I called a girl who always answered the phone when she went to the bathroom. Does this mean that she likes me?

Not necessarily. Some people just respect others politely, so they are embarrassed to hang up when the phone comes. It is also possible that this girl is a careless person. I wish I knew I was going to the bathroom. Why should I tell you? But it may mean that she cares about you a little. Treat you like one of our own. Haha, contact more, and good luck to you.