iOS 16进制颜色的宏

iOS 16进制颜色的宏

// 参数格式为：0xFFFFFF 16进制
#define kColorWithRGB(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]

kColorWithRGB(0xFF0000); 相当于 [UIColor redColor];

// 参数格式为：222,222,222

#define UIColorWithRGB(r, g, b) [UIColor colorWithRed:(r) / 255.f green:(g) / 255.f blue:(b) / 255.f alpha:1.f]

很多地方我们都使用16进制颜色，但iPhone使用的是UIColor对象，不直接支持16进制颜色，为此，需要我们手动将16进制颜色转换为UIColor。

- (UIColor *)getColor:(NSString*)hexColor

{

unsigned int red,green,blue;

NSRange range;

range.length = 2;

range.location = 0;

[[NSScanner scannerWithString:[hexColor substringWithRange:range]]scanHexInt:&red];

range.location = 2;

[[NSScanner scannerWithString:[hexColor substringWithRange:range]]scanHexInt:&green];

range.location = 4;

[[NSScanner scannerWithString:[hexColor substringWithRange:range]]scanHexInt:&blue];

return [UIColor colorWithRed:(float)(red/255.0f)green:(float)(green / 255.0f) blue:(float)(blue / 255.0f)alpha:1.0f];

}

[self.view setBackgroundColor:[self getColor:@"FF0000"]];

个面试题：使用内联函数把@“#ff3344”转成UIColor

- (UIColor *) stringTOColor:(NSString *)str
{
    if (!str || [str isEqualToString:@""]) {
        return nil;
    }
    unsigned red,green,blue;
    NSRange range;
    range.length = 2;
    range.location = 1;
    [[NSScanner scannerWithString:[str substringWithRange:range]] scanHexInt:&red];
    range.location = 3;
    [[NSScanner scannerWithString:[str substringWithRange:range]] scanHexInt:&green];
    range.location = 5;
    [[NSScanner scannerWithString:[str substringWithRange:range]] scanHexInt:&blue];
    UIColor *color= [UIColor colorWithRed:red/255.0f green:green/255.0f blue:blue/255.0f alpha:1];
    return color;
}

0xFF0000 或 #FF0000（#为特殊字符有可能把这种为空）或FF0000

+ (UIColor *) colorWithHexString: (NSString *)color
{
    NSString *cString = [[color stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];

    // String should be 6 or 8 characters
    if ([cString length] < 6) {
        return [UIColor clearColor];
    }

    // strip 0X if it appears
    if ([cString hasPrefix:@"0X"])
        cString = [cString substringFromIndex:2];
    if ([cString hasPrefix:@"#"])
        cString = [cString substringFromIndex:1];
    if ([cString length] != 6)
        return [UIColor clearColor];

    // Separate into r, g, b substrings
    NSRange range;
    range.location = 0;
    range.length = 2;

    //r
    NSString *rString = [cString substringWithRange:range];

    //g
    range.location = 2;
    NSString *gString = [cString substringWithRange:range];

    //b
    range.location = 4;
    NSString *bString = [cString substringWithRange:range];

    // Scan values
    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];
}