QTreeWidget: Keep items hidden even if their parents are reparented

When an item is explicitly hidden, then it should stay that way even if
its parent is reparented. The item itself needs to be explicitly shown
for it to be made visible.

Task-number: QTBUG-54843
Change-Id: I0c6eea9a936f82d5874e3246292bd16365440411
Reviewed-by: Christian Ehrlicher <ch.ehrlicher@gmx.de>
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>

src/widgets/itemviews/qtreewidget.cpp

@@ -1001,7 +1001,6 @@ void QTreeModel::timerEvent(QTimerEvent *ev)
 */
 
 /*!
-  \fn void QTreeWidgetItem::setHidden(bool hide)
   \since 4.2
 
   Hides the item if \a hide is true, otherwise shows the item.
@@ -1012,6 +1011,14 @@ void QTreeModel::timerEvent(QTimerEvent *ev)
   \sa isHidden()
 */
 
+void QTreeWidgetItem::setHidden(bool ahide)
+{
+    if (view) {
+        view->setItemHidden(this, ahide);
+        d->hidden = ahide;
+    }
+}
+
 /*!
   \fn bool QTreeWidgetItem::isHidden() const
   \since 4.2
@@ -1021,6 +1028,11 @@ void QTreeModel::timerEvent(QTimerEvent *ev)
   \sa setHidden()
 */
 
+bool QTreeWidgetItem::isHidden() const
+{
+    return (view ? d->hidden : false);
+}
+
 /*!
   \fn void QTreeWidgetItem::setExpanded(bool expand)
   \since 4.2
@@ -1648,6 +1660,25 @@ void QTreeWidgetItem::setFlags(Qt::ItemFlags flags)
     itemChanged();
 }
 
+void QTreeWidgetItemPrivate::updateHiddenStatus(QTreeWidgetItem *item, bool inserting)
+{
+    QTreeModel *model = (item->view ? qobject_cast<QTreeModel*>(item->view->model()) : 0);
+    if (!model)
+        return;
+    QStack<QTreeWidgetItem *> parents;
+    parents.push(item);
+    while (!parents.isEmpty()) {
+        QTreeWidgetItem *parent = parents.pop();
+        QModelIndex index = model->index(parent, 0);
+        if (parent->d->hidden)
+            item->view->setRowHidden(index.row(), index.parent(), inserting);
+        for (int i = 0; i < parent->children.count(); ++i) {
+            QTreeWidgetItem *child = parent->children.at(i);
+            parents.push(child);
+        }
+    }
+}
+
 void QTreeWidgetItemPrivate::propagateDisabled(QTreeWidgetItem *item)
 {
     Q_ASSERT(item);
@@ -1937,6 +1968,7 @@ void QTreeWidgetItem::insertChild(int index, QTreeWidgetItem *child)
                 stack.push(i->children.at(c));
         }
         children.insert(index, child);
+        d->updateHiddenStatus(child, true);
         model->endInsertItems();
         model->skipPendingSort = wasSkipSort;
     } else {
@@ -1974,6 +2006,7 @@ QTreeWidgetItem *QTreeWidgetItem::takeChild(int index)
     }
     if (index >= 0 && index < children.count()) {
         if (model) model->beginRemoveItems(this, index, 1);
+        d->updateHiddenStatus(children.at(index), false);
         QTreeWidgetItem *item = children.takeAt(index);
         item->par = 0;
         QStack<QTreeWidgetItem*> stack;
@@ -2052,6 +2085,7 @@ void QTreeWidgetItem::insertChildren(int index, const QList<QTreeWidgetItem*> &c
             this->children.insert(index + n, child);
             if (child->par)
                 d->propagateDisabled(child);
+            d->updateHiddenStatus(child, true);
         }
         if (model) model->endInsertItems();
     }
@@ -3099,6 +3133,8 @@ bool QTreeWidget::isItemHidden(const QTreeWidgetItem *item) const
 */
 void QTreeWidget::setItemHidden(const QTreeWidgetItem *item, bool hide)
 {
+    if (!item)
+        return;
     Q_D(QTreeWidget);
     if (item == d->treeModel()->headerItem) {
         header()->setHidden(hide);
@@ -3106,6 +3142,7 @@ void QTreeWidget::setItemHidden(const QTreeWidgetItem *item, bool hide)
         const QModelIndex index = d->index(item);
         setRowHidden(index.row(), index.parent(), hide);
     }
+    item->d->hidden = hide;
 }
 
