我已经检查了几个关于如何将 UIColor 代码转换为十六进制的链接,但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。我希望它在日志中运行我的应用程序时显示。
其次,我在哪里输入RGB色号(R = 30,G = 171,B = 13(?我看到所有示例都使用数组 [0]、[1]、[2],它通常是指索引位置,那么我在哪里添加颜色值呢?
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)];
}
我检查过的链接:
来自 uicolor 的十六进制颜色
如何将十六进制 RGB 颜色代码转换为 UIColor?
我尝试在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。
感谢任何回答的人。
我在 viewDidLoad 中使用什么代码来调用此方法以便在 NSLog 中显示?
Swift 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
}
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)
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)];
}
获取十六进制代码字符串后,调用下面的方法以获取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;
}
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];
最后是使用 alpha 分量并使用右乘数的版本
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)
)
}
}
}
> 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。下面是hexStringFromColor的略微修改版本:
+ (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)];
}
其他 Swift 回答 UI 像 white 这样的 UIColors 崩溃,其中 CGColor 只返回了 2 个组件。
这是一个 Swift 4 版本,它没有这个问题,如果需要,还会在字符串末尾返回透明度信息(Web 格式(。
在生成十六进制字符串之前,首先将颜色转换为 sRGB 颜色空间,以便即使在灰度或其他颜色空间中也能正常工作。
例如:
白色会回来 #FFFFFF
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
}
}
旧版本
此版本无法在非 RGB 色彩空间中正确处理某些颜色。
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
}
}
Swift way:
extension UIColor {
var hexString: String {
cgColor.components![0..<3]
.map { String(format: "%02lX", Int($0 * 255)) }
.reduce("#", +)
}
}
如果您需要带有 alpha 的十六进制,只需从代码中删除[0..<3]
即可。
另一个更安全的实现,可以很好地处理一种组件颜色(如UIColor.white,UIColor.black(:
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($0 * 255)) }.reduce("#", +)
}
extension UIColor {
var hexString: String? {
guard let components = self.cgColor.components else { return nil }
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))
}
}
在 Swift 中,我只是简单地创建了一个 UIColor 的扩展......
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)))
}
}
基于Kampai的回答,这里是SwiftUI版本。
extension Color {
func hexString() -> String {
let components = self.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)))
return hexString
}
}
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)
)
}
}
}
然后调用:
debugPrint("testColor > ", self.testColor().hexString!)
,如果将此扩展用于UIColor,则可以使用.hexCode
。
喜欢这个:
extension UIColor {
var hexCode: String {
get{
let colorComponents = self.cgColor.components!
if colorComponents.count < 4 {
return String(format: "%02x%02x%02x", Int(colorComponents[0]*255.0), Int(colorComponents[0]*255.0),Int(colorComponents[0]*255.0)).uppercased()
}
return String(format: "%02x%02x%02x", Int(colorComponents[0]*255.0), Int(colorComponents[1]*255.0),Int(colorComponents[2]*255.0)).uppercased()
}
}
}
var myColor: UIColor?
myColor = UIColor(red: 1, blue: 1, green: 1, alpha: 1.0)
print(myColor!.hexCode) // output:
// if you use API, you can do something like this:
print("#(myColor!.hexCode)") // output: #FFFFFF
swift 2 答案转换为 swift 3
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))
}
alpha 时的潜在陷阱:十六进制字符串有不同的格式,有些格式的 alpha 位于十六进制字符串的开头,而其他格式的字母位于末尾。根据您的背景,您可能对十六进制字符串的格式有不同的想法。对于Android开发人员来说,它可能会在开始时与alpha一起,对于Web开发人员来说,它可能在字符串的末尾。因此,请始终说明十六进制字符串的格式以避免混淆。Android 十六进制字符串必须在开头包含 alpha。因此,当涉及到十六进制字符串时,这是人们可能会陷入的陷阱(我做到了(,因此说出预期的格式很重要。因此,如果您正在为iOS和Android开发应用程序,那么这个陷阱会怎样。
链接:https://en.wikipedia.org/wiki/RGBA_color_space 有关为什么十六进制字符串可能以不同方式格式化的详细信息,在某些情况下,alpha 在开头。安卓链接 https://developer.android.com/reference/android/graphics/Color.html 和 https://gist.github.com/lopspower/03fb1cc0ac9f32ef38f4
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。
(注意:如果返回color == null
黑色(。
+(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)
];
}
SwiftUI
P3 颜色到十六进制
extension Color {
var hex: String {
guard let colorSpace = CGColorSpace(name: CGColorSpace.displayP3), let color = UIColor(self).cgColor.converted(to: colorSpace, intent: .defaultIntent, options: nil),
let components = color.components, 3 <= components.count else { return "" }
return String(format: "#%02lX%02lX%02lX%02lX", lroundf(Float(components[0] * 255)), lroundf(Float(components[1] * 255)), lroundf(Float(components[2] * 255)), lroundf(Float(components[3] * 255)))
}
}
Swift 5
extension Collection {
public subscript(safe index: Index) -> Element? {
return startIndex <= index && index < endIndex ? self[index] : nil
}
}
extension UIColor {
var hexString: String {
let components = cgColor.components
let r: CGFloat = components?[safe: 0] ?? 0.0
let g: CGFloat = components?[safe: 1] ?? 0.0
let b: CGFloat = components?[safe: 2] ?? 0.0
let hexString = String(format: "#%02lX%02lX%02lX", lroundf(Float(r * 255)), lroundf(Float(g * 255)),
lroundf(Float(b * 255)))
return hexString
}
}