Gradle: download Dependencies of included aar-library

Question

I wrote a library-project cameraBarcodeScanner that is built into an aar file. This library has the following dependencies defined in its build.gradle:

dependencies {
 compile fileTree(dir: 'libs', include: ['*.jar'])
 testCompile 'junit:junit:4.12'
 compile 'com.android.support:appcompat-v7:23.1.0'
 compile 'com.google.zxing:core:3.2.1'
 compile 'com.journeyapps:zxing-android-embedded:3.2.0@aar'
}

I'm using the library in a test-application like so:

dependencies {
 compile(name: 'cameraBarcodeScanner-release', ext: 'aar')
}

Gradle finds the application and is able to build it. However, on runtime, android is not able to find the classes, that are located in zxing-android-embedded. It seems to me, that gradle is not downloading the dependencies of the library-project. I also tried:

dependencies {
 compile(name: 'cameraBarcodeScanner-release', ext: 'aar'){
  transitive = true
}

But this didn't help either. Do I have to expose the library's dependencies in some way? How would you use a library and make gradle download its dependencies?

Thanks in advance!

Answer 1

The aar file doesn't contain the nested (or transitive) dependencies and doesn't have a pom file which describes the dependencies used by the library.

It means that, if you are importing a aar file using a flatDir repo you have to specify the dependencies also in your project.

You should use a maven repository (you have to publish the library in a private or public maven repo), you will not have the same issue.
In this case, gradle downloads the dependencies using the pom file which will contains the dependencies list.