我如何从十六进制字符串格式创建一个UIColor,如#00FF00?
当前回答
self.view.backgroundColor = colorWithHex(hex: yourColorCode)
从hexaDecimalCode创建颜色的代码
func colorWithHex (hex:String) -> UIColor {
var cString:String = hex.trimmingCharacters(in: .whitespacesAndNewlines).uppercased()
if (cString.hasPrefix("#")) {
cString.remove(at: cString.startIndex)
}
if ((cString.count) != 6) {
return UIColor.gray
}
var rgbValue:UInt32 = 0
Scanner(string: cString).scanHexInt32(&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
有cocoapod支持,这很好
https://github.com/mRs-/HexColors
// with hash
NSColor *colorWithHex = [NSColor colorWithHexString:@"#ff8942" alpha:1];
// wihtout hash
NSColor *secondColorWithHex = [NSColor colorWithHexString:@"ff8942" alpha:1];
// short handling
NSColor *shortColorWithHex = [NSColor colorWithHexString:@"fff" alpha:1]
我找到了一个很好的UIColor类别,UIColor+PXExtensions。
用法:UIColor *mycolor = [UIColor pxColorWithHexValue:@"#BADA55"];
而且,为了防止链接到我的要点失败,这里是实际的实现代码:
//
// UIColor+PXExtensions.m
//
#import "UIColor+UIColor_PXExtensions.h"
@implementation UIColor (UIColor_PXExtensions)
+ (UIColor*)pxColorWithHexValue:(NSString*)hexValue
{
//Default
UIColor *defaultResult = [UIColor blackColor];
//Strip prefixed # hash
if ([hexValue hasPrefix:@"#"] && [hexValue length] > 1) {
hexValue = [hexValue substringFromIndex:1];
}
//Determine if 3 or 6 digits
NSUInteger componentLength = 0;
if ([hexValue length] == 3)
{
componentLength = 1;
}
else if ([hexValue length] == 6)
{
componentLength = 2;
}
else
{
return defaultResult;
}
BOOL isValid = YES;
CGFloat components[3];
//Seperate the R,G,B values
for (NSUInteger i = 0; i < 3; i++) {
NSString *component = [hexValue substringWithRange:NSMakeRange(componentLength * i, componentLength)];
if (componentLength == 1) {
component = [component stringByAppendingString:component];
}
NSScanner *scanner = [NSScanner scannerWithString:component];
unsigned int value;
isValid &= [scanner scanHexInt:&value];
components[i] = (CGFloat)value / 256.0f;
}
if (!isValid) {
return defaultResult;
}
return [UIColor colorWithRed:components[0]
green:components[1]
blue:components[2]
alpha:1.0];
}
@end
Swift 2.0版本的解决方案,将处理alpha值的颜色和完美的错误处理:
func RGBColor(hexColorStr : String) -> UIColor?{
var red:CGFloat = 0.0
var green:CGFloat = 0.0
var blue:CGFloat = 0.0
var alpha:CGFloat = 1.0
if hexColorStr.hasPrefix("#"){
let index = hexColorStr.startIndex.advancedBy(1)
let hex = hexColorStr.substringFromIndex(index)
let scanner = NSScanner(string: hex)
var hexValue: CUnsignedLongLong = 0
if scanner.scanHexLongLong(&hexValue)
{
if hex.characters.count == 6
{
red = CGFloat((hexValue & 0xFF0000) >> 16) / 255.0
green = CGFloat((hexValue & 0x00FF00) >> 8) / 255.0
blue = CGFloat(hexValue & 0x0000FF) / 255.0
}
else if hex.characters.count == 8
{
red = CGFloat((hexValue & 0xFF000000) >> 24) / 255.0
green = CGFloat((hexValue & 0x00FF0000) >> 16) / 255.0
blue = CGFloat((hexValue & 0x0000FF00) >> 8) / 255.0
alpha = CGFloat(hexValue & 0x000000FF) / 255.0
}
else
{
print("invalid hex code string, length should be 7 or 9", terminator: "")
return nil
}
}
else
{
print("scan hex error")
return nil
}
}
let color: UIColor = UIColor(red:CGFloat(red), green: CGFloat(green), blue:CGFloat(blue), alpha: alpha)
return color
}
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)
}
}
斯威夫特2.0:
将此方法添加到VC或扩展UIColor。
func colorWithHexString (hex:String) -> UIColor {
var cString:String = hex.stringByTrimmingCharactersInSet(NSCharacterSet.whitespaceAndNewlineCharacterSet()).uppercaseString
if (cString.hasPrefix("#")) {
cString = (cString as NSString).substringFromIndex(1)
}
if (cString.characters.count != 6) {
return UIColor.grayColor()
}
let rString = (cString as NSString).substringToIndex(2)
let gString = ((cString as NSString).substringFromIndex(2) as NSString).substringToIndex(2)
let bString = ((cString as NSString).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(r) / 255.0, green: CGFloat(g) / 255.0, blue: CGFloat(b) / 255.0, alpha: CGFloat(1))
}
用法:
loginButton.tintColor = self.colorWithHexString("#be1337")
OR
let hexColor = self.colorWithHexString("#be1337")
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