我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
抛光扩展从原来的答案@Tom 请随意在这里更新代码
extension UIColor{
convenience init (hexString:String) {
var cleanString:String = hexString.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
if (cleanString.hasPrefix("#")) {
cleanString = cleanString.substringFromIndex(cleanString.startIndex.advancedBy(1))
}
if (cleanString.characters.count != 6) {
self.init()
}
else{
var rgbValue = UInt32()
let scanner = NSScanner(string: cleanString)
scanner.scanHexInt(&rgbValue)
self.init(
red: CGFloat((rgbValue & 0xFF0000) >> 16)/255.0,
green: CGFloat((rgbValue & 0xFF00) >> 8)/255.0,
blue: CGFloat(rgbValue & 0xFF)/255.0,
alpha: 1.0)
}
}
}
其他回答
self.view.backgroundColor = colorWithHex(hex: yourColorCode)
从hexaDecimalCode创建颜色的代码
func colorWithHex (hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) != 6) {
return UIColor.gray
}
var rgbValue:UInt32 = 0
Scanner(string: cString).scanHexInt32(&rgbValue)
return UIColor(
red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: CGFloat(1.0)
)
}
斯威夫特版本:
extension UIColor {
convenience init?(var hex: String) {
hex = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
hex = (hex.hasPrefix("#")) ? hex.substringFromIndex(advance(hex.startIndex, 1)) : hex
var value: UInt32 = 0
if NSScanner(string: hex).scanHexInt(&value) {
if count(hex) == 8 {
self.init(red: CGFloat((value & 0xFF000000) >> 24) / 255.0,
green: CGFloat((value & 0x00FF0000) >> 16) / 255.0,
blue: CGFloat((value & 0x0000FF00) >> 8) / 255.0,
alpha: CGFloat((value & 0x000000FF)) / 255.0)
return
} else if count(hex) == 6 {
self.init(red: CGFloat((value & 0xFF0000) >> 16) / 255.0,
green: CGFloat((value & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(value & 0x0000FF) / 255.0,
alpha: 1.0)
return
}
}
self.init()
return nil
}
}
另一个实现允许字符串“FFF”或“FFFFFF”,并使用alpha:
+ (UIColor *) colorFromHexString:(NSString *)hexString alpha: (CGFloat)alpha{
NSString *cleanString = [hexString stringByReplacingOccurrencesOfString:@"#" withString:@""];
if([cleanString length] == 3) {
cleanString = [NSString stringWithFormat:@"%@%@%@%@%@%@",
[cleanString substringWithRange:NSMakeRange(0, 1)],[cleanString substringWithRange:NSMakeRange(0, 1)],
[cleanString substringWithRange:NSMakeRange(1, 1)],[cleanString substringWithRange:NSMakeRange(1, 1)],
[cleanString substringWithRange:NSMakeRange(2, 1)],[cleanString substringWithRange:NSMakeRange(2, 1)]];
}
if([cleanString length] == 6) {
cleanString = [cleanString stringByAppendingString:@"ff"];
}
unsigned int baseValue;
[[NSScanner scannerWithString:cleanString] scanHexInt:&baseValue];
float red = ((baseValue >> 24) & 0xFF)/255.0f;
float green = ((baseValue >> 16) & 0xFF)/255.0f;
float blue = ((baseValue >> 8) & 0xFF)/255.0f;
return [UIColor colorWithRed:red green:green blue:blue alpha:alpha];
}
我为它创建了一个便利的init:
extension UIColor {
convenience init(hex: String, alpha: CGFloat)
{
let redH = CGFloat(strtoul(hex.substringToIndex(advance(hex.startIndex,2)), nil, 16))
let greenH = CGFloat(strtoul(hex.substringWithRange(Range<String.Index>(start: advance(hex.startIndex, 2), end: advance(hex.startIndex, 4))), nil, 16))
let blueH = CGFloat(strtoul(hex.substringFromIndex(advance(hex.startIndex,4)), nil, 16))
self.init(red: redH/255, green: greenH/255, blue: blueH/255, alpha: alpha)
}
}
然后你可以在项目的任何地方创建一个UIColor,就像这样:
UIColor(hex: "ffe3c8", alpha: 1)
希望这对你有所帮助……
除了颜色,我还喜欢保证alpha,所以我自己写类别
+ (UIColor *) colorWithHex:(int)color {
float red = (color & 0xff000000) >> 24;
float green = (color & 0x00ff0000) >> 16;
float blue = (color & 0x0000ff00) >> 8;
float alpha = (color & 0x000000ff);
return [UIColor colorWithRed:red/255.0 green:green/255.0 blue:blue/255.0 alpha:alpha/255.0];
}
像这样很容易使用
[UIColor colorWithHex:0xFF0000FF]; //Red
[UIColor colorWithHex:0x00FF00FF]; //Green
[UIColor colorWithHex:0x00FF00FF]; //Blue
[UIColor colorWithHex:0x0000007F]; //transparent black
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