iOS Build a Simple iPhone App with Swift Improving Our User Interface Random Colors

The text color/tint color of my button do not change, only the view's background color does so. Any ideas?

@IBAction func showFact() {
        funFactLabel.text = factProvider.randomFact()

        let randomColor = colorProvider.randomColor()
        view.backgroundColor = randomColor // Works
        funFactButton.tintColor = randomColor // Not working
    }

My button is of Type "System".

Solved it! Added this line of code at the top "var tintColor: UIColor!"