Any Android project contain things such as application source code and resource files. Some are generated for you by default, while others should be created if required. Lets have a look at android eclipse project directory structure below :
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| Android Folder Structure |
src - User specified java source code files will be available here.
gen - The gen directory in an Android project contains auto generated files. You can see R.java inside this folder which is a generated class which contains references to certain resources of the project. R.java is automatically created by the Eclipse IDE and any manual changes are not necessary.
res - Android supports resources like images and certain XML configuration files, these can be keep separate from the source code. All these resources should be placed inside the res folder. This res folder will be having sub-folders to keep the resources based on its type.
/res/values - Used to define strings, colors, dimensions, styles and static arrays of strings or integers. By convention each type is stored in a separate file, e.g. strings are defined in the res/values/strings.xml file.
/res/values-v11 is the values of the API version 11, and /res/values-v14 is the values of the API version 14
/res/animator - This folder contains animations in XML for the property animation API which allows to animate arbitrary properties of objects over time
/res/layout - This folder contains the layouts to be used in the application.A layout resource defines the architecture for the UI in an Activity or a component of a UI. These are resource directories in an application that provides different layout designs for different screen sizes
/res/layout - layout for normal screen size or default
/res/layout-small - layout for small screen size
/res/layout-large - layout for large screen size
/res/layout-xlarge -layout for extra-large screen size
/res/layout-xlarge-land - layout for extra-large in landscape orientation
/res/layout-sw600dp - layout for tablets or layout for 7” tablets (600dp wide and bigger)
/res/layout-sw720dp - layout for 10” tablets (720dp wide and bigger)
/res/layout-w600dp - layout for Multi-pane (any screen with 600dp available width or more)
/res/menu - This folder contains menu resources to be used in the application (Options Menu, Context Menu, or submenu)
/res/raw - This folder contains raw resources that can be looked up by their resource IDs. These resources can be referenced from other resources all of the same way we do with other resources.
/res/drawable - Drawable folders are resource directories in an application that provides different l bitmap drawables for medium, high, and extra high density screens.
/res/drawable-mdpi - bitmap for medium density
/res/drawable-hdpi - bitmap for high density
/res/drawable-xhdpi - bitmap for extra high density
/res/drawable-nodpi - bitmap with no pre-scaling
libs - External library files will be placed in this folder. If you want to any external library in your project place the library jar inside this folder and it will be added to the classpath automatically.
assets - This folder contains raw hierarchy of files and directories, with no other capabilities. It is just an unstructured hierarchy of files, allowing you to put anything you want there and later retrieve as raw byte streams.
bin - Bin folder is the area used by the compiler to prepare the files to be finally packaged to the application’s APK file. This includes
· Compiling your Java code into class files
· Putting your resources (including images) into a structure to be zipped into the APK
This is the output directory of the build. This is where you can find the final .apk file and other compiled resources.
AndroidManifest.xml - All the android applications will have an AndroidManifest.xml file in the root directory. This file will contain essential information about the application to the Android system, information the system must have before it can run any of the application's code. This control file describes the nature of the application and each of its components.
ic_launcher-web.png - This is an icon to be used in Google play. Applications on Google Play require a high fidelity version of the application icon. It is not used in your actual app or the launcher, so it is not packaged in the APK.. The specifications for the high-resolution icon are:
32-bit PNG with an alpha channel
512 x 512 pixels
Maximum size of 1024KB.
proguard-project.txt - Everything in the proguard-project.txt file will be in commented out state, because in general most people don't have any project specific needs, just to run ProGuard tool with standard settings.
The ProGuard tool shrinks, optimizes, and obfuscates your code by removing unused code and renaming classes, fields, and methods with semantically obscure names. The result is a smaller sized .apk file that is more difficult to reverse engineer.
project.properties - project.properties is the main project’s properties file containing information such as the build platform target and the library dependencies has been renamed from default.properties in older SDK versions. This file is integral to the project.
