Android Applications Structure

Each android application is a zip archive with extension. You can open it with application like or . The official announcement for file type is . You can unzip file with this command:

Example:

This directory contains external resource like pictures, fonts, sounds, certificate file and etc. It’s a important directory during reverse engineering process. We always look at this directory. For example if you want to bypass certificate pinning, it’s good to look at here for finding certificate file.

Files in the assets directory are not compiled by Android and behave like a file system. You can access the files in assets from Java as well, but they are not indexed, which means they may be slower to access than resources.

Contains the compiled Java or Kotlin classes files that make up the application's codebase. that usually not important for us.

This directory contains share object file (.so) or native (C/C++) libraries which app are using theme. Usually this directory contains another directories with names like x86, armeabi, armeabi-v7a and etc.

Developers usually use C/C++ codes in some situations which they need better performance than Java. For example sometimes we want to do some graphical process like rendering an animation or working with OpenGL and etc.

This directory contains file and folders which related to signing process of apks.

This is similar to folder but a little bit different. The resources directory contains all the resources in its subdirectories, such as images, audio, video, text strings, layouts, themes, and more. Usually this we have multiple instance of this resource for different For example we can see an app icon which is in multiple different sizes that is for Icon size in different screen sizes. Also you may see some images and texts in different languages for multi language support.

Resources are compiled by Android and are easily accessible from your application from the R class. Resources are also indexed, which means they can be accessed quickly and efficiently.

This is an xml file which describe about application components, needed permissions, needed features and some information about package name, main activity and so on.

This file is convert to binary format during compile process.

This file contains codes which is compiled to language that is supported format.

The file is an important component of an Android application's compiled resources. It stands for "Android Resource Compiled" and contains precompiled resources such as strings, layouts, colors, dimensions, and other assets used by the Android application.

When you develop an Android application, you define its resources in XML files under the directory of your project. These resources are typically referenced by their assigned IDs in your Java or Kotlin code. However, when you build the application, these resources are compiled and packaged into the file.

By precompiling the resources into the file, the Android system can efficiently retrieve the required resources without having to parse and process XML files every time. This helps improve the performance of the application and reduces the amount of work required during runtime.