How to export library to Jar in Android Studio?

Question

I have downloaded some library sources and would like to export it as a Jar file using Android Studio. Is there a way to export to jar file using Android studio ?

edit:

The library I want to export as jar is an Android library. It's called "StandOut" and can be downloaded from GitHub. https://github.com/pingpongboss/StandOut

Answer 1

It is not possible to export an Android library as a jar file. It is possible, however, to export it as aar file. Aar files being the new binary format for Android libraries. There's info about them in Google I/O, the New Build System video.

First, build the library in Android Studio or from command line issuing gradle build from your library's root directory.

This will result in <yourlibroot>/libs/build/yourlib.aar file.

This aar file is a binary representation of your library and can be added to your project instead of the library as a dependency project.

To add aar file as a dependency you have to publish it to the maven central or to your local maven repository, and then refer the aar file in your project's gradle.build file.

However, this step is a bit convoluted. I've found a good explanation how to do so here:

http://www.flexlabs.org/2013/06/using-local-aar-android-library-packages-in-gradle-builds

Answer 2

I was able to build a library source code to compiled .jar file, using approach from this solution: https://stackoverflow.com/a/19037807/1002054

Here is the breakdown of what I did:

1. Checkout library repository

In may case it was a Volley library

2. Import library in Android Studio.

I used Android Studio 0.3.7. I've encountered some issues during that step, namely I had to copy gradle folder from new android project before I was able to import Volley library source code, this may vary depending on source code you use.

3. Modify your build.gradle file

// If your module is a library project, this is needed //to properly recognize 'android-library' plugin buildscript {     repositories {         mavenCentral()     }     dependencies {         classpath 'com.android.tools.build:gradle:0.6.3'     } }  apply plugin: 'android-library'  android {     compileSdkVersion 17     buildToolsVersion = 17      sourceSets {         main  {             // Here is the path to your source code             java {                 srcDir 'src'             }         }     } }  // This is the actual solution, as in https://stackoverflow.com/a/19037807/1002054 task clearJar(type: Delete) {     delete 'build/libs/myCompiledLibrary.jar' }  task makeJar(type: Copy) {     from('build/bundles/release/')     into('build/libs/')     include('classes.jar')     rename ('classes.jar', 'myCompiledLibrary.jar') }  makeJar.dependsOn(clearJar, build) 

4. Run gradlew makeJar command from your project root.

I my case I had to copy gradlew.bat and gradle files from new android project into my library project root. You should find your compiled library file myCompiledLibrary.jar in build\libs directory.

I hope someone finds this useful.

Edit:

Caveat

Althought this works, you will encounter duplicate library exception while compiling a project with multiple modules, where more than one module (including application module) depends on the same jar file (eg. modules have own library directory, that is referenced in build.gradle of given module).

In case where you need to use single library in more then one module, I would recommend using this approach: Android gradle build and the support library