ios 如何将 UIColor 转换为 HEX 并在 NSLog 中显示
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How to convert UIColor to HEX and display in NSLog
提问by App Dev Guy
I have checked several links on how to convert UIColor codes to HEX however I am not sure on how to call to the method to display them in NSLog. I haven't got the reputation to comment so posting as a question is my last resort. I want it to display when I run my app in the log.
我已经检查了几个关于如何将 UIColor 代码转换为 HEX 的链接，但是我不确定如何调用该方法以在 NSLog 中显示它们。我没有评论的声誉，所以作为问题发布是我最后的手段。我希望它在我在日志中运行我的应用程序时显示。
Second, where do I input the RGB color number ( R = 30, G = 171, B = 13)? I see that all examples use Array [0], [1], [2] which normally refers to index position, so where do I add the color values?
其次，我在哪里输入 RGB 颜色编号（R = 30，G = 171，B = 13）？我看到所有示例都使用 Array [0], [1], [2] 通常指的是索引位置，那么我在哪里添加颜色值？
I have this code:
我有这个代码：
- (NSString *) hexFromUIColor:(UIColor *)color {
if (CGColorGetNumberOfComponents(color.CGColor) < 4) {
const CGFloat *components = CGColorGetComponents(color.CGColor);
color = [UIColor colorWithRed:components[30] green:components[141] blue:components[13] alpha:components[1]];
}
if (CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor)) != kCGColorSpaceModelRGB) {
return [NSString stringWithFormat:@"#FFFFFF"];
}
return [NSString stringWithFormat:@"#%02X%02X%02X", (int)((CGColorGetComponents(color.CGColor))[0]*255.0), (int)((CGColorGetComponents(color.CGColor))[1]*255.0), (int)((CGColorGetComponents(color.CGColor))[2]*255.0)];
}
Links I have checked:
我检查过的链接：
How to convert HEX RGB color codes to UIColor?
I have tried to call the method in viewDidLoad however it wont work without UIColor. I am sure it's something simple.
我曾尝试在 viewDidLoad 中调用该方法，但是如果没有 UIColor 它将无法工作。我相信这很简单。
Thanks to anyone who answers.
感谢任何回答的人。
What is the code I use in my viewDidLoad to call to this method in order to display in NSLog?
我在 viewDidLoad 中使用什么代码来调用此方法以便在 NSLog 中显示？
回答by Kampai
Swift 5:
斯威夫特 5：
func hexStringFromColor(color: UIColor) -> String {
let components = color.cgColor.components
let r: CGFloat = components?[0] ?? 0.0
let g: CGFloat = components?[1] ?? 0.0
let b: CGFloat = components?[2] ?? 0.0
let hexString = String.init(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))
print(hexString)
return hexString
}
func colorWithHexString(hexString: String) -> UIColor {
var colorString = hexString.trimmingCharacters(in: .whitespacesAndNewlines)
colorString = colorString.replacingOccurrences(of: "#", with: "").uppercased()
print(colorString)
let alpha: CGFloat = 1.0
let red: CGFloat = self.colorComponentFrom(colorString: colorString, start: 0, length: 2)
let green: CGFloat = self.colorComponentFrom(colorString: colorString, start: 2, length: 2)
let blue: CGFloat = self.colorComponentFrom(colorString: colorString, start: 4, length: 2)
let color = UIColor(red: red, green: green, blue: blue, alpha: alpha)
return color
}
func colorComponentFrom(colorString: String, start: Int, length: Int) -> CGFloat {
let startIndex = colorString.index(colorString.startIndex, offsetBy: start)
let endIndex = colorString.index(startIndex, offsetBy: length)
let subString = colorString[startIndex..<endIndex]
let fullHexString = length == 2 ? subString : "\(subString)\(subString)"
var hexComponent: UInt32 = 0
guard Scanner(string: String(fullHexString)).scanHexInt32(&hexComponent) else {
return 0
}
let hexFloat: CGFloat = CGFloat(hexComponent)
