扩展QML - 添加类型示例¶

添加类型示例展示了如何向QML添加一个新的对象类型Person。 Person类型可以像这样在QML中使用：

import examples.adding.people

Person {
    name: "Bob Jones"
    shoe_size: 12
}

声明Person类¶

所有QML类型都映射到C++类型。这里我们声明了一个基本的C++ Person类，其中包含我们希望在QML类型上访问的两个属性 - name和shoeSize。尽管在这个例子中我们为C++类和QML类型使用了相同的名称，但C++类可以有不同的名称，或者出现在命名空间中。

Person 类的实现非常基础。属性访问器只是返回对象实例的成员。

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

运行示例¶

示例中的 main.py 文件包含一个简单的 shell 应用程序，它加载并运行本页开头显示的 QML 片段。

下载这个示例

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/adding 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


if __name__ == '__main__':
    app = QCoreApplication(sys.argv)

    engine = QQmlEngine()
    engine.addImportPath(Path(__file__).parent)
    component = QQmlComponent(engine)
    component.loadFromModule("People", "Main")

    person = component.create()
    if person:
        print(f"The person's name is {person.name}")
        print(f"They wear a {person.shoe_size} sized shoe")
    else:
        print(component.errors())
    del engine
    sys.exit(0)

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 People

Person {
    name: "Bob Jones"
    shoe_size: 12
}

People/qmldir

module People
typeinfo coercion.qmltypes
Main 1.0 Main.qml