Setting QGraphicsView bacground/foreground color

Hi, I want to make entrire QGraphicsView filled with one color. I've tried setting backgroundBrush and foregroundBrush in designer but it does not change anything. QGraphicsView is still white. Could you the correct steps to do such a simple task?

yourscene->setBackgroundBrush(Qt::black);

yourscene->setForegroundBrush(Qt::white);