QTableView and Key-Delete

[Armin]

Hello to all,

I'm new to Qt (using it for 4 weeks, used c++ builder before), using Qt 4.6 with C++ on windows (Qt Creator) and have a small problem detecting press of Key_Delete in a QTableView to manage to delete the whole row of data. I used keyPressEvent(QKeyEvent*) which is triggered on other Keys, but not the delete key. Below is a small example of compilable code, maybe someone has a hint for me. If I comment out the setEditTrigger line, I get the event once (and the contents of the active item is deleted), but then the tableview has no focus when I query that in keyPressEvent() (I later only want to act on delete key when the table has focus).

Thanks in advance
Armin

#include <QtGui>
 
class MyApp : public QWidget
{
public:
  MyApp();
  ~MyApp();
  QStandardItemModel *model;
  QTableView *table;
  QVBoxLayout *layout;
  void keyPressEvent(QKeyEvent *event);
};
MyApp::MyApp() : QWidget()
{
  QStandardItem* item;
 
  table = new(QTableView);
  model = new QStandardItemModel(2, 1);
  table->setModel( model );
 
  for( int r=0; r<2; r++ )
  {
    item = new QStandardItem(QString("Test"));
    model->setItem(r, 0, item);
  }
 
  table->setSelectionMode( QAbstractItemView::SingleSelection );
  table->setEditTriggers(QAbstractItemView::NoEditTriggers);
 
  layout = new QVBoxLayout;
  layout->addWidget(table);
  setLayout(layout);
}
MyApp::~MyApp()
{
}
void MyApp::keyPressEvent(QKeyEvent *event)
{
  switch (event->key())
  {
    case Qt::Key_Return:
    case Qt::Key_Enter:
      qDebug() << "Enter";
      break;
    case Qt::Key_Escape:
      qDebug() << "Escape";
      break;
    case Qt::Key_Insert:
      qDebug() << "Insert";
      break;
    case Qt::Key_Delete:
      qDebug() << "Delete";
      break;
      default:
      qDebug() << "other" << event->key();
      break;
  }
}
int main( int argc, char **argv ) {
  QApplication app( argc, argv );
  MyApp Test;
 
  Test.show();
 
  return app.exec();
}

#include <QtGui>

class MyApp : public QWidget
{
public:
  MyApp();
  ~MyApp();
  QStandardItemModel *model;
  QTableView *table;
  QVBoxLayout *layout;
  void keyPressEvent(QKeyEvent *event);
};
MyApp::MyApp() : QWidget()
{
  QStandardItem* item;

  table = new(QTableView);
  model = new QStandardItemModel(2, 1);
  table->setModel( model );

  for( int r=0; r<2; r++ )
  {
    item = new QStandardItem(QString("Test"));
    model->setItem(r, 0, item);
  }

  table->setSelectionMode( QAbstractItemView::SingleSelection );
  table->setEditTriggers(QAbstractItemView::NoEditTriggers);

  layout = new QVBoxLayout;
  layout->addWidget(table);
  setLayout(layout);
}
MyApp::~MyApp()
{
}
void MyApp::keyPressEvent(QKeyEvent *event)
{
  switch (event->key())
  {
    case Qt::Key_Return:
    case Qt::Key_Enter:
      qDebug() << "Enter";
      break;
    case Qt::Key_Escape:
      qDebug() << "Escape";
      break;
    case Qt::Key_Insert:
      qDebug() << "Insert";
      break;
    case Qt::Key_Delete:
      qDebug() << "Delete";
      break;
      default:
      qDebug() << "other" << event->key();
      break;
  }
}
int main( int argc, char **argv ) {
  QApplication app( argc, argv );
  MyApp Test;

  Test.show();

  return app.exec();
}

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[squidge]

Have you tried subclassing QTableView or installing an event filter? With the former, your function will only be called when the table has focus.

[Armin]

adding an event-filter like shown below gives the same result, the delete key is not shown. When I subclass QTableView, what do I have to overwrite to get all keys?

