When you create a new Android (e.g., via android create project), you get several items in the project’s root directory, including the following:
> AndroidManifest.xml: An XML file describing the application being
built and which components—activities, services, and so on—are
being supplied by that application.
> build.xml: An Ant script for compiling the application and installing it
on the device.
> default.properties and local.properties: Property files used by the
Ant build script.
> assets/: A folder that holds other static files you wish packaged with the application for deployment onto the device.
> bin/: A folder that holds the application once it is compiled.
> gen/: Where Android’s build tools will place source code that they generate.
> libs/: A folder that holds any third-party JARs your application requires.
> src/: A folder that holds the Java source code for the application.
> res/: A folder that holds resources—such as icons, graphic user interface (GUI) layouts, and the like—that are packaged with the compiled Java in the application.
> tests/: A folder that holds an entirely separate Android project used for testing the one you created.