QTreeView new row not visible without layoutChanged

Question

I have implemented a hierarchical qtreeview based on this example: http://doc.qt.io/qt-5/qtwidgets-itemviews-simpletreemodel-example.html

I also use a QSortFilterProxyModel along with the model for filtering

I construct the treeview using an addentry function which is called whenever new data is received by the module. The function is given below:

void cTreeModel::addEntry(QModelIndex& sParentIndex, const tDataID id, cAbstractTreeItem *pParentItem)
        {

           switch (pParentItem->type()) {

           case cAbstractTreeItem::TROOT:
           {
              cAbstractTreeItem* pAItem = pParentItem->hasEntry(id);
              QModelIndex sAItemIndex;
              if(nullptr == pAItem)
              {
                 beginInsertRows(QModelIndex(), getRootItem()->childCount(), getRootItem()->childCount());
                 pAItem = new cATreeItem(id, pParentItem); //essentially m_pParentItem->appendChild(this);
                 endInsertRows();
              }
              else
              {
                 pAItem->updateData();
              }
              sAItemIndex = index(pAItem->row());
              addEntry(sAItemIndex, id, pAItem);
              break;
           }

           case cAbstractTreeItem::TA
           {
              cAbstractTreeItem* pB = pParentItem->hasEntry(id);
              if(nullptr == pB)
              {
                 beginInsertRows(sParentIndex, pParentItem->childCount(), pParentItem->childCount());
                 pB = new cBTreeItem(id, pParentItem); //essentially m_pParentItem->appendChild(this);
                 endInsertRows();
              }
              else
              {
                 pB->updateData();
              }
              QModelIndex sBItemIndex = index(pB->row(), 1, sParentIndex);
              addEntry(sBItemIndex, id, pB);
              break;
           }

           case cAbstractTreeItem::TB:
           {
              cAbstractTreeItem* pTC = pParentItem->hasEntry(id);
              if(nullptr == pTC)
              {
                 beginInsertRows(sParentIndex, pParentItem->childCount(), pParentItem->childCount());
                 pTC = new cCTreeItem(id, pParentItem); //essentially m_pParentItem->appendChild(this);
                 endInsertRows();
              }
              else
              {
                 pTC->updateData();
              }
              QModelIndex sCItemIndex = index(pTC->row(), 2, sParentIndex);
              addEntry(sCItemIndex, id, pTC);
              break;
           }

           case cAbstractTreeItem::TC:
           {
              const tCanGUIData* pData = m_pDataHandler->getEntryByID(id);

              if(nullptr == pData)
              {
                 return;
              }

              break;
           }

           default:
              break;
           }
        }

This function is called as such:

  addEntry(QModelIndex(), DataId, getRootItem());

The structure of data is as follows:

        TA
        |
        | -- TB
        | | | |
        | | | | -- TC
        | | | | -- TC

The addentry functions add entries correctly and send out a datachanged signal but the treeview is not updated.

But if I send out a layoutChanged signal, treeview displays the correct data. Similar case happens if I call beginResetModel and EndResetModel before and after calling addEntry. But in that case another error occurs that when the rate of calling addEntry is too large, if i change selection using arrow keys it crashes in the mapToSource (probably its in the middle of a reset operation and model indices become invalid in the proxy filter)

Any suggestion regarding this?

pleae provide a minimal reproducible example, especially complete — eyllanesc
– eyllanesc, Commented Sep 19, 2018 at 15:45

Mathias · Accepted Answer · 2018-09-18 17:05:24Z

0

Do you call beginInsertRows(...) before inserting new item and endInsertRows() after ?

https://doc.qt.io/qt-5/qabstractitemmodel.html#beginInsertRows

edited Sep 18, 2018 at 17:05

answered Sep 18, 2018 at 16:50

Mathias

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2 Comments

Daniyal Yasin Over a year ago

Yes, I did call these functions. But they didn't do any change

Mathias Over a year ago

Please post your addentry function

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