ios - 我怎样才能用 Swift 编程渐变边框颜色 UIButton

Question

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Answer 1

let gradient = CAGradientLayer()
gradient.frame =  CGRect(origin: CGPointZero, size: self.myButton.frame.size)
gradient.colors = [UIColor.blueColor().CGColor, UIColor.greenColor().CGColor]

let shape = CAShapeLayer()
shape.lineWidth = 2
shape.path = UIBezierPath(rect: self.myButton.bounds).CGPath
shape.strokeColor = UIColor.blackColor().CGColor
shape.fillColor = UIColor.clearColor().CGColor
gradient.mask = shape

self.myButton.layer.addSublayer(gradient)

Swift 3 版本:

    let gradient = CAGradientLayer()
    gradient.frame =  CGRect(origin: CGPoint.zero, size: self.myButton.frame.size)
    gradient.colors = [UIColor.blue.cgColor, UIColor.green.cgColor]

    let shape = CAShapeLayer()
    shape.lineWidth = 2
    shape.path = UIBezierPath(rect: self.myButton.bounds).cgPath
    shape.strokeColor = UIColor.black.cgColor
    shape.fillColor = UIColor.clear.cgColor
    gradient.mask = shape

    self.myButton.layer.addSublayer(gradient)