Get item text from model

[Higgs]

I'm writing phone book software(for educational purposes) I have 1 tableView,one QStandardItemModel,4 buttons(add,edit,delete,clear all)
here is a picture:
Capture.JPG

add button works correctly. But Edit button doesn't work correctly,as I want.
I add one person's number with Add button and then when I want to edit contact,I press edit Button but suddenly it crashes.
Capture.JPG

But,when I add new contact directly in tableView without add button, and then press Edit. That works. I can edit contact without any problems.
Capture.JPG
So,problem is when new contact is added via Add button. I can't see what is the problem.
source code of add and edit buttons

void MainWindow::on_pushButtonAdd_clicked()
{
    ChangeDialog dg;
    dg.setWindowTitle(tr("Add new contact"));
    QStringList list;
    if(dg.exec() == QDialog::Accepted){
        list << dg.GetList();
        for(int i = 0; i < 4;i++){
            QStandardItem *item = new QStandardItem(QString("%1").arg(list.at(i)));
            item->setEditable(false);
            model->setItem(rowCount,i,item);
        }
    }
    rowCount++;
}
 
void MainWindow::on_pushButtonEdit_clicked()
{
    ChangeDialog dg;
    dg.setWindowTitle(tr("Edit contact"));
    QStringList Slist;
 
 
    for(int i = 0; i < 4; i++){
            Slist.append(model->item(rowCount,i)->text());
            //QMessageBox::information(this,"title","asd");
    }
 
    dg.SetList(Slist);
    QStringList list2;
    if(dg.exec() == QDialog::Accepted){
        list2 << dg.GetList();
        for(int i = 0; i < 4;i++){
            QStandardItem *item2 = new QStandardItem(QString("%1").arg(list2.at(i)));
            item2->setEditable(false);
            model->setItem(rowCount,i,item2);
        }
    }
}

void MainWindow::on_pushButtonAdd_clicked()
{
    ChangeDialog dg;
    dg.setWindowTitle(tr("Add new contact"));
    QStringList list;
    if(dg.exec() == QDialog::Accepted){
        list << dg.GetList();
        for(int i = 0; i < 4;i++){
            QStandardItem *item = new QStandardItem(QString("%1").arg(list.at(i)));
            item->setEditable(false);
            model->setItem(rowCount,i,item);
        }
    }
    rowCount++;
}

void MainWindow::on_pushButtonEdit_clicked()
{
    ChangeDialog dg;
    dg.setWindowTitle(tr("Edit contact"));
    QStringList Slist;


    for(int i = 0; i < 4; i++){
            Slist.append(model->item(rowCount,i)->text());
            //QMessageBox::information(this,"title","asd");
    }

    dg.SetList(Slist);
    QStringList list2;
    if(dg.exec() == QDialog::Accepted){
        list2 << dg.GetList();
        for(int i = 0; i < 4;i++){
            QStandardItem *item2 = new QStandardItem(QString("%1").arg(list2.at(i)));
            item2->setEditable(false);
            model->setItem(rowCount,i,item2);
        }
    }
}

To copy to clipboard, switch view to plain text mode 

[anda_skoa]

Where do you get "rowCount" from?

Maybe it is outside the valid range of 0 <= rowCount < mode->rowCount()

If it is then model->item() will return 0 and accessing text() on a null pointer will crash.

Cheers,
_