how to add QSpinBox to a QTableWidget?

Question

I have a QTableWidget and an object of class product called p. I wanna add items to this table. I tried the code below but no use.

void MainWindow:: add_to_basket (product p){

    ui->tableWidget->insertRow(1);

    QLineEdit *qle=new QLineEdit();
    qle->setText(p.get_name());
    ui->tableWidget->setCellWidget(1,1,qle);

    QLineEdit *qle1=new QLineEdit();
    qle1->setText(QString::number(p.get_price()));
    ui->tableWidget->setCellWidget(1,2,qle1);

    QSpinBox *qsb=new QSpinBox();
    qsb->setValue(p.get_count());
    ui->tableWidget->setCellWidget(1,3,qsb);

}

what should I do?

Answer 1

1. QTableWidget should have defined rowCount and columnCount properties. It can be done either via QTableWidget constructor (https://doc.qt.io/qt-5/qtablewidget.html#QTableWidget-1) or via appropriate methods (setRowCounts and setColumnCounts). If it is done already, that's great.
2. insertRow inserts an empty row into the table at given position. ui->tableWidget->insertRow(1) would insert a new row at position 1 only if you have previously defined rowCount and columnCount (see point 1).
3. It depends what is your idea here - if you would like to have at least 4 columns (please note that we are counting from 0 and the QSpinBox is attempted to be put into third column) and insert new product always at first row, your code with point 1 fullfilled will be work fine. But, if your idea is to add a new row each time new product is added, you should rather call ui->tableWidget->insertRow(tableWidget->rowCount()) and use that value to address appropriate row.

You may also want to have a look here for example how to setup QTableWidget: https://wiki.qt.io/How_to_Use_QTableWidget