Extending QML - Methods Example

This example builds on the Extending QML - Adding Types Example, the Extending QML - Object and List Property Types Example and the Extending QML (advanced) - Inheritance and Coercion.

The Methods Example has an additional method in the BirthdayParty class: invite(). invite() is decorated with @Slot so that it can be called from QML.

In example.qml, the invite() method is called in the QtQml.Component.completed() signal handler.

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main.py

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

"""PySide6 port of the qml/examples/qml/referenceexamples/methods example from Qt v6.x"""

from pathlib import Path
import sys

from PySide6.QtCore import QCoreApplication
from PySide6.QtQml import QQmlComponent, QQmlEngine

from person import Person  # noqa: F401
from birthdayparty import BirthdayParty  # noqa: F401


app = QCoreApplication(sys.argv)
engine = QQmlEngine()
engine.addImportPath(Path(__file__).parent)
component = QQmlComponent(engine)
component.loadFromModule("People", "Main")
party = component.create()
if not party:
    print(component.errors())
    del engine
    sys.exit(-1)
host = party.host
print(f"{host.name} is having a birthday!\nThey are inviting:")
for g in range(party.guestCount()):
    name = party.guest(g).name
    print(f"    {name}")
del engine
sys.exit(0)

birthdayparty.py

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

from PySide6.QtCore import QObject, Property, Slot
from PySide6.QtQml import QmlElement, ListProperty

from person import Person


# To be used on the @QmlElement decorator
# (QML_IMPORT_MINOR_VERSION is optional)
QML_IMPORT_NAME = "People"
QML_IMPORT_MAJOR_VERSION = 1


@QmlElement
class BirthdayParty(QObject):

    def __init__(self, parent=None):
        super().__init__(parent)
        self._host = None
        self._guests = []

    @Property(Person)
    def host(self):
        return self._host

    @host.setter
    def host(self, h):
        self._host = h

    def guest(self, n):
        return self._guests[n]

    def guestCount(self):
        return len(self._guests)

    def appendGuest(self, guest):
        self._guests.append(guest)

    @Slot(str)
    def invite(self, name):
        guest = Person(self)
        guest.name = name
        self.appendGuest(guest)

    guests = ListProperty(Person, appendGuest)

person.py

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

from PySide6.QtCore import QObject, Property
from PySide6.QtQml import QmlElement

# To be used on the @QmlElement decorator
# (QML_IMPORT_MINOR_VERSION is optional)
QML_IMPORT_NAME = "People"
QML_IMPORT_MAJOR_VERSION = 1


@QmlElement
class Person(QObject):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._name = ''
        self._shoe_size = 0

    @Property(str)
    def name(self):
        return self._name

    @name.setter
    def name(self, n):
        self._name = n

    @Property(int)
    def shoe_size(self):
        return self._shoe_size

    @shoe_size.setter
    def shoe_size(self, s):
        self._shoe_size = s

People/Main.qml

// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

import QtQuick
import People

BirthdayParty {
    host: Person {
        name: "Bob Jones"
        shoe_size: 12
    }
    guests: [
        Person { name: "Leo Hodges" },
        Person { name: "Jack Smith" },
        Person { name: "Anne Brown" }
    ]

    Component.onCompleted: invite("William Green")
}

People/qmldir

module People
typeinfo coercion.qmltypes
Main 1.0 Main.qml