QT 标题栏隐藏可拖拽

void mousePressEvent(QMouseEvent *e);
void mouseMoveEvent(QMouseEvent *e);
void mouseReleaseEvent(QMouseEvent *e);
QPoint last;

void AddDialog::mousePressEvent(QMouseEvent *e)
{
last = e->globalPos();
}
void AddDialog::mouseMoveEvent(QMouseEvent *e)
{
int dx = e->globalX()-last.x();
int dy = e->globalY()-last.y();

last = e->globalPos();
move(x()+dx,y()+dy);
}
void AddDialog::mouseReleaseEvent(QMouseEvent *e)
{
int dx = e->globalX()-last.x();
int dy = e->globalY()-last.y();

last = e->globalPos();
move(x()+dx,y()+dy);
}