我们知道，要实现窗口移动可以直接鼠标点住窗口的标题栏实现拖拽移动，这是窗口默认的行为，在QT中的事件响应函数为moveEvent。
但是现实中经常需要鼠标点住窗口客户区域实现窗口的拖拽移动，代码实现如下：
Widget.h
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#ifndef WIDGET_H
#define WIDGET_H
#include <QWidget>
class QMouseEvent;
class Widget : public QWidget
{
Q_OBJECT
public:
Widget(QWidget *parent = );
~Widget();
protected:
//拖拽窗口
void mousePressEvent(QMouseEvent *event);
void mouseMoveEvent(QMouseEvent *event);
void mouseReleaseEvent(QMouseEvent *event);
private:
bool m_bDrag;
QPoint mouseStartPoint;
QPoint windowTopLeftPoint;
};
#endif // WIDGET_H
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Widget.cpp
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#include "Widget.h"
#include <QMouseEvent>
Widget::Widget(QWidget *parent)
: QWidget(parent)
, m_bDrag(false)
{
setWindowTitle("窗口拖拽移动");
setFixedSize(640, 480);
}
Widget::~Widget()
{
}
/* QPoint QMouseEvent::pos() const
Returns the position of the mouse cursor, relative to the widget that received the event.
If you move the widget as a result of the mouse event, use the global position returned by globalPos() to avoid a shaking motion.
*/
//拖拽操作
void Widget::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 Widget::mouseMoveEvent(QMouseEvent *event)
{
if(m_bDrag)
{
//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 Widget::mouseReleaseEvent(QMouseEvent *event)
{
if(event->button() == Qt::LeftButton)
{
m_bDrag = false;
}
}
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需要注意的一点：一般定位鼠标坐标使用的是event->pos()和event->globalPos()两个函数，
event->globalPos()获取的鼠标位置是鼠标偏离电脑屏幕左上角（x=0,y=0）的位置；
event->pos()获取的位置是主窗口（widget窗口）左上角（边框的左上角，外左上角）相对于电脑屏幕的左上角的（x=0,y=0）偏移位置
一般不采用前者，使用前者，拖动准确性较低且会产生抖动。
