QTreeWidget中项目的ID已更改

Question

There is something very strange about Qt.

I have a button ui->addPointButton and a QtreeWidget ui->pointListBox . When I click on the button, it adds a point to the tree. mScenePtr is a pointer to the class I put all my points. AddPoint is a class creating a window asking for some information about the point.

void AddPointsWindow::on_addPointButton_clicked(bool clicked)
{
    Q_UNUSED(clicked);

    AddPoint addPointWindow(mScenePtr->getColor_or_texture());
    int addPointWindowResult = addPointWindow.exec();

    if  (addPointWindowResult == QDialog::Accepted)
    {
        SVertex vertex = addPointWindow.getVertex();
        mScenePtr->addVertex(vertex);

        QTreeWidgetItem* itemPtr = new QTreeWidgetItem(ui->pointListBox);
        cout << "id" << ui->pointListBox->indexOfTopLevelItem(itemPtr) << endl;

        //itemPtr->setText(0,QString::number(mScenePtr->getVertexNumber()));
        //itemPtr->setText(0, QString::number(ui->pointListBox->indexOfTopLevelItem(itemPtr)));
        itemPtr->setText(0, "hjhjh");
        cout << "id" << ui->pointListBox->indexOfTopLevelItem(itemPtr) << endl;

        itemPtr->setText(1, QString::number(vertex.x));
        itemPtr->setText(2, QString::number(vertex.y));
        itemPtr->setText(3, QString::number(vertex.z));
        if (color == mScenePtr->getColor_or_texture())
        {
            itemPtr->setText(4, QString::number(vertex.r));
            itemPtr->setText(5, QString::number(vertex.g));
            itemPtr->setText(6, QString::number(vertex.b));
        }
        //ui->pointListBox->insertTopLevelItem(ui->pointListBox->topLevelItemCount(), itemPtr);



        cout << "value : " << vertex.x << endl;

    }
}

In this exemple, I click twice on the buttons, create two points with vertex.x = 0 for the first and 1 for the second.

Look at the three lines in the middle :

            //itemPtr->setText(0,QString::number(mScenePtr->getVertexNumber()));
        //itemPtr->setText(0, QString::number(ui->pointListBox->indexOfTopLevelItem(itemPtr)));
        itemPtr->setText(0, "hjhjh");

If there is only the third line, the result is

id0
id0
value : 0
id1
id1
value : 1

Everythong is ok. But if I put one of the two others lines, the result in both cases is :

id0
id0
value : 0
id1
id0
value : 1

How is it possible ? How can the call to ui->pointListBox->indexOfTopLevelItem(itemPtr) or mScenePtr->getVertexNumber() can change the id of the item ?

Qt 5.5

Answer 1

After using setText , the items in the tree might have sorted automatically.

So in the two commented line cases, when you add the number (using setText ), the nodes are getting sorted and the earlier node has become the top level item.

That is the reason you are seeing two different IDs "before setText " and "after setText ", when you are querying "top level item".

To see the results properly, Turn off the sorting for the tree. (may be in your constructor)

ui->pointListBox->setSortingEnabled(false);