Swift 4 Conversion error - NSAttributedStringKey: Any

Question

I converted my app recently and I keep getting the error

\"Cannot convert value of type \'[String : Any]\' to expected argument type \'[NSAttributedS

Answer 1

leanne's answer is correct for the cases where you still need to use [String : Any] and not [NSAttributedStringKey : Any].

For example, in UIKit UITextView.typingAttributes is still of type [String : Any]. So for that property you have to use converted attributes (including custom ones):

let customAttributeName = "MyCustomAttributeName"
let customValue: CGFloat = 15.0

let normalTextAttributes: [NSAttributedStringKey : Any] =
            [NSAttributedStringKey.font : UIFont.systemFont(ofSize: 14.0),
             NSAttributedStringKey.foregroundColor : UIColor.blue,
             NSAttributedStringKey.backgroundColor : UIColor.clear,
             NSAttributedStringKey(rawValue: customAttributeName): customValue]

textView.typingAttributes = normalTextAttributes.toTypingAttributes()

where toTypingAttributes() is a function defined by extension in any of your project files:

extension Dictionary where Key == NSAttributedStringKey {
    func toTypingAttributes() -> [String: Any] {
        var convertedDictionary = [String: Any]()

        for (key, value) in self {
            convertedDictionary[key.rawValue] = value
        }

        return convertedDictionary
}