1 void MyWidget::mouseMoveEvent(QMouseEvent *event)
 2 {
 3     QPoint P3 = event->globalPos();
 4     QPoint P2 = P3 - L;
 5     this->move(P2);
 6 }
 7 
 8 void MyWidget::mousePressEvent(QMouseEvent *event)
 9 {
10     QPoint P3 = event->globalPos();
11     QPoint P2 = this->geometry().topLeft();
12     L = P3 - P2;    // L是QPoint变量，在.h文件中创建
13 }
14 
15 void MyWidget::mouseReleaseEvent(QMouseEvent *)
16 {
17     this->L = QPoint();
18 }