Foreground Service Notifications on Android

[th3t1m]

I have some trouble with foreground service push notifications
I've tried use many ways (PyJnius, KVDroid, Plyer) it is not working
all of this working on main app(and Plyer and PyJnius only on old version not on api >=31)

This is my case( is the same on Plyer2.2.1 and 2.2.0.dev0)

try:
    import plyer
    plyer.notification.notify(title=mess['_from'], message=mess['text'])
except Exception as e:
    print(f"PUSH SERVICE: FAIL 2: {str(e)}")

try:
    from plyer.platforms.android.notification import AndroidNotification
    notificator = AndroidNotification()
    notificator.notify(title=mess['_from'], message=mess['text'])
except Exception as e:
    print(f"PUSH SERVICE FAIL 3: {str(e)}")

12-20 20:51:18.391  4794  4881 I Push    : PUSH SERVICE: FAIL 2: No usable implementation found!
12-20 20:51:18.391  4794  4881 I Push    : PUSH SERVICE FAIL 3: 'org.kivy.android.PythonService' object has no attribute 'getComponentName'

on buildozer.spec I added all of this

services = Push:./services/push.py:foreground:sticky

and I have java class for this

package com.developer.xmppclient;

import android.content.Intent;
import android.content.Context;
import org.kivy.android.PythonService;

public class ServicePush extends PythonService {

    @Override
    public int startType() {
        return START_STICKY;
    }
    

    @Override
    protected int getServiceId() {
        return 2;
    }
	
    static private void _start(Context ctx, String smallIconName,
                             String contentTitle, String contentText, 
                             String pythonServiceArgument) {
        Intent intent = getDefaultIntent(ctx, smallIconName, contentTitle,
					 contentText, pythonServiceArgument);
        ctx.startService(intent);
    }

    static public void start(Context ctx, String pythonServiceArgument) {
        _start(ctx, "", "XMPP-Client", "Push", pythonServiceArgument);
    }

    static public void start(Context ctx, String smallIconName,
                             String contentTitle, String contentText, 
                             String pythonServiceArgument) {
	_start(ctx, smallIconName, contentTitle, contentText, pythonServiceArgument);
    }    

    static public Intent getDefaultIntent(Context ctx, String smallIconName,
                                          String contentTitle, String contentText, 
                                          String pythonServiceArgument) {
        Intent intent = new Intent(ctx, ServicePush.class);
        String argument = ctx.getFilesDir().getAbsolutePath() + "/app";
        intent.putExtra("androidPrivate", ctx.getFilesDir().getAbsolutePath());
        intent.putExtra("androidArgument", argument);
        intent.putExtra("serviceTitle", "XMPP-Client");
        intent.putExtra("serviceEntrypoint", "./services/push.py");
        intent.putExtra("pythonName", "Push");
        intent.putExtra("serviceStartAsForeground", "true");
        intent.putExtra("pythonHome", argument);
        intent.putExtra("pythonPath", argument + ":" + argument + "/lib");
        intent.putExtra("pythonServiceArgument", pythonServiceArgument);
        intent.putExtra("smallIconName", smallIconName);
        intent.putExtra("contentTitle", contentTitle);
        intent.putExtra("contentText", contentText);
        return intent;
    }

    @Override
    protected Intent getThisDefaultIntent(Context ctx, String pythonServiceArgument) {
        return ServicePush.getDefaultIntent(ctx, "", "", "", 
							     pythonServiceArgument);
    }

    static public void stop(Context ctx) {
        Intent intent = new Intent(ctx, ServicePush.class);
        ctx.stopService(intent);
    }
}

I posted this on the main git (kivy/plyer#793) and discord channels(support/android support/kivymd) and no answer for this.
how can I call push notification from foreground service using Plyer/PyJnius or something else?
Thank you!

[Julian-O]

I note that "Notifications" was a common item that people thought needed work in the recent survey.

[th3t1m]

I found temporary solution for this point (notifications appear in the top curtain of android, but do not cause pop-ups)
but this requires some manual plyer modification
because on new android versions push (from app) working good only via kvdroid(it just working), but from foreground services it big trouble
I post my solution to kivymd discord channel, and can post it here

[Julian-O]

Is there an opportunity for you to issue a PR against Plyer, so everyone can benefit from your change?

