如何在 Swift 中增加自定义 UINavigationBar 类的高度

更新：我最终隐藏了默认导航栏并添加了一个与导航栏相同的 UIView。这听起来可能不太好，但与其修补，不如说UINavigationBar这很好。

这是我UINavigationBar创建的自定义类，用于增加应用程序中导航栏的高度。它对我不起作用。这是代码。

class PPBaseNavigationBar: UINavigationBar {

    ///The height you want your navigation bar to be of
    static let navigationBarHeight: CGFloat = 83.0

    ///The difference between new height and default height
    static let heightIncrease: CGFloat = navigationBarHeight - 44

    override init(frame: CGRect) {
        super.init(frame: frame)
        initialize()
    }

    required init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        initialize()
    }

    private func initialize() {
        let shift = PPBaseNavigationBar.heightIncrease/2.0

        ///Transform all view to shift upward for [shift] point
        self.transform = CGAffineTransform(translationX: 0, y: -shift)
    }

    override func layoutSubviews() {
        super.layoutSubviews()

        let shift = PPBaseNavigationBar.heightIncrease/2.0

        ///Move the background down for [shift] point
        var classNamesToReposition: Array<String>?
        if #available(iOS 10.0, *) {
            classNamesToReposition = ["_UIBarBackground"]
        } else {
            classNamesToReposition =  ["_UINavigationBarBackground"]
        }

        for view: UIView in self.subviews {
            if (classNamesToReposition?.contains(NSStringFromClass(view.classForCoder)))! {
                let bounds: CGRect = self.bounds
                var frame: CGRect = view.frame
                frame.origin.y = bounds.origin.y + shift - 20.0
                frame.size.height = bounds.size.height + 20.0
                view.frame = frame
            }
        }
    }

    override func sizeThatFits(_ size: CGSize) -> CGSize {
        let amendedSize:CGSize = super.sizeThatFits(size)
        let newSize:CGSize = CGSize.init(width: amendedSize.width, height: PPBaseNavigationBar.navigationBarHeight)
        return newSize;
    }
}

除了override func sizeThatFits(_ size: CGSize) -> CGSize {...}不确定之外，所有方法都被调用，为什么？