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Diffstat (limited to 'examples/qml/tutorials/extending-qml-advanced/extended')
4 files changed, 147 insertions, 0 deletions
diff --git a/examples/qml/tutorials/extending-qml-advanced/extended/doc/extended.rst b/examples/qml/tutorials/extending-qml-advanced/extended/doc/extended.rst new file mode 100644 index 000000000..745960535 --- /dev/null +++ b/examples/qml/tutorials/extending-qml-advanced/extended/doc/extended.rst @@ -0,0 +1,41 @@ +.. _qml-extension-objects-example: + +Extending QML - Extension Objects Example +========================================= + +This example builds on the the :ref:`qml-adding-types-example`. + +Shows how to use QmlExtended decorator to provide an extension object to a +QLineEdit without modifying or subclassing it. + +Firstly, the LineEditExtension class is registered with the QML system as an +extension of QLineEdit. We declare a foreign type to do this as we cannot +modify Qt's internal QLineEdit class. + +.. code-block:: python + + @QmlNamedElement("QLineEdit") + @QmlExtended(LineEditExtension) + @QmlForeign(QLineEdit) + class LineEditForeign(QObject): + + +Note the usage of ``QmlNamedElement()`` instead of ``QmlElement()``. +``QmlElement()`` uses the name of the containing type by default, +``LineEditExtension`` in this case. As the class being an extension class is +an implementation detail, we choose the more natural name ``QLineEdit`` +instead. + +The QML engine then instantiates a QLineEdit. + +In QML, a property is set on the line edit that only exists in the +``LineEditExtension`` class: + +.. code-block:: javascript + + QLineEdit { + left_margin: 20 + } + +The extension type performs calls on the ``QLineEdit`` that otherwise will not +be accessible to the QML engine. diff --git a/examples/qml/tutorials/extending-qml-advanced/extended/example.qml b/examples/qml/tutorials/extending-qml-advanced/extended/example.qml new file mode 100644 index 000000000..e4af3bec5 --- /dev/null +++ b/examples/qml/tutorials/extending-qml-advanced/extended/example.qml @@ -0,0 +1,8 @@ +// Copyright (C) 2022 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause + +import examples.extend 1.0 + +QLineEdit { + left_margin: 20 +} diff --git a/examples/qml/tutorials/extending-qml-advanced/extended/extended.pyproject b/examples/qml/tutorials/extending-qml-advanced/extended/extended.pyproject new file mode 100644 index 000000000..127a3a76a --- /dev/null +++ b/examples/qml/tutorials/extending-qml-advanced/extended/extended.pyproject @@ -0,0 +1,3 @@ +{ + "files": ["main.py", "example.qml"] +} diff --git a/examples/qml/tutorials/extending-qml-advanced/extended/main.py b/examples/qml/tutorials/extending-qml-advanced/extended/main.py new file mode 100644 index 000000000..6ee386401 --- /dev/null +++ b/examples/qml/tutorials/extending-qml-advanced/extended/main.py @@ -0,0 +1,95 @@ +# Copyright (C) 2022 The Qt Company Ltd. +# SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause + +"""PySide6 port of the qml/examples/qml/referenceexamples/extended example from Qt v6.x""" + +from pathlib import Path +import sys + +from PySide6.QtCore import QObject, QUrl, Property +from PySide6.QtWidgets import QApplication, QLineEdit +from PySide6.QtQml import (QQmlComponent, QQmlEngine, QmlForeign, QmlExtended, + QmlNamedElement) + + +# To be used on the @QmlElement decorator +# (QML_IMPORT_MINOR_VERSION is optional) +QML_IMPORT_NAME = "examples.extend" +QML_IMPORT_MAJOR_VERSION = 1 + + +class LineEditExtension(QObject): + + def __init__(self, parent=None): + super().__init__(parent) + self._line_edit = parent + + @Property(int) + def left_margin(self): + return self._line_edit.textMargins().left() + + @left_margin.setter + def left_margin(self, m): + margins = self._line_edit.textMargins() + margins.setLeft(m) + self._line_edit.setTextMargins(margins) + + @Property(int) + def right_margin(self): + return self._line_edit.textMargins().right() + + @right_margin.setter + def right_margin(self, m): + margins = self._line_edit.textMargins() + margins.setRight(m) + self._line_edit.setTextMargins(margins) + + @Property(int) + def top_margin(self): + return self._line_edit.textMargins().top() + + @top_margin.setter + def top_margin(self, m): + margins = self._line_edit.textMargins() + margins.setTop(m) + self._line_edit.setTextMargins(margins) + + @Property(int) + def bottom_margin(self): + return self._line_edit.textMargins().bottom() + + @bottom_margin.setter + def bottom_margin(self, m): + margins = self._line_edit.textMargins() + margins.setBottom(m) + self._line_edit.setTextMargins(margins) + + +@QmlNamedElement("QLineEdit") +@QmlExtended(LineEditExtension) +@QmlForeign(QLineEdit) +class LineEditForeign(QObject): + + def __init__(self, parent=None): + super().__init__(parent) + + +if __name__ == '__main__': + app = QApplication(sys.argv) + + qml_file = Path(__file__).parent / "example.qml" + url = QUrl.fromLocalFile(qml_file) + engine = QQmlEngine() + component = QQmlComponent(engine, url) + widget = component.create() + if not widget: + print(component.errors()) + del engine + sys.exit(-1) + + widget.show() + r = app.exec() + # Deleting the engine before it goes out of scope is required to make sure + # all child QML instances are destroyed in the correct order. + del engine + sys.exit(r) |