Qt隐藏系统的窗口框架后如何移动窗口，如何改变其大小？

来源：互联网发布：ubuntu 14.04 安装教程编辑：程序博客网时间：2024/05/21 10:27

做项目时，为了界面美观些，把系统提供的窗口框架去掉后（无框架窗口），最令人恶心的是，无法改变无边框窗口的大小，也无法移动窗口。

1、首先要了解一下九宫格，什么是九宫格？
这里写图片描述

一个窗体可以被划分为上、下、左、右、左上、左下、右上、右下、中间。除了中间部分，其余都要写代码。

设外边框（如左部分）的宽度都为 Padding；

2、在头文件中我们加一个宏定义，及一个用于判断鼠标将要移动方向的枚举：

#define PADDING 1enum Direction   //拖动方向{    UP=0,    DOWN=1,    LEFT,    RIGHT,    LEFTTOP,    LEFTBOTTOM,    RIGHTBOTTOM,    RIGHTTOP,    NONE};

3、在头文件中声明：

public:    void region(const QPoint &currentGlobalPoint);  //鼠标的位置,改变光标protected:    //鼠标按下移动及释放事件    void mousePressEvent(QMouseEvent *event);      void mouseMoveEvent(QMouseEvent *event);    void mouseReleaseEvent(QMouseEvent *event);private:    QPoint m_movePoint;  //鼠标的位置    bool isLeftPressDown;  // 判断左键是否按下    Direction dir;        // 窗口大小改变时，记录改变方向

4、在构造函数中做初始化：

    this->setMinimumHeight(100);    this->setMinimumWidth(150);    this->setWindowFlags(Qt::FramelessWindowHint); // 设置成无边框对话框    this->isLeftPressDown = false;    this->dir= NONE;    this->setMouseTracking(true);   // 追踪鼠标（没有鼠标键被按下也可以追踪鼠标的位置）

5、定义一个方法 void region(const QPoint &currentGlobalPoint);
用于判断鼠标位置，并且改变光标形状。

void MusicWidget::region(const QPoint &currentGlobalPoint){    // 获取窗体在屏幕上的位置区域，topLeft为坐上角点，rightButton为右下角点    QRect rect = this->rect();    QPoint topLeft = this->mapToGlobal(rect.topLeft()); //将左上角的(0,0)转化为全局坐标    QPoint rightButton = this->mapToGlobal(rect.bottomRight());    int x = currentGlobalPoint.x(); //当前鼠标的坐标    int y = currentGlobalPoint.y();    if(((topLeft.x() + PADDING >= x) && (topLeft.x() <= x))            && ((topLeft.y() + PADDING >= y) && (topLeft.y() <= y)))    {        // 左上角        dir = LEFTTOP;        this->setCursor(QCursor(Qt::SizeFDiagCursor));  // 设置光标形状    }else if(((x >= rightButton.x() - PADDING) && (x <= rightButton.x()))              && ((y >= rightButton.y() - PADDING) && (y <= rightButton.y())))    {        // 右下角        dir = RIGHTBOTTOM;        this->setCursor(QCursor(Qt::SizeFDiagCursor));    }else if(((x <= topLeft.x() + PADDING) && (x >= topLeft.x()))              && ((y >= rightButton.y() - PADDING) && (y <= rightButton.y())))    {        //左下角        dir = LEFTBOTTOM;        this->setCursor(QCursor(Qt::SizeBDiagCursor));    }else if(((x <= rightButton.x()) && (x >= rightButton.x() - PADDING))              && ((y >= topLeft.y()) && (y <= topLeft.y() + PADDING)))    {        // 右上角        dir = RIGHTTOP;        this->setCursor(QCursor(Qt::SizeBDiagCursor));    }else if((x <= topLeft.x() + PADDING) && (x >= topLeft.x()))    {        // 左边        dir = LEFT;        this->setCursor(QCursor(Qt::SizeHorCursor));    }else if((x <= rightButton.x()) && (x >= rightButton.x() - PADDING))    {        // 右边        dir = RIGHT;        this->setCursor(QCursor(Qt::SizeHorCursor));    }else if((y >= topLeft.y()) && (y <= topLeft.y() + PADDING))    {        // 上边        dir = UP;        this->setCursor(QCursor(Qt::SizeVerCursor));    }else if((y <= rightButton.y()) && (y >= rightButton.y() - PADDING))    {        // 下边        dir = DOWN;        this->setCursor(QCursor(Qt::SizeVerCursor));    }else    {        // 默认        dir = NONE;        this->setCursor(QCursor(Qt::ArrowCursor));    }}

