iOS中为UIColor创建类别 其中添加了几个常用的方法

// UIColor+UIColor_HexConvert.h

#import

@interface UIColor (HexConvert)

+(UIColor *)colorFromHexString:(NSString*)colorString;

+(NSString*)stringFromColor:(UIColor*)color;

-(void)getRGBComponents:(CGFloat [3])components;

@end

// UIColor+UIColor_HexConvert.m

#import "UIColor+HexConvert.h"

@implementation UIColor (HexConvert)

+(UIColor *)colorFromHexString:(NSString *)colorString

{

NSString *cString = [[colorString stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

if ([cString length] < 6)

return [UIColor whiteColor];

if ([cString hasPrefix:@"#"])

cString = [cString substringFromIndex:1];

if ([cString length] != 6)

return [UIColor whiteColor];

NSRange range;

range.location = 0;

range.length = 2;

NSString *rString = [cString substringWithRange:range];

range.location = 2;

NSString *gString = [cString substringWithRange:range];

range.location = 4;

NSString *bString = [cString substringWithRange:range];

unsigned int r, g, b;

[[NSScanner scannerWithString:rString] scanHexInt:&r];

[[NSScanner scannerWithString:gString] scanHexInt:&g];

[[NSScanner scannerWithString:bString] scanHexInt:&b];

return [UIColor colorWithRed:((float) r / 255.0f)

green:((float) g / 255.0f)

blue:((float) b / 255.0f)

alpha:1.0f];

}

+(NSString *)stringFromColor:(UIColor *)color

{

const CGFloat *cs=CGColorGetComponents(color.CGColor);

NSString *r = [NSString stringWithFormat:@"%@",[self ToHex:cs[0]*255]];

NSString *g = [NSString stringWithFormat:@"%@",[self ToHex:cs[1]*255]];

NSString *b = [NSString stringWithFormat:@"%@",[self ToHex:cs[2]*255]];

return [NSString stringWithFormat:@"#%@%@%@",r,g,b];

}

+(NSString *)ToHex:(int)tmpid

{

NSString *endtmp=@"";

NSString *nLetterValue;

NSString *nStrat;

int ttmpig=tmpid%16;

int tmp=tmpid/16;

switch (ttmpig)

{

case 10:

nLetterValue =@"A";break;

case 11:

nLetterValue =@"B";break;

case 12:

nLetterValue =@"C";break;

case 13:

nLetterValue =@"D";break;

case 14:

nLetterValue =@"E";break;

case 15:

nLetterValue =@"F";break;

default:nLetterValue=[[NSString alloc]initWithFormat:@"%i",ttmpig];

}

switch (tmp)

{

case 10:

nStrat =@"A";break;

case 11:

nStrat =@"B";break;

case 12:

nStrat =@"C";break;

case 13:

nStrat =@"D";break;

case 14:

nStrat =@"E";break;

case 15:

nStrat =@"F";break;

default:nStrat=[[NSString alloc]initWithFormat:@"%i",tmp];

}

endtmp=[[NSString alloc]initWithFormat:@"%@%@",nStrat,nLetterValue];

return endtmp;

}

- (void)getRGBComponents:(CGFloat [3])components

{

CGColorSpaceRef rgbColorSpace = CGColorSpaceCreateDeviceRGB();

unsigned char resultingPixel[4];

CGContextRef context = CGBitmapContextCreate(&resultingPixel,

1,

1,

8,

4,

rgbColorSpace,

(CGBitmapInfo)kCGImageAlphaNoneSkipLast);

CGContextSetFillColorWithColor(context, [self CGColor]);

CGContextFillRect(context, CGRectMake(0, 0, 1, 1));

CGContextRelease(context);

CGColorSpaceRelease(rgbColorSpace);

for (int component = 0; component < 3; component++) {

components[component] = resultingPixel[component] / 255.0f;

}

}

@end