Set specific bit in byte

Solution 1:

Use the bitwise OR (|) and AND (&) operators. To set a bit, namely turn the bit at pos to 1:

my_byte = my_byte | (1 << pos);   // longer version, or
my_byte |= 1 << pos;              // shorthand

To un-set a bit, or turn it to 0:

my_byte = my_byte & ~(1 << pos);  // longer version, or
my_byte &= ~(1 << pos);           // shorthand

For examples, see Advanced Java/Bitwise Operators

Solution 2:

To set a bit:

myByte |= 1 << bit;

To clear it:

myByte &= ~(1 << bit);

Solution 3:

Just to complement Jon‘s answer and driis‘ answer

To toggle (invert) a bit

    myByte ^= 1 << bit;

Solution 4:

The technique you need is to isolate the chosen bit and either set or clear it. You already have the expression to isolate the bit since you're using that to test it above. You can set the bit by ORing it in, or clear the bit by bitwise AND with the 1's complement of the bit.

boolean setBit;
my_byte = setBit
          ? myByte | (1 << i)
          : myByte & ~(1 << i);

Solution 5:

Please see the class java.util.BitSet that do the job for you.

To set : myByte.set(bit); To reset : myByte.clear(bit); To fill with a bool : myByte.set(bit, b); To get the bool : b = myByte.get(bit); Get the bitmap : byte bitMap = myByte.toByteArray()[0];