let floatValue: CGFloat = CGFloat(hexFloat / 255.0)
print(floatValue)
return floatValue
}
How to use
如何使用
let red = CGFloat(30.0)
let green = CGFloat(171.0)
let blue = CGFloat(13.0)
let alpha = CGFloat(1.0)
let color = UIColor(red: CGFloat(red/255.0), green: CGFloat(green/255.0), blue: CGFloat(blue / 255.0), alpha: alpha)
let colorCode = self.hexStringFromColor(color: color)
print(colorCode)
let resultColor = self.colorWithHexString(hexString: colorCode)
print(resultColor)
Objective-C:
目标-C：
- (NSString *)hexStringFromColor:(UIColor *)color {
const CGFloat *components = CGColorGetComponents(color.CGColor);
CGFloat r = components[0];
CGFloat g = components[1];
CGFloat b = components[2];
return [NSString stringWithFormat:@"#%02lX%02lX%02lX",
lroundf(r * 255),
lroundf(g * 255),
lroundf(b * 255)];
}
After getting hex code string, Call below method to get UIColor
得到十六进制码串后，调用下面的方法得到 UIColor
- (UIColor *) colorWithHexString: (NSString *) hexString
{
NSString *colorString = [[hexString stringByReplacingOccurrencesOfString: @"#" withString: @""] uppercaseString];
NSLog(@"colorString :%@",colorString);
CGFloat alpha, red, blue, green;
// #RGB
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];
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;
}
How to use
如何使用
// ( R = 30, G = 171, B = 13)?
CGFloat red = 30.0;
CGFloat green = 171.0;
CGFloat blue = 13.0;
CGFloat alpha = 255.0
UIColor *color = [UIColor colorWithRed:(red/255.0) green:(green/255.0) blue:(blue/255.0) alpha:(alpha/255.0)];
NSString *colorCode = [self hexStringFromColor:color];
NSLog(@"Color Code: %@", colorCode);
UIColor *resultColor = [self colorWithHexString:colorCode];
回答by Valentin Shergin
And finally the version which works with alpha-component and uses right multiplier
最后是与alpha 组件一起使用并使用正确乘数的版本
extension UIColor {
var hexString: String? {
var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0
let multiplier = CGFloat(255.999999)
guard self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) else {
return nil
}
if alpha == 1.0 {
return String(
format: "#%02lX%02lX%02lX",
Int(red * multiplier),
Int(green * multiplier),
Int(blue * multiplier)
)
}
else {
return String(
format: "#%02lX%02lX%02lX%02lX",
Int(red * multiplier),
Int(green * multiplier),
Int(blue * multiplier),
Int(alpha * multiplier)
)
}
}
}
回答by Jeff
Kampai's answer works for RGB colors, but not for monochrome (UIColor colorWithWhite:alpha:). It also doesn't handle alpha, which HEX supports. Here's a slightly modified version of hexStringFromColor:
Kampai 的答案适用于 RGB 颜色，但不适用于单色 (UIColor colorWithWhite:alpha:)。它也不处理 HEX 支持的 alpha。这是 hexStringFromColor 的一个稍微修改的版本：
+ (NSString *)hexStringFromColor:(UIColor *)color
{
CGColorSpaceModel colorSpace = CGColorSpaceGetModel(CGColorGetColorSpace(color.CGColor));
const CGFloat *components = CGColorGetComponents(color.CGColor);
CGFloat r, g, b, a;
if (colorSpace == kCGColorSpaceModelMonochrome) {
r = components[0];
g = components[0];
b = components[0];
a = components[1];
}
else if (colorSpace == kCGColorSpaceModelRGB) {
r = components[0];
g = components[1];
b = components[2];
a = components[3];
}
return [NSString stringWithFormat:@"#%02lX%02lX%02lX%02lX",
lroundf(r * 255),
lroundf(g * 255),
lroundf(b * 255),
lroundf(a * 255)];
}
回答by m_katsifarakis
Other Swift answers crash for UIColors like white, where there are only 2 components returned by CGColor.
