iOS13上的多行导航栏标题截断了。

Question

我有一个视图控制器，我需要在导航栏上显示多行标题。为此，我写了这样一个协议------------------------。

import UIKit

protocol CustomNavigationBar {
    func setupNavigationMultilineTitle(titleText: String, prefersLargeTitles: Bool, largeTitleDisplayMode: UINavigationItem.LargeTitleDisplayMode)
}

然后将其延伸--

extension CustomNavigationBar where Self : UIViewController {

    func setupNavigationMultilineTitle(titleText: String, prefersLargeTitles: Bool = true, largeTitleDisplayMode: UINavigationItem.LargeTitleDisplayMode = .automatic ) {

        self.navigationController?.navigationBar.prefersLargeTitles = prefersLargeTitles
        self.navigationController?.navigationItem.largeTitleDisplayMode = largeTitleDisplayMode
        self.navigationController?.navigationBar.largeTitleTextAttributes = [
            NSAttributedString.Key.foregroundColor: UIColor.black,
            NSAttributedString.Key.font: UIFont.systemFont(ofSize: 18, weight: .semibold)
        ]
        self.title = titleText

        if let navBarSubViews = self.navigationController?.navigationBar.subviews {
            for navItem in navBarSubViews {
                for itemSubView in navItem.subviews {
                    if let largeLabel = itemSubView as? UILabel {
                        largeLabel.text = self.title
                        largeLabel.numberOfLines = 0
                        largeLabel.lineBreakMode = .byWordWrapping
                        largeLabel.sizeToFit()
                    }
                }
            }
        }
    }
}

在我的视图控制器中，我符合这个协议，在viewDidAppear方法里面，我调用了setupNavigationMultilineTitle方法，如下所示----------。

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    self.setupNavigationMultilineTitle(titleText: "This is created for testing This is created for testing This is created for testing This is created for testing This is created for testing")
}

**

这在运行小于iOS13的iPhone上效果不错。

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然而，在运行大于iOS 13的iPhone上，它只是显示一行，然后截断。

**

iOS13中的UINavigationBar有什么变化吗？我研究了一下，发现了一些关于背景颜色的东西，但是没有任何关于使用prefersLargeTitles和largeTitleDisplayMode的多行标题的内容。

谁能帮我在iOS13上把这个弄起来？

谢谢!