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Export libgdx project as Android library including dependencies

I have two, separate Android projects. One is a regular Android application and the other one is a libgdx project.
My goal is to be able to compile the libgdx project as an Android library into aar file, so I could use it in the regular, non libgdx, Android application (I'm going to start the libgdx game's activity from the regular Android project).
The libgdx project consists of several modules (I'm using only the android and the desktop modules), so in my libgdx project I can find 3 modules: android, desktop and core (where basically the whole game's code is resides). When compiling and running the game on Android, the android module kicks in, but it uses the core module as a dependency.
When trying to change the libgdx project into an Android library project and compiling it into aar, it seems like it lacks the needed dependencies (like the core module, in addition to some other dependencies).
How can I create an aar file from the libgdx project which has all the needed dependencies?

So eventually I managed to find a solution for my problem.
Lets start with the fact that my first impression was misleading, and the problem I had was not a libgdx specific problem, but a gradle "problem".
In short, the reason behind that is that the aar/jar files don't contain the transitive dependencies and don't have a pom file which describes the dependencies used by the library.
To overcome this behaviour you need somehow to specify the dependencies in your project. You can choose between 2 approaches:
first approach:
You can use a central repository, such as JCenter, and publish the project as library. In this case, gradle will be able to download the dependencies using the pom file which contains the dependencies list.
Second approach:
You need to manually copy all your dependencies to the libs folder. You can do this relatively easy by writing a small gradle task:
task copyCompileDependenciesToLibs(type: Copy) {
def libsPath = project.projectDir.toString() + "/libs"
from configurations.compile
into libsPath
}
This snippet will copy all your dependencies to the libs folder, and once you compile your library project the dependencies will be included.

How do I use another library in my app?

The title is a little misleading but I honestly don't know how to word it in any other way. This is my project structure:
I want to use the highlighted (fasteranimationscontainer-master) in my current app that I'm working on. I imported it by putting the jar file in my library folder then adding it to my library through Android Studio. But I try to create an object of that imported library, it doesn't show up/import.
I'm still learning how to use android studio so any help would be much appreciated!

1. Library with only the Source Code
To include a library with only the source code (like FasterAnimationsContainer) to your project, you only need to import it as a module from File -> New-> Import Module in Android Studio:
There should be a dialog for the project folder, enter the path where your library reside.
Then you need to add the module to your app build.gradle as a dependency:
android {
...
dependencies {
...
compile project(':fasteranimationscontainer')
...
}
}
Now you can use it in your project.
2. Library from Maven or JCenter
To add dependencies to your project where the library has uploaded to maven or jcenter, you need to modify your app build.gradle file and add extra lines configuring the packages you require. For example, for certain Google or Android, dependencies look like:
android {
...
dependencies {
// Google Play Services
compile 'com.google.android.gms:play-services:6.5.+'
// Support Libraries
compile 'com.android.support:support-v4:22.2.1'
}
}
Try to always read the library README first.
Suggestion:
If you still learning using Android Studio, you can read Using Android Studio. Then read Getting Started with Gradle, because Android Studio is tightly related with Gradle.

Dependencies in Android Gradle project (Intellij IDEA)

I've been migrating to Gradle and I've encountered an awkward issue.
Using Intellij IDEA I found two ways to add a dependency, please see the pictures attached:
As I can see these two way are not interchangeable. But the way B is obviously equivalent to
dependencies {
compile project(':xx-manager-shared')
}
Could anyone explain to me that's the exact difference between these two methods of adding dependencies?
And how should I organise "cross dependencies" in Gradle when
A module depends on B module,
B depends on C
and C depends on A?

It seems in A the dependencies are for the Android module, and in B it is the dependencies required by the Gradle plugin for building, e.g. Annotation processing?
I would recommend you download and try out Android Studio, it looks a lot simpler since it is purpose built for Android development, and you get a simple list of modules, without the tree hierarchy above.
I generally add dependencies by hand, as it doesn't mess up the build.gradle files.
In answering your other question, you are defining circular dependencies, so if you can find a way around it it's best, otherwise you can try adding them, syncing with Gradle and seeing if it works.

How to use forked git project in Android Studio

I am switching from Eclipse to Android Studio. I have couple of 3rd party libraries that I have added features or modified a little bit. Since the libraries in Eclipse are also projects and we can access the code, I had no problem.
In Android Studio compile tag in dependencies is great but in my case I cannot use it unfortunately.
I fork the project and made necessary changes and add the project as a module in Android Studio. Since the library project already has settings.gradle and example and library modules, there is a mess in my project and it does not compile at all.
Has anybody experienced such a problem? What to do and what is the correct way to forked libraries?

What we've done in my project is create gradle scripts for our dependencies that don't have them, and modify the gradle scripts for dependencies that do have them. Gradle does not play very well with modular dependencies, unfortunately: Each sub-project must know its place in the larger overall project. Since you've already forked the github project, modifying it further shouldn't be a problem.

Android/Gradle: Where is this dependency embedded?

I'm using the new Android build system that is based on Gradle, together with the early access preview Android Studio. Now, I have two projects: an Android library project, and an Android app project (basically a demo for the library).
In the library project I have added a dependency to the gson library, so my build.gradle file looks like this:
dependencies {
compile 'com.android.support:support-v4:13.0.+'
compile 'com.google.code.gson:gson:2.2.+'
}
Still, everything works fine and dandy and I'm able to use gson in my library and then my app. But I want to understand where this library is embedded. I've opened both the .aar that is built by the library project and the .apk of the demo app. I was expecting to find the jars for the two dependencies in at least one of these, but I didn't.
So where are they?

From Android Tools website:
These items, plus the output of the compilation of the project’s own source code, are sent to dex for bytecode conversion and inclusion in the final APK.
In other words, they are in your *.dex file inside the APK.

As #SharkyXTS said, the code from any external dependencies is compiled into the final .dex file inside your APK. The reason why you can't find any references to these dependencies in the .aar is because there aren't any.
The .aar format is only supported through Maven for now, so dependencies are found through there. I believe there are plans to eventually support local .aar dependencies (without Maven), but the Android plugin isn't quite there yet. You can see this issue for more information.