小賢的部落格

        let key = "rotationAnimation"

        if isUpdate

        {

            let rotationAnimation = CABasicAnimation(keyPath: "transform.rotation.z")

            let duration: Double = 1.2

            let angle: Double = -360

            rotationAnimation.byValue = angle / 180.0 * M_PI

            rotationAnimation.duration = duration

            rotationAnimation.cumulative = true

            rotationAnimation.repeatCount = .infinity

            rotationAnimation.fillMode = kCAFillModeForwards

            rotationAnimation.removedOnCompletion = false

            imageView.layer.addAnimation(rotationAnimation, forKey: key)

        }

        else

        {

            imageView.layer.removeAnimationForKey(key)

        }

參考資料：

http://stackoverflow.com/questions/2306870/is-there-a-way-to-pause-a-cabasicanimation

http://blog.csdn.net/iosevanhuang/article/details/14488239

http://stackoverflow.com/questions/7082578/cabasicanimation-unlimited-repeat-without-huge-valf