QTreeView selecting items programatically issue

Dariusz

Hey

I'm trying to create undo/redo command system but oh boy getting the selection to work is a headache.

in my undo I store a list of column 0 elements of all selected items as nodes - no modelIndexes as they get messed up once I do drag/drop.

The idea was store as items > retrieve their indexes during undo/redo & select them again. But for some reason I cant get it to work.

Here is how I gather the items:

void myView::mouseReleaseEvent(QMouseEvent *event) {
    dragActive = false;
    QTreeView::mouseReleaseEvent(event);
    //_newSelection = selectionModel()->selection(); //// Cant use QModelIndex, affter drag/drop/etc they all go bad.
    _newSelectionX = selectedIndexes();

    //if (_newSelectionX != _oldSelectionX) {
    std::vector<myNode *> _newSelectedNodes;
    for (int x = 0; x < _newSelectionX.size(); x += model()->columnCount()) { //// get only 1st item from 0 column, well use sibling later to create full selection from indexes.
        myNode *node = static_cast<myNode*>(_newSelectionX[x].internalPointer());
        _newSelectedNodes.emplace_back(node);
    }
    std::vector<myNode *> _oldSelectedNodes;
    for (int x = 0; x < _oldSelectionX.size(); x += model()->columnCount()) {
        myNode *node = static_cast<myNode*>(_oldSelectionX[x].internalPointer());
        _oldSelectedNodes.emplace_back(node);
    }
    selectionCommand::selectionData data;
    data._newSel = _newSelectedNodes;
    data._oldSel = _oldSelectedNodes;
    data._tree = this;
    emit selectionHasChanged(data);

Here is how I undo/redo :

void myView::changeMySelection(selectionCommand::selectionData data, bool undo) {
    clearSelection();
    int columnC = 1;//model()->columnCount() - 2;
    if (undo) {
        for (int x = 0; x < data._oldSel.size(); ++x) {
            QModelIndex itemIndex = data._oldSel[x]->index();
            QModelIndex siblingIndex = itemIndex.sibling(data._oldSel[x]->row(), columnC);
            qDebug() << itemIndex << siblingIndex;
            selectionModel()->select(QItemSelection(itemIndex, itemIndex), QItemSelectionModel::Select);
            //selectionModel()->select(QItemSelection(itemIndex, siblingIndex), QItemSelectionModel::Select);
        }
    } else {
        for (int x = 0; x < data._newSel.size(); ++x) {
            QModelIndex itemIndex = data._newSel[x]->index();
            QModelIndex siblingIndex = itemIndex.sibling(data._newSel[x]->row(), columnC);
            qDebug() << itemIndex << siblingIndex;
            selectionModel()->select(QItemSelection(itemIndex, itemIndex), QItemSelectionModel::Select);

        }
    }
}

Here is the log

QModelIndex(16,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(1,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(0,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(0,1,0x15ac176b620,myModel(0x15ac06366f0))
QModelIndex(1,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(0,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(0,1,0x15ac176b620,myModel(0x15ac06366f0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(1,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(0,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(0,1,0x15ac176b620,myModel(0x15ac06366f0))
QModelIndex(1,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(16,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(15,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(13,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(15,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(16,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(2,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))
QModelIndex(1,0,0x15ac176b620,myModel(0x15ac06366f0)) QModelIndex(-1,-1,0x0,QObject(0x0))

Only some of the selections actually undo/redo. I can not understand at all why on earth I'm getting wrong QModelIndexes. The left model index is valid, so right one next column should be valid as well. duhh !

I even tried on selecting just 1 item (current example) and that only works in some cases. What am I doing wrong here ? :/

raven-worx

@Dariusz
between the undo / redo command calls, does your model get updated (rows/columns added/removed)?

Dariusz

Hey

Nope, I'm only clicking on new rows. I have added my mouseReleaseEvent code in 1st post to show how I'm gathering the items.

VRonin

@Dariusz said in QTreeView selecting items programatically issue:

no modelIndexes as they get messed up once I do drag/drop

QPersistentModelIndex should not get messed up unless the drag-drop implementation has a bug

Dariusz

Hey

Yeah not sure to be honest. I dont use persistend model indexes, they are quite heavy from what I read and sicne I will have thousands of items. I though its more efficient to store pointer to items and then get their indexes from model. I tried storing before the QSelectionModel()->selection() and restoring that, it worked on QTreeWidget system, but on my QAbstractItemModel&treeView seems to be broken. I attached video with me dragging lots of stuff(https://goo.gl/zCiMhv), It seems to be working fine. I fire the before/after remove/add commands and so on. Its puzzling :- ( Over there I store pointers to items in an array>store that in my custom mimeData. The mimeData is used to carry the dragging of data as it should, and at the end of dropMimeData (before row removal/insertion) I store source item row/parent data/ to restore it later/ snipped below.

        //// Drop mime data function
        .... 
        for (int i = count - 1; i >= 0; --i) {
            if (nodes[i]->row() < row && parentNode == nodes[i]->parentNode())
                --row;
            // Remove from old position

            moveCommand::moveData mData;
            mData._node = nodes[i];
            mData._source = sourceModel;
            mData._destination = this;
            mData._sourceRow = nodes[i]->row();
            mData._destinationRow = row;
            //mData._oldParentIndex = createIndex(nodes[i]->row(), 0, nodes[i]); /// obsolete - removed now after clean up - never used it
            //mData._newParentIndex = parent; /// obsolete - removed now after clean up - never used it
            mData._oldParent = nodes[i]->parentNode();
            mData._newParent = parentNode;
            moveData.push_back(mData);

            sourceModel->removeNode(nodes[i]);
            // Insert at new position

            beginInsertRows(parent, row, row);
            parentNode->insertChild(row, nodes[i]);
            endInsertRows();
            ++row;
        }
        emit treeModelItemMoved(moveData);

Updated snipped a little.

Dariusz

SOLVED!

In QAbstractItemModel ::indexFromitem() I had wrong argument passed in createIndex(), I was passing item.parent() instead of item as third arg.. argh!!! Thanks for juggling my brain :- )

The only thing I have to solve now is to re-select items properly after drop action. I wonder whats wrong humhhhh