public func maskCell(fromTop margin: CGFloat) {
layer.mask = visibilityMask(withLocation: margin / frame.size.height)
layer.masksToBounds = true
}
private func visibilityMask(withLocation location: CGFloat) -> CAGradientLayer {
let mask = CAGradientLayer()
mask.frame = bounds
mask.colors = [UIColor.white.withAlphaComponent(0).cgColor, UIColor.white.cgColor]
let num = location as NSNumber
mask.locations = [num, num]
return mask
}
并且在你的ViewController UIScrollViewDelegate
上
func scrollViewDidScroll(_ scrollView: UIScrollView) {
for cell in self.lessonsTableView.visibleCells {
let paddingToDisapear = CGFloat(25)
let hiddenFrameHeight = scrollView.contentOffset.y + paddingToDisapear - cell.frame.origin.y
if (hiddenFrameHeight >= 0 || hiddenFrameHeight <= cell.frame.size.height) {
if let customCell = cell as? LessonTableViewCell {
customCell.maskCell(fromTop: hiddenFrameHeight)
}
}
}
}