我使用此代码从十六进制值创建UIColor。它工作得很完美。
extension UIColor {
convenience init(red: Int, green: Int, blue: Int) {
assert(red >= 0 && red <= 255, "Invalid red component")
assert(green >= 0 && green <= 255, "Invalid green component")
assert(blue >= 0 && blue <= 255, "Invalid blue component")
self.init(red: CGFloat(red) / 255.0, green: CGFloat(green) / 255.0, blue: CGFloat(blue) / 255.0, alpha: 1.0)
}
convenience init(netHex:Int) {
self.init(red:(netHex >> 16) & 0xff, green:(netHex >> 8) & 0xff, blue:netHex & 0xff)
}
}
用法:
var textColor = UIColor(netHex: 0xffffff)
这段代码非常适合Int十六进制代码。但是它需要十六进制代码0xffffff作为Int类型。我有十六进制代码从网络服务。它将类似于"#ffffff“(String而不是Int)。我可以将这个字符串转换为"0xffffff“。但是我不能从“0xffffff”(字符串)转换成0xffffff (Int)。
我需要这样的东西
var textColor = UIColor(netHex: "0xffffff")
或者像这样更好:
var textColor = UIColor(netHex: "#ffffff")
提前谢谢。
发布于 2015-08-03 16:17:05
Xcode 9·Swift 4或更高版本的
extension UIColor {
convenience init?(hexaRGB: String, alpha: CGFloat = 1) {
var chars = Array(hexaRGB.hasPrefix("#") ? hexaRGB.dropFirst() : hexaRGB[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }
case 6: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[0...1]), nil, 16)) / 255,
green: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
alpha: alpha)
}
convenience init?(hexaRGBA: String) {
var chars = Array(hexaRGBA.hasPrefix("#") ? hexaRGBA.dropFirst() : hexaRGBA[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }; fallthrough
case 6: chars.append(contentsOf: ["F","F"])
case 8: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[0...1]), nil, 16)) / 255,
green: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
alpha: .init(strtoul(String(chars[6...7]), nil, 16)) / 255)
}
convenience init?(hexaARGB: String) {
var chars = Array(hexaARGB.hasPrefix("#") ? hexaARGB.dropFirst() : hexaARGB[...])
switch chars.count {
case 3: chars = chars.flatMap { [$0, $0] }; fallthrough
case 6: chars.append(contentsOf: ["F","F"])
case 8: break
default: return nil
}
self.init(red: .init(strtoul(String(chars[2...3]), nil, 16)) / 255,
green: .init(strtoul(String(chars[4...5]), nil, 16)) / 255,
blue: .init(strtoul(String(chars[6...7]), nil, 16)) / 255,
alpha: .init(strtoul(String(chars[0...1]), nil, 16)) / 255)
}
}
if let textColor = UIColor(hexa: "00F") {
print(textColor) // r 0.0 g 0.0 b 1.0 a 1.0
}
if let textColor = UIColor(hexaRGB: "00F") {
print(textColor) // r 0.0 g 0.0 b 1.0 a 1.0
}
UIColor(hexaRGB: "#00F") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGB: "#00F", alpha: 0.5) // r 0.0 g 0.0 b 1.0 a 0.5
UIColor(hexaRGB: "#0000FF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGB: "#0000FF", alpha: 0.5) // r 0.0 g 0.0 b 1.0 a 0.5
UIColor(hexaRGBA: "#0000FFFF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaRGBA: "#0000FF7F") // r 0.0 g 0.0 b 1.0 a 0.498
UIColor(hexaARGB: "#FF0000FF") // r 0.0 g 0.0 b 1.0 a 1.0
UIColor(hexaARGB: "#7F0000FF") // r 0.0 g 0.0 b 1.0 a 0.498
https://stackoverflow.com/questions/31782316
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