Hello,

I am trying to use an editor made of two QDoubleSpinBox when subclassing QStyledItemDelegate. I have no problem connecting the delegate and editor to the model but I failed to have my editor to show up in my view. I had no such problem with a simpler editor (e.g. a single QSpinBox).

Constructor for the Editor
Qt Code: 
  1. Data_editor::Data_editor( QWidget *parent)
  2. :QFrame(parent)
  3. {
  4.   lower_bound_spin_ = new QDoubleSpinBox(this);
  5.   upper_bound_spin_ = new QDoubleSpinBox(this);
  6.  
  7.   QHBoxLayout* layout = new QHBoxLayout(this);
  8.   layout->addWidget(new QLabel("Lower", this));
  9.   layout->addWidget(lower_bound_spin_);
  10.   layout->addStretch();
  11.   layout->addWidget(new QLabel("Upper", this));
  12.   layout->addWidget(upper_bound_spin_);
  13.  
  14.   this->setLayout(layout);
  15.  
  16.   this->setFocusPolicy( Qt::StrongFocus );
  17. }
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Implementation of the delegate
Qt Code: 
  1. QWidget *Data_delegate::createEditor(QWidget *parent,
  2.                                      const QStyleOptionViewItem &option,
  3.                                      const QModelIndex &index) const
  4.  
  5. {
  6.    Data_editor* editor = new Data_editor( parent);
  7.  
  8.    return editor;
  9.  
  10. }
  11.  
  12.  void Data_delegate::paint(QPainter *painter, const QStyleOptionViewItem &option,
  13.                           const QModelIndex &index) const
  14.  {
  15.    QStyledItemDelegate::paint(painter, option, index);
  16. }
  17.  
  18.  
  19. QSize Data_delegate::sizeHint(const QStyleOptionViewItem &option,
  20.                             const QModelIndex &index) const
  21. {
  22.   return QStyledItemDelegate::sizeHint(option, index);
  23.  
  24. }
  25.  
  26. void Data_delegate::updateEditorGeometry(QWidget *editor,
  27.      const QStyleOptionViewItem &option, const QModelIndex &/* index */) const
  28.  {
  29.      editor->setGeometry(option.rect);
  30.  }
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I played a bit with eventFilter and try to record the log of the events passing through
Qt Code: 
  1. bool Data_delegate::eventFilter(QObject *object, QEvent *event)
  2. {
  3.     Data_editor *editor = qobject_cast<Data_editor*>(object);
  4.     if (!editor)
  5.         return false;
  6.  
  7.     QWidget *w_focused = QApplication::focusWidget();
  8.     QEvent::Type t = event->type();
  9.  
  10.     std::string class_name = (w_focused!=0)?w_focused->metaObject()->className():std::string("000");
  11.     ostream_<<class_name <<" "<< QString("%1").arg(t).toStdString()+"\n";
  12.  
  13.     if (event->type() == QEvent::KeyPress) {
  14.         switch (static_cast<QKeyEvent *>(event)->key()) {
  15.         case Qt::Key_Tab:
  16.             emit commitData(editor);
  17.             emit closeEditor(editor, QAbstractItemDelegate::EditNextItem);
  18.             return true;
  19.         case Qt::Key_Backtab:
  20.             emit commitData(editor);
  21.             emit closeEditor(editor, QAbstractItemDelegate::EditPreviousItem);
  22.             return true;
  23.         case Qt::Key_Enter:
  24.         case Qt::Key_Return:
  25.  
  26.             QMetaObject::invokeMethod(this, "_q_commitDataAndCloseEditor",
  27.                                       Qt::QueuedConnection, Q_ARG(QWidget*, editor));
  28.             return false;
  29.         case Qt::Key_Escape:
  30.             // don't commit data
  31.             emit closeEditor(editor, QAbstractItemDelegate::RevertModelCache);
  32.             break;
  33.         default:
  34.             return false;
  35.         }
  36.         if (editor->parentWidget())
  37.             editor->parentWidget()->setFocus();
  38.         return true;
  39.     } else if (event->type() == QEvent::FocusOut || (event->type() == QEvent::Hide && editor->isWindow())) {
  40.         //the Hide event will take care of he editors that are in fact complete dialogs
  41.         //if (!editor->isActiveWindow() || (QApplication::focusWidget() != editor)) {
  42.         if (!editor->isActiveWindow() || (w_focused != editor)) {
  43.             QWidget *w = w_focused;
  44.             //QWidget *w = QApplication::focusWidget();
  45.             while (w) { // don't worry about focus changes internally in the editor
  46.                 if (w == editor)
  47.                     return false;
  48.                 w = w->parentWidget();
  49.             }
  50.             emit commitData(editor);
  51.             emit closeEditor(editor, NoHint);
  52.         }
  53.     } else if (event->type() == QEvent::ShortcutOverride) {
  54.         if (static_cast<QKeyEvent*>(event)->key() == Qt::Key_Escape) {
  55.             event->accept();
  56.             return true;
  57.         }
  58.     }
  59.     return false;
  60. }
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Which output (first column widget className, second Qcolumn Event type):
Data_tree_view 75
Data_tree_view 70
Data_tree_view 70
Data_tree_view 70
Data_tree_view 70
Data_tree_view 69
Data_tree_view 69
Data_tree_view 69
Data_tree_view 69
Data_tree_view 13
Data_tree_view 14
Data_tree_view 17
Data_tree_view 26
Data_editor 8
Data_editor 67
Data_editor 74
Data_editor 12
Data_editor 10
Data_editor 11
Data_editor 12
Data_tree_view 9

The editor is painted (event 12) but is never shown. The last event (which probably occurred when I moved the cursor) is the FocusOut event which commit the data and close the editor.

So what is missing in my delegate/editor such the editor will be shown in my view? Online comments seem to point out to a focus issue but I cannot get it right.

Thanks