Understanding Android File Structure

If you are an Android developer, it is important to have a good understanding of the Android file structure.

This file structure is based on the Linux file system hierarchy and contains several directories and files that serve specific purposes.

This article will guide you through the steps of creating an Android project in Android Studio and provide depth detail main directories in the Android file structure:

Before we start developing apps in android studio, make sure that Android Studio is properly installed on your system. For setup, you can go through our article Android studio Setup.

/systemThis directory contains essential system files and libraries required for the Android operating system to run properly. As a developer, you should avoid making changes to this directory as it can affect the stability of the operating system.
/dataThis directory contains user data and applications installed on the device. It is where your application’s data is stored, such as preferences, databases, and files.
/cacheThis directory contains temporary files that can be deleted to free up storage space. Your application should use this directory to store temporary files that can be safely deleted without affecting the functionality of the app.
/mntThis directory contains mount points for external storage devices such as SD cards or USB drives. You can use this directory to access files on external storage devices.
It is important to note that the file structure may vary slightly between different versions of Android and different devices.

As a developer, you should always test your application on different devices to ensure compatibility with different file structures.

Android File Structure

The file structure of an Android app typically consists of several directories and files that contain the different components of the app.

javaThis directory contains the Java code for your app, including activities, services, and broadcast receivers.

Here’s a brief overview of the file structure:

appThis directory contains the main code for your app.
build.gradleThis file contains the configuration settings for your app’s build process.
resThis directory contains resources for your app, such as layout files, images, and strings.
gradleThis directory contains the Gradle build system configuration files.
assetsThis directory contains any additional assets your app requires, such as fonts, sounds, or videos.
libsThis directory contains any external libraries your app needs.
testThis directory contains the test code for your app.

The file structure may vary slightly depending on the type of app you’re building. However, the above files and directories are commonly found in Android apps.

When creating an Android project in Android Studio, several main files are generated automatically. Here is an overview of some of the main files:

MainActivity.javaThis is the main entry point for the application. It contains the code that initializes and sets up the user interface.
activity_main.xmlThis file contains the layout for the main activity. It defines the structure and appearance of user interface elements.
AndroidManifest.xmlThis file contains critical information about the application, such as its package name, version number, and permissions. It also lists all the activities, services, and broadcast receivers used in the application.
build.gradleThis file contains the build configuration for the application. It specifies the Android SDK version, build tools version, and other settings.
strings.xmlThis file contains all the strings used in the application. It is used for localization, allowing the application to display different languages based on the device’s locale.
styles.xmlThis file contains the styles used in the application. It defines the look and feel of the user interface elements, such as text color, background color, and font size.

These are some of the main files in an Android project. Each file plays a vital role in Android application development and deployment.

Creating an Android Project

Creating an Android project in Android Studio is the first step towards developing an Android application.

Android Studio is a powerful integrated development environment (IDE) for developing Android applications that offers many useful features, including code editing, debugging, and testing tools.

To create an Android project in Android Studio, follow these steps:

Step 1 – Open Android Studio:

Android Studio can be launched on your computer by double-clicking on the shortcut icon or searching for it in the start menu.

Step 2 – Create a new project:

Once Android Studio is launched, you can create your first project by selecting “Create New Project” on the welcome screen or navigating to “File” > “New” > “New Project”.

Step 3 – Choose project type:

After selecting “Create New Project”, you need to choose the type of project you want to create. Android Studio provides several project types, such as “Phone and Tablet” or “Wear OS”, which can be selected based on your requirements.

Step 4 – Choose an activity template:

After selecting the project type, you need to choose an activity template for your project. An activity is the basic building block of an Android application that provides a user interface. Android Studio provides several activity templates, such as “Empty Activity”, “Basic Activity”, or “Fullscreen Activity”, which can be selected based on your project requirements.

Step 5 – Configure the project:

Once the activity template is selected, you need to fill in the project details, such as the project name, package name, and project location. These details will help you organize and manage your project files.

Step 6 – Choose the minimum SDK:

After configuring the project, you need to select the minimum SDK version your app will support. The minimum SDK version determines the lowest Android version your app will run on.

Step 7 – Add dependencies:

Depending on your project requirements, you may need additional libraries or dependencies. These can be added by selecting the “Dependencies” tab and installing the required libraries.

Step 8 – Customize the activity:

Once the project is configured, you can customize the activity by adding a layout file, adjusting the activity settings, and adding any necessary code. This will help you create a user interface and functionality for your app.

Step 9 – Build and run:

Finally, you can build the project and run it on an emulator or a physical device to test your app. This will help you identify any issues and make necessary changes to your app.

By following these steps, you can easily create an Android project in Android Studio and start building your own Android applications.

Android 1st App

Here’s an example of a Hello World app in Android with the necessary files:


package com.example.helloworld;

import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

protected void onCreate(Bundle savedInstanceState) {


<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

android:text="Hello World!" />



<manifest xmlns:android="http://schemas.android.com/apk/res/android"

<activity android:name=".MainActivity">
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />


Here we have a simple MainActivity with a single TextView displaying “Hello World!“. The activity_main.xml file describes the layout of the activity, while the AndroidManifest.xml file declares the app’s package name, activities, and other essential information.

Build and run the application on an emulator or a physical device. The text “Hello World” should be visible on the center of the screen.

Understanding the Android file structure is essential for managing your application’s resources efficiently and providing a seamless user experience. By following best practices and organizing your code and resources in the appropriate directories, you can ensure that your application runs smoothly on any Android device.

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