UIColor *color = [UIColor blueColor];

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

        NSString *alpha = [self getHexByDecimal:CGColorGetAlpha(color.CGColor)*255.0];

        NSString *red = [self getHexByDecimal:components[0]*255.0];

        NSString *green = [self getHexByDecimal:components[1]*255.0];

        NSString *blue = [self getHexByDecimal:components[2]*255.0];

        NSSTring colorStr = [NSString stringWithFormat:@"#%@%@%@%@", alpha, red, green, blue];

/** 十进制转十六进制*/

+ (NSString *)getHexByDecimal:(NSInteger)decimal

{

    NSString *hex =@"";

    NSString *letter;

    NSInteger number;

    for (int i = 0; i<9; i++) {

        number = decimal % 16;

        decimal = decimal / 16;

        switch (number) {

            case 10:

                letter =@"A"; break;

            case 11:

                letter =@"B"; break;

            case 12:

                letter =@"C"; break;

            case 13:

                letter =@"D"; break;

            case 14:

                letter =@"E"; break;

            case 15:

                letter =@"F"; break;

            default:

                letter = [NSString stringWithFormat:@"%ld", number];

        }

        hex = [letter stringByAppendingString:hex];

        if (decimal == 0) {

            break;

        }

    }

    return hex;

}