Android gradle build: how to set global variables

Question

How can I set a global variable that can be accessed from build.gradle and tasks?

Answer 1

Additional, for dynamic global variables you can define global functions in the master build.gradle file:

First, define your function, for example for git branch:

def getGitBranch = { ->
    def stdout = new ByteArrayOutputStream()
    exec {
        commandLine 'git', 'rev-parse', '--abbrev-ref', 'HEAD'
        standardOutput = stdout
    }
    return stdout.toString().trim()
}

In allProjects section set the variable:

allprojects {
    repositories {
        google()
        jcenter()
    }
    project.ext {
        gitBranch="\"${getGitBranch()}\""
    }
}

In your build.gradle files of your sub projects or android modules, get this variable like this:

android {
    compileSdkVersion project.mCompileSdkVersion.toInteger()
    defaultConfig {
        minSdkVersion project.mMinSdkVersion.toInteger()
        ...
        buildConfigField "String", "GitBranch", project.gitBranch
    }
    ...
}

Finally, you can use it in your code like this:

public static String getGitBranch() {
    return BuildConfig.GitBranch;
}