QDoubleSpinBox inside a QTreeWidget

[pcheng]

I have a QTreeWidget in which I made an addRoot function and an addChild function.

In the addRoot I want one column of the widget to be a doublespinbox and so I call it with the following code:

// Testing spinboxes
    QDoubleSpinBox *quantitySpinBox = new QDoubleSpinBox();
    quantitySpinBox->setDecimals(1);
    quantitySpinBox->setSingleStep(0.5);
    ui->treeWidget->setItemWidget(itm, 7, quantitySpinBox);
 
    connect(quantitySpinBox, SIGNAL(editingFinished()), this, SLOT(planQuantity()));

// Testing spinboxes
    QDoubleSpinBox *quantitySpinBox = new QDoubleSpinBox();
    quantitySpinBox->setDecimals(1);
    quantitySpinBox->setSingleStep(0.5);
    ui->treeWidget->setItemWidget(itm, 7, quantitySpinBox);

    connect(quantitySpinBox, SIGNAL(editingFinished()), this, SLOT(planQuantity()));

To copy to clipboard, switch view to plain text mode 

The spinbox appears correctly and works fine in the widget.

The problem arises when I try to access the values in the widget.

I use the following debugging code to see what the values are in the spinboxes.

qDebug() << item->data(7, Qt::DisplayRole).toFloat();

qDebug() << item->data(7, Qt::DisplayRole).toFloat();

To copy to clipboard, switch view to plain text mode 

The result is all 0. Even though I change values throughout the cells it is always 0.

Is there something that I am doing wrong? How can I access the value set inside the spinbox?

Any help will be greatly appreciated because I am stuck here not going anywhere without those values.

Thanks,

Pericles

[Zlatomir]

Do you use setData to put something (the spinbox value) in that "data"? If not you need to take the pointer to the widget of that item (itemWidget) then dynamic cast it to QDoubleSpinBox and use the value() member function.

[pcheng]

I am not using the setData on that widget. I change the value on the UI by clicking the up and down arrows.

I assume I need to access the QDoubleSpinBox within the widget as you stated. So I use the following:

QTreeWidgetItem *item = ui->treeWidget->topLevelItem(i);

QTreeWidgetItem *item = ui->treeWidget->topLevelItem(i);

To copy to clipboard, switch view to plain text mode 

This gives me the item with all the columns. But how do I associate column 7 with a QDoubleSpingBox? Is there a way to assign a specific column to a pointer?

I am now trying to create a new QDoubleSpinBox and then assign column 7 to that so that I can read its value but I can't seem to find a way to do that from the options that item is giving me.

Pericles

[Zlatomir]

Don't create a new QDoubleSpinBox.
See the link in my previous post: QTreeWidget::itemWidget takes a QTreeWidgetItem* and a column and returns the pointer to the QWidget that was set with setItemWidget for that item, in your case this is supposed to be a QDoubleSpinBox* but you get a QWidget* so you need to cast it (use dynamic_cast and don't forget to check for null - for the case that QTreeWidgetItem contains no widget or a different type of widget)

[pcheng]

I tried to follow your instructions and placed this code in the program:

QTreeWidget *myWidget = new QTreeWidget();
        float myValue = dynamic_cast<QDoubleSpinBox*>(myWidget->itemWidget(item, 7))->value();
        qDebug() << myValue;

QTreeWidget *myWidget = new QTreeWidget();
        float myValue = dynamic_cast<QDoubleSpinBox*>(myWidget->itemWidget(item, 7))->value();
        qDebug() << myValue;

To copy to clipboard, switch view to plain text mode 

But I get a segmentation fault when I try to use it on the dynamic_cast line.

I also saw some people use qobject_cast so I tried that too but with no result.

Any ideas what I am doing wrong.

I am sorry but my typecasting is rusty. Very rusty.

Thanks,

Pericles

EDIT. It seems that dynamic_cast<QDoubleSpinBox*>(myWidget->itemWidget(item, 7)) returns NULL as you said. Any ideas on why it does that?

[Zlatomir]

Because you create another treewidget instead of using the one that you already have and you added QSpinbox to it. So don't do: QTreeWidget *myWidget = new QTreeWidget(); (i can guess) you want to use: ui->treeWidget

[pcheng]

Thanks Zlatomir,

That did the trick.

Pericles