Trying to Connect QML Signal to PySide6 Slot using QQuickWidget

[iamontherun]

I am using PySide6 and trying to convert following code example from QT that uses QQuickView to use QQuickWidget

Original QT Example - https://code.qt.io/cgit/pyside/pyside-setup.git/tree/examples/qml/signals/qmltopy4
Orignal Example works well for QQuickView

I am changing the main.py as follows. This does not trigger the slot even though there is no errors.

main.py

import os
from pathlib import Path
import sys
from PySide6.QtCore import QUrl, Slot
from PySide6.QtQuickWidgets import QQuickWidget
from PySide6.QtWidgets import QApplication, QWidget, QVBoxLayout, QMainWindow


@Slot(float)
def sayThis(s):
    print(s)

class MainApp(QMainWindow):

    def __init__(self):
        super().__init__()
        self.initUI()
    
    def initUI(self):
        layout = QVBoxLayout()
        self.wt = QQuickWidget()
        ml_file = os.fspath(Path(__file__).resolve().parent / 'view1.qml')
        self.wt.setSource(QUrl.fromLocalFile(ml_file))

        root = self.wt.rootObject()
        root.textRotationChanged.connect(sayThis)


        layout.addWidget(self.wt)
        self.setLayout(layout)

        container = QWidget()
        container.setLayout(layout)
        self.setCentralWidget(container)


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainApp()
    window.show()
    sys.exit(app.exec())

view1.qml

import QtQuick

Rectangle {
    id: page

    signal buttonClicked
    signal textRotationChanged(double rot)

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

    Text {
        id: helloText
        text: "Hello world!"
        y: 30
        x: page.width/2-width/2
        font.pointSize: 24; font.bold: true
        onRotationChanged: textRotationChanged(rotation)

        states: State {
            name: "down"; when: buttonMouseArea.pressed === true
            PropertyChanges {
                target: helloText;
                rotation: 180;
                y: 100;
            }
        }

        transitions: Transition {
            from: ""; to: "down"; reversible: true
            ParallelAnimation {
                NumberAnimation {
                    properties: "y,rotation"
                    duration: 500
                    easing.type: Easing.InOutQuad
                }
            }
        }
    }

    Rectangle {
        id: button
        width: 150; height: 40
        color: "darkgray"
        anchors.horizontalCenter: page.horizontalCenter
        y: 120
        MouseArea {
            id: buttonMouseArea
            objectName: "buttonMouseArea"
            anchors.fill: parent
            onClicked: {
                buttonClicked()
            }
        }
        Text {
            id: buttonText
            text: "Press me!"
            anchors.horizontalCenter: button.horizontalCenter
            anchors.verticalCenter: button.verticalCenter
            font.pointSize: 16
        }
    }
}

[iamontherun]

@iamontherun example i am using is https://code.qt.io/cgit/pyside/pyside-setup.git/tree/examples/qml/signals/qmltopy3

[iamontherun]

I was able to get it to run by moving the root connect code to the bottom of init. after central widget.

DOES ANYONE KNOW WHY IT WORKS WHEN I ADD SIGNAL CONNECTOR AFTER SETTING THE CENTRAL WIDGET?

import os
from pathlib import Path
import sys
from PySide6.QtCore import QUrl, Slot
from PySide6.QtGui import QGuiApplication
from PySide6.QtQuick import QQuickView
from PySide6.QtQuickWidgets import QQuickWidget
from PySide6.QtWidgets import QApplication, QWidget, QVBoxLayout, QMainWindow

@Slot(float)
def sayThis(s):
    print(s)

class MainApp(QMainWindow):

    def __init__(self):
        super().__init__()
        self.initUI()
    
    def initUI(self):

        wt = QQuickWidget()
        ml_file = os.fspath(Path(__file__).resolve().parent / 'view1.qml')
        wt.setSource(QUrl.fromLocalFile(ml_file))
        self.setCentralWidget(wt)

        self.root = wt.rootObject()
        self.root.textRotationChanged.connect(sayThis)
        


if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = MainApp()
    window.show()
    sys.exit(app.exec())