Develop Reference

How to use a Gradle dependency with local modifications?

I have an Android application using an Android library. The library is a pretty big open-source project on GitHub, and its authors publish the artifacts to Bintray. I can specify the dependency with the usual syntax dependencies { implementation 'group:artifact:version' } in the app's build.gradle.
Now I want to change some code in the library. I git clone it on my machine, I make my changes, then I build the library. But how can I tell my app to use the library I built locally, instead of the one in Bintray?
I don't want to follow the approach in Gradle Local Project Dependency, because that means that the library code is now part of the application project, but I really want to keep things separated.
I think the solution involves publishing to a local Maven repository. I followed the guide at https://proandroiddev.com/tip-work-with-third-party-projects-locally-with-gradle-961d6c9efb02 but the app's Gradle is still picking the original library from Bintray.

Bintray-based projects have the install task. That's the one to be used instead of publishToMavenLocal.
When using install, the artifact version is automatically set to X.X.X before publishing to the local repository. Therefore, in order for the app to pick up the local library, you have to edit the implementation row to group:artifact:X.X.X.
As the guide https://proandroiddev.com/tip-work-with-third-party-projects-locally-with-gradle-961d6c9efb02 suggests, you also need to add mavenLocal() as the first entry in the repositories section in the top-level build.gradle of the application.

aar dependency error in my android project using android-maven-gradle-plugin

I have a problem when using the aar module dependency aar module as the below issue explains.
https://github.com/dcendents/android-maven-gradle-plugin/issues/65
I have a project such like a client-server structure.
It has 3 modules:
app (my server to provide some service) -- apk module
sdk (my sdk to provide some API to communicate with my app) -- aar module
common (something which should include both in my app module and sdk module ,such as utils,beans,etc. --aar module
I do not want to write it in my both app and sdk modules, debugging and modifying should work twice.
Any idea how I can resolve this?

I'm not sure exactly what you did wrong there, but I've created/modify those gradle scripts and they're working great: https://github.com/sensorberg-dev/gradle-scripts
I can see you're trying to "install" on your local maven. To do that, you have to add this line at the end of the build.gradle from the common module this line:
apply from: 'https://raw.githubusercontent.com/sensorberg-dev/gradle-scripts/master/publish-to-local-maven-repo.gradle'
and then add the metadata to the gradle.properties files, like this:
project gradle.properties:
POM_GROUP_ID=com.company.omg
POM_VERSION=0.0.1
POM_PACKAGING=aar
and common module gradle.properties:
POM_ARTIFACT_ID=common
then it's just call: ./gradlew clean installArchives

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.

integrating maven dependency into android Eclipse project, no JAR file

Ok, so, I'm developing an app for the Amazon FireTV, so I have to use Eclipse.
I'm trying to use this socket.io Java client library: https://github.com/nkzawa/socket.io-client.java
at the bottom of this post, i included the installation instructions, which I'm not really sure how to make work with my existing Eclipse project (I'm new to maven). so from my understanding, do i just add a pom.xml file and a test folder? Then paste in their "maven central code" into the pom.xml? Will this cause any issues with the other code in my project? Or, can I just copy and paste all their SRC code into my project, since it's MIT licensed? I'd rather learn how to do this the proper way. The project is not in JAR format, so I was thinking maybe copying the folder structure into my project then using the Project Properties, Add Library option to connect to my code? Maybe?
Their installation instructions, (available in their readme.md):
The latest artifact is available on Maven Central. Add the following dependency to your pom.xml.
<dependencies>
<dependency>
<groupId>com.github.nkzawa</groupId>
<artifactId>socket.io-client</artifactId>
<version>0.3.0</version>
</dependency>
</dependencies>
Or to install it manually, please refer dependencies to pom.xml.
Add it as a gradle dependency for Android Studio, in build.gradle:
compile 'com.github.nkzawa:socket.io-client:0.3.0'

So, I learned that Maven Central has JAR files available for download. That way, you can just include them in your project via the Project Properties dependencies options. Without having to learn Maven.

You need to first understand how Maven works (and what pom.xml stands for). Maven is a tool that helps you automatically install dependencies (files need) for a given project. E.g if a project needs to process json files, it will need to "import" a json library which will then be a dependency for that project. When you add the dependency file above to your project, and run Maven install, it goes and fetches all the dependencies for your socket.io-client to work.
Unfortunately, Maven does work very well in building android application projects and can be fairly complex to setup correctly (from my limited experience). I would advise that you manually download the jar dependencies and then add them to your android classpath if you are not keen on investing a lot of time learning to use Maven.
To manually install the files .. you can create a default maven project (http://www.tech-recipes.com/rx/39279/create-a-new-maven-project-in-eclipse/) in eclipse, add the dependency file above to your pom.xml and run Maven-install. This will download the dependencies you need to your Maven local repository. You can then copy them from there to your android project.
Regarding installing the socket.io client you can find more on these steps here
http://denvycom.com/blog/socket-io-java-android-without-maven/

Android library project with maven dependencies

I have created android library project with some depndencies managed by maven.
Now I'm trying to run library code from android maven application project.
Code I wrote in library runs, but I'm getting NoClassDefFoundError on first call to dependecy.
Is there any way to make this work?

You may want to have a look at http://androidkickstartr.com/. This tool will create correctly mavenized project for you and you can then copy missing parts from pom.xml.