QT实现窗口拖拽移动

QT窗口默认可以直接鼠标点住窗口的标题栏实现拖拽移动，如果需要鼠标点住窗口客户区域实现窗口的拖拽移动，可以通过QMouseEvent事件来实现。

.h文件： 

#include <QWidget>

class QMouseEvent;
class Widget : public QWidget
{
    Q_OBJECT

public:
    Widget(QWidget *parent = 0);
    ~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;
};

.cpp文件：

//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;
    }
}