Qt中从应用程序拖出文件或图片到桌面

void XXXX::mouseMoveEvent(QMouseEvent *event)

{

    this->viewport()->setCursor(Qt::PointingHandCursor);

    QString fileName /*=指向一个本地存在的文件 */;

    if (event->buttons() & Qt::LeftButton)

    {

        int distance = (event->pos() - _startPos).manhattanLength();

        if (distance >= QApplication::startDragDistance() && !this->rect().contains(event->pos()))

        {

            QMimeData *mimeData = new QMimeData;

            mimeData->setData("drag/fileName", fileName.toUtf8());

            QDrag* drag = new QDrag(this);

            drag->setMimeData(mimeData);

            drag->setHotSpot(event->pos());

            drag->exec(Qt::CopyAction, Qt::CopyAction);

        }

    }

    return XXXX::mouseMoveEvent(event);

}

关键点：执行操作设置为 Qt::CopyAction 。