Qt自定义图形实现拖拽效果

在这里自定义图形是通过QPaintEvent事件绘画的图形，也可以通过自定义控件的方式添加到qt中。

首先定义类来自定义图形，这里通过paintEvent事件来实现（主要就是绘画一个图形）

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);

}

接着，主窗口程序通过mousePressEvent() mouseMoveEvent(),实现拖拽移动，

void MainWindow::mousePressEvent(QMouseEvent *event)
{
    qDebug()<<" 1:"<pos();
    //获取控件的对象
    m_pTempWidget =  childAt(event->pos());
    qDebug()<::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::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;
    }
}

就能实现简单的拖拽功能，效果图如下：