When I first jumped into Android development, I went in with a mindset for developing desktop applications. That was a mistake. I think I would have been able to wrap my head around it quicker if I’d thought of it more like web application development. In particular, Activities have to account for a certain amount of statelessness. And users never close or stop an Activity—they just start doing something else. It starts to make sense a lot quicker if you think of Activity classes as web pages.