iOS根据hex值获取颜色UIColor

在开发过程中，很多时候设计给我都是hex格式的颜色值，那么我们这个转成我们需要RGB颜色。

2710245-35d6e212c015af5b.png 2710245-fb982ecbb363a16c.jpg

• 在转换过程中，其实hex值如果是16进制的字符串的话，那么会有固定的长度，如果抛开可能会出现的#，0x的话，那么可能出现的字符长度就是3，6，8.长度是3的话，其实应该是6我们要按位重复添加比如345，那么应该转换成334455，然后获取颜色值。
  8位长度的其实包括alpha的值，在前两位。
  一般我们都是将16进制的颜色值，根据固定的位置取出颜色值，依次是alpha,red,green,blue.
• 还有一种是10进制的颜色值。

设置颜色相关宏定义

#define ssRGB(r, g, b)             [UIColor colorWithRed:((r) / 255.0) green:((g) / 255.0) blue:((b) / 255.0) alpha:1.0]
#define ssRGBAlpha(r, g, b, a)     [UIColor colorWithRed:((r) / 255.0) green:((g) / 255.0) blue:((b) / 255.0) alpha:(a)]

十六进制颜色 Hex

#define ssRGBHex(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]
#define ssRGBHexAlpha(rgbValue,a) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:(a)]

十进制的颜色转换

///十进制的颜色转换
+ (UIColor *)colorWithHex:(NSInteger)hex {
    return [UIColor colorWithRed:((float)((hex & 0xff0000) >> 16))/255.0 green:((float)((hex & 0x00ff00) >> 8))/255.0 blue:((float)(hex & 0x0000ff))/255.0 alpha:1.0];
}

16进制值转换成颜色

///将hex值转换成颜色
+(UIColor*)colorFromHex:(NSString*)hex{
    NSString * newHex = hex;
    if ([newHex hasPrefix:@"#"]) {
        newHex = [newHex substringFromIndex:1];
    }
    if ([newHex hasPrefix:@"0x"]) {
        newHex = [newHex substringFromIndex:2];
    }
    if (newHex.length != 3 && newHex.length != 6 && newHex.length != 8 && newHex.length < 3) {
        return UIColor.clearColor;
    }
    NSRange range = NSMakeRange(0, 2);
    unsigned int alpha = 255,red = 0,green = 0,blue = 0;
    //Check for short hex strings
    if(newHex.length == 3) {
        //Convert to full length hex string
        newHex = [NSString stringWithFormat:@"%@%@%@%@%@%@",
                  [newHex substringWithRange:NSMakeRange(0, 1)],[newHex substringWithRange:NSMakeRange(0, 1)],
                  [newHex substringWithRange:NSMakeRange(1, 1)],[newHex substringWithRange:NSMakeRange(1, 1)],
                  [newHex substringWithRange:NSMakeRange(2, 1)],[newHex substringWithRange:NSMakeRange(2, 1)]];
    }
    
    if (newHex.length == 8) {
        NSString * alphaStr = [newHex substringWithRange:range];
        range.location = 2;
        NSString * redStr = [newHex substringWithRange:range];
        range.location = 4;
        NSString * greenStr = [newHex substringWithRange:range];
        range.location = 6;
        NSString * blueStr = [newHex substringWithRange:range];
        [[NSScanner scannerWithString:alphaStr] scanHexInt:&alpha];
        [[NSScanner scannerWithString:redStr] scanHexInt:&red];
        [[NSScanner scannerWithString:greenStr] scanHexInt:&green];
        [[NSScanner scannerWithString:blueStr] scanHexInt:&blue];
        return [UIColor colorWithRed:[self transferColorValue:red] green:[self transferColorValue:green] blue:[self transferColorValue:blue] alpha:[self transferColorValue:alpha]];
    }
    
    if (newHex.length == 6) {
        NSString * redStr = [newHex substringWithRange:range];
        range.location = 2;
        NSString * greenStr = [newHex substringWithRange:range];
        range.location = 4;
        NSString * blueStr = [newHex substringWithRange:range];
        [[NSScanner scannerWithString:redStr] scanHexInt:&red];
        [[NSScanner scannerWithString:greenStr] scanHexInt:&green];
        [[NSScanner scannerWithString:blueStr] scanHexInt:&blue];
        return [UIColor colorWithRed:[self transferColorValue:red] green:[self transferColorValue:green] blue:[self transferColorValue:blue] alpha:[self transferColorValue:alpha]];
        
    }
    
    return UIColor.clearColor;
}

+(CGFloat)transferColorValue:(unsigned int)value{
    
    return value/255.0;
}

下面是另一种写法

+(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:
            blue=0;
            green=0;
            red=0;
            alpha=0;
            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

• 将颜色转成hex值

///将颜色转成hex值
- (NSString *)hexString {
    
    const CGFloat * value =  CGColorGetComponents(self.CGColor);
    CGFloat alpha =  CGColorGetAlpha(self.CGColor);
    CGFloat red, green, blue;
    
    
    red = roundf(value[0] * 255.f);
    green = roundf(value[1] * 255.f);
    blue = roundf(value[2] * 255.f);
    alpha = roundf(alpha * 255.f);
    
    uint hex = ((uint)alpha << 24) | ((uint)red << 16) | ((uint)green << 8) | ((uint)blue);
    NSLog(@"%u",hex);
    return [NSString stringWithFormat:@"#%08x", hex];
}

获取颜色的RGB值

+ (NSArray *)convertColorToRGB:(UIColor *)color {
    NSInteger numComponents = CGColorGetNumberOfComponents(color.CGColor);
    NSArray *array = nil;
    if (numComponents == 4) {
        const CGFloat *components = CGColorGetComponents(color.CGColor);
        array = @[@((int)(components[0] * 255)),
                  @((int)(components[1] * 255)),
                  @((int)(components[2] * 255))];
    }
    return array;
}