Selected Rows in QTableView, copy to QClipboard


Question

I have a SQLite-Database and I did it into a QSqlTableModel. To show the Database, I put that Model into a QTableView.

Now I want to create a Method where the selected Rows (or the whole Line) will be copied into the QClipboard. After that I want to insert it into my OpenOffice.Calc-Document.

But I have no Idea what to do with the Selected SIGNAL and the QModelIndex and how to put this into the Clipboard.

1
15
5/12/2018 1:28:15 AM

Accepted Answer

To actually capture the selection you use the item view's selection model to get a list of indices. Given that you have a QTableView * called view you get the selection this way:

QAbstractItemModel * model = view->model();
QItemSelectionModel * selection = view->selectionModel();
QModelIndexList indexes = selection->selectedIndexes();

Then loop through the index list calling model->data(index) on each index. Convert the data to a string if it isn't already and concatenate each string together. Then you can use QClipboard.setText to paste the result to the clipboard. Note that, for Excel and Calc, each column is separated from the next by a newline ("\n") and each row is separated by a tab ("\t"). You have to check the indices to determine when you move to the next row.

QString selected_text;
// You need a pair of indexes to find the row changes
QModelIndex previous = indexes.first();
indexes.removeFirst();
foreach(const QModelIndex &current, indexes)
{
    QVariant data = model->data(current);
    QString text = data.toString();
    // At this point `text` contains the text in one cell
    selected_text.append(text);
    // If you are at the start of the row the row number of the previous index
    // isn't the same.  Text is followed by a row separator, which is a newline.
    if (current.row() != previous.row())
    {
        selected_text.append('\n');
    }
    // Otherwise it's the same row, so append a column separator, which is a tab.
    else
    {
        selected_text.append('\t');
    }
    previous = current;
}
QApplication.clipboard().setText(selected_text);

Warning: I have not had a chance to try this code, but a PyQt equivalent works.

26
10/22/2018 7:19:07 PM

I had a similar problem and ended up adapting QTableWidget (which is an extension of QTableView) to add copy/paste functionality. Here is the code which builds on what was provided by quark above:

qtablewidgetwithcopypaste.h

// QTableWidget with support for copy and paste added
// Here copy and paste can copy/paste the entire grid of cells
#ifndef QTABLEWIDGETWITHCOPYPASTE_H
#define QTABLEWIDGETWITHCOPYPASTE_H

#include <QTableWidget>
#include <QKeyEvent>
#include <QWidget>

class QTableWidgetWithCopyPaste : public QTableWidget
{
    Q_OBJECT
public:
  QTableWidgetWithCopyPaste(int rows, int columns, QWidget *parent = 0) :
      QTableWidget(rows, columns, parent)
  {}

  QTableWidgetWithCopyPaste(QWidget *parent = 0) :
  QTableWidget(parent)
  {}

private:
  void copy();
  void paste();

public slots:
  void keyPressEvent(QKeyEvent * event);
};

#endif // QTABLEWIDGETWITHCOPYPASTE_H

qtablewidgetwithcopypaste.cpp

#include "qtablewidgetwithcopypaste.h"
#include <QApplication>
#include <QMessageBox>
#include <QClipboard>
#include <QMimeData>

void QTableWidgetWithCopyPaste::copy()
{
    QItemSelectionModel * selection = selectionModel();
    QModelIndexList indexes = selection->selectedIndexes();

    if(indexes.size() < 1)
        return;

    // QModelIndex::operator < sorts first by row, then by column.
    // this is what we need
//    std::sort(indexes.begin(), indexes.end());
    qSort(indexes);

    // You need a pair of indexes to find the row changes
    QModelIndex previous = indexes.first();
    indexes.removeFirst();
    QString selected_text_as_html;
    QString selected_text;
    selected_text_as_html.prepend("<html><style>br{mso-data-placement:same-cell;}</style><table><tr><td>");
    QModelIndex current;
    Q_FOREACH(current, indexes)
    {
        QVariant data = model()->data(previous);
        QString text = data.toString();
        selected_text.append(text);
        text.replace("\n","<br>");
        // At this point `text` contains the text in one cell
        selected_text_as_html.append(text);

        // If you are at the start of the row the row number of the previous index
        // isn't the same.  Text is followed by a row separator, which is a newline.
        if (current.row() != previous.row())
        {
            selected_text_as_html.append("</td></tr><tr><td>");
            selected_text.append(QLatin1Char('\n'));
        }
        // Otherwise it's the same row, so append a column separator, which is a tab.
        else
        {
            selected_text_as_html.append("</td><td>");
            selected_text.append(QLatin1Char('\t'));
        }
        previous = current;
    }

    // add last element
    selected_text_as_html.append(model()->data(current).toString());
    selected_text.append(model()->data(current).toString());
    selected_text_as_html.append("</td></tr>");
    QMimeData * md = new QMimeData;
    md->setHtml(selected_text_as_html);
//    qApp->clipboard()->setText(selected_text);
    md->setText(selected_text);
    qApp->clipboard()->setMimeData(md);

//    selected_text.append(QLatin1Char('\n'));
//    qApp->clipboard()->setText(selected_text);
}

void QTableWidgetWithCopyPaste::paste()
{
    if(qApp->clipboard()->mimeData()->hasHtml())
    {
        // TODO, parse the html data
    }
    else
    {
        QString selected_text = qApp->clipboard()->text();
        QStringList cells = selected_text.split(QRegExp(QLatin1String("\\n|\\t")));
        while(!cells.empty() && cells.back().size() == 0)
        {
            cells.pop_back(); // strip empty trailing tokens
        }
        int rows = selected_text.count(QLatin1Char('\n'));
        int cols = cells.size() / rows;
        if(cells.size() % rows != 0)
        {
            // error, uneven number of columns, probably bad data
            QMessageBox::critical(this, tr("Error"),
                                  tr("Invalid clipboard data, unable to perform paste operation."));
            return;
        }

        if(cols != columnCount())
        {
            // error, clipboard does not match current number of columns
            QMessageBox::critical(this, tr("Error"),
                                  tr("Invalid clipboard data, incorrect number of columns."));
            return;
        }

        // don't clear the grid, we want to keep any existing headers
        setRowCount(rows);
        // setColumnCount(cols);
        int cell = 0;
        for(int row=0; row < rows; ++row)
        {
            for(int col=0; col < cols; ++col, ++cell)
            {
                QTableWidgetItem *newItem = new QTableWidgetItem(cells[cell]);
                setItem(row, col, newItem);
            }
        }
    }
}

void QTableWidgetWithCopyPaste::keyPressEvent(QKeyEvent * event)
{
    if(event->matches(QKeySequence::Copy) )
    {
        copy();
    }
    else if(event->matches(QKeySequence::Paste) )
    {
        paste();
    }
    else
    {
        QTableWidget::keyPressEvent(event);
    }

}

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