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How can i get a mouse event(clicked,pressed,released,etc...)in my custom graphicsitem contained by a QGraphics View?
JohnYork last edited by
I got a problem while using QGraphicsView:
I derived a subclass from QGraphicsObject class, and implemented it with my own purpose. I want the instance of the subclass can be selected and deselected.
I overrided the QGraphicsItem::mousePressEvent and QGraphicsItem::mouseReleaseEvent:
In the override function of QGraphicsItem::mousePressEvent, I implemented nothing because I don't know what to do,and because the help documents says "If you do reimplement this function, event will by default be accepted (see QEvent::accept()), and this item is then the mouse grabber.".
In the override function of QGraphicsItem::mouseReleaseEvent, I simply set the item's selected property to TRUE by calling function QGraphicsItem::setSelected and passing true to it's parameter.
well,this is all my key implementation.But when I test it, it doesn't works! The function QGraphicsItem::isSelected still returns false after I clicked a mouse left button on the item of subclass.In debug session, a breakpoint in the override function of QGraphicsItem::mousePressEvent can not be reached when I click a mouse left button.
So,what's wrong with my implementation?Can you help me please?thx!
BTW:I can't post my source code currently because they are in my office computer, and now I'm in my home. I will post them later if you need them.
reply to Rondog(I can’t reply the post by clicking reply button on this forum,so I can only reply you on this way,sorry! and I hate this weak forum!):
I'll try your instrument later in my office.
well there is another question I doubted: Does the event not work in QGraphicsItem ?
Rondog last edited by
I haven't use the ones in QGraphicsItem but I have done this by sub-classing the mouse events in QGraphicsView. This would prevent problems like getting a mouse-down event on one item, a move event on another, and a mouse up on a third.
declaration in subclass to QGraphicsView
virtual void mouseDoubleClickEvent(QMouseEvent *event);
virtual void mouseMoveEvent(QMouseEvent *event);
virtual void mousePressEvent(QMouseEvent *event);
virtual void mouseReleaseEvent(QMouseEvent *event);
implementation for QGraphicsView. In my case they are all QGraphicsPixmapItems
d_mouse_down_buttons = event->buttons();
point = this->mapToScene(event->pos());
d_moving_item_moved = false;
d_moving_item = 0;
if((d_mouse_down_buttons & Qt::LeftButton) == Qt::LeftButton)
graphics_item = d_graphics_scene->itemAt(point,this->transform());
d_moving_item = reinterpret_cast<QGraphicsPixmapItem*>(graphics_item);
d_moving_item_last_position = point;