My bike has sat for one year. I bought a new battery one year ago and drove it from my old apartment to my current one. The bike has not been started for one year. I got a used gas tank on ebay and just installed it. I just charged up the battery and put gas in the new tank. It clicked but would not turn over. I tried it until the battery died.

Ok mate few things to consider here, if the bike has been non started and stationary for a year there is a very good chance that one of the following or all of the following has occurred.
Your battery is dead (they don't like just sitting - doesn't matter new or old, if left for extensive time they will die) Your gear / motor oil would be useless - oil can not just sit in bottom of bike for a year it would be glue
Your carbi would be blocked or partially blocked from fuel gum or varnish in jets
If you like this bike I highly recommend oil and filter change, New spark plug (put about 10 drops of oil down the spark plug hole before you put new spark plug back in to lube the piston) clean air filter (or fit new one) Remove carbi and compressed air clean all jets especially the pilot jet and circuit and stick in a new battery
Once all done for the fist start I would find a nice safe hill and push start it. in my experience under this circumstances if you rely on the electric starter you may find you burn it out trying to start so give at least few minutes running motor to flush everything through before trying to electric start would be your best bet
When you get it going I would dump the oil and oil filter again after 2 hours ride time to confirm all the old expired oil is flushed out - just to be safe
good luck regards Jamie