在QAPP EventFilter中替换Qkeyevents

Question

我正在尝试编写一个pyqt5应用程序，该应用程序捕获某些击键，并用其他一些击键替换它们。由于我希望对整个应用程序进行此替换，因此我(也许是错误的(我需要在qApp上进行事件过滤器。搜索后，我将此概念证明拼凑在一起：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt
# Keys to block
kmap = [Qt.Key_U,Qt.Key_I,Qt.Key_O,Qt.Key_P,Qt.Key_J,Qt.Key_K,Qt.Key_L,Qt.Key_M]
class Example(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()
    # The simplest UI
    def initUI(self):               
        self.edit = QtWidgets.QTextEdit()
        QtWidgets.qApp.installEventFilter(self)
        self.setCentralWidget(self.edit)
        # Window placement 
        self.show()
    def sendkeys(self, char, modifier=Qt.NoModifier):
        event = QtGui.QKeyEvent(QtCore.QEvent.KeyPress, 0, modifier, char)
        QtCore.QCoreApplication.postEvent(self, event)
        event = QtGui.QKeyEvent(QtCore.QEvent.KeyRelease, 0, modifier, char)
        QtCore.QCoreApplication.postEvent(self, event)
    def eventFilter(self, obj, event):
        if type(event) == QtGui.QKeyEvent:
            print("Normal stroke %d of type %s to %s" % (event.key(), str(event.type()), str(obj)))
            if event.key() in kmap:
                if type(obj) == QtWidgets.QTextEdit and obj.type() == QtCore.QEvent.KeyPress:
                    sendkeys("c")
                return True
        return super().eventFilter(obj, event)
if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

不幸的是，这无效。完全。

首先，即使我在记录后进行过滤，也会阻止和未阻止的键产生不同的事件：

Normal stroke 66 of type 51 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>
Normal stroke 66 of type 51 to <PyQt5.QtWidgets.QTextEdit object at 0x7ff4800af8b8>
Normal stroke 66 of type 6 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>
Normal stroke 66 of type 6 to <PyQt5.QtWidgets.QTextEdit object at 0x7ff4800af8b8>
Normal stroke 66 of type 7 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>
Normal stroke 66 of type 7 to <PyQt5.QtWidgets.QTextEdit object at 0x7ff4800af8b8>
Normal stroke 66 of type 7 to <__main__.Example object at 0x7ff4800af828>
Normal stroke 77 of type 51 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>
Normal stroke 77 of type 6 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>
Normal stroke 77 of type 7 to <PyQt5.QtGui.QWindow object at 0x7ff4800af948>

第二，sendkeys不起作用 - 笔触永远不会出现。

我不太确定我在误会什么 - 任何指针？

Answer 1

如果您的目标是替换发送的击键，那么您必须做的就是将它们发送到同一对象，而是将它们发送到窗口：

import sys
from PyQt5 import QtCore, QtGui, QtWidgets
from PyQt5.QtCore import Qt
# Keys to block
kmap = [Qt.Key_U,Qt.Key_I,Qt.Key_O,Qt.Key_P,Qt.Key_J,Qt.Key_K,Qt.Key_L,Qt.Key_M]
class Example(QtWidgets.QMainWindow):
    def __init__(self):
        super().__init__()
        self.initUI()
    # The simplest UI
    def initUI(self):               
        self.edit = QtWidgets.QTextEdit()
        self.setCentralWidget(self.edit)
        QtWidgets.qApp.installEventFilter(self)
        # Window placement 
        self.show()
    def sendkeys(self, obj, char, modifier=Qt.NoModifier):
        event = QtGui.QKeyEvent(QtCore.QEvent.KeyPress, 0, modifier, char)
        QtCore.QCoreApplication.postEvent(obj, event)
        event = QtGui.QKeyEvent(QtCore.QEvent.KeyRelease, 0, modifier, char)
        QtCore.QCoreApplication.postEvent(obj, event)
    def eventFilter(self, obj, event):
        if event.type() == QtCore.QEvent.KeyPress and isinstance(obj, QtWidgets.QTextEdit):
            print("Normal stroke %d of type %s to %s" % (event.key(), str(event.type()), str(obj)))
            if event.key() in kmap:
                self.sendkeys(obj, "c")
                return True
        return super().eventFilter(obj, event)
if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())