Create aar file in Android Studio

Question

I'd like to create an aar file for my library in Android Studio, i would've gone with a jar option but my library has resources.

Any idea how to create an aar file from a library?

Answer 1

If your library is set up as an Android library (i.e. it uses the apply plugin: 'com.android.library' statement in its build.gradle file), it will output an .aar when it's built. It will show up in the build/outputs/aar/ directory in your module's directory.

You can choose the "Android Library" type in File > New Module to create a new Android Library.

Answer 2

Retrieve exported .aar file from local builds

If you have a module defined as an android library project you'll get .aar files for all build flavors (debug and release by default) in the build/outputs/aar/ directory of that project.

your-library-project
    |- build
        |- outputs
            |- aar
                |- appframework-debug.aar
                 - appframework-release.aar

If these files don't exist start a build with

gradlew assemble

Library project details

A library project has a build.gradle file containing apply plugin: com.android.library. For reference of this library packaged as an .aar file you'll have to define some properties like package and version.

Example build.gradle file for library (this example includes obfuscation in release):

apply plugin: 'com.android.library'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.0"

    defaultConfig {
        minSdkVersion 9
        targetSdkVersion 21
        versionCode 1
        versionName "0.1.0"
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

Reference .aar file in your project

In your app project you can drop this .aar file in the libs folder and update the build.gradle file to reference this library using the below example:

apply plugin: 'com.android.application'

repositories {
    mavenCentral()
    flatDir {
        dirs 'libs' //this way we can find the .aar file in libs folder
    }
}

android {
    compileSdkVersion 21
    buildToolsVersion "21.0.0"

    defaultConfig {

        minSdkVersion 14
        targetSdkVersion 20
        versionCode 4
        versionName "0.4.0"

        applicationId "yourdomain.yourpackage"
    }

    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
        debug {
            minifyEnabled false
        }
    }
}

dependencies {
    compile 'be.hcpl.android.appframework:appframework:0.1.0@aar'
}

Alternative options for referencing local dependency files in gradle can be found at: http://kevinpelgrims.com/blog/2014/05/18/reference-a-local-aar-in-your-android-project

Sharing dependencies using maven

If you need to share these .aar files within your organization check out maven. A nice write up on this topic can be found at: https://web.archive.org/web/20141002122437/http://blog.glassdiary.com/post/67134169807/how-to-share-android-archive-library-aar-across

About the .aar file format

An aar file is just a .zip with an alternative extension and specific content. For details check this link about the aar format.

Answer 3

just like user hcpl said but if you want to not worry about the version of the library you can do this:

dependencies {
    compile(name:'mylibrary', ext:'aar')
}

as its kind of annoying to have to update the version everytime. Also it makes the not worrying about the name space easier this way.

Answer 4

btw @aar doesn't have transitive dependency. you need a parameter to turn it on: Transitive dependencies not resolved for aar library using gradle

Answer 5

After following the first and second steps mentioned in the hcpl's answer in the same thread, we added , '*.aar'], dir: 'libs' in the our-android-app-project-based-on-gradle/app/build.gradle file as shown below:

...

dependencies {
       implementation fileTree(include: ['*.jar', '*.aar'], dir: 'libs')

...

Our gradle version is com.android.tools.build:gradle:3.2.1