 /*!

src/widgets/itemviews/qtreewidget.h

@@ -82,8 +82,8 @@ public:
     inline void setSelected(bool select);
     inline bool isSelected() const;
 
-    inline void setHidden(bool hide);
+    void setHidden(bool hide);
-    inline bool isHidden() const;
+    bool isHidden() const;
 
     inline void setExpanded(bool expand);
     inline bool isExpanded() const;
@@ -410,12 +410,6 @@ inline void QTreeWidgetItem::setSelected(bool aselect)
 inline bool QTreeWidgetItem::isSelected() const
 { return (view ? view->isItemSelected(this) : false); }
 
-inline void QTreeWidgetItem::setHidden(bool ahide)
-{ if (view) view->setItemHidden(this, ahide); }
-
-inline bool QTreeWidgetItem::isHidden() const
-{ return (view ? view->isItemHidden(this) : false); }
-
 inline void QTreeWidgetItem::setExpanded(bool aexpand)
 { if (view) view->setItemExpanded(this, aexpand); }
 

src/widgets/itemviews/qtreewidget_p.h

@@ -187,13 +187,16 @@ class QTreeWidgetItemPrivate
 {
 public:
     QTreeWidgetItemPrivate(QTreeWidgetItem *item)
-        : q(item), disabled(false), selected(false), rowGuess(-1), policy(QTreeWidgetItem::DontShowIndicatorWhenChildless) {}
+        : q(item), disabled(false), selected(false), hidden(false), rowGuess(-1),
+          policy(QTreeWidgetItem::DontShowIndicatorWhenChildless) {}
     void propagateDisabled(QTreeWidgetItem *item);
+    void updateHiddenStatus(QTreeWidgetItem *item, bool inserting);
     void sortChildren(int column, Qt::SortOrder order, bool climb);
     QTreeWidgetItem *q;
     QVariantList display;
     uint disabled : 1;
     uint selected : 1;
+    uint hidden : 1;
     int rowGuess;
     QTreeWidgetItem::ChildIndicatorPolicy policy;
 };

tests/auto/widgets/itemviews/qtreewidget/tst_qtreewidget.cpp

@@ -160,6 +160,7 @@ private slots:
     void task20345_sortChildren();
     void getMimeDataWithInvalidItem();
     void testVisualItemRect();
+    void reparentHiddenItem();
 
 public slots:
     void itemSelectionChanged();
@@ -3498,5 +3499,34 @@ void tst_QTreeWidget::testVisualItemRect()
     QCOMPARE(r.width(), sectionSize);
 }
 
+void tst_QTreeWidget::reparentHiddenItem()
+{
+    QTreeWidgetItem *parent = new QTreeWidgetItem(testWidget);
+    parent->setText(0, "parent");
+    QTreeWidgetItem *otherParent = new QTreeWidgetItem(testWidget);
+    otherParent->setText(0, "other parent");
+    QTreeWidgetItem *child = new QTreeWidgetItem(parent);
+    child->setText(0, "child");
+    QTreeWidgetItem *grandChild = new QTreeWidgetItem(child);
+    grandChild->setText(0, "grandchild");
+    QVERIFY(child->parent());
+    QVERIFY(grandChild->parent());
+
+    testWidget->expandItem(parent);
+    testWidget->expandItem(otherParent);
+    testWidget->expandItem(child);
+
+    QVERIFY(!parent->isHidden());
+    QVERIFY(!child->isHidden());
+    QVERIFY(!grandChild->isHidden());
+
+    grandChild->setHidden(true);
+
+    QVERIFY(grandChild->isHidden());
+    parent->removeChild(child);
+    otherParent->addChild(child);
+    QVERIFY(grandChild->isHidden());
+}
+
 QTEST_MAIN(tst_QTreeWidget)
 #include "tst_qtreewidget.moc"