How to drag & drop rows within QTableWidget

jarda

Hello all,
I want to drag & drop rows in QTableWidget to change order of rows in the table.
I want only move whole rows, not overwrite or delete.

I've tried
@
table->setDragDropOverwriteMode(false);
table->setDragEnabled(true);
table->setDragDropMode(QAbstractItemView::InternalMove);
item->setFlags(item->flags() & ~(Qt::ItemIsDropEnabled));
@
but it doesn't fully enable to move a row.

My question is: is it possible to get requested behavior just by correct setting of some flags or is it necessary to inherit and re-implement something?
Working example is appreciated.

Thanks in advance,

Jarda

sigrid

The example below allows you to move rows by calling "setMovable(true)":http://doc.qt.nokia.com/4.7/qheaderview.html#setMovable on the header. Does it give you the behavior you want?

@
#include <QtGui>

int main( int argc, char** argv ) {
QApplication a( argc, argv );
QTableWidget table(4,4);
for(int row =0;row<4;row++)
for(int col = 0;col<4;col++)
{
QTableWidgetItem *item = new QTableWidgetItem(QString("Row%1 Col%2").arg(row).arg(col));
item->setFlags(item->flags() | Qt::ItemIsSelectable);
table.setItem(row,col,item);
}
table.verticalHeader()->setMovable(true);
table.show();
return a.exec();
}
@

jarda

Thank you for reply. but I also need to change the number of moved row. When I drag the row number 5 to first row I also need it to become row number 1 and reorder the rest (not only the row number 5 displayed as first).

giesbert

I'm not sure if that is possible within QTableWidget. If you do it with QTableView and a custom model, you would overwrite the drag / drop stuff in the model.

jarda

Thank You Gerolf for reply. Can you please give me a hint (or sample code) how to implement it with custom model?

giesbert

If you look inside the "qt docs":http://doc.qt.nokia.com/4.7/model-view-programming.html there ios a chapter on model view and also on dnd with MVD. I propose you start reading there.

gadlol

I wanted the same functionality for my app. So I searched through internet and didnt find anything. So I had to do it.

So, you can do it with QTableWidget by using the cellEntered(int,int); then takeItem(row, col) and then setItem()...

@connect(ui->tableWidget, SIGNAL(cellEntered(int,int)), this, SLOT(cellEnteredSlot(int,int)));@

@void MainWindow::cellEnteredSlot(int row, int column){

    int colCount=ui->tableWidget->columnCount();

    int rowsel;
    
    if(ui->tableWidget->currentIndex().row()<row) rowsel=row-1; //down

    else if(ui->tableWidget->currentIndex().row()>row) rowsel=row+1; //up

    else return;

            QList<QTableWidgetItem*> rowItems,rowItems1;
            for (int col = 0; col < colCount; ++col)
            {
                    rowItems << ui->tableWidget->takeItem(row, col);
                    rowItems1 << ui->tableWidget->takeItem(rowsel, col);

            }

            for (int cola = 0; cola < colCount; ++cola)
            {
                    ui->tableWidget->setItem(rowsel, cola, rowItems.at(cola));
                    ui->tableWidget->setItem(row, cola, rowItems1.at(cola));

            }

}@

Warning: I think theres a bug.

Although it works fine by clicking and holding the left mouse button and moving mouse up or down, it also works with Mouse WHEEL Scroll.

I have not figure it out yet on how to check if mouse wheel was triggered so not to move selected row.

The doc says:

bq. This signal is only emitted when mouseTracking is turned on, or when a mouse button is pressed while moving into an item.

BUT when you scroll the mouse wheel is not a mouse button press action.

So I think its a BUG. Should I submit it?