Change font in navigation bar in Swift - ios

Question

I'd like to change the font in the navigation bar. However the following code doesn't work, it causes the app to crash.
func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName: UIFont(name: "Lato-Light.ttf", size: 34)!]
return true
}
I am getting the following error:
fatal error: unexpectedly found nil while unwrapping an Optional value(lldb)
I have indeed added the font Lato-Light.ttf to my project so it should be able to find it.

Answer 1

UIFont() is a failable initalizer, it may fail due to several reasons. A forced unwrap using ! crashes your app.
Better initialize it separately and check for success:
if let font = UIFont(name: "Lato-Light.ttf", size: 34) {
UINavigationBar.appearance().titleTextAttributes = [NSFontAttributeName: font]
}
And check if your font file is included in the bundle resources.
Common Mistakes With Adding Custom Fonts to Your iOS App

Answer 2

import UIKit
class TestTableViewController: UITableViewController {
override func viewDidLoad() {
super.viewDidLoad()
configureView()
}
func configureView() {
// Change the font and size of nav bar text
if let navBarFont = UIFont(name: "HelveticaNeue-Thin", size: 20.0) {
let navBarAttributesDictionary: [NSObject: AnyObject]? = [
NSForegroundColorAttributeName: UIColor.whiteColor(),
NSFontAttributeName: navBarFont
]
navigationController?.navigationBar.titleTextAttributes = navBarAttributesDictionary
}
}
}