Can I change the font of my UINavigationController? --> title
As of iOS 5 you can change the font via the appearance proxy.
https://developer.apple.com/documentation/uikit/uiappearance
The following will set the title font for all UINavigationControllers.
NSMutableDictionary *titleBarAttributes = [NSMutableDictionary dictionaryWithDictionary: [[UINavigationBar appearance] titleTextAttributes]];
[titleBarAttributes setValue:[UIFont fontWithName:@"Didot" size:16] forKey:NSFontAttributeName];
[[UINavigationBar appearance] setTitleTextAttributes:titleBarAttributes];
To set the font for the back button, do this:
NSMutableDictionary *attributes = [NSMutableDictionary dictionaryWithDictionary: [[UIBarButtonItem appearance] titleTextAttributesForState:UIControlStateNormal]];
[attributes setValue:[UIFont fontWithName:@"Didot" size:12] forKey:NSFontAttributeName];
[[UIBarButtonItem appearance] setTitleTextAttributes:attributes forState:UIControlStateNormal];
To set the font for the large titles available in iOS 11+, do this:
if (@available(iOS 11.0, *)) {
NSMutableDictionary *largeTitleTextAttributes = [NSMutableDictionary dictionaryWithDictionary: [[UINavigationBar appearance] largeTitleTextAttributes]];
[largeTitleTextAttributes setValue:[UIFont fontWithName:@"Didot" size:32] forKey:NSFontAttributeName];
[[UINavigationBar appearance] setLargeTitleTextAttributes:largeTitleTextAttributes];
}