Table view in qt quick with Python

irakli

Hi.
I am learning qt quick with Python. I have a basic project where I am trying to display a pandas dataframe in a TableView when the button is clicked. I am so far unable to achieve this seemingly simple goal.
Here's my main_window.py that acts as a backend:

from PySide6.QtQml import QmlElement, qmlRegisterType
from PySide6.QtCore import QObject, Signal, Slot, Property

import pandas as pd

from backend.utils import resource_path
from backend.data_models import PandasModel

QML_IMPORT_NAME = "main_window"
QML_IMPORT_MAJOR_VERSION = 1

qmlRegisterType(PandasModel, "App", 1, 0, "PandasModel")


@QmlElement
class MainWindow(QObject):
    loadDataButtonClicked = Signal(PandasModel)

    @Slot()
    def load_data(self):
        df = pd.read_csv(resource_path("data/ssi_template.csv"), low_memory=False)
        print(df.head())
        model = PandasModel(df)
        print(model.roleNames())
        self.loadDataButtonClicked.emit(model)

This is my model in another .py file:

from PySide6.QtCore import QAbstractTableModel, QModelIndex, Qt


class PandasModel(QAbstractTableModel):
    def __init__(self, df, parent=None):
        super().__init__(parent)
        self._dataframe = df

    def rowCount(self, parent=QModelIndex()):
        return len(self._dataframe)

    def columnCount(self, parent=QModelIndex()):
        return len(self._dataframe.columns)

    def roleNames(self):
        roles = {}
        for i, column in enumerate(self._dataframe.columns):
            roles[Qt.UserRole + i + 1] = column.encode('utf-8')
        return roles

    def data(self, index, role=Qt.ItemDataRole.DisplayRole):
        if not index.isValid():
            return None

        if role == Qt.ItemDataRole.DisplayRole:
            value = self._dataframe.iloc[index.row(), index.column()]
            return str(value) if value is not None else ""

        return None

    def headerData(self, section, orientation, role=Qt.ItemDataRole):
        """
        Return dataframe index as vertical header data and columns as horizontal header data.
        """
        if role == Qt.ItemDataRole.DisplayRole:
            if orientation == Qt.Orientation.Horizontal:
                return str(self._dataframe.columns[section])

            if orientation == Qt.Vertical:
                return str(self._dataframe.index[section])

        return None

and here is App.qml:

// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GPL-3.0-only

import QtQuick
import QtQuick.Controls
import Qt.labs.qmlmodels
import DataViewer
import main_window


Window {
    id: mainWindow
    width: Screen.width
    height: Screen.height

    visible: true
    visibility: Window.Maximized
    title: "DataViewer"


    MainScreenForm {  //This is from QDS UI file
        id: mainScreen
        anchors.fill: parent
    }

    MainWindow {  // This is Python backend
        id: main_window
    }


    TableView {
        parent: mainScreen.table_rect
        id: tableView
        anchors.fill: parent

        model = null // Initially it's null

        // Rest of code goes here
    }


    Connections {
        target: mainScreen.load_data_btn
        function onClicked() {
            main_window.load_data()
        }
    }

    Connections {
        target: main_window
        function onLoadDataButtonClicked() {
            tableView.model = main_window.model // Setting the model to the TableView when the button is clicked
        }
    }

}

I could not find relevant info in qt documentation/tutorials, on forums, and even LLMs like chatgpt or gemini could not help me.
Can anyone explain what am I doing wrong so far and how should I proceed?
Even better if someone can provide full example.

friedemannkleint

What exactly is not working? - The QML_IMPORT_NAME should be the module name and it should be consistent for MainWindow and PandasModel . The qmlRegisterType() should not be required, importing PandasModel should suffice.

For examples, see https://doc.qt.io/qtforpython-6/examples/example_qml_usingmodel.html#example-qml-usingmodel , https://doc.qt.io/qtforpython-6/examples/example_qml_editingmodel.html and others.

irakli

@friedemannkleint The data that the model provides is not displayed in the tableview. When button is clicked, it should be emitting signal with the model that carries the data, so model=null is turned into model=actual data, then the data should be displayed on tableview. As you can see I've left part of the TableView block empty so someone could suggest the solution to this.