介绍context 的作用
Context objects are so common, and get passed around so frequently, it can be easy to create a situation you didn’t
intend. Loading resources, launching a new Activity, obtaining a system service, getting internal file paths, and
creating views all require a Context (and that’s not even getting started on the full list!) to accomplish the task. What
I’d like to do is provide for you some insights on how Context works alongside some tips that will (hopefully) allow
you to leverage it more effectively in your applications.