--debug option to any python-for-android command to see
full debug output including the output of all the external tools used
in the compilation and packaging steps.
python-for-android is managed by the Kivy Organisation, and you can get help with any problems using the same channels as Kivy itself:
- by email to the kivy-users Google group
- by irc in the #kivy room at irc.freenode.net
If you find a bug, you can also post an issue on the python-for-android Github page.
Debugging on Android¶
When a python-for-android APK doesn’t work, often the only indication that you get is that it closes. It is important to be able to find out what went wrong.
python-for-android redirects Python’s stdout and stderr to the Android
logcat stream. You can see this by enabling developer mode on your
Android device, enabling adb on the device, connecting it to your PC
(you should see a notification that USB debugging is connected) and
adb logcat. If adb is not in your PATH, you can find it at
/path/to/Android/SDK/platform-tools/adb, or access it through
python-for-android with the shortcut:
python-for-android adb logcat
Running logcat command gives a lot of information about what Android is
doing. You can usually see important lines by using logcat’s built in
functionality to see only lines with the
python tag (or just
When your app crashes, you’ll see the normal Python traceback here, as well as the output of any print statements etc. that your app runs. Use these to diagnose the problem just as normal.
The adb command passes its arguments straight to adb itself, so you
can also do other debugging tasks such as
devices to get the list of connected devices.
Unpacking an APK¶
It is sometimes useful to unpack a pacakged APK to see what is inside, especially when debugging python-for-android itself.
APKs are just zip files, so you can extract the contents easily:
At the top level, this will always contain the same set of files:
$ ls AndroidManifest.xml classes.dex META-INF res assets lib YourApk.apk resources.arsc
The Python distribution is in the assets folder:
$ cd assets $ ls private.mp3
private.mp3 is actually a tarball containing all your packaged
data, and the Python distribution. Extract it:
$ tar xf private.mp3
This will reveal all the Python-related files:
$ ls android_runnable.pyo include interpreter_subprocess main.kv pipinterface.kv settings.pyo assets __init__.pyo interpreterwrapper.pyo main.pyo pipinterface.pyo utils.pyo editor.kv interpreter.kv lib menu.kv private.mp3 widgets.pyo editor.pyo interpreter.pyo libpymodules.so menu.pyo settings.kv
Most of these files have been included by the user (in this case, they come from one of my own apps), the rest relate to the python distribution.
With Python 2, the Python installation can mostly be found in the
lib folder. With Python 3 (using the
the Python installation can be found in a folder named
The following are common problems and resolutions that users have reported.
AttributeError: ‘AnsiCodes’ object has no attribute ‘LIGHTBLUE_EX’¶
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.
AttributeError: ‘Context’ object has no attribute ‘hostpython’¶
This is a known bug in some releases. To work around it, add your
python requirement explicitly,
--requirements=python2,kivy. This also applies when using
buildozer, in which case add python2 to your buildozer.spec requirements.
Exception in thread “main” java.lang.UnsupportedClassVersionError: com/android/dx/command/Main : Unsupported major.minor version 52.0¶
This occurs due to a java version mismatch, it should be fixed by installing Java 8 (e.g. the openjdk-8-jdk package on Ubuntu).
JNI DETECTED ERROR IN APPLICATION: static jfieldID 0x0000000 not valid for class java.lang.Class<org.renpy.android.PythonActivity>¶
This error appears in the logcat log if you try to access
org.renpy.android.PythonActivity from within the new toolchain. To
fix it, change your code to reference