QTreeView internal move: not all columns shown

[Joel Bodenmann]

Simple scenario: QStandardItemModel, QTreeView and a QSortFilterProxyModel.

So far, everything is working as expected. Now I'm working on a feature allowing the user to create a new group (item in the tree view) and then adding existing items into that group (re-parenting via QAbstractItemView::InternalMove).

While the row is being moved as expected, not all columns show up anymore.
Here are two screenshots: Before the move and after the move.

Before move:

After moving the row with ID 5 to the group Test Group 1:

My expectation would have been that after the move (re-parenting), the row would still show all columns (ID, Name and Description). But instead, only the Description column is shown.

Why is this happening and how can I achieve the expected behavior in that each row still populates/shows all the columns accordingly but is just nested in zero or more parent groups?

[SGaist]

Hi,

Did you check that it is the correct index that is moved ? I.e that it's the first column index that you move ?

Do you have the same issue without the proxy ?

[Joel Bodenmann]

@SGaist said in QTreeView internal move: not all columns shown:

I.e that it's the first column index that you move ?

Sorry for the late reply. Your question kind of threw me off. I didn't understand why you'd ask this. As per my understanding this shouldn't matter as I want to remove an entire row. However, knowing you (minus the outstanding beer) I was fairly sure that you wouldn't ask this unless it would be important. Hence I needed some time to think about it :D

So what basically happened is that I only set the Qt::ItemIsDragEnabled flag on ONE item of the row (eg. cell). Hence the other items were not moved (although the row still disappeared in the view). Once I added the Qt::ItemIsDragEnabled flag to all items of the row things started looking more the way I expected.

As mentioned this is my first time using QStandardItemModel. I haven't really faced this issue previously as I'd simply subclass QAbstractItemModel and implementing itemFlags() accordingly.
I feel like I am using the QStandardItemModel incorrectly. To achieve the visual appearance showed in my initial screenshot I am creating three QStandardItems for each row and adding them using invisibleRootItem()->appendRow():

void
model::add(const process& p)
{
    const Qt::ItemFlags flags = Qt::ItemIsEnabled | Qt::ItemIsSelectable | Qt::ItemIsDragEnabled;

    // ID
    auto item_id = new QStandardItem();
    item_id->setText(QString::number(p.id));
    item_id->setFlags(flags);

    // Name
    auto item_name = new QStandardItem();
    item_name->setText(p.name);
    item_name->setFlags(flags);

    // Description
    auto item_description = new QStandardItem();
    item_description->setText(p.description);
    item_description->setFlags(flags);

    invisibleRootItem()->appendRow({ item_id, item_name, item_description });
}

Is this the way to go? It just doesn't feel right.

[SGaist]

I don't see anything wrong. The invisible root item is the initial item that allows to keep together all the others. Whether you have a tree like model or table like does not matter.

[Joel Bodenmann]

Alright, after getting this to work I decided to not use QStandardItemModel anymore but instead directly deriving from QAbstractItemModel as I've usually done. It was a fun little adventure tho.

Thank you for your help!