// Copyright (C) 2021 The Qt Company Ltd. // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only /*! //! [python project wizards] \section2 Creating Widget-Based Qt for Python Applications \l {https://doc.qt.io/qtforpython/index.html}{Qt for Python} enables you to use Qt 6 API in Python applications. You can use the PySide6 modules to gain access to individual Qt modules, such as \l {Qt Core}, \l {Qt GUI}, and \l {Qt Widgets}. If you have not installed PySide6, \QC prompts you to install it after you create the project. Further, it prompts you to install the \l {Python Language Server}{Python language server} that offers services such as code completion and annotations. Select \uicontrol Install to install PySide6 and the language server. You can see the current Python interpreter on the \uicontrol Edit mode toolbar. \image qtcreator-python-interpreter-edit-mode.webp {Python interpreter on the Edit mode toolbar} To see the available interpreters and change their paths, select the interpreter, and then select \uicontrol {Manage Python Interpreters}. Or, select \uicontrol Edit > \uicontrol Preferences > \uicontrol Python > \uicontrol Interpreters. \image qtcreator-python-interpreters.png {Python Interpreters in Preferences} You can add and remove interpreters and clean up references to interpreters that you uninstalled, but that still appear in the list. In addition, you can set the interpreter to use by default. The Qt for Python Application wizards generate a \c {.pyproject} file that lists the files in the Python project and a \c {.py} file that has some boilerplate code. In addition, the widget-based UI wizard creates a \c {.ui} file that has a \QD form, and the Qt Quick Application wizard creates a \c {.qml} file that has Qt Quick controls. The \c{.pyproject} files are JSON-based configuration files that replace the previously used \c {.pyqtc} configuration files. You can still open and use \c {.pyqtc} files, but we recommend that you choose \c{.pyproject} files for new projects. The \uicontrol {Window UI} wizard enables you to create a Python project that has the source file for a class. Specify the PySide version, class name, base class, and source file for the class. \image qtcreator-python-wizard-app-window.png {Qt for Python wizard for creating a widget-based UI} The wizard adds the imports to the source file for access to the QApplication, the base class you selected in the Qt Widgets module, and Qt UI tools: \badcode import sys from PySide6.QtWidgets import QApplication, QWidget \endcode \note It is important that you first create the Python code from your UI form. In PySide6, you can do this by executing \c{pyside6-uic form.ui -o ui_form.py} on a terminal. This enables you to import the class that represents your UI from that Python file. Once you generate the Python code from the UI file, you can import the class: \badcode from ui_form import Ui_Widget \endcode The wizard also adds a main class with the specified name that inherits from the specified base class: \badcode class Widget(QWidget): def __init__(self, parent=None): super().__init__(parent) \endcode The following lines in the main class instantiate the generated Python class from your UI file, and set up the interface for the current class. \badcode self.ui = Ui_Widget() self.ui.setupUi(self) \endcode \note You can access the UI elements of the new class as member variables. For example, if you have a button called \e{button1}, you can interact with it using \c{self.ui.button1}. Next, the wizard adds a main function, where it creates a QApplication instance. As Qt can receive arguments from the command line, you can pass any arguments to the QApplication object. Usually, you do not need to pass any arguments, and you can use the following approach: \badcode if __name__ == "__main__": app = QApplication(sys.argv) \endcode Next, the wizard instantiates the \c MainWindow class and shows it: \badcode widget = Widget() widget.show() ... \endcode Finally, the wizard calls the \c app.exec() method to enter the Qt main loop and start executing the Qt code: \badcode sys.exit(app.exec()) \endcode You can now modify the boilerplate code in the Edit mode to develop your Python application. Select \uicontrol REPL on the toolbar to start the \l{https://pythonprogramminglanguage.com/repl/}{Python interactive shell}. To start the shell and import the current file as a module, select \uicontrol {REPL Import File}. To also import all functions from the file, select \uicontrol {REPL Import *}. Always regenerate the Python code after modifying a UI file. Open the .ui file in the \uicontrol Design mode to create a widget-based UI in \QD. The \uicontrol Window wizard adds similar code to the source file, without the UI bits. The \uicontrol Empty wizard adds similar code to the source file, but it does not add any classes, so you need to add and instantiate them yourself. For more information about the \uicontrol {Qt for Python - Qt Quick Application - Empty} wizard, see \l {Qt Quick Based Python Applications}. For examples of creating Qt for Python applications, see \l {https://doc.qt.io/qtforpython/tutorials/index.html} {Qt for Python Examples and Tutorials}. //! [python project wizards] //! [python qml project wizards] \section1 Qt Quick Based Python Applications The \uicontrol {Qt for Python - Qt Quick Application - Empty} wizard enables you to create a Python project that has a main QML file. Specify the minimum PySide version to run the application. \image qtcreator-python-wizard-qml.png {Qt for Python wizard for creating an empty Qt Quick application} The wizard adds the following imports to the source file for access to QGuiApplication and QQmlApplicationEngine: \badcode import sys from pathlib import Path from PySide6.QtGui import QGuiApplication from PySide6.QtQml import QQmlApplicationEngine \endcode The wizard also adds a main function, where it creates a QGuiApplication instance and passes system arguments to the QGuiApplication object: \badcode if __name__ == "__main__": app = QGuiApplication(sys.argv) ... \endcode The following lines in the main class create a QQmlApplicationEngine instance and load the generated QML file to the engine object: \badcode engine = QQmlApplicationEngine() qml_file = Path(__file__).resolve().parent / "main.qml" engine.load(qml_file) \endcode Finally, the wizard adds code that checks whether the file was successfully loaded. If loading the file fails, the application exits with an error code. If loading succeeds, the wizard calls the \c app.exec() method to enter the Qt main loop and start executing the Qt code: \badcode if not engine.rootObjects(): sys.exit(-1) sys.exit(app.exec()) \endcode Open the .qml file in the \uicontrol Edit mode to design a Qt Quick UI, or use \l{Qt Design Studio Manual}{\QDS}. //! [python qml project wizards] */