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.

volley error when importing module

I've been trying to add the volley library to my android project by downloading this repository https://android.googlesource.com/platform/frameworks/volley and then importing the module to my project by following this guide:
First get latest volley with git (git clone >https://android.googlesource.com/platform/frameworks/volley).
In your current project (android studio) click [File] --> [New] -->[Import >Module].
Now select the directory where you downloaded Volley to.
Now Android studio might guide you to do the rest but continue guide to verify >that everything works correct
Open settings.gradle (find in root) and add (or verify this is included):
include ':app', ':volley'
Now go to your build.gradle in your project and add the dependency:
compile project(":volley").
When gradle tries to sync the project after I've imported the module i get the following error message : Error:Could not download layoutlib-api.jar (com.android.tools.layoutlib:layoutlib-api:24.3.1): No cached version available for offline mode.

I believe you want to use Volley and not contribute to the volley library. if that is the case there are better ways to get volley in your project. let Gradle handle it. Gradle is Build Management tool just like Maven but better, As it gives you more freedom and flexibility.
How to add libraries to gradle in android studio. this link shows a how to add libraries to your android project.
As Android Studio uses Gradle things are pretty neat as it uses the middle ground of ANT and Maven for Build and Management tool.
for volley you can add
compile 'com.mcxiaoke.volley:library:1.0.19'
to the app module of your project. this library can be looked up on Github
or you can do that using android studio's GUI, click on File -> Project Structure
example

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/

add library from Git to Android Studio

I know this must be a pretty basic question, but I'm new to Android Studio and gradle, and I can't find any up-to-date info on this.
I'm trying to add this library to my project: android-segmented-control.
It doesn't look like I can add it to my build.gradle file (correct?). I'd like to do it that way, of course, and not download the project if possible.
If I do need to download the project, how do I link it up with my existing project? Again, I haven't been able to find anything that is current that describes this process for Android Studio 0.5.3

The library you mentioned does not seems to be pushed on maven central or any other maven repository. As this library contains resources files, you cannot add it as a jar.
The only way to use it is clone the git repository and add it as a module to your android app project.
Meanwhile, you can ask the author to make it available on a Maven repository like OSS sonatype

Thanks #Thomas Bouron for the hint !
I have pushed my library to maven center, so you just need to add the following dependency to your build.gradle.
dependencies {
compile 'info.hoang8f:android-segmented:1.0.0'
}
(A little late for #workInAFishBowl but it may be helpful for others.).

The best way to integrate third party library in Android studio

We can find some very good open source libraries for android. I want to know what is the best way to integrate them to our own projects in Android studio. Here are some basic methods:
Copy the source code and resource files into our own project. We need to change a lot of codes (the package name, and the name in xml,etc)
If jar files is provided, I just create libs folder for my project and copy the jar files inside. And add the jar file in Module setting's dependencies. But unfortunately I got a lot of error messages like "Gradle: Package com.google.gson doesn't exist".
Is there a general rule to add third party source or jar files into an existing android studio project? Thanks

I prefer to use central repository for dependencies management. So for gson 2.3 dependency you should add to build.gradle file:
Specify that you want to use maven central repository for your dependency
repositories {jcenter()}
Add compile dependency to gson 2.6.2
dependencies {compile 'com.google.code.gson:gson:2.6.2'}
Android Studio as well as your CI server should easily build your project now. And you can continue app development.
I prefer to use central repository for dependencies management because:
easier scope management - some libraries are only for testing, some should be included to apk and some are part of running environment (like android.jar itself)
easier transitive dependencies management - it is quite hard to collect libraries dependencies and if you use "jar-with-dependencies" you could get error "class already added" during dexing
lighter repository and easier dependency upgrade
Examples:
Robolectric jar should be used for unit testing only and shouldn't be part of apk itself
Repository is clean from different folders with jars, checkout takes much less. No needs to download and replace old jars with new jars
I should notice:
Not many libraries are in maven central and you should make some effort to use them such way in your project
You could much easier get to "class already added" error during dexing with central repository approach
You can mix usage of dependencies from central repository and from lib folder, but I prefer to use only one way for simplicity

Put the Gson jar (in my case, gson-2.2.4.jar) into the libs folder
Right click it and hit 'Add as library'
Ensure that compile files('libs/gson-2.2.4.jar') is in your build.gradle file
Do a clean build (you can probably do this fine in Android Studio, but to make sure I navigated in a terminal to the root folder of my app and typed gradlew clean. I'm on Mac OS X, the command might be different on your system
This series of steps was taken from Android Studio: Add jar as library? and is not my original answer. I am posting them here, again, because your question was the third in search results on Google when looking up this same topic. Hence, copying.
All credits to the one who wrote the steps.

Download & Copy Your .jar file in libs folder then adding one line to build.gradle:
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar']) ----> AS creates this
compile 'com.google.code.gson:gson:2.3.4' ----------> I added this one
}
Do not forget to click "Sync now"
I´m using Android Studio 1.1.0

Download and copy your jar to libs folder then add the following to your app.gradle file and SYNC.
dependencies {
compile 'com.google.code.gson:gson:{version_you_need}'
}
repositories{
flatDir{
dirs 'libs'
}
}