catch (spaceBar+mouse move) event

[prasad.ece2]

hi,
i want to drag my scene, by dragging the mouse on scene & hold space bare (press and hold space bar + drag mouse) .
what is the best place to check this combination and how can i check this condition .
i have QGraphicsView and QGraphicsScene on QMainwindow .

my idea is as below

QGraphicsView:: mouseMoveEvent(QMouseEvent* f_event)
{

If(space bar is pressed and hold) // here how can I check key press event
{
Here we will set drag mode; //QGraphicsView:: ScrollHandDrag

}
}


Thanks in advance :-)