QDesktopWidget上的ApplicationShortcut在PySide2中无法正常运行

Question

由于我当前正在将gui应用程序从Python 2.7.14 / PySide 1.2.4移植到Python 3.7.1 / PySide2 5.11.2，因此我遇到了快捷方式问题。基本上：

• 在QShortcuts上使用Qt.ApplicationShortcut上下文设置QDesktopWidget在PySide2中似乎无法正常工作，而在PySide中则很好。

好像其他人encountered the same issue too。

• 这是一个已知的错误吗？
• 是否存在一种优雅的解决方法，可以将应用程序范围的快捷方式放置在应用程序中的某个位置而无需为此创建不可见的小部件？

Python 3.7.1 / PySide2 5.11.2 （不起作用）

---

# -*- coding: utf-8 -*-
"""Test application wide shortcut on desktop widget fails in PySide2."""
import logging
from datetime import datetime

from PySide2.QtCore import Qt
from PySide2.QtGui import QKeySequence
from PySide2.QtWidgets import QShortcut, QWidget, QApplication


logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)


class Widget(QWidget):
    """Widget with application wide shortcut."""

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)

        shortcut = QShortcut(QKeySequence(Qt.Key_H), QApplication.desktop())
        shortcut.setContext(Qt.ApplicationShortcut)
        shortcut.activated.connect(self.handler)

    def handler(self):
        """Shortcut does not trigger."""
        msg = f"{datetime.now()}"
        logger.info(msg)


# run
app = QApplication()
widget = Widget()
widget.show()
app.exec_()

Python 2.7.14 / PySide 1.2.4 （正在运行）

---

# -*- coding: utf-8 -*-
"""Test application wide shortcut on desktop widget succeeds in PySide."""
import logging
from datetime import datetime

from PySide.QtCore import Qt
from PySide.QtGui import QKeySequence, QShortcut, QWidget, QApplication


logging.basicConfig(level=logging.DEBUG)
logger = logging.getLogger(__name__)


class Widget(QWidget):
    """Widget with application wide shortcut."""

    def __init__(self, *args, **kwargs):
        super(Widget, self).__init__(*args, **kwargs)

        shortcut = QShortcut(QKeySequence(Qt.Key_H), QApplication.desktop())
        shortcut.setContext(Qt.ApplicationShortcut)
        shortcut.activated.connect(self.handler)

    def handler(self):
        """Shortcut does trigger."""
        msg = "{}".format(datetime.now())
        logger.info(msg)


# run
app = QApplication(tuple())
widget = Widget()
widget.show()
app.exec_()

实际用例

---

• 我有一个ApplicationHotkeyHandler，它是一个QObject，它定义了应用程序范围内的所有快捷方式。
• 该实例上的处理程序函数已在QDesktopWidget上注册为应用程序范围的快捷方式，它是Qt基础结构的一部分，似乎是一种仅出于此目的而创建无形，人工小部件的优雅安全的方法保留应用程序快捷方式的方法。

以下是应用程序外观的要点：

---

class ApplicationHotkeyHandler(QObject):
    """Define application wide hotkeys and their handlers here. Shortcuts are
    placed on QDesktopWidget which is an always available part of the Qt
    infrastructure.

    Notes:
        This is a QObject for signals and parenting but not a QWidget
        as we don't have to display anything, so the handler instance cannot 
        serve as parent for QShortcuts.
    """

    @hotkey(QKeySequence(Qt.CTRL + Qt.Key_Q), context=Qt.ApplicationShortcut,)
    def quit(self):
        QApplication.instance().quit()

    ...