Qt自定义图形实现拖拽效果

void QEventView::paintEvent(QPaintEvent *event)
{
  resize(115+m_iLen,36);
  QPainter painter(this);
  painter.setRenderHint(QPainter::Antialiasing);
  painter.setPen(Qt::blue);
 
  //定义箭头的坐标
  static const QPoint pointArr[7] =
  {
   QPoint(0,10),
   QPoint(100+m_iLen,10),
   QPoint(100+m_iLen,0),
   QPoint(115+m_iLen,18),
   QPoint(100+m_iLen,36),
   QPoint(100+m_iLen,26),
   QPoint(0,26)
  };
  int i = 0;
 
  while(i < 7)
  {
    if(i == 6)
      painter.drawLine(pointArr[i],pointArr[0]);
    else
      painter.drawLine(pointArr[i],pointArr[i+1]);
    i++;
  }
  painter.drawText(QPoint(0,22),m_sEventName);
 
}

void MainWindow::mousePressEvent(QMouseEvent *event)
{
  qDebug()<<" 1:"<<event->pos();
  //获取控件的对象
  m_pTempWidget = childAt(event->pos());
  qDebug()<<m_pTempWidget;
  if(!m_pTempWidget || m_pTempWidget == centralWidget())
    return;
  //容器存储自定义图形指针，以及图形的位置
  QMap<QEventView*,QPoint>::iterator iter = m_mapEventPoint.begin();
  while(iter != m_mapEventPoint.end())
  {
    if(iter.key() == m_pTempWidget)
    {
      m_windowInitPoint = iter.key()->frameGeometry().topLeft();
      m_StartPoint = event->pos();
      break;
    }
    ++iter;
  }
}
 
void MainWindow::mouseMoveEvent(QMouseEvent *event)
{
  QMap<QEventView*,QPoint>::iterator iter = m_mapEventPoint.begin();
  while(iter != m_mapEventPoint.end())
  {
    if(iter.key() == m_pTempWidget)
    {
 
      QPoint distance = event->pos() - m_StartPoint;
      iter.key()->move(m_windowInitPoint + distance);
      break;
    }
    ++iter;
  }
}