[SwiftUI] How to set custom font to NavigationBarTitle

You need to install Introspect library.

How to use

It should be used on root of navigationView. If you use

NavigationView {
    VStack { ... }
        // ↓ set custom font
        .navigationTitleFont(font: UIFont.custom.extraBold(ofSize: 20))
}

---

3 Steps

1. Create ViewModifier
2. Add extension method to UIFont
3. Add extension method to View

Step1: Create ViewModifier

import SwiftUI
import Introspect

public struct NavigationTitleFontModifier: ViewModifier {
    public var font: UIFont

    public func body(content: Content) -> some View {
        content
            .introspectNavigationController {
                $0.navigationBar.titleTextAttributes = [.font:font]
            }
    }
}

Step2: Add extension method to UIFont
This is unnecessary. It just for make call custom font easily.

extension UIFont {
    public struct custom {
        static func extraBold(ofSize size: CGFloat) -> UIFont {
            return UIFont(name: "BoldCustomFontName", size: size) ?? UIFont.systemFont(ofSize: size, weight: .bold)
        }
    }
}

Step3: Add extension method to View

public extension View {
    func navigationTitleFont(font: UIFont) -> some View {
        self.modifier(NavigationTitleFontModifier(font: font))
    }
}