ios - Error when instantiating a UIFont in an text attributes dictionary

Question

I'm trying to set the font of the UIBarButtonItem like so:

let barButton = UIBarButtonItem.appearance()
barButton.setTitleTextAttributes([NSFontAttributeName: UIFont(name: "AvenirNext", size: 15], forState: UIControlState.Normal)

But it throws a compiler error saying:

Cannot invoke 'init' with an argument list type '($T7, forState: UIControlState)`

and I have no idea what that means. I have also tried

barButton.titleTextAttributesForState(UIControlState.Normal) =[NSFontAttributeName...]` 

but it appears that it isn't assignable

How can I resolve this?

Answer 1

The initializer of UIFont returns an optional because it may fail due to misspelled font name etc.

You have to unwrap it and check:

if let font = UIFont(name: "AvenirNext", size: 15) {
    barButton.setTitleTextAttributes([NSFontAttributeName: font], forState: UIControlState.Normal)
}

UPDATED for Swift 3

if let font = UIFont(name: "AvenirNext", size: 15) {
    barButton.setTitleTextAttributes([NSFontAttributeName:font], for: .normal)
}