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. You can communicate with the service process from your app using e.g. osc or (a heavier option) twisted.
There are two ways to have services included in your APK.
This basic method works with both the new SDL2 and old Pygame bootstraps. 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 (included automatically with the Pygame
bootstrap, you must add it to the requirements manually with SDL2 if
you wish to use this method):
import android android.start_service(title='service name', description='service description', arg='argument to service')
Arbitrary service scripts¶
This service method is not supported by the Pygame bootstrap.
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.name.ServiceMyservice') mActivity = autoclass('org.kivy.android.PythonActivity').mActivity argument = '' service.start(mActivity, argument)
your.package.name refers to the package identifier of your
APK as set by the
--package argument to python-for-android, and
the name of the service is
ServiceYourservicename, in which
Yourservicename is the identifier passed to the
argument 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.
Services support a range of options and interactions not yet
documented here but all accessible via calling other methods of the