我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
在swift中,我用以下方法创建了一个类扩展,将十六进制代码转换为UIColor。
extension UIColor {
convenience init(R: CGFloat, G: CGFloat, B: CGFloat, alpha: CGFloat) {
self.init(red: R/255.0, green: G/255.0, blue: B/255.0, alpha: alpha)
}
class func colorWithHex(hex: UInt, alpha: CGFloat) -> UIColor {
return UIColor(R: CGFloat((hex & 0xFF0000) >> 16), G: CGFloat((hex & 0x00FF00) >> 8), B: CGFloat(hex & 0x0000FF), alpha: alpha)
}
}
其他回答
使用任何转换器网站将十六进制颜色转换为RGB值(如果你谷歌“十六进制到RGB”,你会看到一吨)。例如,这个:http://www.rgbtohex.net/hextorgb/
然后将颜色属性更改为UIColor。例子:
self.profilePicture.layer.borderColor = [UIColor colorWithRed:0 green:167 blue:142 alpha:1.0].CGColor;
十六进制颜色值是:00a78e转换为RGB: R: 0 G: 167 B: 142
如果你给出的RGB值不在0到1.0之间,你必须将它们除以255。例子:
self.profilePicture.layer.borderColor = [UIColor colorWithRed:83.00/255.0 green:123.00/255.0 blue:53.00/255.0 alpha:1.0].CGColor;
有一个很好的UIColor类别,其中有许多功能。
用法:
textView.textColor = [UIColor colorWithHexString:textColorHex];
NSLog(@"Text Color Hex: %@", textColorHex);
其中textColorHex有一个形式的@“FFFFFF”没有#符号。
有一个很好的帖子是关于如何解决OP的问题,从十六进制字符串中提取UIColor。下面给出的解决方案与其他解决方案不同,因为它支持字符串值,可能包括'0x'或'#'前缀的十六进制字符串表示…(请参阅使用)
这是主要的部分…
- (UIColor *)getUIColorObjectFromHexString:(NSString *)hexStr alpha:(CGFloat)alpha
{
// Convert hex string to an integer
unsigned int hexint = [self intFromHexString:hexStr];
// Create a 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;
}
助手方法……
- (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;
}
用法:
NSString *hexStr1 = @"123ABC";
NSString *hexStr2 = @"#123ABC";
NSString *hexStr3 = @"0x123ABC";
UIColor *color1 = [self getUIColorObjectFromHexString:hexStr1 alpha:.9];
NSLog(@"UIColor: %@", color1);
UIColor *color2 = [self getUIColorObjectFromHexString:hexStr2 alpha:.9];
NSLog(@"UIColor: %@", color2);
UIColor *color3 = [self getUIColorObjectFromHexString:hexStr3 alpha:.9];
NSLog(@"UIColor: %@", color3);
完整的参考文章
Swift 2 +
我已经将这个解决方案移植到Swift 2.2。注意,我已经将alpha参数更改为使用默认设置为1.0。我还根据Swift 2.2中的NSScanner类的要求将int类型更新为UInt32。
func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {
// Convert hex string to an integer
let hexint = Int(self.intFromHexString(hexString))
let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
let blue = CGFloat((hexint & 0xff) >> 0) / 255.0
// Create color object, specifying alpha as well
let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
return color
}
func intFromHexString(hexStr: String) -> UInt32 {
var hexInt: UInt32 = 0
// Create scanner
let scanner: NSScanner = NSScanner(string: hexStr)
// Tell scanner to skip the # character
scanner.charactersToBeSkipped = NSCharacterSet(charactersInString: "#")
// Scan hex value
scanner.scanHexInt(&hexInt)
return hexInt
}
斯威夫特 4+
采用与swift 4相同的变化逻辑,
func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {
// Convert hex string to an integer
let hexint = Int(self.intFromHexString(hexStr: hexString))
let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
let blue = CGFloat((hexint & 0xff) >> 0) / 255.0
// Create color object, specifying alpha as well
let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
return color
}
func intFromHexString(hexStr: String) -> UInt32 {
var hexInt: UInt32 = 0
// Create scanner
let scanner: Scanner = Scanner(string: hexStr)
// Tell scanner to skip the # character
scanner.charactersToBeSkipped = CharacterSet(charactersIn: "#")
// Scan hex value
scanner.scanHexInt32(&hexInt)
return hexInt
}
Swift 5 (iOS 13)+
下面显示了在SDK弃用scanHexInt32的情况下工作的更新。我将代码封装到Swift playground文件中。
//: A UIKit based Playground for presenting user interface
import UIKit
import PlaygroundSupport
class MyViewController : UIViewController {
override func loadView() {
let view = UIView()
view.backgroundColor = .white
let label = UILabel()
label.frame = CGRect(x: 150, y: 200, width: 200, height: 20)
label.text = "Hello World!"
label.textColor = colorWithHexString(hexString: "22F728")
view.addSubview(label)
self.view = view
}
func colorWithHexString(hexString: String, alpha:CGFloat = 1.0) -> UIColor {
// Convert hex string to an integer
let hexint = Int(self.intFromHexString(hexStr: hexString))
let red = CGFloat((hexint & 0xff0000) >> 16) / 255.0
let green = CGFloat((hexint & 0xff00) >> 8) / 255.0
let blue = CGFloat((hexint & 0xff) >> 0) / 255.0
// Create color object, specifying alpha as well
let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
return color
}
func intFromHexString(hexStr: String) -> UInt32 {
var hexInt: UInt32 = 0
// Create scanner
let scanner: Scanner = Scanner(string: hexStr)
// Tell scanner to skip the # character
scanner.charactersToBeSkipped = CharacterSet(charactersIn: "#")
// Scan hex value
hexInt = UInt32(bitPattern: scanner.scanInt32(representation: .hexadecimal) ?? 0)
return hexInt
}
}
// Present the view controller in the Live View window
PlaygroundPage.current.liveView = MyViewController()
彩色十六进制参考 HTML颜色名称和代码 十六进制颜色编码
//UIColorWithHexString
static UIColor * UIColorWithHexString(NSString *hex) {
unsigned int rgb = 0;
[[NSScanner scannerWithString:
[[hex uppercaseString] stringByTrimmingCharactersInSet:
[[NSCharacterSet characterSetWithCharactersInString:@"0123456789ABCDEF"] invertedSet]]]
scanHexInt:&rgb];
return [UIColor colorWithRed:((CGFloat)((rgb & 0xFF0000) >> 16)) / 255.0
green:((CGFloat)((rgb & 0xFF00) >> 8)) / 255.0
blue:((CGFloat)(rgb & 0xFF)) / 255.0
alpha:1.0];
}
使用
self.view.backgroundColor = UIColorWithHexString(@"#0F35C0");
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
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