问题
I'm new to Android. Can someone explain me the concept of Context class/Object. What it is? What it will be used for? Why Context class?
回答1:
Have you seen the android developer's guide? it will answer your questions:
Interface to global information about an application environment. This is an abstract class whose implementation is provided by the Android system. It allows access to application-specific resources and classes, as well as up-calls for application-level operations such as launching activities, broadcasting and receiving intents, etc.
A Context has a lot of functions, but as a developer, you primarily use it to load and access application resources.
回答2:
In programming Android applications, you will hardly ever need to use the Context class directly (not possible at all since Context is abstract), but you will need the child classes that derive from it like Activity, Service etc.
You might want to look these up.
回答3:
You can think of Context, like the end-user-interface that will use that code. When you are in a class you can know based on Context if you have visual screen(Activity), or a running service(Service).
To compare against some other programming example, you can think of Context is equal to Console App, GUI App, or even Applet.
回答4:
I hope if you read this source code you will have answer for the problems:
http://www.devdaily.com/java/jwarehouse/android/core/java/android/content/Context.java.shtml
来源：https://stackoverflow.com/questions/2870678/please-explain-me-context-class-in-android