View渐变控件

重写 Layer

重写 layerClass

通过重写 layerClass 替换 UIView 的默认 layer

override final class var layerClass: AnyClass {
        return CAGradientLayer.self
}

设置渐变色

func setGradientColors(){
        guard let layer = self.layer as? CAGradientLayer else { return }
        layer.colors = [
            UIColor(red: 210/255.0, green: 0, blue: 224/255.0, alpha: 1.0).cgColor,
            UIColor(red: 1.0, green: 61/255.0, blue: 97/255.0, alpha: 1.0).cgColor
        ]
        layer.startPoint = CGPoint(x: 0.0, y: 0.0)
        layer.endPoint = CGPoint(x: 1.0, y: 1.0)
        layer.cornerRadius = 25
}

优势

• 不用新建 layer 添加
• 避免 自动布局时，新增 layer 的 frame 难以确定

由此延伸可以扩展更多
CAShapeLayer
CATextLayer
CATransformLayer
CAGradientLayer
CAReplicatorLayer
CAScrollLayer
CATiledLayer
CAEmitterLayer
CAEAGLLayer
AVPlayerLayer
....