[Qt-interest] EditableTreeMode example crashing with modeltest

[Daniel Price]

From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Tony Rietwyk
Sent: 24 November 2009 23:55
To: qt-interest at trolltech.com
Subject: Re: [Qt-interest] EditableTreeMode example crashing with modeltest

Unfortunately, QTreeView is also very ROW based.  For example, it doesn't allow the background of the parent to extend beneath its visible children.  You can't change the drop indicators that are drawn, etc.  Reimplementing QTreeView is much easier said than done!

Not true!

http://doc.trolltech.com/main-snapshot/stylesheet-examples.html#customizing-qtreeview

-----Original Message-----
From: qt-interest-bounces at trolltech.com [mailto:qt-interest-bounces at trolltech.com] On Behalf Of Daniel Price
Sent: Tuesday, 24 November 2009 21:32
To: qt-interest List
Subject: [Qt-interest] EditableTreeMode example crashing with modeltest
I'm writing a tree model and I've used the Qt EditableTreeModel example (4.5.2)  as a guide.

My model works fine when I had only one column of data but then behaves strangely when I have more than one column (child items added under other tree items do not always show up in the view).

I hooked up Qt's modeltest project (http://labs.trolltech.com/page/Projects/Itemview/Modeltest) and I don't get any errors or problems with one column when inserting child items. But with two columns of data, it asserts on line 328 with the test "index.isValid() == true" .

This code appears to the culprit:

QModelIndex TreeModelAdaptor::index(int row, int column, const QModelIndex &parent) const
{
                if (parent.isValid() && parent.column() != 0)
                                return QModelIndex();

                ....
}

This was copied from the example - the test passes in a valid parent with a non-zero column and gets back an invalid model index, triggering the assert. But my model code is almost identical  to the example.

Can someone explain this code? Why does the code return the root item in this case?

So I tried hooking up EditableTreeModel to ModelTest in MainWindow.cpp:

...
 QFile file(":/default.txt");
                 file.open(QIODevice::ReadOnly);
                 TreeModel *model = new TreeModel(headers, file.readAll());
                  file.close();

new ModelTest(model, this);

                view->setModel(model);
...

And it crashes at startup. Even with no data, the example crashes when used with ModelTest (in the debugger it  breaks on qMalloc()).

Have the Qt examples been verified with ModelTest? Any idea as to what is going on?



Daniel Price
Software Engineer
FXhome Limited

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