我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
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)
}
其他回答
You Can Get UIColor From String Code Like
circularSpinner.fillColor = [self getUIColorObjectFromHexString:@"27b8c8" alpha:9];
//Function For Hex Color Use
- (unsigned int)intFromHexString:(NSString *)hexStr
{
unsigned int hexInt = 0;
// Create scanner
NSScanner *scanner = [NSScanner scannerWithString:hexStr];
// Tell scanner to skip the # character
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"#"]];
// Scan hex value
[scanner scanHexInt:&hexInt];
return hexInt;
}
- (UIColor *)getUIColorObjectFromHexString:(NSString *)hexStr alpha:(CGFloat)alpha
{
// Convert hex string to an integer
unsigned int hexint = [self intFromHexString:hexStr];
// Create color object, specifying alpha as well
UIColor *color =
[UIColor colorWithRed:((CGFloat) ((hexint & 0xFF0000) >> 16))/255
green:((CGFloat) ((hexint & 0xFF00) >> 8))/255
blue:((CGFloat) (hexint & 0xFF))/255
alpha:alpha];
return color;
}
/Function For Hex Color Use
- (unsigned int)intFromHexString:(NSString *)hexStr
{
unsigned int hexInt = 0;
// Create scanner
NSScanner *scanner = [NSScanner scannerWithString:hexStr];
// Tell scanner to skip the # character
[scanner setCharactersToBeSkipped:[NSCharacterSet characterSetWithCharactersInString:@"#"]];
// Scan hex value
[scanner scanHexInt:&hexInt];
return hexInt;
}
- (UIColor *)getUIColorObjectFromHexString:(NSString *)hexStr alpha:(CGFloat)alpha
{
// Convert hex string to an integer
unsigned int hexint = [self intFromHexString:hexStr];
// Create color object, specifying alpha as well
UIColor *color =
[UIColor colorWithRed:((CGFloat) ((hexint & 0xFF0000) >> 16))/255
green:((CGFloat) ((hexint & 0xFF00) >> 8))/255
blue:((CGFloat) (hexint & 0xFF))/255
alpha:alpha];
return color;
}
另一个带有alpha的版本
#define UIColorFromRGBA(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF000000) >> 24))/255.0 green:((float)((rgbValue & 0xFF0000) >> 16))/255.0 blue:((float)((rgbValue & 0xFF00) >> 8 ))/255.0 alpha:((float)((rgbValue & 0xFF))/255.0)]
上面的几个解决方案涉及到一些不必要的nsstring使用。这个UIColor类扩展更简单更快:
+ colorWithHex:(UInt32)hex alpha:(CGFloat)alpha
{
return [UIColor colorWithRed:((hex & 0xFF0000) >> 16)/255.0
green:((hex & 0x00FF00) >> 8)/255.0
blue:( hex & 0x0000FF)/255.0
alpha:alpha];
}
简单来说:
return [UIColor colorWithHex:0x006400 alpha:1.0]; // HTML darkgreen
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
)
}
}
Swift 5, iOS 14
convenience init(hex: String, alpha: CGFloat = 1.0) {
var hexFormatted: String = hex.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines).uppercased()
if hexFormatted.hasPrefix("#") {
hexFormatted = String(hexFormatted.dropFirst())
}
assert(hexFormatted.count == 6, "Invalid hex code used.")
var rgbValue: UInt64 = 0
Scanner(string: hexFormatted).scanHexInt64(&rgbValue)
self.init(red: CGFloat((rgbValue & 0xFF0000) >> 16) / 255.0,
green: CGFloat((rgbValue & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(rgbValue & 0x0000FF) / 255.0,
alpha: alpha)
}
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