QT窗口隨鼠標雙擊移動

#include <QMouseEvent>

void Widget::mousePressEvent(QMouseEvent *event)
{
    flag_move = false;  // 私有bool變量
}

void Dialog::mousePressEvent(QMouseEvent *event)
{
    dragPosition = this->pos() - event->globalPos();
    flag_move = true;
}

void Dialog::mouseMoveEvent(QMouseEvent *event)
{
   if(flag_move&flag_pos) {
       if(event->buttons()&Qt::LeftButton) {
           this->move(event->globalPos() + dragPosition);
           event->accept();
       }
    }
}