(Edit 7/13: I notice that this solution is not support scrollView, so now I'm in research)
I found a perfect solution on Swift5
but sorry for my poor English because I'm Japanese🇯🇵Student.
In case of 2 lines In case of 3 lines
At first, set navigation settings for largeTitle normally in viewDidLoad
//Set largeTitle
navigationItem.largeTitleDisplayMode = .automatic
navigationController?.navigationBar.prefersLargeTitles = true
navigationController?.navigationBar.largeTitleTextAttributes = [.font: UIFont.systemFont(ofSize: (fontSize + margin) * numberOfLines)]//ex) fontSize=26, margin=5, numberOfLines=2
//Set title
title = "multiple large\ntitle is working!"
It is most important point of this solution that font-size at largeTitleTextAttributes
equals actual font-size(+margin) multiplied by number of lines.
Description image
Because, default specification of navigationBar attributes may be able to display only 1 line largeTitle.
Although, somehow, I did notice that in case of label-settings(the label which subview of subview of navigationBar) on direct, it can display any number of lines in 1 line of in case of navigationBar attributes.
So, we should do set big font in navigationbar attributes, and set small font in the label(subview of subview of navigationBar), and take into consideration the margins.
Do label settings direct in viewDidAppear
like this:
//Find label
navigationController?.navigationBar.subviews.forEach({ subview in
subview.subviews.forEach { subsubview in
guard let label: UILabel = subsubview as? UILabel else { return }
//Label settings on direct.
label.text = title
label.font = UIFont.systemFont(ofSize: fontSize)
label.numberOfLines = 0
label.lineBreakMode = .byWordWrapping
label.sizeToFit()
}
})
Therefore, in short, the solution at minimum code is given like this:
import UIKit
class ViewController: UIViewController {
private let fontSize: CGFloat = 26, margin: CGFloat = 5
private let numberOfLines: CGFloat = 2
override func viewDidLoad() {
super.viewDidLoad()
setUpNavigation()
}
override func viewDidAppear(_ animated: Bool) {
super.viewDidAppear(animated)
setMultipleLargeTitle()
}
private func setUpNavigation() {
//Set largeTitle
navigationItem.largeTitleDisplayMode = .automatic
navigationController?.navigationBar.prefersLargeTitles = true
navigationController?.navigationBar.largeTitleTextAttributes = [.font: UIFont.systemFont(ofSize: (fontSize + margin) * numberOfLines)]
//Set title
title = "multiple large\ntitle is working!"
}
private func setMultipleLargeTitle() {
//Find label
navigationController?.navigationBar.subviews.forEach({ subview in
subview.subviews.forEach { subsubview in
guard let label: UILabel = subsubview as? UILabel else { return }
//Label settings on direct.
label.text = title
label.font = UIFont.systemFont(ofSize: fontSize)
label.numberOfLines = 0
label.lineBreakMode = .byWordWrapping
label.sizeToFit()
}
})
}
}
thank you for reading :)