python-for-android Python3/Android-28/Crystax build recipe

[Robert Flatt]

For me Python3/Buildozer fails in incomprehensible ways. I read that some other find this an issue.

I use manual install and run of python-for-android (Python3/Android-28/Crystax):

# Recipe for building a python3 app (written using Kivy) for Android-28/Crystax.
#
# ASSUMES Ubantu 18.04 CLEAN INSTALL
# Tested with Windows Subystem for Unix Ubantu 18.04 and Android Pie
#

sudo apt-get update
sudo apt-get upgrade

### Workaround Issue #1327. Java heap issue - thanks JonasT
### Also add this line to .bashrc
export GRADLE_OPTS="-Xms1724m -Xmx5048m -Dorg.gradle.jvmargs='-Xms1724m -Xmx5048m'"

### Install modified P4A Python 2.7 dependencies
# changes to documentation:
# python3-all-dev replaces python2.7-dev  
# openjdk-8-jdk   replaces openjdk-7-jdk
# apparently not required : libncurses5:i386 libstdc++6:i386 zlib1g:i386

sudo apt-get install -y build-essential ccache git zlib1g-dev python3-all-dev openjdk-8-jdk unzip autoconf libtool

### Install more P4A dependencies
### P4A requires Python 3.6, the default Python version on Ubantu 18 is 3.6
### gradle, virtualenv, pip, pkg, libgl1
### Gradle MUST be installed AFTER openjdk-8-jdk has been installed

sudo apt-get install -y gradle virtualenv python3-pip  pkg-config libgl1-mesa-dev

### Install Python packages
### Versions I get:  Cython 0.29.1 , Kivy 1.10.1,  P4A '0.6.0'
### The P4A version is mostly meaningless it is really a newer 'master'? build
### P4A must be installed with sudo else p4a stub is not created
### P4A requires Cython to be installed with sudo, else it will not find cython
### In some environment with more than one Python version, these two sudo
### might be an issue?

sudo -H pip3 install cython
pip3 install kivy
sudo -H pip3 install git+https://github.com/kivy/python-for-android.git

# Download Crystax and Android Tools (ndk and sdk) to <WHERE_EVER>
# https://www.crystax.net/en/download    crystax-ndk-10.3.2-linux-x86_64.tar.xz
# https://developer.android.com/studio/  sdk-tools-linux-4333796.zip
mkdir <WHERE_EVER>
cd    <WHERE_EVER>
unzip  -d sdk  sdk-tools-linux-4333796.zip
tar xf crystax-ndk-10.3.2-linux-x86_64.tar.xz

# Build the Android Tools
cd <WHERE_EVER>/sdk/tools/bin
./sdkmanager "platforms;android-28"
./sdkmanager "build-tools;28.0.3"

### Install Done
### Build app-version-debug.apk

cd <location of app main.py>

# Create a ".p4a" containing (replace text between and including <>)
# An app may need more options than these:
--dist_name=<XXX>
--private .
--package=com.<YYY>.<XYZ>
--name <ZZZ>
--bootstrap=sdl2
--requirements=python3crystax,kivy
--arch=armeabi-v7a
--icon <ICON>.png
--sdk_dir <WHERE_EVER>/sdk
--ndk_dir <WHERE_EVER>/crystax-ndk-10.3.2
--android_api 28
--ndk_version 10.3.2
--ndk-api 21
--version <0.0.0>

# Build .apk with Python for Android
# the first time this will take a while, and it is verbose
# Some stuff fails and recovers, so relax

p4a apk

# Bump the --version for each modified and installed build
# Sometimes an install fails, uninstall the previous version

# Be amazed by p4a, the developers are doing something wonderful.