tdf#130857 qt weld: Set tree view column header title

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>

include/vcl/builderbase.hxx

@@ -88,6 +88,7 @@ protected:
     static bool extractEntry(stringmap& rMap);
     static OUString extractIconName(stringmap& rMap);
     static bool extractShowExpanders(stringmap& rMap);
+    static OUString extractTitle(stringmap& rMap);
     static OUString extractTooltipText(stringmap& rMap);
     static bool extractVisible(stringmap& rMap);
     void extractClassAndIdAndCustomProperty(xmlreader::XmlReader& reader, OUString& rClass,

vcl/qt5/QtBuilder.cxx

@@ -296,7 +296,16 @@ QObject* QtBuilder::makeObject(QObject* pParent, std::u16string_view sName, std:
     }
     else if (sName == u"GtkTreeViewColumn")
     {
-        SAL_WARN("vcl.qt", "GtkTreeViewColumn properties not evaluated yet");
+        QTreeView* pTreeView = qobject_cast<QTreeView*>(pParentWidget);
+        assert(pTreeView && "Tree view column doesn't have a tree view parent");
+        QStandardItemModel* pModel = qobject_cast<QStandardItemModel*>(pTreeView->model());
+        assert(pModel && "Tree view doesn't have QStandardItemModel set");
+        const int nCol = pModel->columnCount();
+        pModel->insertColumn(nCol);
+        pModel->setHeaderData(nCol, Qt::Horizontal, toQString(extractTitle(rMap)));
+
+        // nothing else to do, return tree view parent for the widget
+        return pTreeView;
     }
     else
     {

vcl/qt5/QtInstanceTreeView.cxx

@@ -644,7 +644,10 @@ void QtInstanceTreeView::clear()
 {
     SolarMutexGuard g;
 
-    GetQtInstance().RunInMainThread([&] { m_pModel->clear(); });
+    GetQtInstance().RunInMainThread([&] {
+        // don't use QStandardItemModel::clear, as that would remove header data as well
+        m_pModel->removeRows(0, m_pModel->rowCount());
+    });
 }
 
 int QtInstanceTreeView::get_height_rows(int) const

vcl/source/window/builder.cxx

@@ -1007,11 +1007,6 @@ namespace
         return f;
     }
 
-    OUString extractTitle(VclBuilder::stringmap &rMap)
-    {
-        return extractStringEntry(rMap, u"title"_ustr);
-    }
-
     bool extractSortIndicator(VclBuilder::stringmap &rMap)
     {
         return extractBoolEntry(rMap, u"sort-indicator"_ustr, false);
@@ -3411,6 +3406,11 @@ bool BuilderBase::extractShowExpanders(VclBuilder::stringmap& rMap)
     return extractBoolEntry(rMap, u"show-expanders"_ustr, true);
 }
 
+OUString BuilderBase::extractTitle(VclBuilder::stringmap &rMap)
+{
+    return extractStringEntry(rMap, u"title"_ustr);
+}
+
 OUString BuilderBase::extractTooltipText(stringmap& rMap)
 {
     OUString sTooltipText;