how to add a library to the dependencies gradle of LIBGDX project

Question

All is in the question , I've tried all the answers I found in SO and others sites but with no luck , this is what I've tried so far :

adding compile fileTree(dir: 'lib', include: '*.jar') to my build.gradle

adding compile files('lib/tween-engine-api-sources.jar') to build.gradle

the library I want to add is Tween engine .

build.gradle file :

buildscript {
    repositories {
        mavenCentral()
        maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
    }
    dependencies {
    }
}

allprojects {
    apply plugin: "eclipse"
    apply plugin: "idea"

    version = '1.0'
    ext {
        appName = 'my-gdx-game'
        gdxVersion = '1.5.4'
        roboVMVersion = '1.0.0-SNAPSHOT'
        box2DLightsVersion = '1.3'
        ashleyVersion = '1.3.1'
        aiVersion = '1.5.0'
    }

    repositories {
        mavenCentral()
        maven { url "https://oss.sonatype.org/content/repositories/snapshots/" }
        maven { url "https://oss.sonatype.org/content/repositories/releases/" }
    }
}

project(":desktop") {
    apply plugin: "java"


    dependencies {
        compile project(":core")

        compile "com.badlogicgames.gdx:gdx-backend-lwjgl:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-platform:$gdxVersion:natives-desktop"
        compile "com.badlogicgames.gdx:gdx-box2d-platform:$gdxVersion:natives-desktop"
        compile "com.badlogicgames.gdx:gdx-bullet-platform:$gdxVersion:natives-desktop"
        compile "com.badlogicgames.gdx:gdx-freetype-platform:$gdxVersion:natives-desktop"
        compile "com.badlogicgames.gdx:gdx-tools:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-controllers-desktop:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-controllers-platform:$gdxVersion:natives-desktop"


    }
}

project(":core") {
    apply plugin: "java"


    dependencies {
        compile "com.badlogicgames.gdx:gdx:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-box2d:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-bullet:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-freetype:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-controllers:$gdxVersion"
        compile "com.badlogicgames.gdx:gdx-ai:$aiVersion"
        compile "com.badlogicgames.ashley:ashley:$ashleyVersion"
        compile "com.badlogicgames.box2dlights:box2dlights:$box2DLightsVersion"

        compile fileTree(dir: 'lib', include: '*.jar')

    }
}

tasks.eclipse.doLast {
    delete ".project"
}

Answer 1

In the wiki article Dependency management with Gradle, you can find all the information you need. There's even an extra part about the Tween Engine.

Your approach should work, however, you need to update Eclipse via a Right-Click on your projects -> Gradle -> Refresh Dependencies.

For me it worked better though to install the dependencies in my local repository and then reference it from there, instead of referencing the lib folder. This is described here.