python - 使用 "keyboard"在失去焦点时打开新窗口

Question

我正在尝试跟踪我的按键，使用模块“键盘”，而 PySide2 小部件未处于焦点状态，效果很好。但是，当我尝试使用“键盘”快捷方式创建新的 Widget 时，程序崩溃了。按下按钮打开一个窗口工作正常。我也可以使用“键盘”调用非 UI 函数，例如。打印功能没有任何问题。

你知道解决这个问题的方法吗？使用“键盘”或任何其他方法打开一个新窗口，而 PySide2 窗口不在焦点上。在这个例子中，我想在“CTRL+D”上打开一个新窗口。 PySide2 和 PyQt5 都存在此问题。

这是我的简化代码:

import sys
import json
import os
import keyboard
from PySide2.QtWidgets import QApplication, QWidget, QGridLayout, QKeySequenceEdit, QLabel, QPushButton, QShortcut
from PySide2.QtCore import Qt, QObject, Signal, Slot # Qt.Key_W beispielsweise

#from PyQt5.QtWidgets import QApplication, QWidget, QGridLayout, QKeySequenceEdit, QLabel, QPushButton, QShortcut
#from PyQt5.QtCore import Qt, QObject, pyqtSignal as Signal, pyqtSlot as Slot # Qt.Key_W beispielsweise


class ConfigWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.initUi()
        self.init_shortcuts()
        self.show()

    def initUi(self):
        self.setGeometry(300,300, 400, 250)
        self.setWindowTitle("Settings")
        grid = QGridLayout()
        self.setLayout(grid)

        self.keyseq = QKeySequenceEdit("CTRL+D")
        grid.addWidget(self.keyseq, 0, 0)

        s_button = QPushButton("Safe")
        grid.addWidget(s_button, 1, 0)

        cl_button = QPushButton("Close")
        grid.addWidget(cl_button, 1, 1)
        cl_button.clicked.connect(self.close)

        open_button = QPushButton("openw")
        grid.addWidget(open_button, 2, 0)
        open_button.clicked.connect(self.call_item_parser)

    def keyPressEvent(self, event): #event:PySide2.QtGui.QKeyEvent
        if event.key() == Qt.Key_Escape:
            self.close()

    # shortcuts are listened to, while program is running
    def init_shortcuts(self):
        str_value = self.keyseq.keySequence().toString()
        print("Binding _price_keyseq to {}".format(str_value))
        keyboard.add_hotkey(str_value, self.call_item_parser)
        # keyboard.add_hotkey(str_value, print, args=("this works")) # this would work


    def call_item_parser(self):
        self.h_w = ParseWindow()
        self.h_w.setWindowTitle("New Window")
        self.h_w.setGeometry(100, 100, 100, 100)
        self.h_w.show()


class ParseWindow(QWidget):
    def __init__(self):
        super().__init__()


app = QApplication(sys.argv)
w = ConfigWindow()
sys.exit(app.exec_())

Answer 1

问题是因为在键盘注册的回调是在辅助线程中执行的，可以通过修改以下部分代码并打印threading.current_thread()来验证。在 Qt 中，禁止在另一个线程中创建任何小部件，因为它们不是线程安全的。

def call_item_parser(self):
    <b>print(threading.current_thread())</b>
    self.h_w = ParseWindow()
    self.h_w.setWindowTitle("New Window")
    self.h_w.setGeometry(100, 100, 100, 100)
    self.h_w.show()

<b>print(threading.current_thread())</b>
app = QApplication(sys.argv)
w = ConfigWindow()
sys.exit(app.exec_())

输出:

<_MainThread(MainThread, started 140144979916608)>
Binding _price_keyseq to ctrl+a
<Thread(Thread-10, started daemon 140144220817152)>

一种可能的解决方案是使用信号将信息发送到主线程，并在主线程中调用回调。

import sys
from functools import partial
import platform
import threading

import keyboard


from PySide2.QtCore import Qt, QObject, Signal, Slot
from PySide2.QtGui import QKeySequence
from PySide2.QtWidgets import (
    QApplication,
    QWidget,
    QGridLayout,
    QKeySequenceEdit,
    QPushButton,
)


class KeyBoardManager(QObject):
    activated = Signal(str)

    def __init__(self, parent=None):
        super().__init__(parent)
        self._callbacks = dict()
        self.activated.connect(self._handle_activated)

    @property
    def callbacks(self):
        return self._callbacks

    def register(self, shortcut, callback, *, args=(), kwargs=None):
        self.callbacks[shortcut] = (callback, args, kwargs or {})
        keyboard.add_hotkey(shortcut, partial(self.activated.emit, shortcut))

    @Slot(str)
    def _handle_activated(self, shortcut):
        values = self.callbacks.get(shortcut)
        if values is not None:
            callback, args, kwargs = self._callbacks[shortcut]

            callback(*args, **kwargs)


class ConfigWindow(QWidget):
    def __init__(self):
        super().__init__()
        self.initUi()
        self.init_shortcuts()
        self.show()

    def initUi(self):
        self.setGeometry(300, 300, 400, 250)
        self.setWindowTitle("Settings")
        grid = QGridLayout(self)

        self.keyseq = QKeySequenceEdit("CTRL+A")
        grid.addWidget(self.keyseq, 0, 0)

        s_button = QPushButton("Safe")
        grid.addWidget(s_button, 1, 0)

        cl_button = QPushButton("Close")
        grid.addWidget(cl_button, 1, 1)
        cl_button.clicked.connect(self.close)

        open_button = QPushButton("openw")
        grid.addWidget(open_button, 2, 0)
        open_button.clicked.connect(self.call_item_parser)

    def keyPressEvent(self, event):  # event:PySide2.QtGui.QKeyEvent
        if event.key() == Qt.Key_Escape:
            self.close()

    # shortcuts are listened to, while program is running
    def init_shortcuts(self):
        self.keyboard_manager = KeyBoardManager()

        str_value = self.keyseq.keySequence().toString()
        if platform.system() == "Linux":
            str_value = str_value.lower()
        print("Binding _price_keyseq to {}".format(str_value))
        self.keyboard_manager.register(str_value, self.call_item_parser)

    def call_item_parser(self):
        print(threading.current_thread())
        self.h_w = ParseWindow()
        self.h_w.setWindowTitle("New Window")
        self.h_w.setGeometry(100, 100, 100, 100)
        self.h_w.show()


class ParseWindow(QWidget):
    pass


def main():
    print(threading.current_thread())
    app = QApplication(sys.argv)
    w = ConfigWindow()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main()

输出:

<_MainThread(MainThread, started 140037641176896)>
Binding _price_keyseq to ctrl+a
<_MainThread(MainThread, started 140037641176896)>