Swift add badge to navigation barButtonItem and UIButton

Question

I am trying to display badge on my notification button, in app as displayed on AppIcon.

So far whatever i have researched is related to Obj. C, but nothing that specifically discussed way to implement that solution into Swift,

Please help to find a solution to add a custom class / code to achieve Badge on UiBarbutton and UiButton.

Researched so far:

https://github.com/Marxon13/M13BadgeView

along with MKBadge class etc.

Answer 1

There is a more elegant solution with an extension for UIButtonItem

extension CAShapeLayer {
    func drawCircleAtLocation(location: CGPoint, withRadius radius: CGFloat, andColor color: UIColor, filled: Bool) {
        fillColor = filled ? color.cgColor : UIColor.white.cgColor
        strokeColor = color.cgColor
        let origin = CGPoint(x: location.x - radius, y: location.y - radius)
        path = UIBezierPath(ovalIn: CGRect(origin: origin, size: CGSize(width: radius * 2, height: radius * 2))).cgPath
    }
}

private var handle: UInt8 = 0

extension UIBarButtonItem {
    private var badgeLayer: CAShapeLayer? {
        if let b: AnyObject = objc_getAssociatedObject(self, &handle) as AnyObject? {
            return b as? CAShapeLayer
        } else {
            return nil
        }
    }

    func addBadge(number: Int, withOffset offset: CGPoint = CGPoint.zero, andColor color: UIColor = UIColor.red, andFilled filled: Bool = true) {
        guard let view = self.value(forKey: "view") as? UIView else { return }

        badgeLayer?.removeFromSuperlayer()

        // Initialize Badge
        let badge = CAShapeLayer()
        let radius = CGFloat(7)
        let location = CGPoint(x: view.frame.width - (radius + offset.x), y: (radius + offset.y))
        badge.drawCircleAtLocation(location: location, withRadius: radius, andColor: color, filled: filled)
        view.layer.addSublayer(badge)

        // Initialiaze Badge's label
        let label = CATextLayer()
        label.string = "\(number)"
        label.alignmentMode = CATextLayerAlignmentMode.center
        label.fontSize = 11
        label.frame = CGRect(origin: CGPoint(x: location.x - 4, y: offset.y), size: CGSize(width: 8, height: 16))
        label.foregroundColor = filled ? UIColor.white.cgColor : color.cgColor
        label.backgroundColor = UIColor.clear.cgColor
        label.contentsScale = UIScreen.main.scale
        badge.addSublayer(label)

        // Save Badge as UIBarButtonItem property
        objc_setAssociatedObject(self, &handle, badge, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
    }

    func updateBadge(number: Int) {
        if let text = badgeLayer?.sublayers?.filter({ $0 is CATextLayer }).first as? CATextLayer {
            text.string = "\(number)"
        }
    }

    func removeBadge() {
        badgeLayer?.removeFromSuperlayer()
    }
}

This great code was created by Stefano Vettor and you can find all the details at: https://gist.github.com/freedom27/c709923b163e26405f62b799437243f4