build.gradle

task build {
    // For each included build run ':app:assembleDebug'
    gradle.includedBuilds.each { build ->
        dependsOn build.task(':app:assembleDebug')
    }
}

task release {
    // For each included build run ':app:build'
    gradle.includedBuilds.each { build ->
        dependsOn build.task(':app:build')
    }
}

task install {
    // For each included build run ':app:installDebug'
    gradle.includedBuilds.each { build ->
        dependsOn build.task(':app:installDebug')
    }
}

task installRelease {
    // For each included build run ':app:installRelease'
    gradle.includedBuilds.each { build ->
        dependsOn build.task(':app:installRelease')
    }
}

task clean {
    // For each included build run 'clean' on each project.
    gradle.includedBuilds.each { build ->
        dependsOn build.task(':clean')
        build.projectDir.eachDir { dir ->
            if (new File(dir, 'build.gradle').isFile()) {
                dependsOn build.task(":${dir.name}:clean")
            }
        }
    }
}