The directory structure of an Android project is well-organized to manage code, resources, and configuration files efficiently. Understanding the project structure helps in maintaining, debugging, and scaling the app.
📂 Android Project Directory Structure Overview
When you create a new Android project in Android Studio, the directory structure looks like this:
MyAndroidApp/
│── .gradle/
│── .idea/
│── app/
│ │── src/
│ │ │── main/
│ │ │ │── java/
│ │ │ │ │── com.example.myapp/
│ │ │ │ │ │── MainActivity.java
│ │ │ │── res/
│ │ │ │ │── layout/
│ │ │ │ │ │── activity_main.xml
│ │ │ │ │── drawable/
│ │ │ │ │── mipmap/
│ │ │ │ │── values/
│ │ │ │ │ │── strings.xml
│ │── build.gradle (Module Level)
│── build/
│── gradle/
│── settings.gradle
│── gradle.properties
│── local.properties
│── build.gradle (Project Level)
│── AndroidManifest.xml
🔹 1. Root Directory (Project Level)
The root directory contains essential files for the entire project.
| File/Folder | Description |
|---|---|
.gradle/ | Stores Gradle build files and caches. |
.idea/ | Stores Android Studio settings & configurations. |
build/ | Contains compiled files and generated APKs. |
gradle/ | Contains Gradle wrapper scripts for project builds. |
local.properties | Stores local system configurations (SDK path). |
settings.gradle | Defines which modules are included in the project. |
build.gradle (Project Level) | Configures project-wide Gradle settings. |
🔹 2. The app/ Module (Main Application Code)
The app/ module is where all application code and resources are stored.
| Folder/File | Description |
|---|---|
src/ | Contains source code (main/, test/, androidTest/). |
AndroidManifest.xml | Defines app components, permissions, and metadata. |
build.gradle (Module Level) | Defines dependencies, plugins, and configurations for the app module. |
🔹 3. The src/ Directory
This contains all the source code and resources.
| Folder | Description |
|---|---|
main/ | The main application source code and resources. |
test/ | Contains unit tests (JUnit, Mockito). |
androidTest/ | Contains UI and instrumented tests (Espresso, UIAutomator). |
🔹 4. The java/ Directory (Source Code)
Contains all the Java/Kotlin source code for the app.
app/src/main/java/com/example/myapp/
│── MainActivity.java
│── adapters/
│── models/
│── utils/
│── viewmodels/
Key Subdirectories:
✔ adapters/ – Contains adapter classes for RecyclerView/ListView.
✔ models/ – Defines data models (e.g., User.java).
✔ utils/ – Utility/helper functions.
✔ viewmodels/ – MVVM architecture ViewModels (if using Jetpack ViewModel).
🔹 Best Practice: Follow package by feature rather than package by layer.
🔹 5. The res/ Directory (App Resources – UI & Assets)
This contains all the XML files for UI elements, images, themes, and app resources.
📁 res/layout/ (UI Layouts)
Contains XML layout files for activities and fragments.
app/src/main/res/layout/
│── activity_main.xml
│── fragment_dashboard.xml
│── list_item.xml
📁 res/drawable/ (Images & Shapes)
Stores vector assets, PNGs, backgrounds, and shape drawables.
app/src/main/res/drawable/
│── logo.png
│── button_background.xml
📁 res/mipmap/ (App Icons)
Contains different resolution icons for the app launcher.
📁 res/values/ (String, Colors, Dimensions)
Contains XML files for strings, colors, styles, and dimensions.
app/src/main/res/values/
│── strings.xml
│── colors.xml
│── styles.xml
│── dimens.xml
| File | Purpose |
|---|---|
strings.xml | Stores text for localization & reusability. |
colors.xml | Defines color codes for UI consistency. |
styles.xml | Defines UI themes & styles. |
dimens.xml | Defines margin, padding, text sizes. |
🔹 Best Practice: Avoid hardcoding values directly in layouts—use values/ instead.
🔹 6. The AndroidManifest.xml File
This defines app permissions, activities, services, and metadata.
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.myapp">
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:theme="@style/AppTheme"
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN"/>
<category android:name="android.intent.category.LAUNCHER"/>
</intent-filter>
</activity>
</application>
</manifest>
🔹 Key Elements:
✔ uses-permission – Requests permissions (e.g., Internet, Camera).
✔ application – Defines app-level settings like theme, backup.
✔ activity – Declares activities and launch behavior.
🔹 7. Gradle Build System
📌 Project-level build.gradle (Global Configurations)
Located at root level (MyAndroidApp/build.gradle).
buildscript {
dependencies {
classpath 'com.android.tools.build:gradle:7.0.0'
}
}
📌 Module-level build.gradle (App Configurations)
Located in app/build.gradle.
plugins {
id 'com.android.application'
}
android {
compileSdkVersion 33
defaultConfig {
applicationId "com.example.myapp"
minSdkVersion 21
targetSdkVersion 33
versionCode 1
versionName "1.0"
}
}
dependencies {
implementation 'androidx.appcompat:appcompat:1.4.0'
implementation 'com.google.android.material:material:1.5.0'
}
🔹 Important Configurations:
✔ compileSdkVersion – Defines the Android SDK version used for compilation.
✔ minSdkVersion – Minimum supported Android version.
✔ dependencies – Lists external libraries used.
🔹 8. The build/ Directory
- Stores compiled APKs, dex files, generated resources.
- Not included in version control (Git).
📝 Summary: Why is Understanding the Directory Structure Important?
✅ Helps in managing large projects efficiently.
✅ Improves collaboration in teams.
✅ Enhances debugging & maintenance.
✅ Follows best practices for scalability & performance