QAbstractListModel with QObject::event()

[Redman]

Hi,

I have a QAbstractListModel.

void
SplashScreenListModel::append(const QString& name, QObject* item) {
   s_instance->beginInsertRows(QModelIndex(), s_instance->m_data.length(),
       s_instance->m_data.length());
   s_instance->m_data.append(SPDataItem(name, item, false));
   s_instance->endInsertRows();

   // Set name for identification in slot
   item->setObjectName(name);
   connect(item, &QObject::event, s_instance.get(),
       &SplashScreenListModel::recEvent); <----- HOW?
}

void
SplashScreenListModel::recEvent(QEvent* e) {
   if (e->type() != QEvent::DynamicPropertyChange)
      return;

   QDynamicPropertyChangeEvent* pc =
       static_cast<QDynamicPropertyChangeEvent*>(e);

   // Not the correct dynamic property
   if (pc->propertyName() != "initialized")
      return;

   // Value is false
   if (!sender()->property(pc->propertyName()).value<bool>())
      return;

   QModelIndex idx = indexByName(sender()->objectName());
   setData(idx, true, SplashScreenListModel::InitializationRole);
}

QObjects have a function [virtual] bool QObject::event(QEvent *e) which can detect QDynamicPropertyChangeEvent.
Since my SplashScreen dependencies can change I dont want to adjust each dependencie. I want to bind to a signal for each QObject so I can filter for QDynamicPropertyChangeEvent in my model. How can I implement that connect() in the append(const QString& name, QObject* item)?

[Redman]

The correct solution in my scenario is to install an event filter.

void
SplashScreenListModel::append(const QString& name, QObject* item) {
   // Get dynamic property initialized value
   // If the returned variant is invalid, the property is not set yet
   QVariant v = item->property("initialized");
   bool initStatus = false;
   if (v.isValid() && v.value<bool>())
      initStatus = true;

   s_instance->beginInsertRows(QModelIndex(), s_instance->m_data.length(),
       s_instance->m_data.length());
   s_instance->m_data.append(SPDataItem(name, item, initStatus));
   s_instance->endInsertRows();

   // Set name for identification in slot
   item->setObjectName(name);
   // Install eventfilter
   item->installEventFilter(s_instance.get());
}

bool
SplashScreenListModel::eventFilter(QObject* obj, QEvent* event) {
   if (event->type() != QEvent::DynamicPropertyChange)
      return QObject::eventFilter(obj, event);  // Default processing

   // We have a QDynamicPropertyChangeEvent at hand
   QDynamicPropertyChangeEvent* pc =
       static_cast<QDynamicPropertyChangeEvent*>(event);

   // Not the correct dynamic property
   if (pc->propertyName() != "initialized")
      return QObject::eventFilter(obj, event);  // Default processing

   // Value is false
   if (!obj->property(pc->propertyName()).value<bool>())
      return true;

   QModelIndex idx = indexByName(obj->objectName());
   setData(idx, true, SplashScreenListModel::InitializationRole);
   return true;
}

[jsulm]

@Redman said in QAbstractListModel with QObject::event():

QObject::event

This is an event handler, not a signal. You cannot connect to event handlers, you can only override event handlers in derived classes.
You could have a base class for all your item where you override QObject::event.

[Redman]

The correct solution in my scenario is to install an event filter.

void
SplashScreenListModel::append(const QString& name, QObject* item) {
   // Get dynamic property initialized value
   // If the returned variant is invalid, the property is not set yet
   QVariant v = item->property("initialized");
   bool initStatus = false;
   if (v.isValid() && v.value<bool>())
      initStatus = true;

   s_instance->beginInsertRows(QModelIndex(), s_instance->m_data.length(),
       s_instance->m_data.length());
   s_instance->m_data.append(SPDataItem(name, item, initStatus));
   s_instance->endInsertRows();

   // Set name for identification in slot
   item->setObjectName(name);
   // Install eventfilter
   item->installEventFilter(s_instance.get());
}

bool
SplashScreenListModel::eventFilter(QObject* obj, QEvent* event) {
   if (event->type() != QEvent::DynamicPropertyChange)
      return QObject::eventFilter(obj, event);  // Default processing

   // We have a QDynamicPropertyChangeEvent at hand
   QDynamicPropertyChangeEvent* pc =
       static_cast<QDynamicPropertyChangeEvent*>(event);

   // Not the correct dynamic property
   if (pc->propertyName() != "initialized")
      return QObject::eventFilter(obj, event);  // Default processing

   // Value is false
   if (!obj->property(pc->propertyName()).value<bool>())
      return true;

   QModelIndex idx = indexByName(obj->objectName());
   setData(idx, true, SplashScreenListModel::InitializationRole);
   return true;
}