Problema da API do Cloud Firestore com listeners, erro Python/Kivy jnius/jnius_proxy.pxi no Android

[IamBrazilian]

I have a problem that I've been stuck for 2 weeks trying to understand and solve. In the application I have a RecycleView, so I also have a system that reads and adds a listener(stream) to a Cloud Firestore document, when data changes in the database it is automatically placed in a DictProperty. But the real problem is in RecycleView, when database data is changed, RecycleView is affected for some reason and an error is returned:

Traceback (most recent call last):
  File "jnius/jnius_proxy.pxi", line 156, in jnius.jnius.invoke0
  File "jnius/jnius_proxy.pxi", line 124, in jnius.jnius.py_invoke0
AttributeError: 'list' object has no attribute 'invoke'

List refers to RecycleView's data attribute

E às vezes retornava esse outro error:

Traceback (most recent call last):
  File "jnius/jnius_proxy.pxi", line 156, in jnius.jnius.invoke0
  File "jnius/jnius_proxy.pxi", line 124, in jnius.jnius.py_invoke0
AttributeError: 'kivy.properties.PropertyStorage' object has no attribute 'invoke'

I have no idea how to solve this, and the reason for this error. Please if anyone can help me. I'm using the cloud firestore API.

Eu sei que a melhor solução é migrar para java, mas estou tentando me familiarizar com o android com python primeiro. Pretendo aprender java no futuro.

main.py

from kivy.properties import DictProperty, BooleanProperty
from kivy.uix.screenmanager import ScreenManager
from kivymd.app import MDApp

class WindowManager(ScreenManager):
    pass

class MyApp(MDApp):
    profile_data = DictProperty(rebind=True)
    registered = BooleanProperty(False)
    loaded_data = BooleanProperty(False)    

    def __init__(self, **kwargs):
        super(MyApp, self).__init__(**kwargs)
        self.sm = WindowManager()

    def build(self):
        return self.sm

    def on_start(self):
        import android_db
        self.bind(profile_data=self.check_profile_data)
        android_db.read_firebase_data("collection", "person")
        return super().on_start()

    def check_profile_data(self, *args):
        if self.profile_data == {}:
            self.registered = False
        elif len(self.profile_data) >= 7:
            self.registered = True

if __name__ == "__main__":
    MyApp().run()

To do the java part I followed this tutorial: https://www.youtube.com/watch?v=aZGXJXzGLhI&t=20s

android_db.py

from jnius import autoclass, cast, PythonJavaClass, java_method
from kivy.app import App

PythonActivity = autoclass("org.kivy.android.PythonActivity")
currentActivity = cast("android.app.Activity", PythonActivity.mActivity)
context = cast("android.content.Context", currentActivity.getApplicationContext())

FirebaseApp = autoclass("com.google.firebase.FirebaseApp")
FirebaseFirestore = autoclass("com.google.firebase.firestore.FirebaseFirestore")
FirebaseApp.initializeApp(context)

db = FirebaseFirestore.getInstance()
APP_INSTANCE = App.get_running_app()

def read_firebase_data(collection:str, document:str):
    ref = db.collection(collection).document(document).get()
    ref.addOnSuccessListener(DataSuccessListener())

listener = None
def stream_firebase_data(collection:str, document:str):
    global listener
    ref = db.collection(collection).document(document)
    if listener is None:
        listener = ref.addSnapshotListener(DataSnapshotListener())

class DataSuccessListener(PythonJavaClass):
    __javainterfaces__ = ["com/google/android/gms/tasks/OnSuccessListener"]
    __javacontext__ = "app"

    @java_method("(Ljava/lang/Object;)V")
    def onSuccess(self, doc):
        data = doc.getData()
        for key in data.keySet():
            APP_INSTANCE.profile_data[key] = data.get(key)
        print(APP_INSTANCE.profile_data)
        stream_firebase_data("collection", doc.id)

class DataSnapshotListener(PythonJavaClass):
    __javainterfaces__ = ["com/google/firebase/firestore/EventListener"]
    __javacontext__ = "app"

    @java_method('(Ljava/lang/Object;Lcom/google/firebase/firestore/FirebaseFirestoreException;)V')
    def onEvent(self, doc, error):
        try:
            data = doc.getData()
            for key in data.keySet():
                APP_INSTANCE.profile_data[key] = data.get(key)
            print(APP_INSTANCE.profile_data)
            APP_INSTANCE.loaded_data = True
        except Exception as e:print(e)

RecycleView.py

from kivy.uix.recycleview import RecycleView

class MyRecycleView(RecycleView):
    pass

RecycleView.kv

<MyRecycleView>:
    viewclass: "MD2Card"
    effect_cls: "ScrollEffect"
    RecycleBoxLayout:
        default_size: None, None
        default_size_hint: 1, None
        size_hint_y: None
        height: self.minimum_height
        orientation: 'vertical'
        spacing: dp(25)
        padding: [0, dp(5), 0, dp(10)]

Location I'm using MyRecycleView

Screen:
    name: "peq"
    MyRecycleView:
        id: small

Screen:
    name: "med"
    MyRecycleView:
        id: mid

Screen:
    name: "gra"
    MyRecycleView:
        id: big

In main.py there is load_data, it is used for when the Cloud Firestore data is loaded and added to the profile_data, load the data attribute of the RecycleView

When the screen containing the RecyclerView is loaded which is before the read_firebase_data function in the main.py file in on_start, this function is done:

def update(self, **kwargs):
        self.app = App.get_running_app()
        self.app.bind(loaded_data=self.testt)

    @mainthread
    def testt(self, *ars):
        if self.app.loaded_data:
            self.ids.small.data = [
            {
                "size_hint":(.75, None),
                "pos_hint":{"center_x":.5},
                "md_bg_color":get_color_from_hex("#8758b3")
            } for _ in range(20)
        ]

This function works great, the data is put in the RecycleView, but when the data is changed an error is returned:

AttributeError: 'list' object has no attribute 'invoke'

Please if anyone can help me I will be very grateful, and I'm sorry if my explanation was not very good. Thank you in advance for your attention.

[dbnicholson]

I was having the same issue and stumbled upon #59. Make sure you keep a reference to the PythonJavaClass instances you create or python might garbage collect it.

[Android-for-Python]

https://github.com/Android-for-Python/Android-for-Python-Users#pyjnius-memory-management

[github-actions[bot]]

👋 We use the issue tracker exclusively for bug reports and feature requests. However, this issue appears to be a support request. Please use our support channels to get help with the project. Let us know if this comment was made in error, and we'll be happy to reopen the issue.