[th3t1m]

I can, but it not only plyer modification, it require adding "drawable" dir into root folder and put icon file (because this is on of the reason why it not working)
I write full manual today on 2 languages

[th3t1m]

Как починить PUSH оповещения в foreground service для Android API >= 31 (RU)
Нашел что-то вроде промежуточного решения
проверял на plyer2.0.0 и 2.1.0 (последнюю 2.2.0.dev0 не проверял)
Из коробки эта штука (оповещения в фоне) не работает потому что

JVM exception occurred: com.test.test.testservice: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent. Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.

Проблему я решал следующим образом

1. в файле buildozer.spec находим строку android.add_resources = data/legal_icons:drawable и раскомментируем ее (если нет, то добавить строку) - это одна из проблем когда push нотификатор не может найти иконку
2. создать соответвующую директорию в корне ./data/legal_icons и положить файл icon.png (как файл лого) - нужен для отображения иконки пушки
3. далее наследуемся просто копируем файл python3.11/site-packages/plyer/platforms/android/notification.py (я брал его из venv) и кладем себе отдельно (для дальнейшего вызова его придется чуток модифицировать) он будет нашей реализацией(базируется на plyer==2.0.0 (также можно и просто сделать модикфикацию самого файла, но я пошел другим путем)
   3.1) во всем этом классе нужно найти функцию _set_open_behavior и добавить туда обработку PendingIntent в зависимости от версии android_api
   Ниже код модифицированной фунции

def _set_open_behavior(notification):
        '''
        Open the source application when user opens the notification.

        .. versionadded:: 1.4.0
        '''

        # create Intent that navigates back to the application
        app_context = activity.getApplication().getApplicationContext()
        notification_intent = Intent(app_context, python_act)

        # set flags to run our application Activity
        notification_intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
        notification_intent.setAction(Intent.ACTION_MAIN)
        notification_intent.addCategory(Intent.CATEGORY_LAUNCHER)
        
        # Тут мы закомментировали обработку 
        # get our application Activity
        # pending_intent = PendingIntent.getActivity(
        #     app_context, 0, notification_intent, 0
        # )

        # а тут добавили обработку api_version
        if api_version >= 31:
            pending_intent = PendingIntent.getActivity(
                app_context, 0, notification_intent, PendingIntent.FLAG_MUTABLE
            )
        else:
            pending_intent = PendingIntent.getActivity(
                app_context, 0, notification_intent, PendingIntent.FLAG_IMMUTABLE  # 0
            )

        notification.setContentIntent(pending_intent)
        notification.setAutoCancel(True)

чтобы код отработал возможно придется импортировать api_version
from android import api_version

Из нюансов

1. PUSH оповещения работают только в шторке (т.е. само всплывающее оповещение не работает) - этот пункт пока не знаю как починить
2. вызов производить следующим образом

 notificator = MyAndroidNotification()
 notificator.notify(
                                title=mess['_from'],
                                message=mess['text'],
                                app_name="com.developer.appname",
                                ticker="abc", app_icon="icon.png"
                            )

у себя я переименовал класс AndroidNotification в MyAndroidNotification (делать это не обязательно)

3. Пушки работают только со звуком, вибрацию нужно подавать отдельно (с ней проблем не возникает даже в сервисах)
   Если у кого есть подобная проблема с PUSH оповещением в Foreground сервисе можете проверить, обратная связь приветствуется

[th3t1m]

How to fix PUSH notifications in foreground service for Android API >= 31 (EN)
Found something like an intermediate solution
checked on plyer2.0.0 and 2.1.0 (did not check the latest 2.2.0.dev0)
Out of the box this thing (notifications in the background) does not work because

JVM exception occurred: com.test.test.testservice: Targeting S+ (version 31 and above) requires that one of FLAG_IMMUTABLE or FLAG_MUTABLE be specified when creating a PendingIntent. Strongly consider using FLAG_IMMUTABLE, only use FLAG_MUTABLE if some functionality depends on the PendingIntent being mutable, e.g. if it needs to be used with inline replies or bubbles.

