Change UINavigationBar back button text and font from AppDelegate using Swift

Question

I need to change UINavigationBar back bar button text from AppDelegate to apply changes to all the Views in my app.

I've changed the title font style using:

UINavigationBar.appearance().titleTextAttributes = [
            NSFontAttributeName: UIFont(name: "MyCustomFont", size: 20)!
]

But I don't know how to access to the left bar button to make changes on it.

Answer 1

Swift 3.0,4.0

Simply you can achieve it with extension of UINavigationItem. According to many search there is no way to change left button text with app delegate.

extension UINavigationItem{

    override open func awakeFromNib() {
        super.awakeFromNib()

        let backItem = UIBarButtonItem()
        backItem.title = "Hello"


        if let font = UIFont(name: "Copperplate-Light", size: 32){
            backItem.setTitleTextAttributes([NSFontAttributeName:font], for: .normal)
        }else{

            print("Font Not available")
        }
        /*Changing color*/
        backItem.setTitleTextAttributes([NSForegroundColorAttributeName: UIColor.green], for: .normal)

        self.backBarButtonItem = backItem
    }

}

Update:

You can change Back Button arrow colour from AppDelegate on didFinishLaunchingWithOptions,

 /*It will change back arrow color only if you use  backItem.setTitleTextAttributes, else it will change whole text color*/
 UINavigationBar.appearance().tintColor = UIColor.orange

Answer 2

To change the image color you can either use the font file and change the color or use the image with the color you needed.

let yourBackButtonIcon = //YourImage here
let navigationBar = UINavigationBar.appearance()
navigationBar.backIndicatorImage = yourBackButtonIcon
navigationBar.backIndicatorTransitionMaskImage = yourBackButtonIcon

To change the back button title text color

navigationBar.titleTextAttributes = [NSFontAttributeName: yourFont,
NSForegroundColorAttributeName: yourColor]

Note:-

Above code should be inside the AppDelegate class of applicationDidFinishLaunching method

Answer 3

Try this:

1. Subclass the UINavigationController and use it. Then make your viewDidLoad like so: (change the attributes according to your need)

   //
   //  NavConViewController.swift
   //  customattributedbackbtn
   //
   //  Created by Glenn Posadas on 8/12/17.
   //  Copyright © 2017 Glenn Posadas. All rights reserved.
   //
   
   import UIKit
   
   class NavConViewController: UINavigationController {
   
       override func viewDidLoad() {
           super.viewDidLoad()
   
           let font = UIFont(name: "Helvetica-Light", size: 12)!
           var attributes: [String : Any] = [NSFontAttributeName : font]
   
           attributes[NSForegroundColorAttributeName] = UIColor.black
   
           UIBarButtonItem.appearance(whenContainedInInstancesOf: [UINavigationBar.self, NavConViewController.self]).setTitleTextAttributes(attributes, for: .normal)
       }
   }
   

Sample output:

Default

Attributed

Answer 4

This should help you

UIBarButtonItem.appearance().setTitleTextAttributes([NSFontAttributeName: UIFont(name: "MyCustomFont", size: 20)!], for: .normal)