Access problem of QML objects to nestet custom properties in PySide 6

Szczempus

Hello guys. This is my first forum post here so sorry if I make some mistakes in the problem description.

I'm developing an app with PySide backed and QML fronted. On the python side, I have my main.py where creating root context property of my AppCore class. Appcore.py stores custom properties of other classes for handling specific tasks. For example, ProjectMenager holds information about project properties and methods related to service-specific tasks. On QML side I have a lot of custom QML Objects that use those nested properties.

My problem is that invoking a function from ProjectMenager class to create project returns an error:

AttributeError: 'PySide6.QtGui.QGuiApplication' object has no attribute 'child_event'

The above exception was the direct cause of the following exception:

SystemError: PyEval_EvalFrameEx returned a result with an error set
file:///C:/Users/BardKrzysztof/Desktop/TensorflowAPI/Pyside6_App/dialogs/NewProjectDialog.qml:34:
Error: PyEval_EvalFrameEx returned a result with an error set

What's more, property binding in QML Text Object, won't get property value of that PtojectMenager, despite of having it in a variable (check several times)

Could somebody say where is problem and how to resolve it?

main.py

# This Python file uses the following encoding: utf-8

import sys
from PySide6 import *
from __feature__ import snake_case
from __feature__ import true_property

from PySide6.QtGui import QGuiApplication
from PySide6.QtQml import QQmlApplicationEngine, qmlRegisterType

from appcore import *

app = QGuiApplication(sys.argv)

engine = QQmlApplicationEngine()

opencv = OpencvImageProvider()
prMang = ProjectMenager()
paintHan = PaintHandler()

appCore = Appcore(projectMenager=prMang, opencvMenager=opencv, paintHandler=paintHan)

engine.root_context().set_context_property('appCore', appCore)

engine.quit.connect(app.quit)
engine.load('main.qml')

sys.exit(app.exec())

appcore.py

# This Python file uses the following encoding: utf-8
from PySide6.QtCore import Slot, Property, QObject, Signal
from PySide6.QtQml import QmlElement, QmlSingleton

import os
from projectMenager import ProjectMenager
from opencvImageProvider import OpencvImageProvider
from paintHandler import PaintHandler


class Appcore(QObject):

    projectMenagerChanged = Signal()
    opencvImageProviderChanged = Signal()
    paintHandlerChanged = Signal()

    def __init__(self, projectMenager: ProjectMenager, opencvMenager: OpencvImageProvider, paintHandler: PaintHandler):
        super(Appcore, self).__init__()
        self.projectMenager = projectMenager
        self.opencvMenager = opencvMenager
        self.paintHandler = paintHandler

        print(self.projectMenager)

    """
    Property setters and getters
    """

    def get_project_menager(self):
        return self.projectMenager

    def get_opnecv_menager(self):
        return self.opencvMenager

    def get_paint_handler(self):
        return self.paintHandler

    """
    Properties exposed to QML
    """
    prMeg = Property(ProjectMenager, get_project_menager, notify=projectMenagerChanged)
    openCV = Property(OpencvImageProvider, get_opnecv_menager, notify=opencvImageProviderChanged)
    paintHan = Property(PaintHandler, get_paint_handler, notify=paintHandlerChanged)

projectMenager.py

# This Python file uses the following encoding: utf-8
from PySide6.QtCore import Slot, Property, Signal, QObject

import os


class ProjectMenager(QObject):

    projectNameChanged = Signal()
    projectDescriptionChanged = Signal()
    projectLocationChanged = Signal()
    projectDateChanged = Signal()
    projectPathChanged = Signal()

    def __init__(self):
        super().__init__()
        self.projectName = None
        self.projectDescription = None
        self.projectLocation = None
        self.projectDate = None
        self.path = None

    @Slot(str, str, str, str)
    def create_new_project(self, name, desc, loc, date):
        self.projectName = name
        self.projectDescription = desc
        self.projectLocation = loc
        self.projectDate = date
        self.path = os.getcwd()

        print("Otrzymałem dane")

    ... 

    def get_project_name(self):
        return self.projectName

    def get_project_des(self):
        return self.projectDescription

    def get_project_loc(self):
        return self.projectLocation

    def get_project_date(self):
        return self.projectDate

    def get_project_path(self):
        return self.path

    """
    Properties
    """
    project_name = Property(str, get_project_name, notify=projectNameChanged)
    project_desc = Property(str, get_project_des, notify=projectDescriptionChanged)
    project_loc = Property(str, get_project_loc, notify=projectLocationChanged)
    project_date = Property(str, get_project_date, notify=projectDateChanged)
    project_path = Property(str, get_project_path, notify=projectPathChanged)

part of NewProjectDialog.qml

import QtQuick 2.15
import QtQuick.Controls 2.15
import QtQuick.Dialogs
//import QtGraphicalEffects 1.0

import "../GUI/Colors.js" as Colors

Item{

    id: control

    ...

    function acc(){

        console.log("fcn acc")
        appCore.prMeg.create_new_project(newProjectDialog.projectName, newProjectDialog.projectDescription,
                                newProjectDialog.projectLocation, newProjectDialog.projectDate)
        console.log("New project passed")
//        console.log(projectMenager.project_name, projectMenager.project_path)
        control.clear()
        newProjectDialog.close()

    }


    width: 300
    height: 440


    Dialog{
        id: newProjectDialog

        property string projectName: projectNameInput.text
        property string projectDescription: projectDescriptionInput.text
        property string projectLocation: projectLocationInput.text
        property string projectDate: projectDateInput.text
        ...
}

property biding that isn't working

        Text {
            text: appCore.prMeg.project_name
            anchors.bottom: parent.bottom
            anchors.margins: parent.height/10
        }

Szczempus

So, I think that I found a solution.
First of all, that error above was caused because of my __feature__ imports in the main.py file.
In order to that property binding in Text QML Object, it was needed to emit a python signal with string and it worked.