[FIXED] PYQT QTableView Delegate can not show createEditor when applied with Proxy

Issue

I'm having problem to show the Editor Widget when Delegate is applied with the Proxy situation. -> self.table.setModel(self.proxy)

If the Delegate is applied to the View/Model structure, then there is no problem at all. -> #self.table.setModel(self.model)

Refer to: https://www.pythonfixing.com/2021/10/fixed-adding-row-to-qtableview-with.html

See the code below:

from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
import sys

class Delegate(QItemDelegate):
    def __init__(self):
        QItemDelegate.__init__(self)
        self.type_items = ["1", "2", "3"]

    def createEditor(self, parent, option, index):
        if index.column() == 0:
            comboBox = QComboBox(parent)
            comboBox.addItems(self.type_items)
            return comboBox
        # no need to check for the other columns, as Qt automatically creates a
        # QLineEdit for string values and QTimeEdit for QTime values;
        return super().createEditor(parent, option, index)
        

class TableModel(QAbstractTableModel):
    def __init__(self, data):
        super(TableModel, self).__init__()
        self._data = data

    def appendRowData(self, data):
        self.beginInsertRows(QModelIndex(), self.rowCount(), self.rowCount())
        self._data.append(data)
        self.endInsertRows()

    def data(self, index, role=Qt.DisplayRole):
        if role in (Qt.DisplayRole, Qt.EditRole):
            return self._data[index.row()][index.column()]

    def setData(self, index, value, role=Qt.EditRole):
        if role == Qt.EditRole:
            self._data[index.row()][index.column()] = value
            self.dataChanged.emit(index, index)
            return True
        return False

    def rowCount(self, index=None):
        return len(self._data)

    def columnCount(self, index=None):
        return len(self._data[0])

    def flags(self, index):
        # allow editing of the index
        return super().flags(index) | Qt.ItemIsEditable
        

class CustomProxyModel(QSortFilterProxyModel):
    def __init__(self, parent=None):
        super().__init__(parent)
        self._filters = dict()

    @property
    def filters(self):
        return self._filters

    def setFilter(self, expresion, column):
        if expresion:
            self.filters[column] = expresion
        elif column in self.filters:
            del self.filters[column]
        self.invalidateFilter()

    def filterAcceptsRow(self, source_row, source_parent):
        for column, expresion in self.filters.items():
            text = self.sourceModel().index(source_row, column, source_parent).data()
            regex = QRegExp(
                expresion, Qt.CaseInsensitive, QRegExp.RegExp
            )
            if regex.indexIn(text) == -1:
                return False
        return True
        

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)

        localWidget = QWidget()

        self.table = QTableView(localWidget)

        data = [["1", "Hi", QTime(2, 1)], ["2", "Hello", QTime(3, 0)]]

        self.model = TableModel(data)
        
        self.proxy = CustomProxyModel()   # Customized Filter
        self.proxy.setSourceModel(self.model)
       
        #self.table.setModel(self.model)    # Original code, for View/Model
        self.table.setModel(self.proxy)     # Revised code, for View/Proxy/Model
        
        self.table.setItemDelegate(Delegate())

        self.add_row = QPushButton("Add Row", localWidget)
        self.add_row.clicked.connect(self.addRow)

        for row in range(self.model.rowCount()):
            for column in range(self.model.columnCount()):
                index = self.model.index(row, column)
                self.table.openPersistentEditor(index)    # openPersistentEditor for createEditor

        layout_v = QVBoxLayout()
        layout_v.addWidget(self.table)
        layout_v.addWidget(self.add_row)
        localWidget.setLayout(layout_v)
        self.setCentralWidget(localWidget)
        self.show()
        
    def addRow(self):
        row = self.model.rowCount()

        new_row_data = ["3", "Howdy", QTime(9, 0)]
        self.model.appendRowData(new_row_data)

        for i in range(self.model.columnCount()):
            index = self.model.index(row, i)
            self.table.openPersistentEditor(index)    # openPersistentEditor for createEditor
            
app = QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())

1. Test with View/Model, Widget Editor display.

2. Test with View/Proxy/Model, Widget Editor not display.

Solution

Any attempt to access the view indexes must use the view's model.

Your code doesn't work because the index you are providing belongs to another model, so the editor cannot be created because the view doesn't recognize the model of the index as its own: the view uses the proxy model, while you're trying to open an editor for the source model.

While in this case the simplest solution would be to use self.proxy.index(), the proper solution is to always refer to the view's model.

Change both self.model.index(...) to self.table.model().index(...).

Answered By - musicamante