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Avoid using repetitive dependency while adding aar file as Modular Dependencies

I have created a module library (i.e aar ) and have uploaded the same in Jcenter. When I add the library as the Gradle dependency it fetches the other dependencies automatically whereas when I add the aar file as module dependency, I have to explicitly add the dependencies to the project Gradle file. Is there any way that I can avoid adding the dependencies that are already added to the library to the main project.
Awaiting reply.
Thanks.

why i should add dependencies that in aar file to my project?

I created the my Android Archive Library aar file that have it's own dependency in it's Gradle.
I use this library in many projects of mine, but why I should add aar dependency to my application dependencies? as we know benefit of using aar vs jar is aar can have and hold it's own resources and dependencies.

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.

Android can't find the third library on AAR

My AAR includes a picasso library, but in my java code can't find picasso.
Here is my build.gradle:
and here is my multi-image-selector AAR gradle:

Why you not using only
compile 'com.squareup.picasso:picasso:2.5.2'

The aar file doesn't contain the nested 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.
In your case you have to add in your app (not the library):
compile 'com.android.support:appcompat-v7:23.0.1'
compile 'com.squareup.picasso:picasso:2.5.2'

If you use the gradle maven plugin to deploy the aar to a local repo, then you can get transitive dependencies to work. Here's how to do that:
How to use maven plugin to publish a library as an aar
How to enable transitive dependencies on the library dependency

Assume that you have one app and one library module. In your library module you use Picasso as dependency.
Let me explain step by step, with possible scenarios.
1- If you add your library module to your app module as the following :
implementation(project(":myLibrary"))
Your library works correctly.
2- If you add your library module to your app module as the following :
implementation files('../libs/mainLibrary-debug.aar')
You may get a crash if you don't put Picasso dependency to your app module. You have two options to get rid of this crash.
2.a.First option is to add Picasso library to your app module.
2.b.The second option is to compile you aar using any fat aar plugin. If you use a fat aar plugin, when you generate aar, it automatically downloads Picasso library and put it in aar. In this way, you don't need to add Picasso dependency into your app module. There are several fat aar plugins available, here is one of them : https://github.com/kezong/fat-aar-android

Gradle sync not auto-resolve Android library project dependencies with #aar annotation

I've created an Android library project found here: https://github.com/dbotha/Android-Photo-Picker
The photo-picker library project itself has several dependencies of it's own:
// library build.gradle
dependencies {
compile 'com.android.support:appcompat-v7:22.2.1'
compile 'com.squareup.picasso:picasso:2.5.2'
}
I've made this library project available on Maven Central so that it can be easily added to applications as a dependency:
// application build.gradle
dependencies {
compile 'ly.kite:photo-picker:1.1.2#aar'
}
The problem though is that when I come to add it as a dependency to a new Android application project it crashes because it can't find the Picasso dependency from the library project:
Caused by: java.lang.ClassNotFoundException: Didn't find class "com.squareup.picasso.Picasso" on path
It's only when I explicitly add this dependency to the applications build.gradle do things work.
My libraries POM file dependencies looks correct: https://repo1.maven.org/maven2/ly/kite/photo-picker/1.1.2/photo-picker-1.1.2.pom
So I'm curious if applications that include my photo-picker library as a dependency always need to explicitly add all the photo-picker library dependencies too?

You are using the #aar notation.
It means that you want to download only the aar artifact, and no dependencies.
You can check this part of documentation:
Check the 1.4.1.2. Artifact only notation section:
An artifact only notation creates a module dependency which downloads only the artifact file with the specified extension. Existing module descriptors are ignored.
Using the #aar notation if you want to download the dependencies, you should add transitive=true.
I'd expect that omitting #aar it should work.

Multiple AAR files

I am using Android Studio 1.2
I create a private library I want to use that one in another application.
To use it I create an AAR files, but this AAR don't work. I have in my library a dependency to an AAR file.
The AAR files do not the dependencies?
If I use the jar and I includ ans create all the dependencies the project works fine.
NOTE :
I know how to importe the AAR file. The problem is to use an AAR in the AAR..
Thanks.

If I'm understanding your question correctly, there are 3 projects involved:
Library Project 2 --> Library Project 1 --> Application Project
You are editing "Library Project 1" and have added to it's app/build.grade a dependency on the Library Project 2's aar. Something like this: compile 'com.arasthel:gnavdrawer-library:1.1.5'
I am not sure where you are running into an issue, but I'll attempt an answer anyway. If I'm completely off-base, can you please elaborate on how the AAR dependency is not working? Any error messages?, a class/resource not found, etc.
I think it's unlikely you are unable to use a class from Library Project 2 inside Library Project 1, because I just tried this myself and it seems to be working just fine. It's worth noting that the Library Project 1 aar file will NOT include classes or resources from Library Project 2. Library Project 2 will be noted as a dependency in Library Project 1's pom if published using gradle's maven plugin to publish Library Project 1.
My guess is that you are having a problem in the Application Project? Perhaps the class from Library Project 2 is not found in the Application Project?
If that is correct, then there are two possible solutions:
Enable transitive dependencies on the aar dependency in the Application project's app/build.gradle: Instead of compile 'com.example:myLibrary:versionX', make it compile('com.example:myLibrary:versionX'){transitive=true}. I just verified this causes gradle to read Library Project 1's pom and automatically add dependencies found there into the Application Project.
If you would like to use transitive dependencies, your Library Project will need to be generating a pom and publishing it along with the aar. See https://stackoverflow.com/a/30085677/431296 for some additional information on how I have this working.
Manually add the dependency on Library Project 2 to the Application Project - so that your Application has a dependency line for both Libraries. Depending on your specific situation this may or may not be a workable solution.

Add following code to you project build.gradle file, and you should put you AAR file to the libs folder.
repositories {
mavenCentral()
flatDir {
dirs 'libs'
}
}
And finally add compile info to your dependencies:
dependencies {
compile(name:'AARFileName', ext:'aar')
}