pyjnius and bluetooth low energy

[am...@prodeo.es]

Hello I'm trying using pyjnius for new bluetooth low energy (androidapi 18)

I've done compiling kivylauncher with BLUETOOTH and BLUETOOTH_ADMIN privileges.

For detecting devices, we need to define a LeScanCallback....

from jnius import autoclass

from jnius import PythonJavaClass, java_method, JavaClass, MetaJavaClass

BluetoothAdapter = autoclass('android.bluetooth.BluetoothAdapter')

btAdapter = BluetoothAdapter.getDefaultAdapter()

class LeScanCallback(PythonJavaClass):

    __javacontext__ = 'app'

    __javainterfaces__ = ['android.bluetooth.BluetoothAdapter$LeScanCallback']

    

    def __init__( self, callback ):

        super( LeScanCallback, self).__init__()

        self.callback = callback

    

    @java_method( '(Landroid/bluetooth/BluetoothDevice;IB[])V' )

    def onLeScan( self, device, rssi, scanRecord):

        print device, rssi, scanRecord

        @run_on_ui_thread

        def run():

            self.callback( device, rssi, scanRecord )

        return

def cb_devices( device, rssi, scanRecord ):

    print 'callback'

    print device, rssi, scanRecord

    

# when I call this, app hangs, without error. logcat doesn't say anything.

mybtLeScan = LeScanCallback( cb_devices )

# never goes here

btAdapter.startLeScan( mybtLeScan )

What can be the problem?, the pyjnius api usage is similar as other examples I've seen.

Best regards.

Angel

[Michael Kinzl]

I am having exactly the same problem implementing the LeScanCallback with pyjnius PythonJavaClass. My code is very similar to yours, I also use API 18 and the app is built with buildozer. It seems the app starts hanging when super(LeScanCallback, self).__init__() is called, but I cannot figure out what the reason is.

Did you already find a solution for your problem. If yes, I would very much appreciate if you could share it.

Best regards,
Michael

[Arnaud Waels]

Hi

I'm trying to do exactly the same, and i have indeed the same issue. Instanciation of LeScanCallback() class freezes the app.

[Mathieu Virbel]

Hey guys,

There is few issues with the code itself:

- __javacontext__ = 'app' -> not needed, as the interface LeScanCallback is declared in android, the java file doesn't exist in your application itself

- the definition for onLeScan is wrong (that's why it's stuck, it goes into an infinite loop)

  declaring a "Byte []" in java = "[B" for the definition. So the full signature is: @java_method('(Landroid/bluetooth/BluetoothDevice;I[B)V')

- you probably don't need an inner @run_on_ui_thread for calling the callback. Whatever you do, the scan method will be called in another thread than the main thread i guess, so don't change your UI directly.

- after btAdapter.startLeScan(...), you need to sleep a little, otherwise the application will leave directly, and you might never see the result

- during the execution, the LeScanCallback needed to implement an hashCode method.

- i'm not sure about the getDefaultAdapter, the android documentation used something else: http://developer.android.com/about/versions/android-4.3.html#Wireless

Anyway, here is the corrected example:

__version__ = '1.0'

from jnius import autoclass

from jnius import PythonJavaClass, java_method

Context = autoclass('android.content.Context')

PythonActivity = autoclass('org.renpy.android.PythonActivity')

BluetoothAdapter = autoclass('android.bluetooth.BluetoothAdapter')

activity = PythonActivity.mActivity

btManager = activity.getSystemService(Context.BLUETOOTH_SERVICE)

btAdapter = btManager.getAdapter()

class LeScanCallback(PythonJavaClass):

    __javainterfaces__ = ['android/bluetooth/BluetoothAdapter$LeScanCallback']

    

    def __init__(self, callback):

        super(LeScanCallback, self).__init__()

        self.callback = callback

    @java_method('()I')

    def hashCode(self):

        return id(self)

    @java_method('(Landroid/bluetooth/BluetoothDevice;I[B)V')

    def onLeScan( self, device, rssi, scanRecord):

        print device, rssi, scanRecord

        self.callback(device, rssi, scanRecord)

def cb_devices( device, rssi, scanRecord ):

    print 'callback'

    print device, rssi, scanRecord

mybtLeScan = LeScanCallback(cb_devices)

btAdapter.startLeScan( mybtLeScan )

import time

time.sleep(3)

Enjoy!

Mathieu

[Arnaud Waels]

Great !
Indeed it works like a charm, Thanks a lot !

But i'm now facing another issue with __javainterfaces__

I'm trying to go further, performing Rssi update using connectGatt. Which needs the following callback at setup http://developer.android.com/reference/android/bluetooth/BluetoothGattCallback.html

So i'm obviously doing it the same way for the callback, but BluetoothGattCallback is an Abstract Class so i get the error : 'android.bluetooth.BluetoothGattCallback is not an interface'. I assume the pb lies there but i can't find how to deal with abstract classes with pyjnius..

BluetoothGattCallback = autoclass('android.bluetooth.BluetoothGattCallback')


class BluetoothGattCallback2(PythonJavaClass):
    __javainterfaces__ = ['android/bluetooth/BluetoothGattCallback']

    def __init__(self, callback):
        super(BluetoothGattCallback2, self).__init__()
        self.callback = callback

    @java_method('(Landroid/bluetooth/BluetoothGatt;II)V')
    def onReadRemoteRssi(self, device, rssi, status):
        print device, rssi, status
        self.callback(device, rssi, status)


W/System.err( 8927): java.lang.IllegalArgumentException: android.bluetooth.BluetoothGattCallback is not an interface

Best regards,
A

2014/1/21 Mathieu Virbel <m...@kivy.org>:

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[Mathieu Virbel]

There is no way to implement abstract class with pyjnius, and it wont
have a way ever i guess.

