GrabDuck

kivy/python-for-android

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Getting up and running on python-for-android (p4a) is a simple process and should only take you a couple of minutes. We'll refer to Python for android as p4a in this documentation.

Concepts

  • requirements: For p4a, your applications dependencies are requirements similar to the standard requirements.txt, but with one difference: p4a will search for a recipe first instead of installing requirements with pip.
  • recipe: A recipe is a file that defines how to compile a requirement. Any libraries that have a Python extension must have a recipe in p4a, or compilation will fail. If there is no recipe for a requirement, it will be downloaded using pip.
  • build: A build refers to a compiled recipe.
  • distribution: A distribution is the final "build" of all your compiled requirements, as an Android project that can be turned directly into an APK. p4a can contain multiple distributions with different sets of requirements.
  • bootstrap: A bootstrap is the app backend that will start your application. Your application could use SDL2 as a base, or Pygame, or a web backend like Flask with a WebView bootstrap. Different bootstraps can have different build options.

Installation

Installing p4a

p4a is now available on on Pypi, so you can install it using pip:

pip install python-for-android

You can also test the master branch from Github using:

pip install git+https://github.com/kivy/python-for-android.git

Installing Dependencies

p4a has several dependencies that must be installed:

  • git
  • ant
  • python2
  • cython (can be installed via pip)
  • a Java JDK (e.g. openjdk-7)
  • zlib (including 32 bit)
  • libncurses (including 32 bit)
  • unzip
  • virtualenv (can be installed via pip)
  • ccache (optional)
  • autoconf (for ffpyplayer_codecs recipe)
  • libtool (for ffpyplayer_codecs recipe)

On recent versions of Ubuntu and its derivatives you may be able to install most of these with:

sudo dpkg --add-architecture i386
sudo apt-get update
sudo apt-get install -y build-essential ccache git zlib1g-dev python2.7 python2.7-dev libncurses5:i386 libstdc++6:i386 zlib1g:i386 openjdk-7-jdk unzip ant ccache autoconf libtool

On Arch Linux (64 bit) you should be able to run the following to install most of the dependencies (note: this list may not be complete). gcc-multilib will conflict with (and replace) gcc if not already installed. If your installation is already 32-bit, install the same packages but without lib32- or -multilib:

sudo pacman -S jdk7-openjdk python2 python2-pip python2-kivy mesa-libgl lib32-mesa-libgl lib32-sdl2 lib32-sdl2_image lib32-sdl2_mixer sdl2_ttf unzip gcc-multilib gcc-libs-multilib

Installing Android SDK

You need to download and unpack the Android SDK and NDK to a directory (let's say $HOME/Documents/):

Then, you can edit your ~/.bashrc or other favorite shell to include new environment variables necessary for building on android:

# Adjust the paths!
export ANDROIDSDK="$HOME/Documents/android-sdk-21"
export ANDROIDNDK="$HOME/Documents/android-ndk-r10e"
export ANDROIDAPI="14"  # Minimum API version your application require
export ANDROIDNDKVER="r10e"  # Version of the NDK you installed

You have the possibility to configure on any command the PATH to the SDK, NDK and Android API using:

  • --sdk_dir PATH as an equivalent of $ANDROIDSDK
  • --ndk_dir PATH as an equivalent of $ANDROIDNDK
  • --android_api VERSION as an equivalent of $ANDROIDAPI
  • --ndk_ver PATH as an equivalent of $ANDROIDNDKVER

Usage

Build a Kivy application

To build your application, you need to have a name, version, a package identifier, and explicitly write the bootstrap you want to use, as well as the requirements:

p4a apk --private $HOME/code/myapp --package=org.example.myapp --name "My application" --version 0.1 --bootstrap=sdl2 --requirements=python2,kivy

This will first build a distribution that contains python2 and kivy, and using a SDL2 bootstrap. Python2 is here explicitely written as kivy can work with python2 or python3.

You can also use --bootstrap=pygame, but this bootstrap is deprecated for use with Kivy and SDL2 is preferred.

Build a WebView application

To build your application, you need to have a name, version, a package identifier, and explicitly use the webview bootstrap, as well as the requirements:

p4a apk --private $HOME/code/myapp --package=org.example.myapp --name "My WebView Application" --version 0.1 --bootstrap=webview --requirements=flask --port=5000

You can also replace flask with another web framework.

Replace --port=5000 with the port on which your app will serve a website. The default for Flask is 5000.

Build an SDL2 based application

This includes e.g. PySDL2.

To build your application, you need to have a name, version, a package identifier, and explicitly write the sdl2 bootstrap, as well as the requirements:

p4a apk --private $HOME/code/myapp --package=org.example.myapp --name "My SDL2 application" --version 0.1 --bootstrap=sdl2 --requirements=your_requirements

Add your required modules in place of your_requirements, e.g. --requirements=pysdl2 or --requirements=vispy.

Other options

You can pass other command line arguments to control app behaviours such as orientation, wakelock and app permissions. See :ref:`bootstrap_build_options`.

Rebuild everything

If anything goes wrong and you want to clean the downloads and builds to retry everything, run:

p4a clean_all

If you just want to clean the builds to avoid redownloading dependencies, run:

p4a clean_builds && p4a clean_dists

Getting help

If something goes wrong and you don't know how to fix it, add the --debug option and post the output log to the kivy-users Google group or irc channel #kivy at irc.freenode.net .

See :doc:`troubleshooting` for more information.

Advanced usage

Recipe management

You can see the list of the available recipes with:

p4a recipes

If you are contributing to p4a and want to test a recipes again, you need to clean the build and rebuild your distribution:

p4a clean_recipe_build RECIPENAME
p4a clean_dists
# then rebuild your distribution

You can write "private" recipes for your application, just create a p4a-recipes folder in your build directory, and place a recipe in it (edit the __init__.py):

mkdir -p p4a-recipes/myrecipe
touch p4a-recipes/myrecipe/__init__.py

Distribution management

Every time you start a new project, python-for-android will internally create a new distribution (an Android build project including Python and your other dependencies compiled for Android), according to the requirements you added on the command line. You can force the reuse of an existing distribution by adding:

p4a apk --dist_name=myproject ...

This will ensure your distribution will always be built in the same directory, and avoids using more disk space every time you adjust a requirement.

You can list the available distributions:

p4a distributions

And clean all of them:

p4a clean_dists

Configuration file

python-for-android checks in the current directory for a configuration file named .p4a. If found, it adds all the lines as options to the command line. For example, you can add the options you would always include such as:

--dist_name my_example
--android_api 19
--requirements kivy,openssl

Going further

See the other pages of this doc for more information on specific topics: