ios - 如何制作UIView的渐变边框？

Question

我想做一个像下图这样的渐变边框:

但我不知 Prop 体怎么做，即我应该使用什么渐变颜色来做到这一点？如何设置我的 View 以显示像图像一样的边框？

我正在使用以下代码来获取边框:

 self.view.layer.borderColor = [UIColor orangeColor].CGColor;
 self.view.layer.borderWidth = 2.0f;

Answer 1

这就是我所做的并且效果很好

   extension CALayer {
    func addGradienBorder(colors:[UIColor],width:CGFloat = 1) {
        let gradientLayer = CAGradientLayer()
        gradientLayer.frame =  CGRect(origin: CGPointZero, size: self.bounds.size)
        gradientLayer.startPoint = CGPointMake(0.0, 0.5)
        gradientLayer.endPoint = CGPointMake(1.0, 0.5)
        gradientLayer.colors = colors.map({$0.CGColor})

        let shapeLayer = CAShapeLayer()
        shapeLayer.lineWidth = width
        shapeLayer.path = UIBezierPath(rect: self.bounds).CGPath
        shapeLayer.fillColor = nil
        shapeLayer.strokeColor = UIColor.blackColor().CGColor
        gradientLayer.mask = shapeLayer

        self.addSublayer(gradientLayer)
    }

}