Detect when mouse is not in QGraphicsScene

Question

I am having a class inherited from QGraphicsScene. I have a mouseMoveEvent in this class. Based on the mouse move I am sending the co ordinates via signal to the main window. I have multiple GraphicViews in main window. Based on the scene from which the signal is received I am display the scene co ordinates using QGraphicsTextItem. The problem is when I move out of the scene area I am unable to hide the QGraphicsTextItem. Can someone give me a work around for this?

 Class Scene::QGraphicsScene
 {
    void MouseMoveEvent(QGraphicsSceneMouseEvent *Event)
    {
       int XPos = event.x();
       int YPos = event.y();
       emit SignalPos(XPos,YPos);
    }
 }

 //In Main Window
 connect(scene1,SignalPos(int,int),this,SlotPos1(int,int);
 //Similarly for scene2,scene3,scene4

 void MainWindow::SlotPos(int X, int Y)
 { 
     m_qgtxtItemX.setText(QString::x);   
    //I want to hide this once I am out of scene.It is a member variable. I tried
    //taking local variable but it didn't work.
    //Similarly for y and other slots
 }

score 1 · Answer 1 · answered Sep 02 '14 at 02:59

Install an event filter on the scene.

scene1->installEventFilter(this);

then implement the method in the class that is referenced by "this":

bool eventFilter(QObject *watched, QEvent *event) {
    if (event->type() == QEvent::Leave)
    {
        qDebug() << "Mouse left the scene";
    }       
    return false;
}

Just tried it and it worked! If you are installing the event filter on more than one object, please use "watched" to differentiate between them.

Best,

Detect when mouse is not in QGraphicsScene

1 Answers1