Swift 将徽章添加到导航 barButtonItem 和 UIButton

Question

我正在尝试在我的通知按钮上显示徽章，在应用程序中显示在 AppIcon 上。

到目前为止，我所研究的一切都与 Obj 有关。 C，但没有具体讨论将该解决方案实现到 Swift 中的方法，

请帮助找到解决方案，添加自定义类/代码以在 UiBarbutton 和 UiButton 上实现 Badge。

目前研究:

https://github.com/Marxon13/M13BadgeView

连同 MKBadge 类等

Answer 1

有一个更优雅的解决方案，带有 UIButtonItem 的扩展

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()
    }
}

这个很棒的代码是由 Stefano Vettor 创建的，您可以在以下位置找到所有详细信息: https://gist.github.com/freedom27/c709923b163e26405f62b799437243f4