Is it possible to declare a variable in Gradle usable in Java?

Question

Is it possible to declare a variable in Gradle usable in Java ? Basically I would like to declare some vars in the build.gradle and then getting it (obviously) at build time

Answer 1

You can create build config field overridable via system environment variables during build:

Fallback is used while developing, but you can override the variable when you run the build on Jenkins or another tool.

In your app build.gradle:

buildTypes {
        def serverUrl =  '\"' + (System.getenv("SERVER_URL")?: "http://default.fallback.url.com")+'\"'
        debug{
            buildConfigField "String", "SERVER_URL", serverUrl
        }
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
            buildConfigField "String", "SERVER_URL", serverUrl
        }
    } 

The variable will be available as BuildConfig.SERVER_URL.