UIColors 的其他 Swift 答案会崩溃，例如白色，其中 CGColor 仅返回 2 个组件。
Here's a Swift 4version that does not have that problem and also returns transparency information in the end of the string if that is required (web format).
这是一个没有这个问题的Swift 4版本，如果需要（网络格式），还会在字符串的末尾返回透明度信息。
The color is first converted to the sRGB colorspace before generating the HEX String to work properly even with Grayscale or other color spaces.
在生成 HEX 字符串之前，颜色首先转换为 sRGB 颜色空间，即使使用灰度或其他颜色空间也能正常工作。
For example:
例如：
White will return #FFFFFF
白色将返回#FFFFFF
White with 50% opacity will return #FFFFFF7F
不透明度为 50% 的白色将返回#FFFFFF7F
extension UIColor {
var hexString: String {
let cgColorInRGB = cgColor.converted(to: CGColorSpace(name: CGColorSpace.sRGB)!, intent: .defaultIntent, options: nil)!
let colorRef = cgColorInRGB.components
let r = colorRef?[0] ?? 0
let g = colorRef?[1] ?? 0
let b = ((colorRef?.count ?? 0) > 2 ? colorRef?[2] : g) ?? 0
let a = cgColor.alpha
var color = String(
format: "#%02lX%02lX%02lX",
lroundf(Float(r * 255)),
lroundf(Float(g * 255)),
lroundf(Float(b * 255))
)
if a < 1 {
color += String(format: "%02lX", lroundf(Float(a * 255)))
}
return color
}
}
OLD VERSION
旧版本
This version did not work properly with certain colors in non-RGB color spaces.
此版本无法在非 RGB 颜色空间中使用某些颜色正常工作。
extension UIColor {
var hexString: String {
let colorRef = cgColor.components
let r = colorRef?[0] ?? 0
let g = colorRef?[1] ?? 0
let b = ((colorRef?.count ?? 0) > 2 ? colorRef?[2] : g) ?? 0
let a = cgColor.alpha
var color = String(
format: "#%02lX%02lX%02lX",
lroundf(Float(r * 255)),
lroundf(Float(g * 255)),
lroundf(Float(b * 255))
)
if a < 1 {
color += String(format: "%02lX", lroundf(Float(a)))
}
return color
}
}
回答by Joel Kopelioff
In Swift, I simply created an extension to UIColor...
在 Swift 中，我只是为 UIColor 创建了一个扩展......
extension UIColor
{
var hexString:NSString {
let colorRef = CGColorGetComponents(self.CGColor)
let r:CGFloat = colorRef[0]
let g:CGFloat = colorRef[1]
let b:CGFloat = colorRef[2]
return NSString(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)), lroundf(Float(b * 255)))
}
}
回答by Isuru
Swift 2 version of the accepted answer. I converted into a UIColorextension.
已接受答案的 Swift 2 版本。我转换成UIColor扩展。
extension UIColor {
var hexString: String {
let components = CGColorGetComponents(self.CGColor)
let red = Float(components[0])
let green = Float(components[1])
let blue = Float(components[2])
return String(format: "#%02lX%02lX%02lX", lroundf(red * 255), lroundf(green * 255), lroundf(blue * 255))
}
}
回答by MrG
This is the correct order if you need the colors for Android. the alpha goes first:
如果您需要 Android 的颜色，这是正确的顺序。阿尔法先行：
extension UIColor {
var hexString: String? {
var red: CGFloat = 0
var green: CGFloat = 0
var blue: CGFloat = 0
var alpha: CGFloat = 0
let multiplier = CGFloat(255.999999)
guard self.getRed(&red, green: &green, blue: &blue, alpha: &alpha) else {
return nil
}
if alpha == 1.0 {
return String(
format: "#%02lX%02lX%02lX",
Int(red * multiplier),
Int(green * multiplier),
Int(blue * multiplier)
)
}
else {
return String(
format: "#%02lX%02lX%02lX%02lX",
Int(alpha * multiplier),
Int(red * multiplier),
Int(green * multiplier),
Int(blue * multiplier)
)
}
}
}
Then call as:
然后调用为：
debugPrint("testColor > ", self.testColor().hexString!)
