将色值转换成 UIColor

在日常开发中常常需要将一些特定的字符串转换成颜色值, 例如#898989, 下面就是一个小 Demo 将字符串转换成色值!

NSString *cString = [[colorStr stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString];
    if ([cString hasPrefix:@"#"]) {
    
        cString = [cString substringFromIndex:1];
    }
    if ([cString length] != 6) {
    
        return [UIColor blackColor];
    }
    
    // 开始分离 RGB 颜色
    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;
    
    // 将16进制转换成10进制
    [[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];

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另外还可以用宏定义快速实现获取 color

#define UIColorFromRGB(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 UIColorFromRGBA(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])

 

eg: UIColorFromRGB(0x898989)