How to create a Combo box in a Tablview Model

[uzairsaeed702]

I am definitely not an expert, but I have successfully used a ProgressBar delegate as follows. In my MainWindow, I set the item delegate for the view as follows:

ui->tableView->setItemDelegate(new ProgressBarDelegate());

ui->tableView->setItemDelegate(new ProgressBarDelegate());

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ProgressBarDelegate is a class derived from QStyledItemDelegate and here's the paint method:

void ProgressBarDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if (!index.isValid())
        return;
 
    int col = index.column();
 
    if (col == 5)
    {
        int progress = index.data().toInt();
        QStyleOptionProgressBar progressBarOption;
        progressBarOption.rect = QRect(option.rect.x(), option.rect.y() + 5 , option.rect.width(), option.rect.height() / 1.5);
        if (progress == 100)
        {
            QApplication::style()->drawItemText(painter, option.rect, Qt::AlignCenter|Qt::AlignVCenter, option.palette, true, QString::number(progress) + "%");
        }
        else
        {
            progressBarOption.minimum = 0;
            progressBarOption.maximum = 100;
            progressBarOption.progress = progress;
            progressBarOption.text = QString::number(progress) + "%";
            progressBarOption.textVisible = true;
            progressBarOption.textAlignment = Qt::AlignCenter|Qt::AlignVCenter;
            QApplication::style()->drawControl(QStyle::CE_ProgressBar, &progressBarOption, painter);
        }
    }
    else
    {
        QStyledItemDelegate::paint(painter, option, index);
    }
 
    return;
}

void ProgressBarDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
    if (!index.isValid())
        return;

    int col = index.column();

    if (col == 5)
    {
        int progress = index.data().toInt();
        QStyleOptionProgressBar progressBarOption;
        progressBarOption.rect = QRect(option.rect.x(), option.rect.y() + 5 , option.rect.width(), option.rect.height() / 1.5);
        if (progress == 100)
        {
            QApplication::style()->drawItemText(painter, option.rect, Qt::AlignCenter|Qt::AlignVCenter, option.palette, true, QString::number(progress) + "%");
        }
        else
        {
            progressBarOption.minimum = 0;
            progressBarOption.maximum = 100;
            progressBarOption.progress = progress;
            progressBarOption.text = QString::number(progress) + "%";
            progressBarOption.textVisible = true;
            progressBarOption.textAlignment = Qt::AlignCenter|Qt::AlignVCenter;
            QApplication::style()->drawControl(QStyle::CE_ProgressBar, &progressBarOption, painter);
        }
    }
    else
    {
        QStyledItemDelegate::paint(painter, option, index);
    }

    return;
}

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So you'll see that the delegate is set at the view level and then in the paint method, I only override how the progress bar I want in column 5 is drawn and I call the base class paint method for all other columns.

If I am following your thread correctly, I believe you should be able to take a similar approach.

Good luck.

Hey jthomps,

That looks helpful to me and it gives the clear idea to play for with custom columns . I will try to do it through delegates hopefully it will work.

Thanks

Regards
Uzair saeed

If you only want customised behaviour for a couple of columns (or rows) then you only apply a custom delegate to those columns (or rows). This is exactly what your own linked combo box delegate does.

Jthomps approach is also a way to achieve the goal. The paint() and createEditor() functions look at which column they are being asked to act on and modify their behaviour accordingly. This method ties the delegate fairly closely to this particular view, i.e. You cannot reuse this delegate class on another view with 8 columns to get customised behaviour on columns 3 and 6.

Yes i am getting the idea now but in actually Model View concept is bit confusing i guess i have to study that way more time to get the clear idea. But i will try today.

Thanks ChrisW67

---

Added after 5 minutes:

Let me get this straight:
- you want the delegate in certain columns only
- you ignore the existance of setItemDelegateForColumn, which does exactly that
- you keep pretending that your problem is not solved

Only reason to do that is to troll, right?

Cheers,
_

Hey,

It was my previous try but i am getting the combo box in each columns . Problem is only that Model View concept is bit confusing and if i go with QTableWidget its easy but takes time . Actually later from that combo box i have to attach the event which can invoke the dialog so for that complexity i am planing which method would be easy for me. So i am asking question and i am beginner that is why trying approaches .

Thanks

[ChrisW67]

Yes true but in that example everything is handled by QSqlTableModel class which automatically detects the queries and place the combo box where it is necessary , which is invalid in my case. My model

The example you linked to has nothing to do with an SQL model. The model data can come from anywhere as long as it is presented using the QAbstractItemModel interface. The model provides data only.

The rendering of data in a view has nothing to do with the model. The view passes the painting and editor creation for each cell to a delegate, either the default one or one you provide, and the delegate decides what to display for the data the model is providing. The model may provide data indicating a colour, font, icon etc. but the view delegate can choose how to use (or ignore) that information when displaying the data. The type of editor provided for a cell is entirely decided by the delegate.

[uzairsaeed702]

The example you linked to has nothing to do with an SQL model. The model data can come from anywhere as long as it is presented using the QAbstractItemModel interface. The model provides data only.

The rendering of data in a view has nothing to do with the model. The view passes the painting and editor creation for each cell to a delegate, either the default one or one you provide, and the delegate decides what to display for the data the model is providing. The model may provide data indicating a colour, font, icon etc. but the view delegate can choose how to use (or ignore) that information when displaying the data. The type of editor provided for a cell is entirely decided by the delegate.

Hey ChrisW67,

Now i understand everything , i am sorry this model view concept is confusing . I will try to alter the delegate class with Paint and create editor and will try to play with it. Hopefully i will achieve my target. I will stick to model view concept instead of QtableWidget .

Thanks for the motivation.

[anda_skoa]

It was my previous try but i am getting the combo box in each columns

I highly doubt it.
Unless you are still calling setItemDelegate() instead of the correct method.

Cheers,
_