Common Feature Pack descriptions in Android

In Android, various packages are written in android.*, and the description of the important package is as follows:
Android.app: Provides a high-level program model and provides a basic operating environment
Android.content: Contains a variety of classes for accessing and publishing data on a device
Android.database: Browsing and manipulating databases through content providers
Android.graphics: The underlying graphics library, which contains the canvas, color filters, dots, rectangles, can draw them directly onto the screen.
Android.location: Classes for targeting and related services
Android.media: Provides some classes to manage multiple audio and video media interfaces
Android.net: A class that provides help for network access, more than the usual java.net.* interface
Android.os: Provides system services, message transmission, IPC mechanisms
ANDROID.OPENGL: Tools to provide OpenGL
Android.provider: Provides class access to Android content providers
Android.telephony: Providing API interaction with call-related calls
Android.view: Provides a basic interface framework for the user interface
Android.util: Methods involving tools, such as the operation of a time-date
Android.webkit: Default Browser operator interface
Android.widget: Contains various UI elements (mostly visible) used in the application's screen

Reference: http://blog.csdn.net/xyz_lmn/article/details/4347674

Common Feature Pack descriptions in Android