PyJNIus

Python module to access Java class as Python class, using JNI.

(Work in progress.)

Quick overview

>>> from jnius.reflect import autoclass
>>> autoclass('java.lang.System').out.println('Hello world')
Hello world

>>> Stack = autoclass('java.util.Stack')
>>> stack = Stack()
>>> stack.push('hello')
>>> stack.push('world')
>>> print stack.pop()
world
>>> print stack.pop()
hello

Usage on desktop

You need java JDK installed (openjdk will do), cython, and make to build it

make

That's it! you can run the tests with

make tests

To make sure everything is running right.

Usage with python-for-android

• Get http://github.com/kivy/python-for-android
• Compile a distribution with -m "pyjnius kivy"
• Then, you can do this kind of things:

from time import sleep
from jnius import autoclass

Hardware = autoclass('org.renpy.android.Hardware')
print 'DPI is', Hardware.getDPI()

Hardware.accelerometerEnable()
for x in xrange(20):
    print Hardware.accelerometerReading()
    sleep(.1)

It will output something like:

I/python  ( 5983): Android kivy bootstrap done. __name__ is __main__
I/python  ( 5983): Run user program, change dir and execute main.py
I/python  ( 5983): DPI is 160
I/python  ( 5983): [0.0, 0.0, 0.0]
I/python  ( 5983): [-0.0095768067985773087, 9.3852710723876953, 2.2218191623687744]
I/python  ( 5983): [-0.0095768067985773087, 9.3948478698730469, 2.2218191623687744]
I/python  ( 5983): [-0.0095768067985773087, 9.3948478698730469, 2.2026655673980713]
I/python  ( 5983): [-0.028730420395731926, 9.4044246673583984, 2.2122423648834229]
I/python  ( 5983): [-0.019153613597154617, 9.3852710723876953, 2.2026655673980713]
I/python  ( 5983): [-0.028730420395731926, 9.3852710723876953, 2.2122423648834229]
I/python  ( 5983): [-0.0095768067985773087, 9.3852710723876953, 2.1835119724273682]
I/python  ( 5983): [-0.0095768067985773087, 9.3756942749023438, 2.1835119724273682]
I/python  ( 5983): [0.019153613597154617, 9.3948478698730469, 2.2122423648834229]
I/python  ( 5983): [0.038307227194309235, 9.3852710723876953, 2.2218191623687744]
I/python  ( 5983): [-0.028730420395731926, 9.3948478698730469, 2.2026655673980713]
I/python  ( 5983): [-0.028730420395731926, 9.3852710723876953, 2.2122423648834229]
I/python  ( 5983): [-0.038307227194309235, 9.3756942749023438, 2.2026655673980713]
I/python  ( 5983): [0.3926490843296051, 9.3086557388305664, 1.3311761617660522]
I/python  ( 5983): [-0.10534487664699554, 9.4331550598144531, 2.1068975925445557]
I/python  ( 5983): [0.26815059781074524, 9.3469638824462891, 2.3463177680969238]
I/python  ( 5983): [-0.1149216815829277, 9.3852710723876953, 2.31758713722229]
I/python  ( 5983): [-0.038307227194309235, 9.41400146484375, 1.8674772977828979]
I/python  ( 5983): [0.13407529890537262, 9.4235782623291016, 2.2026655673980713]

Advanced example

When you use autoclass, it will discover all the methods and fields within the object, and resolve it. For now, it can be better to declare and use only what you need. The previous example can be done manually:

from time import sleep
from java import MetaJavaClass, JavaClass, JavaMethod, JavaStaticMethod

class Hardware(JavaClass):
    __metaclass__ = MetaJavaClass
    __javaclass__ = 'org/renpy/android/Hardware'
    vibrate = JavaStaticMethod('(D)V')
    accelerometerEnable = JavaStaticMethod('(Z)V')
    accelerometerReading = JavaStaticMethod('()[F')
    getDPI = JavaStaticMethod('()I')
    
# use that new class!
print 'DPI is', Hardware.getDPI()

Hardware.accelerometerEnable()
for x in xrange(20):
    print Hardware.accelerometerReading()
    sleep(.1)