImage(named: "closeNav"), style: .plain, target: self, action: #selector(self.closeView))

    navigationItem.leftBarButtonItems = [fixedSpace, menuBtn]

    navigationBar.items = [navigationItem]

    if let showCart = showCart {

        let cartCountLabel: UILabel = {
            let label = UILabel(frame: CGRect(x: 0, y: -0, width: 20, height: 20))
            label.textAlignment = .center
            label.layer.cornerRadius = label.bounds.size.height / 2
            label.translatesAutoresizingMaskIntoConstraints = false
            label.backgroundColor = .clear
            label.layer.masksToBounds = true
            label.textColor = .white
            label.minimumScaleFactor = 10/UIFont.labelFontSize
            label.adjustsFontSizeToFitWidth = true
            return label
        }()

        let shoppingBagButton: UIButton = {
            let button = UIButton(frame: CGRect(x: 0, y: 0, width: 22, height: 22))
            button.setBackgroundImage(UIImage(named: "shopping_bag"), for: .normal)
            return button
        }()

        let rightBarButtonItem = UIBarButtonItem(customView: shoppingBagButton)

        navigationItem.setRightBarButtonItems([rightBarButtonItem], animated: true)

        shoppingBagButton.addTarget(self, action: #selector(shoppingBagButtonTouched(button:)), for: .touchUpInside)

        shoppingBagButton.addSubview(cartCountLabel)
        cartCountLabel.anchorCenterXToSuperview()
        cartCountLabel.anchorCenterYToSuperview(constant: 2)
    }

    navigationBar.addSubview(titleLabel)

    view.addSubview(navigationBar)

    titleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    titleLabel.bottomAnchor.constraint(equalTo: navigationBar.bottomAnchor, constant: -10).isActive = true
    titleLabel.heightAnchor.constraint(equalToConstant: 20.0).isActive = true
    titleLabel.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 90).isActive = true
}
}

在每个控制器中，我都有这样的代码来设置标题标签和购物车标签，但是当我在扩展程序中创建导航栏时它不起作用。

var titleLabelText: String = "title not set"

var cartCount: String? {
    didSet {
        cartCountLabel.text = cartCount
    }
}

func getCartCount() {
    ServerUtility.getCartCountApi { (cartCount) in
        if let count = cartCount as Int? {
            if count > 0 {
                self.cartCount = "\(count)"
            }
        } else {
            self.cartCount = "0"
        }
    }
}

Answer 1

你可能最好创建一个扩展UIViewController这样的基类：

class BaseViewController: UIViewController {
        let cartCountLabel: UILabel = {
            let label = UILabel(frame: CGRect(x: 0, y: -0, width: 20, height: 20))
            label.textAlignment = .center
            label.layer.cornerRadius = label.bounds.size.height / 2
            label.translatesAutoresizingMaskIntoConstraints = false
            label.backgroundColor = .clear
            label.layer.masksToBounds = true
            label.textColor = .white
            label.minimumScaleFactor = 10/UIFont.labelFontSize
            label.adjustsFontSizeToFitWidth = true
            return label
        }()

func shoppingBagButtonTouched(button: UIButton) {
    -----        
}

func closeView() {
    dismiss(animated: true, completion: nil)
}

func setupNavigationHeader(showCart: Bool? = true) {

    let navigationBar: UINavigationBar = {
        let navBar = UINavigationBar(frame: CGRect(0, 0, self.view.frame.size.width, Constants.HEADER_HEIGHT))
        return navBar
    }()

    let navigationItem = UINavigationItem()

    self.automaticallyAdjustsScrollViewInsets = false

    UINavigationBar.appearance().barTintColor = .red

    UINavigationBar.appearance().tintColor = .white

    let titleLabel: UILabel = {
        let label = UILabel()
        label.textAlignment = .center
        label.translatesAutoresizingMaskIntoConstraints = false
        label.backgroundColor = .clear
        label.layer.masksToBounds = true
        label.minimumScaleFactor = 10/UIFont.labelFontSize
        label.adjustsFontSizeToFitWidth = true
        label.numberOfLines = 1
        label.text = "not set"
        label.textColor = .white
        return label
    }()

    let fixedSpace = UIBarButtonItem(barButtonSystemItem: .fixedSpace, target: nil, action: nil)

    let menuBtn = UIBarButtonItem(image: UIImage(named: "closeNav"), style: .plain, target: self, action: #selector(self.closeView))

    navigationItem.leftBarButtonItems = [fixedSpace, menuBtn]

    navigationBar.items = [navigationItem]

    if let showCart = showCart {

        let shoppingBagButton: UIButton = {
            let button = UIButton(frame: CGRect(x: 0, y: 0, width: 22, height: 22))
            button.setBackgroundImage(UIImage(named: "shopping_bag"), for: .normal)
            return button
        }()

        let rightBarButtonItem = UIBarButtonItem(customView: shoppingBagButton)

        navigationItem.setRightBarButtonItems([rightBarButtonItem], animated: true)

        shoppingBagButton.addTarget(self, action: #selector(shoppingBagButtonTouched(button:)), for: .touchUpInside)

        shoppingBagButton.addSubview(cartCountLabel)
        cartCountLabel.anchorCenterXToSuperview()
        cartCountLabel.anchorCenterYToSuperview(constant: 2)
    }

    navigationBar.addSubview(titleLabel)

    view.addSubview(navigationBar)

    titleLabel.centerXAnchor.constraint(equalTo: view.centerXAnchor).isActive = true
    titleLabel.bottomAnchor.constraint(equalTo: navigationBar.bottomAnchor, constant: -10).isActive = true
    titleLabel.heightAnchor.constraint(equalToConstant: 20.0).isActive = true
    titleLabel.widthAnchor.constraint(equalToConstant: UIScreen.main.bounds.width - 90).isActive = true
}
}

然后，您可以从基类派生所有视图控制器实例，如下所示：

class MyViewController:BaseViewController {
var titleLabelText: String = "title not set"

var cartCount: String? {
    didSet {
        cartCountLabel.text = cartCount
    }
}

func getCartCount() {
    ServerUtility.getCartCountApi { (cartCount) in
        if let count = cartCount as Int? {
            if count > 0 {
                self.cartCount = "\(count)"
            }
        } else {
            self.cartCount = "0"
        }
    }
}
}

我没有通过运行验证上面的代码，因此可能需要稍微调整一下：）