Can a guy really like you, but never talk to you?

There is this guy that I like. I’ve been told he likes me too, but I’m not convinced. We are both really shy. He stares at me a lot & when I see him he looks away really fast & pretends to be doing something else. When we pass each other in the hallway he looks down at the floor, messes with his hair, or he walks by really fast. If he is with his friends they always hit him or something & and he looks up at me, but looks away really fast. His friends I don’t even know are always staring at me or they whisper about me as I walk by. His one friend always does stuff like this. Today he walked past my table at lunch & as I looked up he made eye contact with me the whole time he walked by. He always looks back at me or starts talking to some other guys I don’t know when I walk by. I don’t even know him. The guy I like never talks to me though. Even when I have said stuff to him he looks at the ground and gives short quick responses. I always hear that if a guy likes you they will always try to talk to you and be by you. If I’m talking to one of his friends he stays off to the side & waits for me to leave before he comes over. He used to sit in front of me & he would always lean back to try & crack his back, but he would lean really far back that he almost hit my head with his. He would always lean on my desk & stuff like that. I noticed that he doesn’t do this stuff to the girl he sits in front of now. I always though that if he did like me he would start to talk to me by now. I mean we’ve had the same class since August and schools out in less than a month. He’s always doing stuff like this, but he won’t talk to me even if I talk to him. Can guys still like a girl even if they don’t talk to them? How can I show him that I do like him; since we’re both really shy?