Android aar dependencies

Question

I am new to Gradle build system, I have a library project which includes dependencies like Retrofit, okhttp etc.

I compiled my project and created an aar file. I created a dummy project and added my library aar as a dependency.

Now if I don't add Retrofit and okhttp as dependency in my dummy app's build.gradle file, my app crashes with class not found exception.

My Question is : Since the library aar file already includes Retrofit and okhttp as dependency then why do I need to add them explicitly in dummy app's build.gradle file too? Is there a workaround.

Here is my library build.gradle

    apply plugin: 'com.android.library'
    buildscript {
        repositories {
            mavenCentral()
            jcenter()
        }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.0.+'
    }
}
allprojects {
    repositories {
        jcenter()
    }
}
android {
    compileSdkVersion 22
    buildToolsVersion "21.1.2"

    defaultConfig {
        minSdkVersion 14
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }}
    dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.+'
    compile 'com.android.support:recyclerview-v7:21.+'
    compile 'com.android.support:cardview-v7:21.+'
    compile 'com.google.android.gms:play-services:6.5.87'
    compile 'com.squareup.okhttp:okhttp:2.2.0'
    compile 'com.squareup.retrofit:retrofit:1.9.0'
    }

Answer 1

I was able to resolve this by adding the aar file to a local maven repository. Somehow just adding aar in libs folder and including it as a dependency does not fixes the problem.

If you encounter similar problem just modify your library project build.gradle with these additions

 apply plugin: 'maven'

   version = "1.0"
   group = "com.example.lib"



buildscript {
    repositories {
        mavenCentral()
        mavenLocal()
    }

    dependencies {
        classpath 'com.github.dcendents:android-maven-plugin:1.0'
    }
}
    repositories {
       mavenLocal()
     }

uploadArchives {
    repositories {
        mavenDeployer {
            repository(url: "file://${System.env.HOME}/.m2/repository/")
        }
    }
}

Run the task in the terminal provided in the Android studio itself as ./gradlew uploadArchives

Then in your app module's build.gradle file, add the library as dependency

compile ('com.example.app:ExampleLibrary:1.0@aar') {
        transitive = true;
    }