1. Add-ons stores additional libraries, such as GoogleMaps. Of course, if you install OphoneSDK, there will also be some class libraries in it. It can also be add-ons made by the manufacturer itself. This file is optional during development. If you don't use the api here, you don't need to download it.
2. docs Here is the Android SDKAPI reference documentation, all APIs can be found here.
3. As a copyright protection component of AndroidMarket, market_licensing is generally used for anti-piracy when releasing paid applications to the electronic market.
4. platforms is the real file of the SDK of each platform, which will be divided according to the APILevel of the SDK version, here for Android2.2, there is an android-8 folder after entering, and android-8 is Android2 after entering. 2 The main files of the SDK, in which ant is the ant compilation script, data saves some system resources, images is the emulator image file, skins is the skin of the Android emulator, templates is the default template created by the project, and android.jar is the version. The main framework file of the tools directory contains important compilation tools, such as aapt, aidl, reverse debugging tool dexdump and compilation script dx. At least one platform must be installed.
5. platform-tools saves some common tools, such as adb, and aapt, aidl, dx and other files, Android123 prompts, here and the tools folder in the platforms directory are somewhat duplicated, mainly since android2.3, these tools are divided into common . must be installed
6. Samples is the default sample project that comes with the Android SDK. The apidemos in it is strongly recommended for beginners to run and learn. For SQLite database operations, you can check the NotePad example. For game development Snake and LunarLander are good examples. For Android theme development Home It is the theme design principle of the androidm5 era.
7. tools As the tools folder in the root directory of the SDK, it contains important tools, such as ddms to start Android debugging tools, such as logcat, screenshots and file managers, and draw9patch is to draw the scalable png of the android platform Picture tool, sqlite3 can operate SQLite database on PC, monkeyrunner is a good stress test application, simulates random user keystrokes, mksdcard is a tool for creating emulator SD image, emulator is the main program of android emulator, but from Starting from android 1.5, you need to enter appropriate parameters to start the emulator, and traceview is an important debugging tool on the android platform.
8. usb_driver As the name suggests, it saves the drivers of the official google models on the android platform, such as nexus one, nexus s, and also supports some old model drivers, such as htc dream, htc magic and Motorola's droid.