Hey, I am creating a game and currently have 1 activity with a custom view and a thread. I want to show a "new game" dialog menu when the game is over..how would I implement this? Do I need to make my "game view" into a new activity?

I would create a new activity itself for that purpose. Thus you can put into it not only a button, but a message / game rankings / whatever and apply to it wathever theme you want.

When you got the whole new activity created, you should start (or start for result) this new activity when the game reaches it´s end.