If I take the battery out of an android and put it back in will I lose my contacts, photos, etc?

My phone is stuck. All I have is a black screen showing the time and date, with the time not updating. It's almost an hour behind now. I can't get it off of that screen, and it won't even turn off. I'm tempted to take the battery out but I'm afraid I might lose everything. Does anybody have another suggestion?