I solved the problem as follows

1. in the buildozer.spec file we find the line android.add_resources = data/legal_icons:drawable and uncomment it (if not, add the line) - this is one of the problems when the push notifier cannot find the icon
2. create a directory in the root ./data/legal_icons and put the file icon.png (as a logo file) - needed to display the push notification icon
3. then copy the file python3.11/site-packages/plyer/platforms/android/notification.py (I took it from venv) and put it separately (for further calling it you will have to modify it a little) it will be our implementation (based on plyer==2.0.0 (you can also simply modify the file itself, but I went the other way)
   3.1) in this entire class you need to find the function _set_open_behavior and add PendingIntent processing there depending on the version of android_api
   Below is the modified function code

def _set_open_behavior(notification):
         '''
         Open the source application when user opens the notification.

         .. versionadded:: 1.4.0
         '''

         # create an Intent that navigates back to the application
         app_context = activity.getApplication().getApplicationContext()
         notification_intent = Intent(app_context, python_act)

         # set flags to run our application Activity
         notification_intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
         notification_intent.setAction(Intent.ACTION_MAIN)
         notification_intent.addCategory(Intent.CATEGORY_LAUNCHER)
        
         # Here we commented out the processing
         # get our application Activity
         # pending_intent = PendingIntent.getActivity(
         # app_context, 0, notification_intent, 0
         # )

         # and here we added api_version processing
         if api_version >= 31:
             pending_intent = PendingIntent.getActivity(
                 app_context, 0, notification_intent, PendingIntent.FLAG_MUTABLE
             )
         else:
             pending_intent = PendingIntent.getActivity(
                 app_context, 0, notification_intent, PendingIntent.FLAG_IMMUTABLE # 0
             )

         notification.setContentIntent(pending_intent)
         notification.setAutoCancel(True)

For the code to work, you may have to import api_version
from android import api_version

Of the nuances

1. PUSH notifications only work in the curtain (i.e. the pop-up notification itself does not work) - I don’t know how to fix this point yet
2. make the call as follows

  notificator = MyAndroidNotification()
  notificator.notify(
                                 title=mess['_from'],
                                 message=mess['text'],
                                 app_name="com.developer.appname",
                                 ticker="abc", app_icon="icon.png"
                             )

I renamed the class AndroidNotification to MyAndroidNotification (this is not necessary)

3. Guns work only with sound, vibration must be supplied separately (there are no problems with it even in services)
   If anyone has a similar problem with PUSH notifications in the Foreground service, you can check it out, feedback is welcome

[th3t1m]

This part need to be added into buildozer.spec

android.add_resources = data/legal_icons:drawable

Full code of notificator.py (modificated)

'''
Module of Android API for plyer.notification.

.. versionadded:: 1.0.0

.. versionchanged:: 1.4.0
    Fixed notifications not displaying due to missing NotificationChannel
    required by Android Oreo 8.0+ (API 26+).

.. versionchanged:: 1.4.0
    Added simple toaster notification.

.. versionchanged:: 1.4.0
    Fixed notifications not displaying big icons properly.
    Added option for custom big icon via `icon`.
'''

from android import python_act, api_version
from android.runnable import run_on_ui_thread
from jnius import autoclass, cast

from plyer.facades import Notification
from plyer.platforms.android import activity, SDK_INT

AndroidString = autoclass('java.lang.String')
Context = autoclass('android.content.Context')
NotificationBuilder = autoclass('android.app.Notification$Builder')
NotificationManager = autoclass('android.app.NotificationManager')
Drawable = autoclass("{}.R$drawable".format(activity.getPackageName()))
PendingIntent = autoclass('android.app.PendingIntent')
Intent = autoclass('android.content.Intent')
Toast = autoclass('android.widget.Toast')
BitmapFactory = autoclass('android.graphics.BitmapFactory')


class MyAndroidNotification(Notification):
    '''
    Implementation of Android notification API.

    .. versionadded:: 1.0.0
    '''

    def __init__(self):
        self._ns = None
        self._channel_id = activity.getPackageName()

    def _get_notification_service(self):
        if not self._ns:
            self._ns = cast(NotificationManager, activity.getSystemService(
                Context.NOTIFICATION_SERVICE
            ))
        return self._ns

    def _build_notification_channel(self, name):
        '''
        Create a NotificationChannel using channel id of the application
        package name (com.xyz, org.xyz, ...) and channel name same as the
        provided notification title if the API is high enough, otherwise
        do nothing.

