有没有办法停止QGraphicsScene？

Question

我有一个从某个位置向上移动的椭圆。

void Equalizer::advance(int phase) 
{ 
    if(!phase) return; 

    QPointF location = this->pos(); 
    setPos(mapToParent(0 , -(speed))); 
} 

尽管我希望它在到达某个y坐标时停止移动。我怎么做？

Answer 1

不更新其y位置，当它到达指定的y坐标，

void Equalizer::advance(int phase) 
{ 
    if(!phase) return; 

    QPointF location = this->pos(); 

    if(location.y() <= specifiedY) 
    { 
     //If the speed at which the ellipse is moving is great enough to take it beyond the specifiedY, set it to the specifiedY before the return. 
     setPos(pos().x(), specifiedY); // assuming specifiedY is in scene coordinates 
     return; 
    }   
    setPos(mapToParent(0 , -(speed))); 
}