How to create a SIGNAL for QTableWidget from keyboard?

Question

I have a table and move around inside with left, right, up, down buttons. Now I need to create a SIGNAL when I stay in a certain cell and press SPACE button. This SIGNAL should bring also the coordinate of that cell. I tried with standard signals of QTableWidget but it does not work. How can I solve this?

Try to achieve it by reimplement [keyPressEvent()](http://doc.qt.io/qt-5/qabstractitemview.html#keyPressEvent), when you are on the right cell and the ```QKeyEvent``` is ```space```, send your signal. — thibsc, May 31 '17 at 12:12
@ThibautB. Yeah, I also thought about that already, but still dont know how to send the coordinate of the cell. — trangan, May 31 '17 at 12:15
use [currentIndex()](http://doc.qt.io/qt-5/qabstractitemview.html#currentIndex), you get a ```QModelIndex```, so you have the ```row``` and the ```column```. — thibsc, May 31 '17 at 12:18

lena · Accepted Answer · 2017-06-01T10:02:43.560

7

Create a separate header file i.e. "customtable.h" and then in the Designer you can Promote the existing QTableWidget to this class.

class customTable:public QTableWidget
{
   Q_OBJECT
   public:
      customTable(QWidget* parent=0):QTableWidget(parent){}       
   protected:
      void keyPressEvent(QKeyEvent *e)
      {
         if(e->key()==Qt::Key_Space)
         {
            emit spacePressed(this->currentRow(),this->currentColumn());
         }
         else { QTableWidget::keyPressEvent(e); }
      }
   signals:
      spacePressed(int r, int c);
};

edited Jun 01 '17 at 10:02

answered May 31 '17 at 12:24

lena

1,181
12
36

1

thanks. I think I should add `else { QTableWidget::keyPressEvent(event);}` here. Otherwise other buttons do not work :) – trangan May 31 '17 at 14:14
@htmlamateur right, thanks, I've added an edit to my answer – lena Jun 01 '17 at 10:03

score 6 · Answer 2 · answered Jun 02 '17 at 20:03

You can use an event filter to do this:

class TableSpaceWatcher : public QObject {
  Q_OBJECT
  bool eventFilter(QObject * receiver, QEvent * event) override {
    auto table = qobject_cast<QTableWidget*>(receiver);
    if (table && event->type() == QEvent::KeyPress) {
       auto keyEvent = static_cast<QKeyEvent*>(event);
       if (keyEvent->key() == Qt::Key_Space)
          emit spacePressed(table->currentRow(), table->currentColumn());
    }
    return false;
  }
public:
  using QObject::QObject;
  Q_SIGNAL void spacePressed(int row, int column);
  void installOn(QTableWidget * widget) {
     widget->installEventFilter(this);
  }
};

QTableWidget table;
TableSpaceWatcher watcher;
watcher.installOn(&table);

How to create a SIGNAL for QTableWidget from keyboard?

2 Answers2

Linked