【编程语言】Android--ADT与SDK之间的关系

SDK：Software Development Kit 软件开发工具包 含有jar包和编译工具，以及模拟器

The Android SDK provides you the API libraries and developer tools necessary to build, test, and debug apps for Android.

安卓SDK里面有所有用于软件开发的API库函数和用于安卓程序编译、运行，测试，调试的应用程序。

It
includes the essential Android SDK components and a version of the Eclipse IDE with built-in ADT (Android Developer Tools) to
streamline your Android app development.

SDK Tools, Revision 21.1.0 (February 2013)

Dependencies:

Android SDK Platform-tools revision 16 or later.
If you are developing in Eclipse with ADT, note that the SDK Tools r21.1.0 is designed for use with ADT 21.1.0 and later. If you haven't already, update your ADT
Plugin to 21.1.0.
If you are developing outside Eclipse, you must have Apache Ant 1.8 or later

安装SDK，需要安装一些平台相关工具，且在ADT bundle里面。
ADT：Android
Development Tools 安卓平台开发工具箱，一个依赖并需要内嵌于eclipse的插件，需要通过ADT工具在Eclipse上面开发android程序。

It
includes the essential Android SDK components and a version of the Eclipse IDE with built-in ADT (Android Developer Tools) to
streamline your Android app development.

ADT里面包含android
SDK里面的一些重要组件和一个内嵌ADT的eclipse的集成开发环境

ADT
extends the capabilities of Eclipse to let you quickly set up new Android projects, create an application UI, add packages based on the Android Framework API, debug your applications using the Android SDK tools, and even export signed (or unsigned)

.apk

files
in order to distribute your application.

ADT允许你快速建立android程序，创建应用UI。依据框架添加包文件，使用SDK中的调试工具进行调试程序，导出APK文件。

通过阅读文档发现，ADT其实是用来支撑SDK里面的相关运行工具的。

With a single download, the ADT Bundle includes everything you need to begin developing apps:

Eclipse + ADT plugin
Android SDK Tools
Android Platform-tools
The latest Android platform
The latest Android system image for the emulator
由此，得出结论ADT是平台相关插件，需要先安装ADT然后再安装SDK。