Android Support Library特性全解--翻译

Android Support Library包是一个代码库的集合，这个集合提供Android framework API的向下兼容版本，并提供原本只通过库（译者注：这个库指新版本的库）的API才能使用的功能。每一个Support Library是针对一个特定的Android API级别向下兼容的。这种设计意味着你的应用可以使用库（译者注：这个库指新版本的库）的功能，并且可以和运行Android1.6（API level 4）或以上版本的设备兼容。

原文：The Android Support Library package is a set of code libraries that provide backward-compatible versions of Android framework APIs as well as features that are only available through the library APIs. Each Support Library is backward-compatible to a specific Android API level. This design means that your applications can use the libraries' features and still be compatible with devices running Android 1.6 (API level 4) and up.

这个指南提供了一些信息，这些信息包括利用Support Library可以使用哪些功能，如何在你的开发环境中使用这些功能，以及库的发布管理。

原文：This guide provides information about what features are enabled by the Support Libraries, how to use them in your development environment and information about library releases.

概述
对于应用开发者来说，在Android项目中引入Support Library是一种最佳做法，这依赖于你的应用设置的目标平台版本的范围和它用到的API。利用库提供的功能可以帮助你提升应用的外观，提升系统性能并扩大应用的用户使用范围。如果你使用了Android code template（代码模板）工具，你会注意到所有的应用模板默认包含了一个或多个Support Library。

原文：Including the Support Libraries in your Android project is considered a best practice for application developers, depending on the range of platform versions your app is targeting and the APIs that it uses. Using the features the libraries provide can help you improve the look of your application, increase performance and broaden the reach of your application to more users. If you use the Android code template tools, you will notice that all the Android application templates include one or more of the Support Libraries by default.

每一个Support Library设定了一个目标的基础Android API级别，并且提供了不通的功能集合。为了高效地使用这些库，需要着重考虑一下你想使用哪些功能，并且理解每一个库在不同的Android API级别都支持哪些功能。开始前，回顾一下Support Library Features指南。然后，进入Support Library Setup主题学习一下如何将Support Library合并到你的应用。想要了解更多关于Support Library API的细节，查看API参考中的android.support包。

原文：The Support Libraries each target a base Android API level and each provides a different set of features. In order to effectively use the libraries, it is important to consider what features you want to support and understand what features are supported by each library at what Android API level. To get started, review the Support Library Features guide. After that, go to the Support Library Setup topic to learn how to incorporate the Support Libraries into your application. For more details about Support Library APIs, see the android.support packages in the API reference.

版本修订

关于版本修订可以查看这里：http://developer.Android.com/tools/support-library/index.html#revisions