问如何在集合视图中添加声音反馈，比如pickerview？

EN

class ViewController {
    var lastOffsetWithSound: CGFloat = 0
}

extension ViewController: UIScrollViewDelegate {
    func scrollViewDidScroll(_ scrollView: UIScrollView) {
        if let flowLayout = ((scrollView as? UICollectionView)?.collectionViewLayout as? UICollectionViewFlowLayout) {
            let lineHeight = flowLayout.itemSize.height + flowLayout.minimumLineSpacing
            let offset = scrollView.contentOffset.y
            let roundedOffset = offset - offset.truncatingRemainder(dividingBy: lineHeight)
            if abs(lastOffsetWithSound - roundedOffset) > lineHeight {
                lastOffsetWithSound = roundedOffset
                print("play sound feedback here")
            }
        }
    }
}

touchesBegan(_:with:)
touchesMoved(_:with:)

let touch: UITouch = touches.first as! UITouch
if (touch.view == collectionView){
    println("This is your CollectionView")
}else{
    println("This is not your CollectionView")
}