QTextEdit: Overwrite Ctrl-Z with undo() in PyQt4

Question

I subclassed QTextEdit

class Q_My_TextEdit(QtGui.QTextEdit):
    def __init__(self, *args):
        QtGui.QTextEdit.__init__(self, *args)

    def undo(self):
        print("undo")
        #my own undo code

In my other class:

self.textedit=Q_My_TextEdit()

def keyPressEvent(self,event):
    if event.key()==(Qt.Key_Control and Qt.Key_Z):
        self.textedit.undo()

If you type some text into your QTextEdit, and hit CTRL-Z, it gets undo-ed, but without calling the function "undo". So how does it work in detail?

The background is, in a second step I want to set new Text (setText()), so the undo stack is deleted. I already have running code that makes the undo itself, but I can't trigger it on CTRL-Z, because with the "Z" the keyshortcut is somehow reserved. For example, if I call my own undo with event.key()==(Qt.Key_Control and Qt.Key_Y), it works.

Answer 1

In C++ you would have to install an event filter, probably with PyQt this is similar (overwrite virtual bool eventFilter(QObject* pObject, QEvent* pEvent); in your editor class). CTRL-Z gets probably filtered by the QTextEdit event filter thus it never gets to keyPressEvent.

Answer 2

Ah, So additionally to the keyPressEvent which I have in my second class, you have to put it also into the Subclass!

class Q_My_TextEdit(QtGui.QTextEdit):
    def __init__(self, *args):
        QtGui.QTextEdit.__init__(self, *args)

    def keyPressEvent(self,event):
        if event.key()==(Qt.Key_Control and Qt.Key_Z):
            self.undo()
        #To get the remaining functionality back (e.g. without this, typing would not work):
        QTextEdit.keyPressEvent(self,event)

    def undo(self):
        print("undo")
        #my own undo code

But now I can't type into my textedit any more! How can I solve this?

--> Solved. See Properly handling a keyPressEvent in a Subclassed PyQT LineEdit