[Development] Move QAction from QtWidgets to QtGui

[Иван Комиссаров]

Sorry for reanimating old thread:)

I was looking at QAction code and didn't see big dependecies on qtwidgets.

Isn't possible to implement this solution, keeping source and binary compatibility:

We add QGuiAction to QtGui module. It has exact API like current QAction (which is discussable, but it's not my main idea) except it doesn't have associatedWidgets method. Instead, it have assotiatedObjects method and stores abstract QObjects (which are QWidgets, QGraphicsWidgets or QML items).

QAction becomes a simple wrapper around QGuiAction and adds associatedWidgets method which looks like this:

QList<QWidget*> associatedWidgets() 
{
     QList<QWidget*> result;
     foreach (QObject *object, assotiatedObjects()) {
          if (QWidget *w = qobject_cast<QWidget *>(object) )
              result.append(w);
     }
     return result;
}

The next thing to fix - is ~QAction(), it should remove itself from added objects.
I suggest to use destroyed(QObject*) signal and move that code into the QWidget itself.
Second solution is to send RemoveAction event to objects.
Third solution requires RTTI - we can add c++ interface to a QWidgetPrivate that allows to remove actions from it and use dynamic_cast to cast object's d_ptr to that interface (hack, yeah)

I prefer signal, anyway - it' widget's problems to track objects it refers too. And in most cases QWidgets becomes deleted before it's Actions.

Advantages - current code keeps working, no breaking compatibility we can write code that is not dependent on the QWidgets and share between qml/widgets code.
Disadvantages - QAction will work a bit slower.

Иван Комиссаров