6、接下来对三个鼠标事件进行重载：

mousePressEvent

//鼠标按下事件void MusicWidget::mousePressEvent(QMouseEvent *event){    switch(event->button())    {        case Qt::LeftButton:            isLeftPressDown = true;            if(dir != NONE)            {                this->mouseGrabber(); //返回当前抓取鼠标输入的窗口            }            else            {                m_movePoint = event->globalPos() - this->frameGeometry().topLeft();                //globalPos()鼠标位置，topLeft()窗口左上角的位置            }            break;        case Qt::RightButton:            this->setWindowState(Qt::WindowMinimized);            break;        default:            MusicWidget::mousePressEvent(event);    }}

mouseMoveEvent

//鼠标移动事件void MusicWidget::mouseMoveEvent(QMouseEvent *event){    QPoint globalPoint = event->globalPos();   //鼠标全局坐标    QRect rect = this->rect();  //rect == QRect(0,0 680x412)    QPoint topLeft = mapToGlobal(rect.topLeft());    QPoint bottomRight = mapToGlobal(rect.bottomRight());    if (this->windowState() != Qt::WindowMaximized)    {        if(!isLeftPressDown)  //没有按下左键时        {            this->region(globalPoint); //窗口大小的改变——判断鼠标位置，改变光标形状        }        else        {            if(dir != NONE)            {                QRect newRect(topLeft, bottomRight); //定义一个矩形                switch(dir)                {                    case LEFT:                        if(bottomRight.x() - globalPoint.x() <= this->minimumWidth())                        {                            newRect.setLeft(topLeft.x());  //小于界面的最小宽度时，设置为左上角横坐标为窗口x                            //只改变左边界                        }                        else                        {                            newRect.setLeft(globalPoint.x());                        }                        break;                    case RIGHT:                        newRect.setWidth(globalPoint.x() - topLeft.x());  //只能改变右边界                        break;                    case UP:                        if(bottomRight.y() - globalPoint.y() <= this->minimumHeight())                        {                            newRect.setY(topLeft.y());                        }                        else                        {                            newRect.setY(globalPoint.y());                        }                        break;                    case DOWN:                        newRect.setHeight(globalPoint.y() - topLeft.y());                        break;                    case LEFTTOP:                        if(bottomRight.x() - globalPoint.x() <= this->minimumWidth())                        {                            newRect.setX(topLeft.x());                        }                        else                        {                            newRect.setX(globalPoint.x());                        }                        if(bottomRight.y() - globalPoint.y() <= this->minimumHeight())                        {                            newRect.setY(topLeft.y());                        }                        else                        {                            newRect.setY(globalPoint.y());                        }                        break;                     case RIGHTTOP:                          if (globalPoint.x() - topLeft.x() >= this->minimumWidth())                          {                              newRect.setWidth(globalPoint.x() - topLeft.x());                          }                          else                          {                              newRect.setWidth(bottomRight.x() - topLeft.x());                          }                          if (bottomRight.y() - globalPoint.y() >= this->minimumHeight())                          {                              newRect.setY(globalPoint.y());                          }                          else                          {                              newRect.setY(topLeft.y());                          }                          break;                     case LEFTBOTTOM:                          if (bottomRight.x() - globalPoint.x() >= this->minimumWidth())                          {                              newRect.setX(globalPoint.x());                          }                          else                          {                              newRect.setX(topLeft.x());                          }                          if (globalPoint.y() - topLeft.y() >= this->minimumHeight())                          {                              newRect.setHeight(globalPoint.y() - topLeft.y());                          }                          else                          {                              newRect.setHeight(bottomRight.y() - topLeft.y());                          }                          break;                      case RIGHTBOTTOM:                          newRect.setWidth(globalPoint.x() - topLeft.x());                          newRect.setHeight(globalPoint.y() - topLeft.y());                          break;                      default:                          break;                }                this->setGeometry(newRect);            }            else            {                move(event->globalPos() - m_movePoint); //移动窗口                event->accept();            }        }    } }

mouseReleaseEvent

//鼠标释放事件void MusicWidget::mouseReleaseEvent(QMouseEvent *event)  {    if (event->button() == Qt::LeftButton)    {        isLeftPressDown = false;        if (dir != NONE)        {            this->releaseMouse(); //释放鼠标抓取            this->setCursor(QCursor(Qt::ArrowCursor));        }    }}

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