Xcode 11 | Swift 5
如果有人正在寻找一个快速和简单的方法来添加一个渐变视图:
extension UIView {
func addGradient(colors: [UIColor] = [.blue, .white], locations: [NSNumber] = [0, 2], startPoint: CGPoint = CGPoint(x: 0.0, y: 1.0), endPoint: CGPoint = CGPoint(x: 1.0, y: 1.0), type: CAGradientLayerType = .axial){
let gradient = CAGradientLayer()
gradient.frame.size = self.frame.size
gradient.frame.origin = CGPoint(x: 0.0, y: 0.0)
// Iterates through the colors array and casts the individual elements to cgColor
// Alternatively, one could use a CGColor Array in the first place or do this cast in a for-loop
gradient.colors = colors.map{ $0.cgColor }
gradient.locations = locations
gradient.startPoint = startPoint
gradient.endPoint = endPoint
// Insert the new layer at the bottom-most position
// This way we won't cover any other elements
self.layer.insertSublayer(gradient, at: 0)
}
}
关于如何使用扩展的例子:
// Testing
view.addGradient()
// Two Colors
view.addGradient(colors: [.init(rgb: 0x75BBDB), .black], locations: [0, 3])
// Full Blown
view.addGradient(colors: [.init(rgb: 0x75BBDB), .black], locations: [0, 3], startPoint: CGPoint(x: 0.0, y: 1.5), endPoint: CGPoint(x: 1.0, y: 2.0), type: .axial)
可选地，使用以下命令输入十六进制数字。init(rgb: 0x75BBDB)
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
}
convenience init(rgb: Int) {
self.init(
red: (rgb >> 16) & 0xFF,
green: (rgb >> 8) & 0xFF,
blue: rgb & 0xFF
)
}
}
