python-for-android (p4a) is a development tool that packages Python apps into binaries that can run on Android devices.
This tool was originally developed for apps produced with the Kivy framework, and is managed by the same team. However, it can be used to build other types of Python apps for Android.
p4a is often used in conjunction with Buildozer, which can download, install and keep up-to-date any necessary prerequisites (including p4a itself), for a number of target platforms, using a specification file to define the build.
Thomas Hansen wrote a detailed answer on the (old) kivy-users mailing list
Basically, you need to root the device, remove the SystemUI package, add some lines to the xml configuration, and you're done.
The following are common problems and resolutions that users have reported.
This is a known bug in some releases. To work around it, add your python
requirement explicitly, e.g. --requirements=python3,kivy. This also applies
when using buildozer, in which case add python3 to your buildozer.spec
requirements.
This can happen when you try to include a very long filename, which doesn’t
normally happen but can occur accidentally if the p4a directory contains a
.buildozer directory that is not excluded from the build (e.g. if buildozer
was previously used). Removing this directory should fix the problem, and is
desirable anyway since you don’t want it in the APK.
This means that your SDK is missing the required platform tools. You need to
install the platforms;android-XX package in your SDK, using the android or
sdkmanager tools (depending on SDK version).
If using buildozer this should be done automatically, but as a workaround you
can run these from ~/.buildozer/android/platform/android-sdk-XX/tools/android
Your hostpython3 was compiled without SSL support. You need to install the SSL
development files before rebuilding the hostpython3 recipe. Remember to always
clean the build before rebuilding (p4a clean builds, or with buildozer buildozer android clean).
On Ubuntu and derivatives:
apt install libssl-dev
p4a clean builds # or with: buildozer `buildozer android clean
On macOS:
brew install openssl
p4a clean builds # or with: buildozer `buildozer android clean
This occurs if your version of colorama is too low, install version
0.3.3 or higher.
If you install python-for-android with pip or via setup.py, this
dependency should be taken care of automatically.
This is a known bug in some releases. To work around it, add your
python requirement explicitly,
e.g. :code:--requirements=python3,kivy. This also applies when using
buildozer, in which case add python3 to your buildozer.spec requirements.
This can happen when you try to include a very long filename, which doesn't normally happen but can occur accidentally if the p4a directory contains a .buildozer directory that is not excluded from the build (e.g. if buildozer was previously used). Removing this directory should fix the problem, and is desirable anyway since you don't want it in the APK.
This means that your SDK is missing the required platform tools. You
need to install the platforms;android-19 package in your SDK,
using the android or sdkmanager tools (depending on SDK
version).
If using buildozer this should be done automatically, but as a
workaround you can run these from
~/.buildozer/android/platform/android-sdk-20/tools/android.
You do not have the libffi headers available to python-for-android, so you need to install them. On Ubuntu and derivatives these come from the libffi-dev package.
After installing the headers, clean the build (p4a clean builds, or with buildozer delete the .buildozer directory within your app directory) and run python-for-android again.