回答by Artem Sydorenko
Swift way:
快捷方式：
extension UIColor {
var hexString: String {
cgColor.components![0..<3]
.map { String(format: "%02lX", Int( var hexString: String {
var r: CGFloat = 0, g: CGFloat = 0, b: CGFloat = 0
getRed(&r, green: &g, blue: &b, alpha: nil)
return [r, g, b].map { String(format: "%02lX", Int(var hexString: String {
let components = self.cgColor.components
let red = Float((components?[0])!)
let green = Float((components?[1])!)
let blue = Float((components?[2])!)
return String(format: "#%02lX%02lX%02lX", lroundf(red * 255), lroundf(green * 255), lroundf(blue * 255))
}
* 255)) }.reduce("#", +)
}
* 255)) }
.reduce("#", +)
}
}
If you need hex with alpha just remove [0..<3]from code.
如果您需要带 alpha 的十六进制，只需[0..<3]从代码中删除。
Another safer implementation, that works fine with one component colors (like UIColor.white, UIColor.black):
另一个更安全的实现，它适用于一个组件颜色（如 UIColor.white、UIColor.black）：
+(NSString*)hexStringFromColor:(UIColor *)color
{
CGFloat r = 0, g = 0, b = 0, a = 1;
if (color) {
[color getRed:&r green:&g blue:&b alpha:&a];
}
return [NSString stringWithFormat:@"#%02lX%02lX%02lX%02lX",
lroundf(a * 255.0),
lroundf(r * 255.0),
lroundf(g * 255.0),
lroundf(b * 255.0)
];
}
回答by Haris
The swift 2 answer converted to swift 3
swift 2 的答案转换为 swift 3
##代码##回答by Grant Luck
Potential Trap When Dealing With Alpha: HEX strings come in different formats, some have their alpha at the start of the hex string and other formats have it at the end. Depending on your background you may have a different idea of how the hex string is formatted. For Android developers it will likely be with the alpha at the start, for Web developers it will likely be at the end of the string. SO ALWAYS STATE THE FORMAT OF THE HEX STRINGto avoid confusion. Android hex strings are required to have the alpha at the start. So that is a trap people may fall into when it comes to hex strings (I did) and is thus important to say what the expected format is. So if you are developing an app for both iOS and Android what out for this trap.
处理 Alpha 时的潜在陷阱：十六进制字符串有不同的格式，有些在十六进制字符串的开头有它们的 alpha，而其他格式在末尾有它。根据您的背景，您可能对十六进制字符串的格式有不同的看法。对于 Android 开发人员，它可能会在开头带有 alpha，对于 Web 开发人员，它可能会在字符串的末尾。所以一定要说明十六进制字符串的格式以避免混淆。Android 十六进制字符串需要以字母开头。因此，这是人们在使用十六进制字符串时可能陷入的陷阱（我做到了），因此重要的是要说明预期的格式是什么。因此，如果您正在为 iOS 和 Android 开发应用程序，请注意这个陷阱。
Links: https://en.wikipedia.org/wiki/RGBA_color_spacefor details on why a HEX string maybe formatted in different ways, some cases with the alpha at the start. Android links https://developer.android.com/reference/android/graphics/Color.htmland https://gist.github.com/lopspower/03fb1cc0ac9f32ef38f4
链接：https: //en.wikipedia.org/wiki/RGBA_color_space详细了解为什么 HEX 字符串可能以不同方式格式化，某些情况下以 alpha 开头。Android 链接https://developer.android.com/reference/android/graphics/Color.html和https://gist.github.com/lopspower/03fb1cc0ac9f32ef38f4
PLEASE NOTE FOR #AARRGGBBHex string format Use the following code so the Alpha is at the start of the string.
请注意 #AARRGGBB十六进制字符串格式 使用以下代码使 Alpha 位于字符串的开头。
(Note: if color == nullblack is returned).
（注意：如果color == null返回黑色）。
