我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
你可以创建UIColor的扩展类:-
扩展UIColor {
// MARK: - getColorFromHex /** 此函数将颜色十六进制代码转换为RGB。
- parameter color hex string.
- returns: RGB color code.
*/
class func getColorFromHex(hexString:String)->UIColor{
var rgbValue : UInt32 = 0
let scanner:NSScanner = NSScanner(string: hexString)
scanner.scanLocation = 1
scanner.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))
}
}
其他回答
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
一个简明的解决方案:
// Assumes input like "#00FF00" (#RRGGBB).
+ (UIColor *)colorFromHexString:(NSString *)hexString {
unsigned rgbValue = 0;
NSScanner *scanner = [NSScanner scannerWithString:hexString];
[scanner setScanLocation:1]; // bypass '#' character
[scanner scanHexInt:&rgbValue];
return [UIColor colorWithRed:((rgbValue & 0xFF0000) >> 16)/255.0 green:((rgbValue & 0xFF00) >> 8)/255.0 blue:(rgbValue & 0xFF)/255.0 alpha:1.0];
}
swift 2.0+。 这段代码对我来说很好。
extension UIColor {
/// UIColor(hexString: "#cc0000")
internal convenience init?(hexString:String) {
guard hexString.characters[hexString.startIndex] == Character("#") else {
return nil
}
guard hexString.characters.count == "#000000".characters.count else {
return nil
}
let digits = hexString.substringFromIndex(hexString.startIndex.advancedBy(1))
guard Int(digits,radix:16) != nil else{
return nil
}
let red = digits.substringToIndex(digits.startIndex.advancedBy(2))
let green = digits.substringWithRange(Range<String.Index>(start: digits.startIndex.advancedBy(2),
end: digits.startIndex.advancedBy(4)))
let blue = digits.substringWithRange(Range<String.Index>(start:digits.startIndex.advancedBy(4),
end:digits.startIndex.advancedBy(6)))
let redf = CGFloat(Double(Int(red, radix:16)!) / 255.0)
let greenf = CGFloat(Double(Int(green, radix:16)!) / 255.0)
let bluef = CGFloat(Double(Int(blue, radix:16)!) / 255.0)
self.init(red: redf, green: greenf, blue: bluef, alpha: CGFloat(1.0))
}
}
此代码包括字符串格式检查。 如。
let aColor = UIColor(hexString: "#dadada")!
let failed = UIColor(hexString: "123zzzz")
据我所知,我的代码在维护可失败条件的语义和返回可选值方面没有任何缺点。这应该是最好的答案。
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))
}
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;
}
推荐文章
- 如何删除默认的导航栏空间在SwiftUI导航视图
- 如何在iOS中使用Swift编程segue
- Swift -整数转换为小时/分钟/秒
- Swift:声明一个空字典
- 在成功提交我的应用程序后,“太多符号文件”
- 首先添加一个UIView,甚至是导航栏
- 我如何改变UIButton标题颜色?
- 如何从UIImage (Cocoa Touch)或CGImage (Core Graphics)获取像素数据?
- 在Swift中如何调用GCD主线程上的参数方法?
- NSLayoutConstraints是可动画的吗?
- iOS -构建失败,CocoaPods无法找到头文件
- CFNetwork SSLHandshake iOS 9失败
- 请求失败:不可接受的内容类型:文本/html使用AFNetworking 2.0
- 缺少推荐的图标文件-该包不包含iPhone / iPod Touch的应用程序图标,像素为“120x120”,png格式
- 以编程方式创建segue