android Framework几个重要的包

这些包最好能够背会，非常熟悉，每天看看即可

android:

Contains resource classes used by applications included in the platform and defines application permissions for system

features.

android.app:

Contains high-level classes encapsulating the overall Android application model.

An Android application is defined using one or more of Android's four core application components. Two such application

components are defined in this package: Activity and Service. The other two components are from the android.content package:

BroadcastReceiver and ContentProvider.

android.content:

Contains classes for accessing and publishing data on a device. 主要包含以下几个类：

ContentProvider/ContentResolver

Intent/IntentFilter

android.content.pm.PackageManager

android.content.res.Resources

android.os:

Provides basic operating system services, message passing, and inter-process communication on the device.

几个重要的类：

Bundle