我如何从十六进制字符串格式创建一个UIColor，如#00FF00?
当前回答
斯威夫特的版本。作为函数或扩展使用。
Function func UIColorFromRGB(colorCode: String, alpha: Float = 1.0) -> UIColor{
var scanner = NSScanner(string:colorCode)
var color:UInt32 = 0;
scanner.scanHexInt(&color)
let mask = 0x000000FF
let r = CGFloat(Float(Int(color >> 16) & mask)/255.0)
let g = CGFloat(Float(Int(color >> 8) & mask)/255.0)
let b = CGFloat(Float(Int(color) & mask)/255.0)
return UIColor(red: r, green: g, blue: b, alpha: CGFloat(alpha))
}
extension UIColor {
convenience init(colorCode: String, alpha: Float = 1.0){
var scanner = NSScanner(string:colorCode)
var color:UInt32 = 0;
scanner.scanHexInt(&color)
let mask = 0x000000FF
let r = CGFloat(Float(Int(color >> 16) & mask)/255.0)
let g = CGFloat(Float(Int(color >> 8) & mask)/255.0)
let b = CGFloat(Float(Int(color) & mask)/255.0)
self.init(red: r, green: g, blue: b, alpha: CGFloat(alpha))
}
}
let hexColorFromFunction = UIColorFromRGB("F4C124", alpha: 1.0)
let hexColorFromExtension = UIColor(colorCode: "F4C124", alpha: 1.0)
Hex Color from interface builder.
其他回答
extension UIColor {
convenience init(hexaString: String, alpha: CGFloat = 1) {
let chars = Array(hexaString.dropFirst())
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)}
}
用法:
let redColor = UIColor(hexaString: "#FF0000") // r 1,0 g 0,0 b 0,0 a 1,0
let transparentRed = UIColor(hexaString: "#FF0000", alpha: 0.5) // r 1,0 g 0,0 b 0,0 a 0,5
另一种选择是将六值转换为无符号整数，并从中提取相应的值:
extension UIColor {
convenience init(hexaString: String, alpha: CGFloat = 1) {
self.init(hexa: UInt(hexaString.dropFirst(), radix: 16) ?? 0, alpha: alpha)
}
convenience init(hexa: UInt, alpha: CGFloat = 1) {
self.init(red: .init((hexa & 0xff0000) >> 16) / 255,
green: .init((hexa & 0xff00 ) >> 8) / 255,
blue: .init( hexa & 0xff ) / 255,
alpha: alpha)
}
}
let purpleColor = UIColor(hexaString: "#FF00FF") // r 1,0 g 0,0 b 1,0 a 1,0
let transparentYellow = UIColor(hexaString: "#FFFF00", alpha: 0.5) // r 1,0 g 1,0 b 0,0 a 0,5
你可以做这样的扩展
extension UIColor {
convenience init(hex: UInt, alpha: CGFloat = 1) {
self.init(
red: CGFloat((hex & 0xFF0000) >> 16) / 255.0,
green: CGFloat((hex & 0x00FF00) >> 8) / 255.0,
blue: CGFloat(hex & 0x0000FF) / 255.0,
alpha: alpha
)
}
}
像这样用在任何地方
let color1 = UIColor(hex: 0xffffff)
let color2 = UIColor(hex: 0xffffff, alpha: 0.2)
使用Xcode的原生颜色文字功能来轻松地添加十六进制颜色。
在你的代码中输入颜色文字，然后让Xcode自动完成剩下的工作。
颜色选择界面将允许你粘贴十六进制颜色:#FF9300
宏的git差异将显示RGB值而不是十六进制值:
let orange = #colorLiteral(red: 1, green: 0.5763723254, blue: 0, alpha: 1)
但它仍然是一种简单的方法来粘贴十六进制没有任何第三方工具或扩展。
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];
}
我已经找到了一个与Android使用的十六进制格式字符串100%兼容的解决方案，我发现这在进行跨平台移动开发时非常有用。它让我在两个平台上都使用一种颜色。您可以在没有归属的情况下随意重用，如果您愿意，也可以在Apache许可下重用。
#import "UIColor+HexString.h"
@interface UIColor(HexString)
+ (UIColor *) colorWithHexString: (NSString *) hexString;
+ (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length;
@end
@implementation UIColor(HexString)
+ (UIColor *) colorWithHexString: (NSString *) hexString {
NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];
CGFloat alpha, red, blue, green;
switch ([colorString length]) {
case 3: // #RGB
alpha = 1.0f;
red = [self colorComponentFrom: colorString start: 0 length: 1];
green = [self colorComponentFrom: colorString start: 1 length: 1];
blue = [self colorComponentFrom: colorString start: 2 length: 1];
break;
case 4: // #ARGB
alpha = [self colorComponentFrom: colorString start: 0 length: 1];
