如何在导航栏中设置多行大标题？(iOS 11的新功能)

Question

我正在其中一个应用程序中的导航栏中添加大标题.问题是标题有点长,所以我需要在大标题中添加两行.如何在导航栏中添加两行大标题？

这不是关于默认导航栏标题!这是关于iOS 11中引入的大标题.因此,请务必考虑大型标题来添加建议.谢谢

Answer 1

根据@krunal回答,这对我有用:

extension UIViewController {

func setupNavigationMultilineTitle() {
    guard let navigationBar = self.navigationController?.navigationBar else { return }
    for sview in navigationBar.subviews {
        for ssview in sview.subviews {
            guard let label = ssview as? UILabel else { break }
            if label.text == self.title {
                label.numberOfLines = 0
                label.lineBreakMode = .byWordWrapping
                label.sizeToFit()
                UIView.animate(withDuration: 0.3, animations: {
                    navigationBar.frame.size.height = 57 + label.frame.height
                })
            }
        }
    }
}

在UIViewController中:

override func viewDidLoad() {
    super.viewDidLoad()
    self.title = "This is a multiline title"
    setupNavigationMultilineTitle()
}

override func viewDidAppear(_ animated: Bool) {
    super.viewDidAppear(animated)
    setupNavigationMultilineTitle()
}

并在大标题上设置字体和颜色:

navigation.navigationBar.largeTitleTextAttributes = [NSAttributedStringKey.foregroundColor: .red, NSAttributedStringKey.font: UIFont.boldSystemFont(ofSize: 30)]

Answer 2

获取导航项子视图并从中查找UILabel.

试试看,看看:

self.navigationController?.navigationBar.prefersLargeTitles = true
self.navigationController?.navigationItem.largeTitleDisplayMode = .automatic

self.title = "This is multiline title for navigation bar"
self.navigationController?.navigationBar.largeTitleTextAttributes = [                     
                                NSAttributedStringKey.foregroundColor: UIColor.black,
                                NSAttributedStringKey.font : UIFont.preferredFont(forTextStyle: .largeTitle)
                                ]

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

结果如下: