如何让我的颜色渐变显示在自定义UIView Swift中

class GradientView: UIView {
    override class var layerClass: AnyClass {
        return CAGradientLayer.self
    }
    
    var gradientLayer: CAGradientLayer {
        return layer as! CAGradientLayer
    }
    
    func setGradientColors(colors: [UIColor]) {
        gradientLayer.colors = colors.map { $0.cgColor }
    }
}

let gradientView = GradientView(frame: CGRect(x: 0, y: 0, width: 200, height: 200))
gradientView.center = view.center
view.addSubview(gradientView)

gradientView.setGradientColors(colors: [UIColor.red, UIColor.blue])