python-for-android supports the use of Android Services, background tasks running in separate processes. These are the closest Android equivalent to multiprocessing on e.g. desktop platforms, and it is not possible to use normal multiprocessing on Android. Services are also the only way to run code when your app is not currently opened by the user.
Services must be declared when building your APK. Each one
will have its own main.py file with the Python script to be run.
Please note that python-for-android explicitly runs services as separated
processes by having a colon “:” in the beginning of the name assigned to
android:process attribute of the
This is not the default behavior, see Android service documentation.
You can communicate with the service process from your app using e.g.
osc or (a heavier option)
There are two ways to have services included in your APK.
This is the older method of handling services. It is recommended to use the second method (below) where possible.
Create a folder named
service in your app directory, and add a
service/main.py. This file should contain the Python code
that you want the service to run.
To start the service, use the
start_service function from the
android module (you may need to add
android to your app
import android android.start_service(title='service name', description='service description', arg='argument to service')
Arbitrary service scripts¶
This method is recommended for non-trivial use of services as it is more flexible, supporting multiple services and a wider range of options.
To create the service, create a python script with your service code
and add a
when calling python-for-android. The
myservice name before the
colon is the name of the service class, via which you will interact
with it later. You can add multiple
--service arguments to include multiple services, which you
will later be able to stop and start from your app.
To run the services (i.e. starting them from within your main app code), you must use PyJNIus to interact with the java class python-for-android creates for each one, as follows:
from jnius import autoclass service = autoclass('your.package.domain.package.name.ServiceMyservice') mActivity = autoclass('org.kivy.android.PythonActivity').mActivity argument = '' service.start(mActivity, argument)
your.package.domain.package.name refers to the package identifier
of your APK.
If you are using buildozer, the identifier is set by the
package.domain values in your buildozer.spec file.
The name of the service is
is the name specied by one of the
services values, but with the first
letter upper case.
If you are using python-for-android directly, the identifier is set by the
argument to python-for-android. The name of the service is
Myservice is the identifier that was previously passed to the
argument, but with the first letter upper case. You must also pass the
argument parameter even if (as here) it is an empty string. If you
do pass it, the service can make use of this argument.
The service argument is made available to your service via the ‘PYTHON_SERVICE_ARGUMENT’ environment variable. It is exposed as a simple string, so if you want to pass in multiple values, we would recommend using the json module to encode and decode more complex data.
from os import environ argument = environ.get('PYTHON_SERVICE_ARGUMENT', '')
Services support a range of options and interactions not yet
documented here but all accessible via calling other methods of the
The app root directory for Python imports will be in the app
root folder even if the service file is in a subfolder. To import from
your service folder you must use e.g.
import module, if the service file is in the
It is possible to make services restart automatically when they exit by
setAutoRestartService(True) on the service object.
The call to this method should be done within the service code:
from jnius import autoclass PythonService = autoclass('org.kivy.android.PythonService') PythonService.mService.setAutoRestartService(True)