我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
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];
}
其他回答
我发现最简单的方法是使用宏。只要把它包括在你的标题中,它就可以在你的整个项目中使用。
#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
Uicolor宏十六进制值
这段代码的格式化版本:
#define UIColorFromRGB(rgbValue) \
[UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 \
green:((float)((rgbValue & 0x00FF00) >> 8))/255.0 \
blue:((float)((rgbValue & 0x0000FF) >> 0))/255.0 \
alpha:1.0]
用法:
label.textColor = UIColorFromRGB(0xBC1128);
迅速:
static func UIColorFromRGB(_ rgbValue: Int) -> UIColor! {
return UIColor(
red: CGFloat((Float((rgbValue & 0xff0000) >> 16)) / 255.0),
green: CGFloat((Float((rgbValue & 0x00ff00) >> 8)) / 255.0),
blue: CGFloat((Float((rgbValue & 0x0000ff) >> 0)) / 255.0),
alpha: 1.0)
}
这是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)
用法:
var color1 = hexStringToUIColor("#d3d3d3")
斯威夫特4:
func hexStringToUIColor (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3:
func hexStringToUIColor (hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
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)
)
}
斯威夫特2:
func hexStringToUIColor (hex:String) -> UIColor {
var cString:String = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet() as NSCharacterSet).uppercaseString
if (cString.hasPrefix("#")) {
cString = cString.substringFromIndex(cString.startIndex.advancedBy(1))
}
if ((cString.characters.count) != 6) {
return UIColor.grayColor()
}
var rgbValue:UInt32 = 0
NSScanner(string: cString).scanHexInt(&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)
)
}
沙德源代码:/ gist: de147c42d7b3063ef7bc
下面是Swift 1.2版本,作为UIColor的扩展。这允许你这样做
let redColor = UIColor(hex: "#FF0000")
我觉得这是最自然的做法。
extension UIColor {
// Initialiser for strings of format '#_RED_GREEN_BLUE_'
convenience init(hex: String) {
let redRange = Range<String.Index>(start: hex.startIndex.advancedBy(1), end: hex.startIndex.advancedBy(3))
let greenRange = Range<String.Index>(start: hex.startIndex.advancedBy(3), end: hex.startIndex.advancedBy(5))
let blueRange = Range<String.Index>(start: hex.startIndex.advancedBy(5), end: hex.startIndex.advancedBy(7))
var red : UInt32 = 0
var green : UInt32 = 0
var blue : UInt32 = 0
NSScanner(string: hex.substringWithRange(redRange)).scanHexInt(&red)
NSScanner(string: hex.substringWithRange(greenRange)).scanHexInt(&green)
NSScanner(string: hex.substringWithRange(blueRange)).scanHexInt(&blue)
self.init(
red: CGFloat(red) / 255,
green: CGFloat(green) / 255,
blue: CGFloat(blue) / 255,
alpha: 1
)
}
}
斯威夫特4
你可以像这样在扩展中创建一个非常方便的构造函数:
extension UIColor {
convenience init(hexString: String, alpha: CGFloat = 1.0) {
var hexInt: UInt32 = 0
let scanner = Scanner(string: hexString)
scanner.charactersToBeSkipped = CharacterSet(charactersIn: "#")
scanner.scanHexInt32(&hexInt)
let red = CGFloat((hexInt & 0xff0000) >> 16) / 255.0
let green = CGFloat((hexInt & 0xff00) >> 8) / 255.0
let blue = CGFloat((hexInt & 0xff) >> 0) / 255.0
let alpha = alpha
self.init(red: red, green: green, blue: blue, alpha: alpha)
}
}
以后再用
let color = UIColor(hexString: "#AABBCCDD")
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")
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