我如何从十六进制字符串格式创建一个UIColor，如#00FF00?
当前回答
您可以使用各种在线工具将HEX字符串转换为实际的UIColor。查看uicolor.org或UI颜色选择器。输出将被转换为Objective-C代码，如下所示:
[UIColor colorWithRed:0.93 green:0.80 blue:0.80 alpha:1.0];
可以嵌入到应用程序中。希望这能有所帮助!
其他回答
我最终为UIColor创建了一个类别，我可以在我的其他项目中重用，并添加了这个函数:
+ (UIColor *)colorFromHex:(unsigned long)hex
{
return [UIColor colorWithRed:((float)((hex & 0xFF0000) >> 16))/255.0
green:((float)((hex & 0xFF00) >> 8))/255.0
blue:((float)(hex & 0xFF))/255.0
alpha:1.0];
}
用法是这样的:
UIColor *customRedColor = [UIColor colorFromHex:0x990000];
这比传递字符串并将其转换为数字然后移位位要快得多。
你也可以从你的.pch文件中导入类别，这样你就可以很容易地在你的应用程序中到处使用colorFromHex，就像它内置到UIColor中一样:
#ifdef __OBJC__
#import <UIKit/UIKit.h>
#import <Foundation/Foundation.h>
// Your other stuff here...
#import "UIColor+HexColor.h"
#endif
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)
}
}
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.
大多数发布的解决方案使用了Scanner，但至少在现代Swift中你并不真正需要它。相反，你可以简单地使用UInt init和基数16，然后使用基本的二进制操作来获得UIColor组件:
func stringToColor(color: String) -> UIColor {
guard let i = UInt(color, radix: 16) else {
return UIColor.white
}
return UIColor(
red: CGFloat((i & 0xFF0000) >> 16) / 255.0,
green: CGFloat((i & 0xFF00) >> 8) / 255.0,
blue: CGFloat(i & 0xFF) / 255.0,
alpha: 1.0
)
}
这个解决方案期望输入像“FF00FF”，你可能需要删除前面的哈希符号(#)，如果你的字符串中有一个。
我发现最简单的方法是使用宏。只要把它包括在你的标题中，它就可以在你的整个项目中使用。
#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]
Uicolor宏十六进制值
这段代码的格式化版本:
#define UIColorFromRGB(rgbValue) \
[UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 \
green:((float)((rgbValue & 0x00FF00) >> 8))/255.0 \
blue:((float)((rgbValue & 0x0000FF) >> 0))/255.0 \
alpha:1.0]
用法:
label.textColor = UIColorFromRGB(0xBC1128);
迅速:
static func UIColorFromRGB(_ rgbValue: Int) -> UIColor! {
return UIColor(
red: CGFloat((Float((rgbValue & 0xff0000) >> 16)) / 255.0),
green: CGFloat((Float((rgbValue & 0x00ff00) >> 8)) / 255.0),
blue: CGFloat((Float((rgbValue & 0x0000ff) >> 0)) / 255.0),
alpha: 1.0)
}
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