QQMLApplicationEngine failed to load component; Number generator is not a type

SCP173

I am trying to run an example from QT5 Cadaques book - the full official source code can be found from this link here in this directory: ch20-python-assets\ch20-python\src\class

I get a QQMLApplicationEngine failed to load component; Number generator is not a type error
when running the class.py file. I am using Python 3.8.9 and PySide6 on Windows 10 Pro. Am I missing something obvious?

eyllanesc

@SCP173

Try with:

import sys
import random

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

from PySide6.QtCore import QObject, Signal, Slot

class NumberGenerator(QObject):
    def __init__(self):
        QObject.__init__(self)
    
    nextNumber = Signal(int)

    @Slot()
    def giveNumber(self):
        self.nextNumber.emit(random.randint(0, 99))


if __name__ == '__main__':
    app = QGuiApplication(sys.argv)
    engine = QQmlApplicationEngine()
    
    qmlRegisterType(NumberGenerator, 'Generators', 1, 0, 'NumberGenerator')
    
    engine.load(QUrl("main.qml"))
    
    if not engine.rootObjects():
        sys.exit(-1)    
    
    sys.exit(app.exec())

import QtQuick 2.0
import QtQuick.Window 2.0
import QtQuick.Controls 2.0

import Generators 1.0

Window {
    id: root
    
    width: 640
    height: 480
    visible: true
    title: "Hello Python World!"
    
    Flow {
        Button {
            text: "Give me a number!"
            onClicked: numberGenerator.giveNumber();
        }
        Label {
            id: numberLabel
            text: "no number"
        }
    }
    
    NumberGenerator {
        id: numberGenerator
        
        // Signal argument names are not propagated from Python to QML, so we need to re-emit the signal
        signal reNextNumber(int number)
        Component.onCompleted: numberGenerator.nextNumber.connect(reNextNumber)
    }
    
    Connections {
        target: numberGenerator
        function onReNextNumber(number){
            numberLabel.text = number
        }
    }
}