将值转换为二进制，然后翻转Java中的所有位

Question

First of all i receive a hex color code from a parameter 'col'. I then convert this value to the binary equivalent and then need to flip all the bits and convert it back to the hex value. Then the hex value needs to be padded out to 6 characters.

public String invertColor(String col)
{
    String inverted = col;

    int i = Integer.parseInt(inverted, 16);
    String bin = Integer.toBinaryString(i);
    System.out.println(bin);

    int binary = Integer.parseInt(bin,2);
    System.out.println(binary);


    return inverted;
}

This is the code i have so far, i have been racking my brains all morning and just cannot seem to get a working solution. Any help at all would be appreciated.

Thanks

Answer 1

使用按位非运算符~ 。

int flipped = ~i;

Answer 2

Are we counting all the 0's preceding the binary representation in 32 bits, or do we only take the binary representation with no preceding 0's? Because that makes a difference when flipping. If it's the former, you can just use the operator ~.

    int flip = ~i;

But if it's the second one, there's a little more work to do.

Answer 3

    public String invertColor(String col)
{
    String inverted = col;
    int i = Integer.parseInt(inverted, 16);
   String bin = Integer.toBinaryString(i);
   String flipped = "";
   for (int j = 0; j < bin.length(); j++) {
     if (bin.charAt(j) == '0') flipped += "1";
     else flipped += "0";
   }
   int k = Integer.parseInt(flipped, 2);
   inverted = Integer.toHexString(k);
   return inverted;

}

This should work. Basically this code builds a string by concatenating 1 if the current character is 0, and 0 otherwise. Then k is the integer represented by the flipped string, and inverted is the hex value.