How to Add a JAR as a Library in Android Studio

22 May 2024 Stephan Petzl Leave a comment Tech-Help

Adding a JAR file as a library in Android Studio can be a bit tricky if you’re unfamiliar with the steps. This guide will walk you through the process, ensuring that your JAR file is correctly included in your project and available during development and runtime.

Steps to Add a JAR File as a Library

1. Place the JAR File in the Project:
   • Create a libs folder at the top level of your module directory, if it doesn’t already exist.
   • Copy the JAR file (e.g., gson-2.2.4.jar) into the libs folder.
2. Add the JAR File as a Library:
   • Right-click on the JAR file in the libs folder and select Add as Library.
3. Update the build.gradle File:
   • Ensure that the following line is included in the dependencies section of your build.gradle file:

     implementation files('libs/gson-2.2.4.jar')

   • Alternatively, if you have multiple JAR files, you can use:

     implementation fileTree(dir: 'libs', include: '*.jar')

4. Perform a Clean Build:
   • Navigate to the root directory of your project and run the following command in the terminal:

     ./gradlew clean

   • This step ensures that any previous build artifacts are removed and the project is rebuilt from scratch.

Common Issues and Solutions

If you encounter a ClassDefNotFoundException during runtime, ensure that you have followed all the steps correctly, especially the Add as Library step and the clean build process.

Additional Tips

• For Android Studio 3.0 and later, use implementation instead of compile in the build.gradle file.
• If you prefer not to manually manage JAR files, consider using Gradle dependencies from Maven Central. For example:

  dependencies {
      implementation 'com.google.code.gson:gson:2.8.6'
  }

For more detailed steps on managing dependencies, you can refer to our Advanced Configuration guide.

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