Question

我想在按钮点击后将渐变颜色设置为背景以下是我的代码，我在上遇到崩溃，因为case将objGrediantView作为CAGradientLayer（）在sender.subviews中

检查是否有Grediant

func setGrediantView(sender: AnyObject, topColor: UIColor, bottomColor: UIColor){

    for case let objGrediantView as CAGradientLayer() in sender.subviews {
        if objGrediantView {
            // show error
            return
        }
    }


    let colorTop =  topColor.cgColor
    let colorBottom = bottomColor.cgColor

    let gradientLayer = CAGradientLayer()
    gradientLayer.colors = [ colorTop, colorBottom]
    gradientLayer.locations = [ 0.0, 1.0]
    gradientLayer.frame = sender.bounds

    sender.layer.insertSublayer(gradientLayer, at: 0)

}

func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    print("You selected cell #\(indexPath.item)!")
    let dicData = items[indexPath.item]
  //  self.objProfileView.backgroundColor = UIColor.white
     self.setGrediantView(sender: objProfileView, topColor: (dicData["top"]!), bottomColor: (dicData["bottom"]!))
}

Answer 1

重写文本（你的代码是不可编译的，我真的很想知道你是怎么做到的）：

    for sublayer in (sender.layer.sublayers ?? []) {
        if sublayer is CAGradientLayer  {
            // show error
            return
        }
    }

如何在swift中检查和设置grediant视图？

1 个答案: