PySide6

Warnings

• breaking When migrating from PySide2 to PySide6, the primary change required is updating import statements from `PySide2.*` to `PySide6.*`.
  Fix: Replace `from PySide2` with `from PySide6` in all import statements.
• breaking The `QAction` class, used for creating toolbars and menus, has been moved from `PySide6.QtWidgets` to `PySide6.QtGui` in Qt6.
  Fix: Update imports for `QAction` to `from PySide6.QtGui import QAction`.
• breaking High DPI (dots per inch) scaling is enabled by default in Qt6. The previously used attributes like `Qt.AA_EnableHighDpiScaling` and `Qt.AA_UseHighDpiPixmaps` are deprecated and have no effect.
  Fix: Remove any explicit High DPI scaling attributes from your application initialization code.
• gotcha `QMouseEvent.pos()` and `QMouseEvent.globalPos()` now return a `QPointF` object (floating-point coordinates), unlike in Qt5 where they returned integer tuples.
  Fix: If integer coordinates are strictly required, convert the `QPointF` to `QPoint` using `.toPoint()`, e.g., `event.pos().toPoint()`.
• gotcha Functions named `exec_()` (e.g., `QApplication.exec_()`, `QDialog.exec_()`) have been renamed to `exec()` in PySide6 to avoid conflict with the `exec` keyword in Python 3.
  Fix: Replace calls to `exec_()` with `exec()`.
• gotcha Qt Enums no longer necessarily inherit to the top-level `Qt` object. For example, `Qt.AlignCenter` might not be directly accessible and requires explicit import or a more specific path.
  Fix: For enums, use their full path (e.g., `QtCore.Qt.AlignmentFlag.AlignCenter`) or import the specific enum class if available.
• gotcha PySide6 offers an experimental `snake_case` feature (via `from __feature__ import snake_case`) to align method naming with PEP8. However, this is an opt-in feature and can lead to inconsistent code if not applied uniformly across a project, especially with auto-generated UI code.
  Fix: Decide on a consistent naming convention. If using `snake_case`, ensure all new code and potentially existing code (or auto-generated UI code) adheres to it to avoid mixed styles.

Install

• pip install PySide6 Install PySide6

Imports

• QApplication

  from PySide6.QtWidgets import QApplication

• QMainWindow

  from PySide6.QtWidgets import QMainWindow

• QWidget

  from PySide6.QtWidgets import QWidget

• QLabel

  from PySide6.QtWidgets import QLabel

• QPushButton

  from PySide6.QtWidgets import QPushButton

• QVBoxLayout

  from PySide6.QtWidgets import QVBoxLayout

• QAction

  from PySide6.QtGui import QAction

  QAction was moved from QtWidgets to QtGui in Qt6/PySide6.
• Qt (for enums like alignment)

  from PySide6.QtCore import Qt

Quickstart

This quickstart code creates a basic PySide6 application with a main window, a label displaying 'Hello, PySide6!', and a button. Clicking the button changes the label's text and prints a message to the console. It demonstrates fundamental concepts like QApplication, QMainWindow, widgets, layouts, and signal/slot connections.

import sys
from PySide6.QtWidgets import QApplication, QMainWindow, QLabel, QVBoxLayout, QWidget, QPushButton
from PySide6.QtCore import Qt

class MyWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        self.setWindowTitle('PySide6 Hello World!')
        self.setGeometry(100, 100, 400, 200)

        layout = QVBoxLayout()
        label = QLabel('Hello, PySide6!')
        label.setAlignment(Qt.AlignCenter)
        layout.addWidget(label)

        button = QPushButton('Click Me!')
        button.clicked.connect(self.on_button_click)
        layout.addWidget(button)

        container = QWidget()
        container.setLayout(layout)
        self.setCentralWidget(container)

    def on_button_click(self):
        print('Button clicked!')
        self.centralWidget().findChild(QLabel).setText('You clicked the button!')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    window = MyWindow()
    window.show()
    sys.exit(app.exec())