Opens & Highlights the apk in explorer/finder after a release build.

open-after-build.gradle

applicationVariants.all { variant ->
        variant.assemble.doLast {
            //If this is a 'release' build, reveal the compiled apk in finder/explorer
            if (variant.buildType.name.contains('release')) {

                def path = null
                variant.outputs.each { output ->
                    path = "${rootDir}/${project.name}/build/outputs/apk/release/${output.outputFileName}"
                }

                task openReleaseFile(type: Exec) {
                    if (System.properties['os.name'].toLowerCase().contains('mac os x')) {
                        ['open', '-R', path].execute()
                    } else if (System.properties['os.name'].toLowerCase().contains('windows')) {
                        ['explorer', '/select,', path].execute()
                    }
                }
            }
        }
    }