[FIXED] Get Selected Item from QAbstractListModel

Issue

How do i retrieve the correctly selected item from my custom QAbstractListModel which contains a custom sorting algorithm?

You can test the tool by simply making selections in the UI and looking at the console. You can see it's printing the wrong information for the selected item.

I'm assuming the issue relates to how i use the selection indexes to get the item in the Model.

complete code:

import os, sys
from PySide import QtGui, QtCore


class ExplorerItem(object):
    def __init__(self, name, tags):
        self.name = name
        self.tags = tags


class ElementModel(QtCore.QAbstractListModel):
    TagsRole = QtCore.Qt.UserRole + 1
    NameRole = QtCore.Qt.UserRole + 2

    def __init__(self, *args, **kwargs):
        QtCore.QAbstractListModel.__init__(self, *args, **kwargs)
        self._items = []
        self._icons = {}

    def rowCount(self, index=QtCore.QModelIndex()):
        return len(self._items)

    def addItem(self, item):
        self.beginInsertRows(QtCore.QModelIndex(), self.rowCount(), self.rowCount())
        self._items.append(item)
        self.endInsertRows()

    def getItem(self, index):
        row = index.row()
        if index.isValid() and 0 <= row < self.rowCount():
            return self._items[row]

    def data(self, index, role=QtCore.Qt.DisplayRole):
        if not index.isValid():
            return None
        if 0 <= index.row() < self.rowCount():
            item = self._items[index.row()]
            if role == ElementModel.TagsRole:
                return item.tags
            elif role == ElementModel.NameRole:
                return item.colors
            elif role == QtCore.Qt.DisplayRole:
                return item.name
            elif role == QtCore.Qt.TextAlignmentRole:
                return QtCore.Qt.AlignCenter


class ExplorerSortModel(QtGui.QSortFilterProxyModel):

    def __init__(self, *args, **kwargs):
        super(ExplorerSortModel, self).__init__(*args, **kwargs)
        self._patterns = {}
        self.setDynamicSortFilter(True)
        self.setSourceModel(ElementModel())
        self.sort(0, QtCore.Qt.AscendingOrder)


    def set_pattern(self, role, value):
        self._patterns[role] = value


    def lessThan(self, left, right):
        leftData = self.sourceModel()._items[left.row()]
        rightData = self.sourceModel()._items[right.row()]

        if leftData and rightData:
            l = getattr(leftData, 'name', '')
            r = getattr(rightData, 'name', '')
            return l > r

        return True


    def filterAcceptsRow(self, sourceRow, sourceParent):
        sm = self.sourceModel()
        ix = sm.index(sourceRow)
        if ix.isValid():
            val = True
            for role, fvalue in self._patterns.items():
                value = ix.data(role)
                val = val and self.filter(value, fvalue, role)
            return val
        return False


    @staticmethod
    def filter(value, fvalue, role):
        '''
        fvalue: search value
        value: properties value being tested
        '''
        if role == ElementModel.TagsRole:
            if fvalue == []:
                return True
            else:
                return all(any(x in y for y in value) for x in fvalue)
        elif role == ElementModel.NameRole:
            return True
        else:
            return False


class QExplorerWidget(QtGui.QWidget):

    def __init__(self, *args, **kwargs):
        super(QExplorerWidget, self).__init__(*args, **kwargs)
        self.resize(400,400)

        # control
        self.ui_explorer = QtGui.QListView()
        self.ui_explorer.setResizeMode(QtGui.QListView.Adjust)
        self.ui_explorer.setEditTriggers(QtGui.QAbstractItemView.NoEditTriggers)
        self.ui_explorer.setMovement(QtGui.QListView.Static)
        self.ui_explorer.setSpacing(10)

        self.explorer_model = ExplorerSortModel()
        self.ui_explorer.setModel(self.explorer_model)

        self.ui_explorer_selection = self.ui_explorer.selectionModel()

        lay = QtGui.QVBoxLayout()
        lay.addWidget(self.ui_explorer)
        self.setLayout(lay)

        # connections
        self.ui_explorer_selection.selectionChanged.connect(self.changed_selection)

        # test data
        self.explorer_model.sourceModel().addItem(ExplorerItem('John',['john','sports']))
        self.explorer_model.sourceModel().addItem(ExplorerItem('Apple',['apple','fruit']))
        self.explorer_model.sourceModel().addItem(ExplorerItem('Kevin',['kevin','money']))
        self.explorer_model.sourceModel().addItem(ExplorerItem('Zoo',['zoo','animals']))


    def changed_selection(self):
        indexes =  self.ui_explorer_selection.selectedIndexes()
        for index in indexes:
            item = self.explorer_model.sourceModel().getItem(index)
            print item.name, item.tags, index


if __name__ == '__main__':
    ''
    app = QtGui.QApplication(sys.argv)
    ex = QExplorerWidget()
    ex.show()
    sys.exit(app.exec_())

Solution

The QModelIndex of the selectedIndexes belong to the model that was established in the view, and in this case it is the ExplorerSortModel, so these indexes can not be passed directly to the getItem() method of ElementModel since that method expects that the QModelIndex belongs to ElementModel.

In your case you must convert that QModelIndex belonging to ExplorerSortModel to the corresponding QModelIndex that belongs to ElementModel using the mapSource() method.

def changed_selection(self):
    indexes =  self.ui_explorer_selection.selectedIndexes()
    for index in indexes:
        ix_source = self.explorer_model.mapToSource(index)
        item = self.explorer_model.sourceModel().getItem(ix_source)
        print(item.name, item.tags)

Answered By - eyllanesc