Android是基于Linux內核的操作系統，早期由Google開發，后由開放手機聯盟開發。它采用了軟件堆層的架構，主要分為三部分。底層以Linux內核工作為基礎，只提供基本功能；其他的應用軟件則由各公司自行開發，以Java作為編寫程序的一部分。另外，為了推廣此技術，Google和其它幾十個手機公司建立了開放手機聯盟。Android在未公開之前常被傳聞為Google電話或GPhone。目前最新版本為Android2.2。2010年谷歌開發者大會上，Android2.2發布，名稱為Froyo，意為凍酸奶。

就在5月20日的谷歌I/O大會基調演講中，Android2.2（代號Froyo）正式公布。緊接著沒多久，Android2.2 SDK就開始正式提供下載。

此外，Adobe的Flash Player 10.1 for Android也開始正式提供beta下載，但需要使用2.2版本的Android訪問，看來只有少量使用2.2的內部人員才能參與測試吧。

Android 2.2系統新增了許多功能，比如便攜式熱點功能、在Android Browser中增加了對Adobe Flash的支持、以及對Android Market進行了一些完善。谷歌表示，除了新增加許多企業功能之外，Android 2.2在性能和速度上均有提高，給Android瀏覽器增加了V8 Java腳本引擎，另外還增加了許多新的API和服務。

Android 2.2 SDK 正式版下載地址（官方網站需要翻墻）
http://developer.android.com/sdk/android-2.2.html

Adobe Flash Player 10.1 for Android
http://labs.adobe.com/downloads/flashplayer10.html#android

Quick Start
The steps below provide an overview of how to get started with the Android SDK. For detailed instructions, start with the Installing the SDK guide.

1. Prepare your development computer

Read the System Requirements document and make sure that your development computer meets the hardware and software requirements for the Android SDK. Install any additional software needed before downloading the Android SDK. In particular, you may need to install the JDK (version 5 or 6 required) and Eclipse (version 3.4 or 3.5, needed only if you want develop using the ADT Plugin).

2. Download and install the SDK starter package

Select a starter package from the table at the top of this page and download it to your development computer. To install the SDK, simply unpack the starter package to a safe location and then add the location to your PATH.

3. Install the ADT Plugin for Eclipse

If you are developing in Eclipse, set up a remote update site at https://dl-ssl.google.com/android/eclipse/. Install the Android Development Tools (ADT) Plugin, restart Eclipse, and set the "Android" preferences in Eclipse to point to the SDK install location. For detailed instructions, see ADT Plugin for Eclipse.

4. Add Android platforms and other components to your SDK

Use the Android SDK and AVD Manager, included in the SDK starter package, to add one or more Android platforms (for example, Android 1.6 or Android 2.0) and other components to your SDK. If you aren't sure what to add, see Which components do I need?

To launch the Android SDK and AVD Manager on Windows, execute SDK Setup.exe, at the root of the SDK directory. On Mac OS X or Linux, execute the android tool in the /tools/ folder. For detailed instructions, see Adding SDK Components.

Done!