Restrict NSTextField to only allow numbers

Question

How do I restrict a NSTextfield to allow only numbers/integers? I\'ve found questions like this one, but they didn\'t help!

Answer 1

Swift 2.0 custom formatter with 0 instead of empty space :

class OnlyIntegerValueFormatter: NSNumberFormatter {

    override func isPartialStringValid(partialString: String, newEditingString newString: AutoreleasingUnsafeMutablePointer, errorDescription error: AutoreleasingUnsafeMutablePointer) -> Bool {

        if partialString.isEmpty {
            newString.memory = "0"
            return false
        }

        if Int(partialString) < 0 {
            NSBeep()
            return false
        } else {
            return true
        }
    }
}