How to access the iOS system font programmatically

Question

I am trying to change the font size of the title of a navigation bar. I know I can set its attributes using:

var attributes = [ NSForegroundColorAttributeName: UIColor.blackColor(), NSFontAttributeName: UIFont(name: "the font name", size: 18)! ]

...

 self.navigationController?.navigationBar.titleTextAttributes = attributes

What I cannot seem to find is the correct 'System' font name.

I was after the default, a.k.a System, font name. I tried printing all the available fonts only to discover it does not belong to a family and does not seem to have an explicit name.

Answer 1

I think you need:

NSFontAttributeName : UIFont.systemFontOfSize(19.0) 

Or the bold version:

NSFontAttributeName : UIFont.boldSystemFontOfSize(19.0) 

See this guide for more info on user interface guidelines and fonts.

Answer 2

You can access the system font like this, and even set the weight of the font:

• Swift 3, Swift 4

  UIFont.systemFont(ofSize: 18, weight: UIFontWeightLight)

• Swift 2

  UIFont.systemFontOfSize(18, weight: UIFontWeightLight)

For the font weight you have the choice between those constants, there available from iOS 8.2:

UIFontWeightUltraLight, UIFontWeightThin, UIFontWeightLight, UIFontWeightRegular, UIFontWeightMedium, UIFontWeightSemibold, UIFontWeightBold, UIFontWeightHeavy, UIFontWeightBlack 

Answer 3

SWIFT 4+: shorter version

UIFont.systemFont(ofSize: 14.0, weight: .regular)