What you need to do is to write an implementation of the class in Java.
The goal is to register a method to call for each method that we could
extend. The steps would be:

1. Create yourself the interface, with the exact same definitions as the
abstract class (let's call it OnBluetoothGattCallback)
2. Implement the abstract class BluetoothGattCallback with a method for
setting a callback object of the type OnBluetoothGattCallback)
3. Implement each method and call the correct method of the callback
object instead.

So at the end, you should have something like that:

public class BluetoothGattImplem extends BluetoothGattCallback {

public interface OnBluetoothGattCallback {
// ... all the methods from BluetoothGattCallback here ...
// like:
void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic);
}

// private storage for the callback object
private OnBluetoothGattCallback callback = null;

// method to set the callback object
void setCallback(OnBluetoothGattCallback callback) {
this.callback = callback;
}

// implement all the methods, and redirect to the callback object
void onCharacteristicChanged(BluetoothGatt gatt,
BluetoothGattCharacteristic characteristic) {
if (this.callback)
this.callback.onCharacteristicChanged(gatt, characteristic);
}

// ... do the same of all the next methods ...


4. Put the java into src/org/myapp, don't forget the "package
org.myapp;" in the java file too.
5. Then, you can... implement a
"org/myapp/BluetoothGattImplem$OnBluetoothGattCallback" instead, as you
wanted to do it.
6. Don't forget to use __javacontext__ = 'app', because you're going to
implement a java class that you defined, not a java class available on
the system api.
7. To use it, just do:

class PyBluetoothGattCallback(...):
__javainterfaces__ =
["org/myapp/BluetoothGattImplem$OnBluetoothGattCallback"]
__javacontext__ = 'app'
# ... implem here

BluetoothGattImplem = autoclass('org/myapp/BluetoothGattImplem')
pycallback = PyBluetoothGattCallback()
bg = BluetoothGattImplem()
bg.setCallback(pycallback)

8. You're done.



That's a general way that works for all the abstract class. It would be
nice for us to have a way for auto generating this java code / python
code anyway. If somebody hear me... :)


Good luck!

Mathieu





Le 21/01/2014 19:36, Arnaud Waels a �crit :

> 2014/1/21 Mathieu Virbel <m...@kivy.org <mailto:m...@kivy.org>>:

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[Arnaud Waels]

oh ok
it sounds like a journey but i'm trying!

Thanks a lot!

2014/1/21 Mathieu Virbel <txp...@gmail.com>

> <mailto:am...@prodeo.es> a écrit :

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[Gabriel Pettier]

Would this repos be the right place to scrap for classes to
auto-generate code for?
https://github.com/android/platform_frameworks_base/search?q=abstract&ref=cmdform

(i tried to use kivy-remote-shell/pyjnias to have some way to introspect
that, but i didn't find one)

> > <mailto:am...@prodeo.es> a écrit :

[Gabriel Pettier]

This is WIP (and untested), but feedback welcome:

i cloned g...@github.com:android/platform_frameworks_base.git

installed plyj and jinja2 ind a virtualenv, and wrote this:

https://gist.github.com/8855677

(need to create an `interfaces` dir where you run it, that is next to
your clone of platform_frameworks_base, implementations will be produced
into this dir)

then

python parse.py

[Gabriel Pettier]

So a few versions more, after much fixin', i'm actually trying to make
buildozer build the generated code.

first, i generate the classes using this command:

./parse.py platform_frameworks_base ~/kivy-remote-shell/.buildozer/android/platform/python-for-android/dist/default/src/ Impl org.kivy.android_interfaces

this make files/classes with an `Impl` suffix, as an
`org.kivy.android_interfaces` package, which are placed in the src files
of my default dist for buildozer's default distrubution for
kivy-remote-shell.

then i run:

buildozer android debug

and it sadly fails:

http://paste.ubuntu.com/6897865/

I don't have much idea for the first errors yet, if you guys have ideas.

[Mathieu Virbel]

Hey,

I think some class cannot be used at all.


1/

The very first error is about "package com.android.internal.widget does
not exist":
[javac] import com.android.internal.widget.*;

-> i guess com.android.internal is hidden to us.

2/

cannot find symbol "symbol: class Trace"
[javac] import android.os.Trace;

-> no os.trace availadble for us too.


ETC.

You need to see what is accessible from user or not. :)

[Gabriel Pettier]

So, i've been looking into this a bit more, and it's looking a bit tidy.

A lot of packages fail to be found by the build system, and some of them
are actually needed by the defined interfaces, i'm not sure why they
aren't found, but it's problematic.

I updated the parser, code is there:
https://gist.github.com/8907228

and the currently used blacklist look like this, i'm pretty sure some of
it shouldn't be there, though (android.os and android.util should be
found, no?) and i'm still getting 100+ errors.

https://gist.github.com/8907320

i use:

./parse.py platform_frameworks_base ~/kivy-remote-shell/.buildozer/android/platform/python-for-android/dist/default/src/ Impl org.kivy.android_interfaces -b blacklist.txt -c

to build.

I'm thinking about putting the whole plateform_framework_base dir into
src/ but i guess it's not the best idea ever.

Maybe it's something about the order of compilation, i don't know.

https://gist.github.com/tshirtman/8907413

ideas welcome.

[Mike]

Do you had success?

Same problem here and I'm searching for some kivy code.

Regards, Mike.

[Mike]

I appreciate your general approach, but what about abstract classes which extend an abstract class with abstract methods? You have to process the latter, too.

(I tried your parse.py, with additional check if having a return value or not, and with "if (this.implem != null)" instead of "if (this.implem)").

[Gabriel Pettier]

Ah, that's a fair point, didn't think about going recursive for that,
i'll try to have a look into this soonish.

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