TreeView as view for ComboBox

[niko]

Hello,

is this supported?


int main(int argc, char **argv)
{
QApplication app(argc,argv);
QDirModel* model = new QDirModel();
QTreeView* view = new QTreeView();
view->setModel(model);
QComboBox* combo = new QComboBox();
combo->setView(view);
combo->setModel(model);
combo->show();
app.exec();
}


If so - what do I make wrong?
(The view isn't rendered correctly - only 10px height, selecting a file doesn't work)

thanks,
niko

[jpn]

Here's something you can start with. ;)

[niko]

I'm getting the same result as before; see attached screenshot.

Does it work better for you?

(Qt version 4.3.3)

[jpn]

What if you change in showPopup():

setRootModelIndex(QModelIndex());
to

setRootModelIndex(static_cast<QDirModel*>(model())->index(QDir::rootPath()));
?

[niko]

great! that works now!!

Why did you add the eventFilter and the skipNextHide? I disabled it and it still worked for me.

thanks,
niko

[jpn]

Why did you add the eventFilter and the skipNextHide? I disabled it and it still worked for me.
Otherwise you can't expand/collapse branches without the popup view getting hid...

[niko]

aah, i see :D

many thanks!!

[niko]

I have to bring this topic up again, because the solution is not really working for me.
The problem is that QComboBox calculates the height of the popup by counting the root-items.
Jpn suggested using another root, so that there are more items. But in my case this doesn't work - as it can happen that there is only one item.

My modified testcase:


#include <QtGui>

class TreeComboBox : public QComboBox
{
public:
TreeComboBox(QWidget* parent = 0) : QComboBox(parent), skipNextHide(false)
{
QTreeView* v = new QTreeView(this);
setView(v);
v->header()->hide();
v->viewport()->installEventFilter(this);
}

bool eventFilter(QObject* object, QEvent* event)
{
if (event->type() == QEvent::MouseButtonPress && object == view()->viewport())
{
QMouseEvent* mouseEvent = static_cast<QMouseEvent*>(event);
QModelIndex index = view()->indexAt(mouseEvent->pos());
if (!view()->visualRect(index).contains(mouseEvent->pos()))
skipNextHide = true;
}
return false;
}

virtual void showPopup()
{
setRootModelIndex(QModelIndex());
QComboBox::showPopup();
}

virtual void hidePopup()
{
setRootModelIndex(view()->currentIndex().parent());
setCurrentIndex(view()->currentIndex().row());
if (skipNextHide)
skipNextHide = false;
else
QComboBox::hidePopup();
}

private:
bool skipNextHide;
};

int main(int argc, char* argv[])
{
QApplication app(argc, argv);
TreeComboBox combo;
QStandardItemModel model;
model.appendRow(new QStandardItem("Test1"));
model.item(0)->appendRow(new QStandardItem("Test1.1"));
model.item(0)->appendRow(new QStandardItem("Test1.2"));
model.item(0)->appendRow(new QStandardItem("Test1.3"));
combo.setModel(&model);
combo.show();
app.exec();
}

[jpn]

I can't think of any better solution than faking the amount of top level items:


class Model : public QStandardItemModel
{
public:
int rowCount(const QModelIndex& index = QModelIndex()) const
{
int count = QStandardItemModel::rowCount(index);
return !index.isValid() ? qMax(10, count) : count; // at least 10 when top-level
}
};

This will, however, give false branches whilst expanding the tree. I guess one could get rid of them with a hackish reimplementation of QTreeView::drawBranches().

[niko]

That dind't help - because for those non-existing items the TreeView returned a height of 0 in the visualRect function.

My solution was to re-implement visualRect for the TreeView - and modify the height of the last top-level row.

see attached source.

However I still have a problem:
steps to reproduce (with attached application):
* open popup
* select 1.2
* open popup again
* close branch
* Test 1 gets the new root?!

[oscar]

Setting minimum size helped me avoiding the height problem, although it's not perfect:


comboBox->view()->setMinimumHeight(comboBox->count()*10);

Regards,
Oscar

[mugabe]

However I still have a problem:
steps to reproduce (with attached application):
* open popup
* select 1.2
* open popup again
* close branch
* Test 1 gets the new root?!

Does anyone know how to solve this?

removing lines
setRootModelIndex(view()->currentIndex().parent());
setCurrentIndex(view()->currentIndex().row());
will solve this problem partially.

If ComboBox is non-editable it work correct, but if it is editable bug comes back.