        .. versionadded:: 1.4.0
        '''

        if SDK_INT < 26:
            return

        channel = autoclass('android.app.NotificationChannel')

        app_channel = channel(
            self._channel_id, name, NotificationManager.IMPORTANCE_DEFAULT
        )
        self._get_notification_service().createNotificationChannel(
            app_channel
        )
        return app_channel

    @run_on_ui_thread
    def _toast(self, message):
        '''
        Display a popup-like small notification at the bottom of the screen.

        .. versionadded:: 1.4.0
        '''
        Toast.makeText(
            activity,
            cast('java.lang.CharSequence', AndroidString(message)),
            Toast.LENGTH_LONG
        ).show()

    @staticmethod
    def _set_icons(notification, icon=None):
        '''
        Set the small application icon displayed at the top panel together with
        WiFi, battery percentage and time and the big optional icon (preferably
        PNG format with transparent parts) displayed directly in the
        notification body.

        .. versionadded:: 1.4.0
        '''
        app_icon = Drawable.icon
        notification.setSmallIcon(app_icon)

        bitmap_icon = app_icon
        if icon is not None:
            bitmap_icon = BitmapFactory.decodeFile(icon)
            notification.setLargeIcon(bitmap_icon)
        elif icon == '':
            # we don't want the big icon set,
            # only the small one in the top panel
            pass
        else:
            bitmap_icon = BitmapFactory.decodeResource(
                python_act.getResources(), app_icon
            )
            notification.setLargeIcon(bitmap_icon)

    def _build_notification(self, title):
        '''
        .. versionadded:: 1.4.0
        '''
        if SDK_INT < 26:
            noti = NotificationBuilder(activity)
        else:
            self._channel = self._build_notification_channel(title)
            noti = NotificationBuilder(activity, self._channel_id)
        return noti

    @staticmethod
    def _set_open_behavior(notification):
        '''
        Open the source application when user opens the notification.

        .. versionadded:: 1.4.0
        '''

        # create Intent that navigates back to the application
        app_context = activity.getApplication().getApplicationContext()
        notification_intent = Intent(app_context, python_act)

        # set flags to run our application Activity
        notification_intent.setFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP)
        notification_intent.setAction(Intent.ACTION_MAIN)
        notification_intent.addCategory(Intent.CATEGORY_LAUNCHER)

        # get our application Activity
        # pending_intent = PendingIntent.getActivity(
        #     app_context, 0, notification_intent, 0
        # )
        if api_version >= 31:
            pending_intent = PendingIntent.getActivity(
                app_context, 0, notification_intent, PendingIntent.FLAG_MUTABLE
            )
        else:
            pending_intent = PendingIntent.getActivity(
                app_context, 0, notification_intent, PendingIntent.FLAG_IMMUTABLE  # 0
            )

        notification.setContentIntent(pending_intent)
        notification.setAutoCancel(True)

    def _open_notification(self, notification):
        if SDK_INT >= 16:
            notification = notification.build()
        else:
            notification = notification.getNotification()

        self._get_notification_service().notify(0, notification)

    def _notify(self, **kwargs):
        noti = None
        message = kwargs.get('message').encode('utf-8')
        ticker = kwargs.get('ticker').encode('utf-8')
        title = AndroidString(
            kwargs.get('title', '').encode('utf-8')
        )
        icon = kwargs.get('app_icon')
        # decide whether toast only or proper notification
        if kwargs.get('toast'):
            self._toast(message)
            return
        else:
            noti = self._build_notification(title)
        # set basic properties for notification
        noti.setContentTitle(title)
        noti.setContentText(AndroidString(message))
        noti.setTicker(AndroidString(ticker))
        # set additional flags for notification
        self._set_icons(noti, icon=icon)
        self._set_open_behavior(noti)
        # launch
        self._open_notification(noti)


def instance():
    '''
    Instance for facade proxy.
    '''
    return MyAndroidNotification()

[th3t1m]

@Julian-O check pls

[Julian-O]

Check? What do you want me to check? I haven't any expertise in this.

[th3t1m]

Ok, I hope someone can check this method and approve its work

[NikitaKokarev]

Hope this solution to send Android notifications using Plyer can be helpful to someone:
https://github.com/NikitaKokarev/PlyerNotification
I changed the plyer notification logic depending on api_version >= 31.