16进制颜色(html颜色值)字符串转为UIColor

最新推荐文章于 2021-07-03 04:18:36 发布

原创最新推荐文章于 2021-07-03 04:18:36 发布 · 437 阅读

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本文介绍了一种将十六进制颜色字符串转换为UIColor对象的方法。该方法首先对输入字符串进行预处理，移除可能存在的'#'或'0X'前缀，并将其转换为大写形式。随后分离出红色、绿色和蓝色部分对应的子字符串，利用NSScanner扫描这些子字符串并解析为十六进制整数。最后，将这些整数值转换为0到1之间的浮点数，用于创建并返回UIColor对象。

+ (UIColor *)colorWithHexString: (NSString *) stringToConvert
    {
    NSString *cString = [[stringToConvertstringByTrimmingCharactersInSet:[NSCharacterSetwhitespaceAndNewlineCharacterSet]] uppercaseString];

    // String should be 6 or 8 characters
    if ([cString length] < 6) returnDEFAULT_VOID_COLOR;

    // strip 0X if it appears
    if ([cString hasPrefix:@"0X"]) cString = [cStringsubstringFromIndex:2];
    f ([cString hasPrefix:@"#"]) cString = [cStringsubstringFromIndex:1];
    if ([cString length] != 6) return DEFAULT_VOID_COLOR;
    // Separate into r, g, b substrings
    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];

    // 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];
    }