Add this lane to your Fastfile and run fastlane installAll type:{BUILD_TYPE} in command line. Replace BUILD_TYPE with the build type you want to build.

For example: fastlane installAll type:Debug

This command will build all flavors of given type and install it to your device. Currently, it doesn’t work if you have more than one device attached. Make sure you have only one. In the future I’m planning to add option to select target device.

lane :installAll do |options|

    gradle(task: "clean")

    gradle(task: "assemble",
       build_type: options[:type])

    lane_context[SharedValues::GRADLE_ALL_APK_OUTPUT_PATHS].each do | apk |

        puts "Uploading APK to Device: " + apk

        begin
            adb(
                command: "install -r #{apk}"
            )
        rescue => ex
            puts ex
        end
    end
end