Make the `extractTitle` helper function used by
VclBuilder a static method in the BuilderBase
base class for reuse by QtBuilder.
In QtBuilder::makeObject, when encountering a "GtkTreeViewColumn"
object, add a new column to the QTreeView and set the
column title in the underlying model using
QStandardItemModel::setHeaderData.
Return the parent (tree view).
(Returning no object would cause WidgetBuilder::handleObject
to call WidgetBuilder::insertObject again, and thus result
in every column being processed twice, i.e. the double
amount of columns would be inserted).
Adjust QtInstanceTreeView::clear to no longer
call QStandardItemModel::clear [1], as that would
not only remove the "actual" items, but also the
header items, i.e. the column titles would get lost
as well. Remove all rows instead.
With this in place, the tree view in Writer's
"Tool" -> "XML Filter Settings" dialog has the
correct data + title set on open in a WIP branch
where support for that dialog is declared in
QtInstanceBuilder. (Other aspects in the dialog
still need to be addressed however.)
[1] https://doc.qt.io/qt-6/qstandarditemmodel.html#clear
Change-Id: I59956c007ed73cddb299ad2374afd88199ddc94d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/178063
Tested-by: Jenkins
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
