How can I get the key without modifiers on keyPressEvent in Qt?

Question

Consider this PySide 6 example:

from PySide6.QtCore import *  # noqa
from PySide6.QtGui import *  # noqa
from PySide6.QtWidgets import *  # noqa


class TableWidget(QTableWidget):
    def __init__(self):
        super().__init__()
        self.setColumnCount(2)
        self.setHorizontalHeaderLabels(["Key", "Value"])
        self.setColumnWidth(1, 800)
        self._sequence_format = QKeySequence.PortableText
        self._modifier_order = [
            self.modifier_to_string(modifier)
            for modifier in (Qt.ControlModifier, Qt.AltModifier, Qt.ShiftModifier)
        ]

    def modifier_to_string(self, modifier):
        return QKeySequence(modifier.value).toString(self._sequence_format).lower()

    def key_to_string(self, key):
        if key in (
            Qt.Key_Shift,
            Qt.Key_Control,
            Qt.Key_Alt,
            Qt.Key_Meta,
            Qt.Key_AltGr,
        ):
            return None
        else:
            return QKeySequence(key).toString(self._sequence_format).lower()

    def shortcut_from_event(self, event):
        key = event.key()
        modifiers = event.modifiers()
        vk = event.nativeVirtualKey()
        key_string = self.key_to_string(key)
        vk_string = self.key_to_string(vk)
        modifier_strings = tuple(
            self.modifier_to_string(modifier) for modifier in modifiers
        )
        shortcut_tpl = (key_string, modifier_strings)

        shortcut_lst = []
        for modifier_string in self._modifier_order:
            if modifier_string in shortcut_tpl[1]:
                shortcut_lst.append(modifier_string)
        shortcut_lst.append(shortcut_tpl[0])
        if None in shortcut_lst:
            shortcut = None  # noqa
        else:
            shortcut = "".join(shortcut_lst)  # noqa

        return {
            "shortcut": shortcut,
            "key": key,
            "modifiers": modifiers,
            "vk": vk,
            "key_string": key_string,
            "vk_string": vk_string,
            "modifier_strings": modifier_strings,
        }

    def keyPressEvent(self, event):
        table = self
        item = self.shortcut_from_event(event)

        if item:
            table.clearContents()
            table.setRowCount(0)

            row_position = 0
            for k, v in sorted(item.items(), reverse=True):
                table.insertRow(row_position)
                table.setItem(row_position, 0, QTableWidgetItem(k))
                table.setItem(row_position, 1, QTableWidgetItem(str(v)))
            # table.resizeColumnsToContents()

        # return super().keyPressEvent(event)


if __name__ == "__main__":
    import sys

    app = QApplication(sys.argv)
    w = TableWidget()
    w.resize(800, 600)
    w.show()
    sys.exit(app.exec())

I'd like to know: How can I create a shortcut string using the modifiers that follows the modifier_order and the unaffected key string? For instance, right now:

• If I press key +

  

• If I press Shift + +

  

• If I press AltGr + +

  

But I'd like to modify the code so the shortcut created will be +, Shift + plus and Ctrl + Alt + plus, respectively.

How can I achieve this behaviour? Similar to all keys, I'd like to get the string of the unaffected key without any modifiers on top.

Answer 1

From the Qt documentation:

Warning: This function cannot always be trusted. The user can confuse it by pressing both Shift keys simultaneously and releasing one of them, for example.

The alternative suggested there is to use the keyboard modifiers from the application itself.

Following this answer, it does seem that this approach works better. So, in your case just switch this line

modifiers = event.modifiers()

with this one:

modifiers = Qt.QtWidgets.QApplication.keyboardModifiers()

I also suggest for you to map the Qt types to your own readable strings in the shortcut tuple in order to produce the desirable output value.