How do I share dependencies between Android modules

Question

I have an Android application module (app) and an Android library module (library). Both app and library contain these same dependencies:

dependencies {
    compile 'com.squareup.okhttp:okhttp:2.4.0'
    compile 'com.squareup.retrofit:retrofit:1.9.0'
    compile 'io.reactivex:rxjava:1.0.13'
    compile 'io.reactivex:rxandroid:0.25.0'
}

However when I try to add that block to the project build.gradle, it complains about not knowing the "compile" DSL.

EDIT: I'm asking about putting this dependencies block in the PROJECT build.gradle, to avoid repeating in each module's build.gradle.

Answer 1

As of Gradle Plugin version 3.0.0 there is a nicer way to do this. We can control whether each dependency is available for only the current module, or for the current module AND any modules which depend on it. This will allow us to easily share dependencies across modules within a project.

Here's how we used to declare dependencies:

• compile 'example.dependency:1.0.0'

Here are the new configurations which should replace compile:

• implementation 'example.dependency:1.0.0' --> this dependency is only used within this module
• api 'example.dependency:1.0.0' --> this dependency will also be available in any builds that depend on this module

Here's how to do that with the architecture you mentioned in the question. Assuming that we have a module named 'library' that is consumed by the 'app' module, we can use the api configuration to declare that the dependency should be shared with any module that depends on it.

library module build.gradle

dependencies {

    // dependencies marked 'implementation' will only be available to the current module
    implementation 'com.squareup.okhttp:okhttp:2.4.0'

    // any dependencies marked 'api' will also be available to app module
    api 'com.squareup.retrofit:retrofit:1.9.0'
    api 'io.reactivex:rxjava:1.0.13'
    api 'io.reactivex:rxandroid:0.25.0'
}

app module build.gradle:

dependencies {

    // declare dependency on library module
    implementation project(':library')

    // only need to declare dependencies unique to app 
    implementation 'example.dependency:1.0.0'
}

Please see this guide for further information and diagrams.

Answer 2

The dependencies block(closure) needs DependencyHandler as delegate

You need to pass DependencyHandler of each project to shared dependencies in project gradle.build.

project build.gradle

ext.sharedGroup = {dependencyHandler->
    delegate = dependencyHandler

    compile 'com.squareup.okhttp:okhttp:2.4.0'
    compile 'com.squareup.retrofit:retrofit:1.9.0'
    compile 'io.reactivex:rxjava:1.0.13'
    compile 'io.reactivex:rxandroid:0.25.0'
}

app build.gradle

dependencies {
    sharedGroup dependencies
}

ref. https://github.com/b1uec0in/DependencyVersionResolver

(see 2. Using default dependency group. This sample explains many other tips for sharing library version, sdk versions ... for large project that have many modules.)

Answer 3

You could do something like this where the project build.gradle will specify the dependencies needed as variable names then in the app build.gradle files you just need to include the variable names. This is very useful when you have many modules and don't want to edit everyone when a version number changes!

project build.gradle

buildscript {
    ext {
        googlePlayServicesVersion = '7.5.0'
        supportLibVersion = '22.2.0'
    }
... (the rest of your repositories/dependency info here) ...
}

ext {
    minSdkVersion=16
    targetSdkVersion=21
    buildToolsVersion='22.0.1'
    compileSdkVersion=21

    //Android Dependencies
    supportV4 = 'com.android.support:support-v4:' + supportLibVersion
    supportAnnotations = 'com.android.support:support-annotations:' + supportLibVersion
    recyclerView = 'com.android.support:recyclerview-v7:' + supportLibVersion
    cardView = 'com.android.support:cardview-v7:' + supportLibVersion
    palette = 'com.android.support:palette-v7:' + supportLibVersion
    appCompat = 'com.android.support:appcompat-v7:' + supportLibVersion
    multidex = 'com.android.support:multidex:1.0.1'
    appCompat = 'com.android.support:appcompat-v7:' + supportLibVersion
    supportDesign = 'com.android.support:design:' + supportLibVersion
    playServicesAnalytics = 'com.google.android.gms:play-services-analytics:' + googlePlayServicesVersion
}

app build.gradle file

dependencies {
   compile rootProject.ext.supportV4
    compile rootProject.ext.appCompat
    compile rootProject.ext.supportAnnotations
    compile rootProject.ext.recyclerView
    compile rootProject.ext.cardView
    compile rootProject.ext.palette
    compile rootProject.ext.appCompat
    compile rootProject.ext.multidex
    compile rootProject.ext.supportDesign
    compile rootProject.ext.playServicesAnalytics

}

Hope that this helps!

Answer 4

Based on @SMKS answer, I would prefer this solution for transitive option capability and simplicity

project build.gradle

buildscript {
... (the rest of your repositories/dependency info here) ...
}

ext {
        googlePlayServicesVersion = '7.5.0'
        supportLibVersion = '22.2.0'
}

app build.gradle file

dependencies {
    compile 'com.android.support:support-v4:' + supportLibVersion
    compile ' com.android.support:support-annotations:' + supportLibVersion
    compile = 'com.android.support:recyclerview-v7:' + supportLibVersion {
        transitive = true // do not know if this make sens/interest just for example
    }
   ...
}

Answer 5

Share libraries using ext block in the root project module

This is an easy way to use the library across all modules in the android project

Please follow these steps:

1. Add ext block (it is used to define extra properties for the project) in root project gradle file
2. Add common libraries in with variable name in ext block e.g name = [ libraries without implementation keyword ]
3. Used this ext block in module level using implementation and variable name e.g implementation variable_name

See below code for complete implementation

build.gradle :project

buildscript {
... (the rest of your repositories here) ...
}

ext { **// ext block start here**




appModuleLibraries = [
            commonLibraries,
            /*Projects*/
            project(':hco-cutout'),
            project(':utils')

    ]

commonLibraries = [
        /*Android Libs*/
        'androidx.core:core-ktx:1.7.0',
        'androidx.appcompat:appcompat:1.4.1',
        'com.google.android.material:material:1.5.0',
        'androidx.constraintlayout:constraintlayout:2.1.3',
        /*Gesture viw for image zooming */
        'com.alexvasilkov:gesture-views:2.5.2',


]
cutoutModulleLibraries = [
        commonLibraries,
        project(':utils'),
        // Selfie segmentation
        'com.google.mlkit:segmentation-selfie:16.0.0-beta4',

        /*checker board drawable*/
        'com.github.duanhong169:checkerboarddrawable:1.0.2',
]
} **// ext block end here**

build.gradle :app

      dependencies {
    
      /*App Module Libraries in root project gradle*/

        implementation appModuleLibraries
    }

build.gradle :cutout

 dependencies {
    /*cutout Module Libraries in root project gradle*/

    implementation cutoutModulleLibraries

    implementation project(':utils')

}

Hope that this helps!