我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
有cocoapod支持,这很好
https://github.com/mRs-/HexColors
// with hash
NSColor *colorWithHex = [NSColor colorWithHexString:@"#ff8942" alpha:1];
// wihtout hash
NSColor *secondColorWithHex = [NSColor colorWithHexString:@"ff8942" alpha:1];
// short handling
NSColor *shortColorWithHex = [NSColor colorWithHexString:@"fff" alpha:1]
其他回答
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
}
}
swift 1.2更新
class func colorWithHexString (hex:String) -> UIColor {
var cString: NSString = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
if (cString.hasPrefix("#")) {
cString = cString.substringFromIndex(1)
}
if (count(cString as String) != 6) {
return UIColor.grayColor()
}
var rString: String = cString.substringToIndex(2)
var gString: String = (cString.substringFromIndex(2) as NSString).substringToIndex(2)
var bString: String = (cString.substringFromIndex(4) as NSString).substringToIndex(2)
var r:CUnsignedInt = 0, g:CUnsignedInt = 0, b:CUnsignedInt = 0;
NSScanner(string: rString).scanHexInt(&r)
NSScanner(string: gString).scanHexInt(&g)
NSScanner(string: bString).scanHexInt(&b)
return UIColor(red: CGFloat(Float(r) / 255.0), green: CGFloat(Float(g) / 255.0), blue: CGFloat(Float(b) / 255.0), alpha: CGFloat(1))
}
伊森·斯特里德回答的简单例子。一个接受十六进制字符串并返回UIColor的函数。 (你可以输入十六进制字符串格式:#ffffff或ffffff)
例子:
func hexStringToUIColor (hex:String) -> UIColor {
var cString: String = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
if let range = cString.range(of: cString) {
cString = cString.substring(from: cString.index(range.lowerBound, offsetBy: 1))
}
}
if ((cString.characters.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)
)
}
用法:
var color1 = hexStringToUIColor("#d3d3d3")
试试这个:这段代码将从十六进制颜色字符串返回UIColor
- (UIColor*)colorWithHexString:(NSString*)hex
{
NSString *cString = [[hex stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
// String should be 6 or 8 characters
if ([cString length] < 6) return [UIColor grayColor];
// strip 0X if it appears
if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];
if ([cString length] != 6) return [UIColor grayColor];
// Separate into r, g, b substrings
NSRange range;
range.location = 0;
range.length = 2;
NSString *rString = [cString substringWithRange:range];
range.location = 2;
NSString *gString = [cString substringWithRange:range];
range.location = 4;
NSString *bString = [cString substringWithRange:range];
// Scan values
unsigned int r, g, b;
[[NSScanner scannerWithString:rString] scanHexInt:&r];
[[NSScanner scannerWithString:gString] scanHexInt:&g];
[[NSScanner scannerWithString:bString] scanHexInt:&b];
return [UIColor colorWithRed:((float) r / 255.0f)
green:((float) g / 255.0f)
blue:((float) b / 255.0f)
alpha:1.0f];
}
为UIColor创建优雅的扩展:
extension UIColor {
convenience init(string: String) {
var uppercasedString = string.uppercased()
uppercasedString.remove(at: string.startIndex)
var rgbValue: UInt32 = 0
Scanner(string: uppercasedString).scanHexInt32(&rgbValue)
let red = CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0
let green = CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0
let blue = CGFloat(rgbValue & 0x0000FF) / 255.0
self.init(red: red, green: green, blue: blue, alpha: 1)
}
}
创建红色:
let red = UIColor(string: "#ff0000")
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