轉載自：http://blog.csdn.net/dongjideyu/article/details/25187381
SDK 的版本是： http://dl.google.com/android/android-sdk_r17-linux.tgz
參考 http://developer.android.com/sdk/exploring.html
目錄：
SDK：
- platform-tools
- api
- adb
- fastboot
- NOTICE.txt
- source.properties
- tools
- ant
- apps
- lib
- proguard
- support
- templates
- adb_has_moved.txt
- android
- ddms
- dmtracedump
- draw9patch
- emulator
- emulator64-arm
- emulator64-mips
- emulator64-x86
- emulator-arm
- emulator-mips
- emulator-x86
- etc1tool
- hierarchyviewer
- hprof-conv
- jobb
- lint
- mksdcard
- monitor
- monkeyrunner
- NOTICE.txt
- source.properties
- sqlite3
- traceview
- uiautomatorviewer
- zipalign
<sdk>/build-tools/
tools目錄里面包含了重要的編譯工具，比如aapt、aidl、逆向調試工具dexdump和編譯腳本dx。
<sdk>/platform/
存放Android SDK Platforms平臺相關文件，包括字體、res資源、皮膚、模板等
platforms是每個平臺的SDK真正的文件，里面會根據APILevel劃分的SDK版本，這里就以Android2.2來說，進入后有一個android-8的文件夾，android-8進入后是Android2.2SDK的主要文件，其中ant為ant編譯腳本，data保存著一些系統資源，images是模擬器映像文件，skins則是Android模擬器的皮膚，templates是工程創建的默認模板，android.jar則是該版本的主要framework文件.
<sdk>/platform-tools/
Contains platform-dependent tools for developing and debugging your application.
These tools support the latest features of the Android platform and are typically updated only when a new platform becomes available.
These tools are always backward compatible with older platforms, but you must be sure that you have the latest version of these tools when you install a new SDK platform.
<sdk>/tools/
Contains tools for debugging and testing, plus other utilities that are required to develop an app.
If you've just installed the SDK starter package, then you already have the latest version of this package.
Make sure you keep this up to date.
ddms用于啟動Android調試工具
draw9patch則是繪制android平臺的可縮放png圖片的工具
sqlite3可以在PC上操作SQLite數據庫
monkeyrunner則是一個不錯的壓力測試應用，模擬用戶隨機按鍵
mksdcard則是模擬器SD映像的創建工具，
emulator是Android SDK模擬器主程序
traceview作為android平臺上重要的調試工具。(具體可參考 http://www.cnblogs.com/devinzhang/archive/2011/12/18/2291592.html)