#include <QtGui>
 
class MyApp : public QWidget
{
public:
  MyApp();
  ~MyApp();
  QStandardItemModel *model;
  QTableView *table;
  QVBoxLayout *layout;
  void keyPressEvent(QKeyEvent *event);
  bool eventFilter(QObject* object, QEvent* event);
};
MyApp::MyApp() : QWidget()
{
  QStandardItem* item;
 
  table = new(QTableView);
  model = new QStandardItemModel(2, 1);
  table->setModel( model );
 
  for( int r=0; r<2; r++ )
  {
    item = new QStandardItem(QString("Test"));
    model->setItem(r, 0, item);
  }
 
  table->setSelectionMode( QAbstractItemView::SingleSelection );
  table->setEditTriggers(QAbstractItemView::NoEditTriggers);
 
  layout = new QVBoxLayout;
  layout->addWidget(table);
  setLayout(layout);
  installEventFilter(this);
}
MyApp::~MyApp()
{
}
void MyApp::keyPressEvent(QKeyEvent *event)
{
  switch (event->key())
  {
    case Qt::Key_Return:
    case Qt::Key_Enter:
      qDebug() << "Enter";
      break;
    case Qt::Key_Escape:
      qDebug() << "Escape";
      break;
    case Qt::Key_Insert:
      qDebug() << "Insert";
      break;
    case Qt::Key_Delete:
      qDebug() << "Delete";
      break;
    default:
      qDebug() << "other" << event->key();
      break;
  }
}
bool MyApp::eventFilter(QObject* object, QEvent* event)
{
  if (event->type()==QEvent::KeyPress)
  {
    QKeyEvent* pKeyEvent=static_cast<QKeyEvent*>(event);
    if (pKeyEvent->key() == Qt::Key_Delete)
    {
      if (table->hasFocus())
      {
        qDebug() << "Event filter: Focus yes, Delete key pressed";
      }
      else
      {
        qDebug() << "Event filter: Focus NO, Delete key pressed";
      }
      return TRUE;
    }
    qDebug() << "Event filter: other key pressed";
  }
  return QWidget::eventFilter(object, event);
}
 
int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  MyApp Test;
 
  Test.show();
 
  return app.exec();
}

#include <QtGui>

class MyApp : public QWidget
{
public:
  MyApp();
  ~MyApp();
  QStandardItemModel *model;
  QTableView *table;
  QVBoxLayout *layout;
  void keyPressEvent(QKeyEvent *event);
  bool eventFilter(QObject* object, QEvent* event);
};
MyApp::MyApp() : QWidget()
{
  QStandardItem* item;

  table = new(QTableView);
  model = new QStandardItemModel(2, 1);
  table->setModel( model );

  for( int r=0; r<2; r++ )
  {
    item = new QStandardItem(QString("Test"));
    model->setItem(r, 0, item);
  }

  table->setSelectionMode( QAbstractItemView::SingleSelection );
  table->setEditTriggers(QAbstractItemView::NoEditTriggers);

  layout = new QVBoxLayout;
  layout->addWidget(table);
  setLayout(layout);
  installEventFilter(this);
}
MyApp::~MyApp()
{
}
void MyApp::keyPressEvent(QKeyEvent *event)
{
  switch (event->key())
  {
    case Qt::Key_Return:
    case Qt::Key_Enter:
      qDebug() << "Enter";
      break;
    case Qt::Key_Escape:
      qDebug() << "Escape";
      break;
    case Qt::Key_Insert:
      qDebug() << "Insert";
      break;
    case Qt::Key_Delete:
      qDebug() << "Delete";
      break;
    default:
      qDebug() << "other" << event->key();
      break;
  }
}
bool MyApp::eventFilter(QObject* object, QEvent* event)
{
  if (event->type()==QEvent::KeyPress)
  {
    QKeyEvent* pKeyEvent=static_cast<QKeyEvent*>(event);
    if (pKeyEvent->key() == Qt::Key_Delete)
    {
      if (table->hasFocus())
      {
        qDebug() << "Event filter: Focus yes, Delete key pressed";
      }
      else
      {
        qDebug() << "Event filter: Focus NO, Delete key pressed";
      }
      return TRUE;
    }
    qDebug() << "Event filter: other key pressed";
  }
  return QWidget::eventFilter(object, event);
}

int main( int argc, char **argv )
{
  QApplication app( argc, argv );
  MyApp Test;

  Test.show();

  return app.exec();
}

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[squidge]

You are installing an event filter MyApp (itself). Try table->installEventFilter(this) which would install it where you want it.

Alternatively, try to override QAbstractItemView::keyPressEvent

[Armin]

Now it works, many thanks for yout help.
regards Armin