Custom context menu in QTreeView

Hi all,

I have a QTreeView and QStandardItemModel and want to add a context menu so that new child node(s) can be added to the current node.

At construction, I'd like to have three empty tree nodes
<checkbox><icon>Rectangles
<checkbox><icon>Circles
<checkbox><icon>Squares

and to enable a right click on each of those nodes to add/delete/modify. I started with an ActionsContextMenu but then I need the node's index, so I successfully created a custom context menu.

Code:

---

...
  // set context menu policy
   projectTreeView->setContextMenuPolicy(Qt::CustomContextMenu);
   ...
 
  // initialize the model with three empty nodes
  QStandardItemModel *model = new QStandardItemModel();
  model->setHorizontalHeaderItem(0, new QStandardItem());
  m_dm[0] = new QStandardItem(QIcon(":/images/myIcon.png"), "Rectangles");
  m_dm[1] = new QStandardItem(QIcon(":/images/myIcon.png"), "Circles");
  m_dm[2] = new QStandardItem(QIcon(":/images/myIcon.png"), "Squares");
  for (int i=0; i<3; ++i) {
    model->appendRow(m_dm[i]);
  }
  m_ui.projectTreeView->setModel(model);
  ...
 
  // create an add action and connect it to a signal
  m_addAction = new QAction(tr("Add new"), m_ui.projectTreeView);
  connect(m_addAction, SIGNAL(triggered()), this, SLOT(addObject()));
 
  // connect custom context menu
  connect(m_ui.projectTreeView, SIGNAL(customContextMenuRequested( const QPoint& )), this, SLOT(showContextMenu(const QPoint &)));
 
  ...
  void showContextMenu(const QPoint& pnt)
  {
  QList<QAction *> actions;
  if (m_ui.projectTreeView->indexAt(pnt).isValid()) {
    actions.append(m_addAction);
  }
  if (actions.count() > 0)
    QMenu::exec(actions, m_ui.projectTreeView->mapToGlobal(pnt));
  }
 
  ...
  void MainWindow::addObject()
  {
     // HOW am I going to get access to the node's index to insert a new child row??? 
  }

---

I got the code to compile and the addObject() method is invoked properly. My question is how am I going to get access to the corresponding node index to insert a child node appropriately?

Thanks in advance.

try to use QAbstractItemView::currentIndex.

Thanks. Follow-up questions,
1) I want to setCheckable on the tree top level nodes to true when it has children + when check/uncheck a parent's checkbox, all children will be checked/unchecked accordingly. Do I have to subclass QStandardItem?

2) Children node always has a checkbox or radiobox, and toggling child node checkbox/radiobox won't change its parent checked state. Do I have to subclass QStandardItem?

3) when create a child node, I want to use a different default icon and/or naming convention by the parent's type (i.e. Squares, Circles, ...). I don't want to just rely on the name of the parent's node if I don't have to. If so, can I use QStandardItem then somehow utilizing Qt role/type OR do I need to subclass QStandardItem?

In general, I want to avoid subclassing QStandardItem, QStandardItemModel, and QTreeView unless I have to.

Quote:

---

Originally Posted by ttvo

Thanks. Follow-up questions,
1) I want to setCheckable on the tree top level nodes to true when it has children + when check/uncheck a parent's checkbox, all children will be checked/unchecked accordingly. Do I have to subclass QStandardItem?

---

try this code

Code:

---

...
QTreeWidget *tree = new QTreeWidget;
tree->setColumnCount(1);
 
QTreeWidgetItem *root = new QTreeWidgetItem(QStringList(QString("root")));
root->setCheckState(0, Qt::Unchecked);
tree->insertTopLevelItem(0, root);
 
for (int i = 0; i < 10; ++i) {
	QTreeWidgetItem *item = new QTreeWidgetItem(root, QStringList(QString("item: %1").arg(i)));
	item->setCheckState(0, Qt::Unchecked);
	for (int j = 0; j < 10; ++j) {
		QTreeWidgetItem *itm = new QTreeWidgetItem(item, QStringList(QString("item: %1").arg(i)));
		itm->setCheckState(0, Qt::Unchecked);
	}		
}	
 
connect(tree, SIGNAL(itemChanged(QTreeWidgetItem *, int)), SLOT(itemChanged(QTreeWidgetItem *, int)));
....
void MyWidget::itemChanged(QTreeWidgetItem *item, int)
{
	changeItemState(item);
}
 
void MyWidget::changeItemState(QTreeWidgetItem *item)
{
	if (!item)
		return;
 
	for (int i = 0; i < item->childCount(); ++i) {
		QTreeWidgetItem *child = item->child(i);
		child->setCheckState(0, item->checkState(0));
		changeItemState(child);
	}
}

---

I don't test it, but hope you got idea.
PS. I don't see any reason to subclass QStandardItem in second and third points.

I added

Code:

---

connect(model, SIGNAL(itemChanged(QStandardItem * item)), SLOT(myItemChanged(QStandardItem *item)));
 
// where QStandardItemModel *model = new QStandardItemModel();

---

from my MainWindow (inherits from QMainWindow) and

Code:

---

void MainWindow::myItemChanged(QStandardItem *item)
{
  changeItemState(item);
}
 
void MainWindow::changeItemState(QStandardItem *item)
{
  if (!item)
    return;
  for (int i=0; i<item->rowCount(); ++i) {
    QStandardItem *child = item->child(i);
    child->setCheckable(item->checkState());
    changeItemState(child);
  }
}

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similar to your example but the two methods weren't invoked at all when I toggle the checkbox.

Quote:

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Originally Posted by ttvo

I added

Code:

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connect(model, SIGNAL(itemChanged(QStandardItem * item)), SLOT(myItemChanged(QStandardItem *item)));
 
// where QStandardItemModel *model = new QStandardItemModel();

---

---

The correct code is:

Code:

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connect(model, SIGNAL(itemChanged(QStandardItem * )), SLOT(myItemChanged(QStandardItem *)));

---