pop动画

func ani() {

    amountLab.text = "0"
    let prop = POPAnimatableProperty.property(withName: "countup") { (ani) in

        ani?.writeBlock = { obj,values in


            guard let lab = obj as? UILabel else { return }
            guard let a = values?[0] else { return }

            lab.text = String(format: "%d", Int(a))
        }
        } as? POPAnimatableProperty


    let aniBase = POPBasicAnimation.easeOut()
    aniBase?.property = prop
    aniBase?.fromValue = 0
    aniBase?.toValue = 80
    aniBase?.duration = 1
    aniBase?.beginTime = CACurrentMediaTime() + 0.5

    amountLab.pop_add(aniBase, forKey: "countup")
}