Class Overview
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.
应用环境全局信息的接口。这是一个抽象类，由android系统对其提供实现方法。它让你可以得到应用程序的详细的资源和类，并且能上升到应用程序级的调用操作，如启动应用程序，广播，接受intent等等。