How to make a button flash or blink?

Question

I am trying to change a button\'s color (just a flash/blink) to green when a scan is correct and red when there\'s a problem. I am able to do this with a view like so

Answer 1

This UIView extension "blinks" a view and changes the background colour:

/**
 Blinks a view with a given duration and optional color.

 - Parameter duration: The duration of the blink.
 - Parameter color: The color of the blink.
 */
public func blink(withDuration duration: Double = 0.25, color: UIColor? = nil) {

    alpha = 0.2
    UIView.animate(withDuration: duration, delay: 0.0, options: [.curveEaseInOut], animations: {
        self.alpha = 1.0
    })

    guard let newBackgroundColor = color else { return }
    let oldBackgroundColor = backgroundColor

    UIView.animate(withDuration: duration, delay: 0.0, options: [.curveEaseInOut], animations: {
        self.backgroundColor = newBackgroundColor
        self.backgroundColor = oldBackgroundColor
    })

}

You would then use as follows:

buttonScan.blink(color: .green)