Directly Connecting QML Component Signals to Python Functions

Teach how to connect signals of specific QML components to Python functions using object names.

Key Features:

• Assigning `objectName` in QML: Sets objectName properties to identify QML objects.

• Finding QML Objects in Python: Uses findChild to get references to QML objects.

• Connecting Component Signals to Python Functions: Connects signals directly to Python functions.

Download this example

main.py

# Copyright (C) 2022 The Qt Company Ltd.
# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
from __future__ import annotations

import os
from pathlib import Path
import sys
from PySide6.QtCore import QObject, QUrl
from PySide6.QtGui import QGuiApplication
from PySide6.QtQuick import QQuickView


def sayThis(s):
    print(s)


if __name__ == '__main__':
    app = QGuiApplication(sys.argv)
    view = QQuickView()
    qml_file = os.fspath(Path(__file__).resolve().parent / 'view.qml')
    view.setSource(QUrl.fromLocalFile(qml_file))
    if view.status() == QQuickView.Status.Error:
        sys.exit(-1)

    root = view.rootObject()
    button = root.findChild(QObject, "buttonMouseArea")
    button.clicked.connect(lambda: sayThis("clicked button (signal directly connected)"))

    view.show()
    res = app.exec()
    # Deleting the view before it goes out of scope is required to make sure all child QML instances
    # are destroyed in the correct order.
    del view
    sys.exit(res)

view.qml

// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

import QtQuick

Rectangle {
    id: page

    width: 500; height: 200
    color: "lightgray"

    Rectangle {
        id: button
        width: 150; height: 40
        color: "darkgray"
        anchors.horizontalCenter: page.horizontalCenter
        anchors.verticalCenter: page.verticalCenter
        MouseArea {
            id: buttonMouseArea
            objectName: "buttonMouseArea"
            anchors.fill: parent
        }
        Text {
            id: buttonText
            text: "Press me!"
            anchors.horizontalCenter: button.horizontalCenter
            anchors.verticalCenter: button.verticalCenter
            font.pointSize: 16
        }
    }
}