Hi Jérôme,
I assume that parent.isValid is checking the parent QModelIndex by
calling parent.model().columnCount within the DummyModel. There used to
be a Qt utility to check that your models have the correct overrides.
Note that the source model cannot rely on the proxy model for anything -
it must be self contained.
Regards, Tony
On 18/12/2017 1:04 AM, Jérôme Laheurte wrote:
I’m trying to use a QAbstractProxyModel (more specifically a
QIdentityProxyModel) to present differently columned models for the
same underlying model. So the source model doesn’t implement
column-related stuff, but the proxy model does. It goes like this:
/#!/usr/bin/env python3/
/#-*- coding: ISO-8859-1 -*-/
*from* PyQt5 *import* QtCore, QtWidgets
*class* DummyModel(QtCore.QAbstractItemModel):
*def* rowCount(self, parent):
*if* parent.isValid():
*return* 0
*return* 10
*def* parent(self, index):
*return* QtCore.QModelIndex()
*def* index(self, row, column, parent):
*if* parent.isValid():
*return* QtCore.QModelIndex()
*return* self.createIndex(row, column)
*class* ProxyModel(QtCore.QIdentityProxyModel):
*def* __init__(self, model):
super().__init__()
self.setSourceModel(model)
*def* columnCount(self, parent):
*return* 3
*def* data(self, index, role):
*if* index.isValid() *and* role == QtCore.Qt.DisplayRole:
*return* 'Item #%d,%d' % (index.row(), index.column())
*class* MainWindow(QtWidgets.QMainWindow):
*def* __init__(self):
super().__init__()
view = QtWidgets.QTreeView(self)
view.setModel(ProxyModel(DummyModel()))
self.setCentralWidget(view)
self.show()
self.raise_()
*if* __name__ == '__main__':
app = QtWidgets.QApplication([])
win = MainWindow()
app.exec_()
Unfortunately running this gives me this on the console:
NotImplementedError: QAbstractItemModel.columnCount() is abstract and
must be overridden
And nothing displays unless I define `columnCount` in the source
model. So my guess is that some method in QAbstractProxyModel *other
than columnCount()* calls sourceModel()->columnCount() directly
instead of the proxy’s version. Is that a bug ?
Best regards
Jérôme Laheurte
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