Android : send byte with bluetooth

I would like to send a byte via bluetooth but can not figure out how to change my java code. My code sends a string and not a byte, but if I try to change it gives me error the Activity Main. This is the code:

public void write(String income) {

        try {
            mmOutStream.write(income.getBytes());
            for(int i=0;i<income.getBytes().length;i++)
            Log.v("outStream"+Integer.toString(i),Character.toString((char)(Integer.parseInt(Byte.toString(income.getBytes()[i])))));
            try {
                Thread.sleep(20);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        } catch (IOException e) { }
}

I tried to change so

 public void write(byte[] bytes) {

    try {

        mmOutStream.write(bytes);

    } catch (IOException e) { }

}

but in the MainActivity get this error:

The method write(byte[]) is undefined for the type Bluetooth

and this is the comand

Bluetooth.write(new byte[]{(byte) prova});

can anyone help me? Thanks.