Buildozer compiles simple android kivy application, but fails while packaging - python-2.7

Question

This is the output of buildozer:
buildozer android debug
# Check configuration tokens
# Ensure build layout
# Check configuration tokens
# Preparing build
# Check requirements for android
# Install platform
# Apache ANT found at /root/.buildozer/android/platform/apache-ant-1.8.4
# Android SDK found at /root/.buildozer/android/platform/android-sdk-21
# Android NDK found at /root/.buildozer/android/platform/android-ndk-r9c
# Android packages already installed.
# Check application requirements
# Compile platform
# Distribution compiled.
# Build the application #1
# Package the application
Traceback (most recent call last):
File "/bin/buildozer", line 5, in <module>
run()
File "/usr/lib/python2.7/site-packages/buildozer/__init__.py", line 1215, in run
Buildozer().run_command(sys.argv[1:])
File "/usr/lib/python2.7/site-packages/buildozer/__init__.py", line 842, in run_command
self.target.run_commands(args)
File "/usr/lib/python2.7/site-packages/buildozer/target.py", line 85, in run_commands
func(args)
File "/usr/lib/python2.7/site-packages/buildozer/target.py", line 97, in cmd_debug
self.buildozer.build()
File "/usr/lib/python2.7/site-packages/buildozer/__init__.py", line 178, in build
self.target.build_package()
File "/usr/lib/python2.7/site-packages/buildozer/targets/android.py", line 397, in build_package
version = self.buildozer.get_version()
File "/usr/lib/python2.7/site-packages/buildozer/__init__.py", line 554, in get_version
' (looking for `{1}`)'.format(fn, regex))
Exception: Unable to find capture version in ./main.py
(looking for `__version__ = '(.*)'`)
I'm trying to compile a simple probability calculator I designed. I can't post the code, because I'm going to try to publish it. However, I'm willing to answer any questions I need to to get this to work.
Judging by the output of buildozer, I think it's looking for a line in main.py that I didn't know I needed. Unfortunately, I don't have any idea what that line would look like. However, in buildozer.spec, there is a line that says this:
version.regex = __version__ = '(.*)'
version.filename = %(source.dir)s/main.py
The first line looks like the line in the output and the second references the main.py file. Does anyone know what these lines mean? I am new to buildozer, so I'm not quite sure what to do here. Thanks in advance for your help.

Answer 1

By default, buildozer looks for a line in your main.py of the form __version__ = 'something'. This is used to set the apk version, a required field.
You can either add this line to your main.py, or comment out the version check and uncomment the alternative version method on the next lines of buildozer.spec. This lets you set the version string in buildozer.spec itself.

Answer 2

Add version = '0.1' at the top of your main.py file so you can package your application without any error.