I will return into question about " Do I need implement function dragEnterEvent,DragMoveEvent?" because I see in documentation QT that they wrote

void QGraphicsItem::dropEvent ( QGraphicsSceneDragDropEvent * event ) [virtual protected]

This event handler, for event event, can be reimplemented to receive drop events for this item. Items can only receive drop events if the last drag move event was accepted.

so How I have interpret this description?