How to control collapse/expand in QTreeView

[JonB]

@Vinoth-Rajendran4
Well, I don't know if there is a neater way to do it, but I assume you can always define your own slot for http://doc.qt.io/qt-5/qtreeview.html#expand (and others) and have it not call the base slot on certain nodes of your choice?

[Vinoth Rajendran4]

@JonB : Thanks for your reply. Can you please provide an abstract code, of blocking base slot .
An simple example to get me started.

[JonB]

@Vinoth-Rajendran4
I don't do C++. You'll have to fill in details/corrections.

1. Don't use a QTreeView directly if you are doing that at present. Create a sub-class MyTreeView deriving from QTreeView.

2. In that sub-class, override the expand slot (http://doc.qt.io/qt-5/qtreeview.html#expand). https://stackoverflow.com/questions/29170751/override-qt-slot-in-subclass may help you. You probably only need to do like https://stackoverflow.com/a/29172350/489865.

3. Normally your override method would look like

void MyTreeView::expand(const QModelIndex &index)
{
    QTreeView::expand(index);
}

i.e. it's your job to call the base method to actually still do the expand if you override.

Try commenting out the call to the base QTreeView::expand(index);. This should completely stop the tree view from actually expanding nodes, right? Then do whatever to check whether the index parameter refers to your current directory, and make it so in that case only it does not do the expand. So it ends up like

void MyTreeView::expand(const QModelIndex &index)
{
    if (isCurrentDirectoryIndex(index))
        return;
    QTreeView::expand(index);
}

Then you'll be done :)

[Vinoth Rajendran4]

@JonB : Since expand slot (http://doc.qt.io/qt-5/qtreeview.html#expand) isn't virtual , how i override it ??

[JonB]

@Vinoth-Rajendran4
As I said I'm not C++, so I'm afraid that is above my pay grade.

If you can't do that, you might have to do something like intercept the clicks yourself, or can you "disable" an individual item, or maybe you can even derive from QFileSystemModel for your model and have that pretend that current directory has no children at all? These are just ideas....

Edit Here's a thought: can you use http://doc.qt.io/qt-5/qfilesystemmodel.html#flags to clear the http://doc.qt.io/qt-5/qt.html Qt::ItemIsEnabled flag/setDisabled on the current directory in the model? Would that stop user expanding it?

[mrjj]

Hi
There is also
http://doc.qt.io/qt-5/qtreeview.html#itemsExpandable-prop

[JonB]

@mrjj There is, but that is tree-wide. OP only wants to not-expand one node....

[mrjj]

@JonB
Ahh, i missed that. sounded like he wanted for all view.
TreeWidget has setChildIndicatorPolicy(QTreeWidgetItem::DontShowIndicator);
so i assume there is a model alternative to that.
Im not sure if it actually disabled expanding or if its just cosmetic .

[Vinoth Rajendran4]

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[Vinoth Rajendran4]

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[Vinoth Rajendran4]

@JonB said in How to control collapse/expand in QTreeView:

, or maybe you can even derive from QFileSystemModel for your model and have that pretend that current directory has no children at all?

found the solution with https://stackoverflow.com/a/18007243 , just as your idea :)