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// 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
the project is created. Further, it prompts you to install the
\l {Python Language Server}{Python language server} that provides services
such as code completion and annotations. Select \uicontrol Install to install
PySide6 and the language server.
To view and manage the available Python interpreters, 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 have been uninstalled, but 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 contains
some boilerplate code. In addition, the widget based UI wizard creates a
\c {.ui} file that contains a \QD form, and the Qt Quick Application wizard
creates a \c {.qml} file that contains 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 contains the source file for a class. Specify
the PySide version, class name, base class, and 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 to provide
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 UI elements of the new class can be accessed 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
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 {Creating 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 Creating Qt Quick Based Python Applications
The \uicontrol {Qt for Python - Qt Quick Application - Empty} wizard enables
you to create a Python project that contains 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 to provide 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]
*/
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