抛物线动画(加入购物车效果)

加入购物车的抛物线动画, 如图:

直接上代码...

// 这里为了方便调用, 直接写了UIView的扩展.
extension UIView {
    /**
     加入购物车
     
     - parameter duration:  时间
     - parameter endPoint:  终点坐标
     - parameter completed: 完成之后的回调
     */
    func animateWithStartView(duration duration: NSTimeInterval, endPoint: CGPoint, completed: (Void->Void)? = nil) {
        let view = self.copyView()
        
        // 开始坐标
        let startX = view.frame.origin.x + view.frame.size.width / 2
        let startY = view.frame.origin.y + view.frame.size.height / 2
        
        // 中心点坐标
        let centerX = startX + (endPoint.x - startX) / 2
        let centerY = startY + (endPoint.y - startY) / 2 - 500
        let centerPoint = CGPoint(x: centerX, y: centerY)
        
        // 路径
        let path = UIBezierPath()
        path.moveToPoint(CGPoint(x: startX, y: startY))
        path.addQuadCurveToPoint(endPoint, controlPoint: centerPoint)
        
        // 动画
        let animation = CAKeyframeAnimation(keyPath: "position")
        animation.path = path.CGPath
        animation.removedOnCompletion = false
        animation.fillMode = kCAFillModeForwards
        animation.duration = duration
        animation.autoreverses = false
        animation.timingFunction = CAMediaTimingFunction(name: kCAMediaTimingFunctionEaseIn)
        delay(0.01) {
            view.layer.addAnimation(animation, forKey: "ParabolaAnimation")
        }
        UIView.animateWithDuration(duration, animations: { () -> Void in
            var rect = view.frame
            rect.size.height = 10
            rect.size.width = 10
            view.frame = rect
        }) { _ in
            view.removeFromSuperview()
            completed?()
        }
    }
    
    /**
     复制一个view对象
     
     - returns: 赋值得到的新对象
     */
    private func copyView() -> UIView {
        let view = NSKeyedUnarchiver.unarchiveObjectWithData(NSKeyedArchiver.archivedDataWithRootObject(self))! as! UIView
        self.superview?.addSubview(view)
        return view
    }
    
    /**
     延时操作
     
     - parameter duration:  时长(秒)
     - parameter completed: 回调
     */
    private func delay(duration: NSTimeInterval, completed: ()->Void) {
        let delay = dispatch_time(DISPATCH_TIME_NOW, Int64(duration * Double(NSEC_PER_SEC)))
        dispatch_after(delay, dispatch_get_main_queue()) {
            completed()
        }
    }
}

使用

// 终点坐标
let rect = UIScreen.mainScreen().bounds
let endPoint = CGPoint(x: rect.width, y: rect.height)

// 开启动画
imageView.animateWithStartView(duration: 1, endPoint: endPoint)