QListWidget->clear()

[StrikeByte]

Try using this:

The QListWidget destroys your array of QListWidgetItems during the clear (so the first time it's not a problem the second time is). this code generates new items when they are needed

qDebug("inside updatelist");
    quint8 qIndex;
 
    ui->listWidget->setWrapping(false);
    // ui->listWidget->clear();
 
    qDebug()<<"total items = "<<tot_items;
    for (qIndex = 0; qIndex < tot_items; ++qIndex)
    {
    qDebug("inside for loop");
    QString item_val = QString(ItemsInList[qIndex].name).append("\n").append(QString("$").append(ItemsInList[qIndex].price));
    qDebug()<<"list widget string to be populated = "<<item_val;
    QListWidgetItem * item = new QListWidgetItem;
    item.setText(item_val);
    QString icon = QString("/home/charvi123/QtSDK/Projects/scanIt/numbers/") + QString("%1").arg((qIndex + 1), 0, 10) + QString(".png");
    item.setIcon(QIcon(icon));
    ui->listWidget->addItem(item);
    }
    ui->listWidget->setFocus();

qDebug("inside updatelist");
    quint8 qIndex;
     
    ui->listWidget->setWrapping(false);
    // ui->listWidget->clear();
     
    qDebug()<<"total items = "<<tot_items;
    for (qIndex = 0; qIndex < tot_items; ++qIndex)
    {
    qDebug("inside for loop");
    QString item_val = QString(ItemsInList[qIndex].name).append("\n").append(QString("$").append(ItemsInList[qIndex].price));
    qDebug()<<"list widget string to be populated = "<<item_val;
    QListWidgetItem * item = new QListWidgetItem;
    item.setText(item_val);
    QString icon = QString("/home/charvi123/QtSDK/Projects/scanIt/numbers/") + QString("%1").arg((qIndex + 1), 0, 10) + QString(".png");
    item.setIcon(QIcon(icon));
    ui->listWidget->addItem(item);
    }
    ui->listWidget->setFocus();

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Question why do you want to save the data twice? once in the item array and once in the listwidget
For this i would use the QStandardItemModel in combination with the QListView