How to filter a table view using SortFilterProxyModel

[DrakeSoft]

Hi,

I have tried to create a sample program to help me figure out how the SortFilterProxyModel works in PyQT.

from PyQt5.QtWidgets import (QApplication, QMainWindow,
                             QTableWidget, QTableWidgetItem, QMenu, QAction, QDialog,
                             QInputDialog, QTableView,  QHeaderView, QLineEdit, QLabel, QVBoxLayout)
from PyQt5.QtGui import QIcon, QStandardItemModel

import sys

from PyQt5.QtCore import Qt, QSortFilterProxyModel, QModelIndex, QRegExp

headers = ["Word", "Meaning", ""]


NUMBER_OF_COLUMNS = 2
NUMBER_OF_ROWS = 6


class TableView(QTableView):
    def __init__(self, title, rows, columns):
        QTableView.__init__(self)

        self.proxyModel = SortFilterProxyModel()
        # This property holds whether the proxy model is dynamically sorted and filtered whenever the contents of the source model change
        self.proxyModel.setDynamicSortFilter(True)
        self.model = QStandardItemModel(
            rows, columns, self)
        self.model.setHeaderData(0, Qt.Horizontal, "Word")
        self.model.setHeaderData(1, Qt.Horizontal, "Meaning")
        self.setWindowTitle(title)
        self.setSampleData()
        self.horizontalHeader().setSectionResizeMode(QHeaderView.Stretch)
        self.horizontalHeader().setSectionResizeMode(QHeaderView.ResizeToContents)
        self.setAlternatingRowColors(True)
        self.setSortingEnabled(True)
        self.verticalHeader().hide()
        self.setSelectionMode(QTableView.SingleSelection)
        self.setSelectionBehavior(QTableView.SelectRows)
        self.clicked.connect(self.getItem)
        self.filterSTring = ""

    def setSampleData(self):
        self.model.setData(self.model.index(
            0, 0, QModelIndex()), "Abundance", Qt.DisplayRole)
        self.model.setData(self.model.index(
            0, 1, QModelIndex()), "A very large quantity of something", Qt.DisplayRole)
        self.model.setData(self.model.index(
            1, 0, QModelIndex()), "Belonging", Qt.DisplayRole)
        self.model.setData(self.model.index(
            1, 1, QModelIndex()), "An affinity for a place or situation.", Qt.DisplayRole)
        self.model.setData(self.model.index(
            2, 0, QModelIndex()), "Candor", Qt.DisplayRole)
        self.model.setData(self.model.index(
            2, 1, QModelIndex()), "The quality of being open and honest in expression; frankness", Qt.DisplayRole)
        self.proxyModel.setSourceModel(self.model)
        self.setModel(self.proxyModel)

    def setFilterString(self, string):
        self.filterString = "^" + string

    def getItem(self, index):

        mapped_index = self.proxyModel.mapToSource(index)
        item = self.model.itemFromIndex(mapped_index)
        print(item.text() + "  ")
        item = self.model.data(mapped_index)
        row = mapped_index.row()
        column = mapped_index.column()
        data = mapped_index.data()
        item = self.model.itemFromIndex(mapped_index)
        print(item.text() + "  " + str(row) + "  " + str(column) + "  " + data)

    def filterRegExpChanged(self):

        syntax = QRegExp.RegExp  # can be one of QRegExp.RegExp2, QRegExp.WildCard, QRegExp.RegExp2 etc, see https://doc.qt.io/qt-5/qregexp.html#PatternSyntax-enum
        caseSensitivity = Qt.CaseInsensitive
        regExp = QRegExp(self.filterString,
                         caseSensitivity, syntax)
        # This property holds the QRegExp used to filter the contents of the source model
        self.proxyModel.setFilterRegExp(regExp)


class SortFilterProxyModel(QSortFilterProxyModel):
    def __init__(self):
        super().__init__()

    def filterAcceptsRow(self, sourceRow, sourceParent):
        result = False
        if self.filterKeyColumn() == 0: # only interested in the first column

            index = self.sourceModel().index(sourceRow, 0, sourceParent)
            data = self.sourceModel().data(index)
            # we could additionally filter here on the data
            return True

        # Otherwise ignore
        return super(SortFilterProxyModel, self).filterAcceptsRow(sourceRow, sourceParent)


class WordSelector(QDialog):
    def __init__(self, parent=None):
        QDialog.__init__(self, parent)
        self.parent = parent
        self.lastStart = 0
        self.initUI()

    def initUI(self):

        self.table = TableView("Words",
                               NUMBER_OF_ROWS, NUMBER_OF_COLUMNS)
        layout = QVBoxLayout()
        self.filterLabel = QLabel("  Filter")
        layout.addWidget(self.filterLabel)
        self.filter = QLineEdit(self)
        self.filter.setStyleSheet(
            "background-color: #FFFFFF; padding:1px 1px 1px 1px")
        self.filter.setFixedWidth(120)
        self.filter.returnPressed.connect(self.lookupWord)
        layout.addWidget(self.filter)
        layout.addWidget(self.table)
        self.setGeometry(300, 300, 500, 300)
        self.setWindowTitle("Find and Replace")
        self.setLayout(layout)

    def lookupWord(self):
        self.table.setFilterString(self.filter.text())
        self.table.filterRegExpChanged()


def main(args):
    app = QApplication(args)

    wordSelector = WordSelector()
    wordSelector.show()
    sys.exit(app.exec_())


if __name__ == "__main__":
    main(sys.argv)

I want to be able to filter the contents of the table view based on the filter I set in the filter text box.
So, for example, if I type "a", then only the words beginning with a will appear.
In time I will make the filter customisable, but this is my first attempt.

I can see filterRegExpChanged being invoked, but I never see the filter influencing the contents of the table.
Any suggestions. Am I missing something here?