我试图应用渐变作为一个视图(故事板的主视图)的背景色。代码运行，但没有任何变化。我使用xCode Beta 2和Swift。
代码如下:
class Colors {
let colorTop = UIColor(red: 192.0/255.0, green: 38.0/255.0, blue: 42.0/255.0, alpha: 1.0)
let colorBottom = UIColor(red: 35.0/255.0, green: 2.0/255.0, blue: 2.0/255.0, alpha: 1.0)
let gl: CAGradientLayer
init() {
gl = CAGradientLayer()
gl.colors = [ colorTop, colorBottom]
gl.locations = [ 0.0, 1.0]
}
}
然后在视图控制器中:
let colors = Colors()
func refresh() {
view.backgroundColor = UIColor.clearColor()
var backgroundLayer = colors.gl
backgroundLayer.frame = view.frame
view.layer.insertSublayer(backgroundLayer, atIndex: 0)
}
}
}
只需要指定视图的框架，你想在其中显示渐变颜色。
let firstColor = UIColor(red: 69/255, green: 90/255, blue: 195/255, alpha: 1.0).CGColor
let secondColor = UIColor(red: 230/255, green: 44/255, blue: 75/255, alpha: 1.0).CGColor
let gradientLayer = CAGradientLayer()
gradientLayer.colors = [ firstColor, secondColor]
gradientLayer.locations = [ 0.0, 1.0]
gradientLayer.frame = CGRectMake(0, 0, 375, 64)// You can mention frame here
self.view.layer.addSublayer(gradientLayer)
你提供给渐变的颜色必须是CGColor类型。设置CGColor数组为gl。colors。
正确的代码是:
class Colors {
var gl:CAGradientLayer!
init() {
let colorTop = UIColor(red: 192.0 / 255.0, green: 38.0 / 255.0, blue: 42.0 / 255.0, alpha: 1.0).cgColor
let colorBottom = UIColor(red: 35.0 / 255.0, green: 2.0 / 255.0, blue: 2.0 / 255.0, alpha: 1.0).cgColor
self.gl = CAGradientLayer()
self.gl.colors = [colorTop, colorBottom]
self.gl.locations = [0.0, 1.0]
}
}
易于使用的扩展swift 3
extension CALayer {
func addGradienBorder(colors:[UIColor] = [UIColor.red,UIColor.blue], width:CGFloat = 1) {
let gradientLayer = CAGradientLayer()
gradientLayer.frame = CGRect(origin: .zero, size: self.bounds.size)
gradientLayer.startPoint = CGPoint(x:0.0, y:0.5)
gradientLayer.endPoint = CGPoint(x:1.0, y: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.black.cgColor
gradientLayer.mask = shapeLayer
self.addSublayer(gradientLayer)
}
}
用你的观点，例子
yourView.addGradienBorder(color: UIColor.black, opacity: 0.1, offset: CGSize(width:2 , height: 5), radius: 3, viewCornerRadius: 3.0)
如果你有视图集合(多视图)，请这样做
func setGradientBackground() {
let v:UIView
for v in viewgradian
//here viewgradian is your view Collection Outlet name
{
let layer:CALayer
var arr = [AnyObject]()
for layer in v.layer.sublayers!
{
arr.append(layer)
}
let colorTop = UIColor(red: 216.0/255.0, green: 240.0/255.0, blue: 244.0/255.0, alpha: 1.0).cgColor
let colorBottom = UIColor(red: 255.0/255.0, green: 255.0/255.0, blue: 255.0/255.0, alpha: 1.0).cgColor
let gradientLayer = CAGradientLayer()
gradientLayer.colors = [ colorBottom, colorTop]
gradientLayer.startPoint = CGPoint(x: 1.0, y: 0.0)
gradientLayer.endPoint = CGPoint(x: 0.0, y: 1.0)
gradientLayer.frame = v.bounds
v.layer.insertSublayer(gradientLayer, at: 0)
}
}
对于swift应用CAGradientLayer到任何对象(水平和垂直)
func makeGradientColor(`for` object : AnyObject , startPoint : CGPoint , endPoint : CGPoint) -> CAGradientLayer {
let gradient: CAGradientLayer = CAGradientLayer()
gradient.colors = [(UIColor(red: 59.0/255.0, green: 187.0/255.0, blue: 182.0/255.0, alpha: 1.00).cgColor), (UIColor(red: 57.0/255.0, green: 174.0/255.0, blue: 236.0/255.0, alpha: 1.00).cgColor)]
gradient.locations = [0.0 , 1.0]
gradient.startPoint = startPoint
gradient.endPoint = endPoint
gradient.frame = CGRect(x: 0.0, y: 0.0, width: object.frame.size.width, height: object.frame.size.height)
return gradient
}
如何使用
let start : CGPoint = CGPoint(x: 0.0, y: 1.0)
let end : CGPoint = CGPoint(x: 1.0, y: 1.0)
let gradient: CAGradientLayer = self.makeGradientColor(for: vwTop, startPoint: start, endPoint: end)
vwTop.layer.insertSublayer(gradient, at: 0)
let start1 : CGPoint = CGPoint(x: 1.0, y: 1.0)
let end1 : CGPoint = CGPoint(x: 1.0, y: 0.0)
let gradient1: CAGradientLayer = self.makeGradientColor(for: vwTop, startPoint: start1, endPoint: end1)
vwBottom.layer.insertSublayer(gradient1, at: 0)
您可以在这里检查输出
如果你需要改变渐变的方向你必须使用startPoint和endPoint。
let gradient: CAGradientLayer = CAGradientLayer()
gradient.colors = [UIColor.blue.cgColor, UIColor.red.cgColor]
gradient.locations = [0.0 , 1.0]
gradient.startPoint = CGPoint(x: 0.0, y: 1.0)
gradient.endPoint = CGPoint(x: 1.0, y: 1.0)
gradient.frame = CGRect(x: 0.0, y: 0.0, width: self.view.frame.size.width, height: self.view.frame.size.height)
self.view.layer.insertSublayer(gradient, at: 0)
