你可以在iPhone中使用Quartz动画渐变吗？

import UIKit
import QuartzCore

let gradientLayer = CAGradientLayer()
gradientLayer.frame = view.bounds
gradientLayer.colors = [UIColor.red.cgColor, UIColor.blue.cgColor]
gradientLayer.startPoint = CGPoint(x: 0, y: 0)
gradientLayer.endPoint = CGPoint(x: 1, y: 1)

view.layer.addSublayer(gradientLayer)

let animation = CABasicAnimation(keyPath: "colors")
animation.duration = 3.0
animation.fromValue = [UIColor.red.cgColor, UIColor.blue.cgColor]
animation.toValue = [UIColor.green.cgColor, UIColor.yellow.cgColor]
animation.repeatCount = Float.infinity

gradientLayer.add(animation, forKey: "colors")