Custom delegate item editor widget appearing in the wrong place

Question

I am trying to use a custom delegate to popup custom date and time editors for use inside of a qtreeview. Everything I read says that to get the editor widget to show up in the correct spot, over the current index, you reimpliment the updateEditorGeometry method and use editor.setGeometry(option.rect) to set the position.

I cannot seem to figure this out though. Here is what I have so far. When double clicking on column 1 it shows the editor in the very top left of my screen.

from PyQt5 import QtWidgets, QtGui, QtCore
from PyQt5.QtCore import Qt
import datetime


class NspDateEdit(QtWidgets.QWidget):

    editingFinished = QtCore.pyqtSignal()

    def __init__(self, parent=None):
        super(NspDateEdit, self).__init__(parent)
        # self.resize(137, 25)
        # self.setMaximumSize(QtCore.QSize(120, 25))

        self.date_edit = QtWidgets.QDateEdit()
        self.date_edit.setCalendarPopup(True)
        self.check_box = QtWidgets.QCheckBox()
        self.check_box.setText("")

        self.main_layout = QtWidgets.QHBoxLayout()
        self.main_layout.addWidget(self.date_edit)
        self.main_layout.addWidget(self.check_box)
        self.main_layout.setContentsMargins(2, 0, 0, 0)
        self.setLayout(self.main_layout)

        self.check_box.stateChanged.connect(self._on_state_change)
        self.date_edit.editingFinished.connect(self._on_editingFinished)

        self.setDate(None)

    def _on_state_change(self):
        state = self.checkState()
        if state:
            current_date = self.date_edit.date()
            current_date_py = current_date.toPyDate()
            current_date_str = current_date_py.strftime('%Y-%m-%d')
            if current_date_str == '2000-01-01':
                new_date = datetime.datetime.now().date()
            else:
                new_date = current_date_py
            self.setDate(new_date)
        else:
            self.setDate(None)
        self.editingFinished.emit()

    def _on_editingFinished(self):
        self.editingFinished.emit()

    def checkState(self):
        state = self.check_box.checkState()
        if state == Qt.Checked:
            return True
        else:
            return False

    def setDate(self, val):
        self.date_edit.setEnabled(True)
        if val is None:
            self.check_box.setCheckState(Qt.Unchecked)
            self.date_edit.setEnabled(False)
        else:
            self.date_edit.setDate(val)
            self.check_box.setCheckState(Qt.Checked)

    def date(self):
        if self.checkState():
            return self.date_edit.date().toPyDate()
        else:
            return None


class NspAbstractItemDelegate(QtWidgets.QStyledItemDelegate):

    def __init__(self):
        super(NspAbstractItemDelegate, self).__init__()

    def createEditor(self, parent, option, index):
        editor = NspDateEdit()
        editor.setWindowFlags(QtCore.Qt.Popup)
        return editor

    def setEditorData(self, editor, index):
        data = index.data()
        formatted = datetime.datetime.strptime(data, '%m/%d/%y').date()
        editor.setDate(formatted)

    def setModelData(self, editor, model, index):
        data = editor.date()
        txt = data.strftime('%m/%d/%y')
        model.setData(index, txt)

    def updateEditorGeometry(self, editor, option, index):
        editor.setGeometry(option.rect)


class testTreeview(QtWidgets.QWidget):
    def __init__(self, parent=None):
        super(testTreeview, self).__init__(parent)
        self.mainTree = QtWidgets.QTreeView()

        self.testButton = QtWidgets.QPushButton()

        self.lo = QtWidgets.QVBoxLayout()
        self.lo.addWidget(self.mainTree)
        self.lo.addWidget(self.testButton)
        self.setLayout(self.lo)

        self.model = QtGui.QStandardItemModel()
        self.mainTree.setModel(self.model)

        self.populate()

        self.testButton.clicked.connect(self._on_clicked_button)
        self.mainTree.setItemDelegateForColumn(0, NspAbstractItemDelegate())

    def _on_clicked_button(self):
        self.mainTree.edit(self.mainTree.currentIndex())  #, QtWidgets.QAbstractItemView.EditTrigger(), None)

    def populate(self):

        row = [QtGui.QStandardItem('05/12/15'), QtGui.QStandardItem('07/13/18'), ]
        row2 = [QtGui.QStandardItem('12/21/21'), QtGui.QStandardItem('11/05/17'), ]
        all_rows = list(row)
        all_rows.extend(row2)
        for item in all_rows:
            item.setEditable(True)
        root = self.model.invisibleRootItem()
        root.appendRow(row)
        root.appendRow(row2)


if __name__ == "__main__":
    from PyQt5 import QtCore, QtGui, QtWidgets

    app = QtWidgets.QApplication([])
    volume = testTreeview()
    volume.show()
    app.exec_()

Answer 1

When you set the Qt::Popup flag, the widget position must be absolute, that is to say with respect to the screen, but option.rect is a QRect relative to the viewport, so the solution is to convert that relative path to absolute using mapToGlobal but for that you must pass a parent to the editor

def createEditor(self, parent, option, index):
    editor = NspDateEdit(parent)
    editor.setWindowFlags(QtCore.Qt.Popup)
    return editor

# ...

def updateEditorGeometry(self, editor, option, index):
    r = QtCore.QRect(option.rect)
    if editor.windowFlags() & QtCore.Qt.Popup and editor.parent() is not None:
        r.setTopLeft(editor.parent().mapToGlobal(r.topLeft()))
    editor.setGeometry(r)