88 lines
3.5 KiB
ReStructuredText
88 lines
3.5 KiB
ReStructuredText
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Services
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========
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python-for-android supports the use of Android Services, background
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tasks running in separate processes. These are the closest Android
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equivalent to multiprocessing on e.g. desktop platforms, and it is not
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possible to use normal multiprocessing on Android. Services are also
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the only way to run code when your app is not currently opened by the user.
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Services must be declared when building your APK. Each one
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will have its own main.py file with the Python script to be run. You
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can communicate with the service process from your app using e.g. `osc
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<https://pypi.python.org/pypi/python-osc>`__ or (a heavier option)
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`twisted <https://twistedmatrix.com/trac/>`__.
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Service creation
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----------------
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There are two ways to have services included in your APK.
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Service folder
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~~~~~~~~~~~~~~
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This basic method works with both the new SDL2 and old Pygame
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bootstraps. It is recommended to use the second method (below) where
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possible.
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Create a folder named ``service`` in your app directory, and add a
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file ``service/main.py``. This file should contain the Python code
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that you want the service to run.
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To start the service, use the :code:`start_service` function from the
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:code:`android` module (included automatically with the Pygame
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bootstrap, you must add it to the requirements manually with SDL2 if
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you wish to use this method)::
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import android
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android.start_service(title='service name',
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description='service description',
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arg='argument to service')
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.. _arbitrary_scripts_services:
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Arbitrary service scripts
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~~~~~~~~~~~~~~~~~~~~~~~~~
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.. note:: This service method is *not supported* by the Pygame bootstrap.
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This method is recommended for non-trivial use of services as it is
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more flexible, supporting multiple services and a wider range of
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options.
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To create the service, create a python script with your service code
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and add a :code:`--service=myservice:/path/to/myservice.py` argument
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when calling python-for-android. The ``myservice`` name before the
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colon is the name of the service class, via which you will interact
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with it later. You can add multiple
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:code:`--service` arguments to include multiple services, which you
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will later be able to stop and start from your app.
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To run the services (i.e. starting them from within your main app
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code), you must use PyJNIus to interact with the java class
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python-for-android creates for each one, as follows::
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from jnius import autoclass
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service = autoclass('your.package.name.ServiceMyservice')
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mActivity = autoclass('org.kivy.android.PythonActivity').mActivity
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argument = ''
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service.start(mActivity, argument)
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Here, ``your.package.name`` refers to the package identifier of your
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APK as set by the ``--package`` argument to python-for-android, and
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the name of the service is ``ServiceYourservicename``, in which
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``Yourservicename`` is the identifier passed to the ``--service``
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argument with the first letter upper case. You must also pass the
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``argument`` parameter even if (as here) it is an empty string. If you
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do pass it, the service can make use of this argument.
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Services support a range of options and interactions not yet
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documented here but all accessible via calling other methods of the
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``service`` reference.
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.. note:: The app root directory for Python imports will be in the app
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root folder even if the service file is in a subfolder. To import from
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your service folder you must use e.g. ``import service.module``
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instead of ``import module``, if the service file is in the
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``service/`` folder.
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