Android Gradle - send variable to dependency

Question

I have gradle modules: app and library module libApp. Each one of them has own gradle file. app.gradle:

productFlavors {
     prod {somevariable = false}
     debug {somevariable = true}
}

dependencies {
    implementation project(':libApp')
}

And libApp.gradle:

defaultConfig {
    buildConfigField "boolean", "SOME_VARIABLE_FROM_APP_MODULE", somevariable
}

How to force gradle to compile project libApp in app module with somevariable dependent on product flavor ?

Answer 1

You can do this with flavors.

In the library module's build.gradle, define a flavor dimension that corresponds to the variable's value:

android {
    /* ... */

    flavorDimensions "someVar"

    productFlavors {
        someVarTrue {
            dimension "someVar"
            buildConfigField "boolean", "SOME_VARIABLE_FROM_APP_MODULE", 'true'
        }

        someVarFalse {
            dimension "someVar"
            buildConfigField "boolean", "SOME_VARIABLE_FROM_APP_MODULE", 'false'
        }
    }
}

In the app module's build.gradle, define which app flavor should use which library flavor:

android {
    /* ... */

    flavorDimensions "environment"

    productFlavors {
        prod {
            dimension "environment"
        }

        dev {
            dimension "environment"
        } // note: naming a flavor "debug" might create a conflict with the default "debug" configuration
    }
}

dependencies {
    /* ... */
    prodImplementation project(path: ':libApp', configuration: 'someVarTrue')
    devImplementation project(path: ':libApp', configuration: 'someVarFalse')
}

You might want to see this article for some more details.

Answer 2

You can create ext block in your project level build.gradle which encapsulates custom properties and makes them available to all modules in the project.

ext {
    somevariable = true
}

While accessing it, you can simply

defaultConfig {
    buildConfigField "boolean", "SOME_VARIABLE_FROM_APP_MODULE", ext.somevariable
}