How to perform action before and after user edits element in QTableView?

Rodrigo B.

I have a QTableView and would like to perform certain actions before and after the user edits certain elements in the view.

At first I naively introduced the code for these actions in my model's setData model, but then the actions are performed in other circumstances, for example when a row is dragged and dropped (since that invokes setData as well). I am not sure there is a way for me to tell when setData is being invoked as a result of manual editing, and when it is invoked because of other events.

So, in summary, how can I insert code that is run only before and after the user edits an element in a QTableView? Thanks.

eyllanesc

@Rodrigo-B Use a delegate:

#include <QApplication>
#include <QStandardItemModel>
#include <QStyledItemDelegate>
#include <QTableView>

#include <QDebug>

class Delegate: public QStyledItemDelegate{
public:
    using QStyledItemDelegate::QStyledItemDelegate;
    void setEditorData(QWidget *editor, const QModelIndex &index) const{
        if(editor->isHidden()){
            qDebug() << "before";
        }
        QStyledItemDelegate::setEditorData(editor, index);
    }
    void setModelData(QWidget *editor, QAbstractItemModel *model, const QModelIndex &index) const{
        QStyledItemDelegate::setModelData(editor, model, index);
        qDebug() << "after";
    }
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QTableView w;
    w.setItemDelegate(new Delegate(&w));
    QStandardItemModel model(4, 4);
    w.setModel(&model);
    w.show();
    return a.exec();
}

Rodrigo B.

Great, thank you!

Can you please tell me why you need to check editor->isHidden()?

eyllanesc

@Rodrigo-B When testing my code I verified that setEditorData was called 2 times so to avoid it use that condition.

Rodrigo B.

@eyllanesc Thank you!

Does anyone know why this is called twice? It seems like it should be called only once.

eyllanesc

@Rodrigo-B I would have to check the source code of the class but I am lazy to do so, if you want to understand the cause or check the source code or debug Qt.