//鼠标拖动窗体移动

    void mousePressEvent(QMouseEvent *event);

    void mouseMoveEvent(QMouseEvent *event);

    void mouseReleaseEvent(QMouseEvent *event);

    bool        m_bDrag;

    QPoint      mouseStartPoint;

    QPoint      windowTopLeftPoint;

//实现鼠标拖拽移动

void MainWindow::mousePressEvent(QMouseEvent *event)

{

    if(event->button() == Qt::LeftButton)

    {

        m_bDrag = true;

        //获得鼠标的初始位置

        mouseStartPoint = event->globalPos();

        //mouseStartPoint = event->pos();

        //获得窗口的初始位置

        windowTopLeftPoint = this->frameGeometry().topLeft();

    }

}



void MainWindow::mouseMoveEvent(QMouseEvent *event)

{

    if(m_bDrag)

    {   //这里if语句判断，让鼠标在特定控件上进行拖动才有效，比如自绘标题栏控件

        if(!ui->label->underMouse()){

            return;

        }

        //获得鼠标移动的距离

        QPoint distance = event->globalPos() - mouseStartPoint;

        //QPoint distance = event->pos() - mouseStartPoint;

        //改变窗口的位置

        this->move(windowTopLeftPoint + distance);

    }

}



void MainWindow::mouseReleaseEvent(QMouseEvent *event)

{

    if(event->button() == Qt::LeftButton)

    {

        m_bDrag = false;

    }

}