red = [self colorComponentFrom: colorString start: 1 length: 1];
green = [self colorComponentFrom: colorString start: 2 length: 1];
blue = [self colorComponentFrom: colorString start: 3 length: 1];
break;
case 6: // #RRGGBB
alpha = 1.0f;
red = [self colorComponentFrom: colorString start: 0 length: 2];
green = [self colorComponentFrom: colorString start: 2 length: 2];
blue = [self colorComponentFrom: colorString start: 4 length: 2];
break;
case 8: // #AARRGGBB
alpha = [self colorComponentFrom: colorString start: 0 length: 2];
red = [self colorComponentFrom: colorString start: 2 length: 2];
green = [self colorComponentFrom: colorString start: 4 length: 2];
blue = [self colorComponentFrom: colorString start: 6 length: 2];
break;
default:
[NSException raise:@"Invalid color value" format: @"Color value %@ is invalid. It should be a hex value of the form #RBG, #ARGB, #RRGGBB, or #AARRGGBB", hexString];
break;
}
return [UIColor colorWithRed: red green: green blue: blue alpha: alpha];
}
+ (CGFloat) colorComponentFrom: (NSString *) string start: (NSUInteger) start length: (NSUInteger) length {
NSString *substring = [string substringWithRange: NSMakeRange(start, length)];
NSString *fullHex = length == 2 ? substring : [NSString stringWithFormat: @"%@%@", substring, substring];
unsigned hexComponent;
[[NSScanner scannerWithString: fullHex] scanHexInt: &hexComponent];
return hexComponent / 255.0;
}
@end
迅速:
extension UIColor {
convenience init?(hexString: String?) {
let input: String! = (hexString ?? "")
.replacingOccurrences(of: "#", with: "")
.uppercased()
var alpha: CGFloat = 1.0
var red: CGFloat = 0
var blue: CGFloat = 0
var green: CGFloat = 0
switch (input.count) {
case 3 /* #RGB */:
red = Self.colorComponent(from: input, start: 0, length: 1)
green = Self.colorComponent(from: input, start: 1, length: 1)
blue = Self.colorComponent(from: input, start: 2, length: 1)
break
case 4 /* #ARGB */:
alpha = Self.colorComponent(from: input, start: 0, length: 1)
red = Self.colorComponent(from: input, start: 1, length: 1)
green = Self.colorComponent(from: input, start: 2, length: 1)
blue = Self.colorComponent(from: input, start: 3, length: 1)
break
case 6 /* #RRGGBB */:
red = Self.colorComponent(from: input, start: 0, length: 2)
green = Self.colorComponent(from: input, start: 2, length: 2)
blue = Self.colorComponent(from: input, start: 4, length: 2)
break
case 8 /* #AARRGGBB */:
alpha = Self.colorComponent(from: input, start: 0, length: 2)
red = Self.colorComponent(from: input, start: 2, length: 2)
green = Self.colorComponent(from: input, start: 4, length: 2)
blue = Self.colorComponent(from: input, start: 6, length: 2)
break
default:
NSException.raise(NSExceptionName("Invalid color value"), format: "Color value \"%@\" is invalid. It should be a hex value of the form #RBG, #ARGB, #RRGGBB, or #AARRGGBB", arguments:getVaList([hexString ?? ""]))
}
self.init(red: red, green: green, blue: blue, alpha: alpha)
}
static func colorComponent(from string: String!, start: Int, length: Int) -> CGFloat {
let substring = (string as NSString)
.substring(with: NSRange(location: start, length: length))
let fullHex = length == 2 ? substring : "\(substring)\(substring)"
var hexComponent: UInt64 = 0
Scanner(string: fullHex)
.scanHexInt64(&hexComponent)
return CGFloat(Double(hexComponent) / 255.0)
}
}
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