Qt实现无标题无边窗口的整体 拖拽 功能

　　在没有标题栏和边框的情况下想拖动窗体，如果不单独处理是不能拖动的，想实现这个拖动功能其实很简单，只需要重写以下三个鼠标函数即可：

mousePressEvent、mouseMoveEvent、mouseReleaseEvent。

window.h头文件：

#ifndef _WINDOW_H
#define _WINDOW_H

#include <QMainWindow>
#include <QApplication>
#include <QMouseEvent>

namespace Ui {
class Window;
}

class Window : public QMainWindow
{
    Q_OBJECT

public:
    explicit Window (QWidget* parent = 0);
    ~Window();

protected:
    void mousePressEvent(QMouseEvent *event);
    void mouseMoveEvent(QMouseEvent *event);
    void mouseReleaseEvent(QMouseEvent *event);

private:
    Ui::Window* m_ui;

    bool m_move;
    QPoint m_startPoint;
    QPoint m_windowPoint;

};

#endif

window.cpp文件:

#include "Window.h"
#include "ui_Window.h"

Window::Window (QWidget* parent) : QMainWindow (parent)
{
    m_ui = new Ui::Window;
    m_ui->setupUi (this);

    /*设置无边、无标题栏窗口*/
    this->setWindowFlags(Qt::FramelessWindowHint
                         | Qt::WindowSystemMenuHint
                         | Qt::WindowMinMaxButtonsHint);
   
    /*给是否移动的标志初始化为false*/
    m_move = false;
}


Window::~Window()
{
    delete m_ui;
}

void Window::mousePressEvent(QMouseEvent *event)
{
    /*当鼠标左键点击时.*/
    if (event->button() == Qt::LeftButton)
    {
        m_move = true;
        /*记录鼠标的世界坐标.*/
        m_startPoint = event->globalPos();
        /*记录窗体的世界坐标.*/
        m_windowPoint = this->frameGeometry().topLeft();
    }
}

void Window::mouseMoveEvent(QMouseEvent *event)
{
    if (event->buttons() & Qt::LeftButton)
    {
        /*移动中的鼠标位置相对于初始位置的相对位置.*/
        QPoint relativePos = event->globalPos() - m_startPoint;
        /*然后移动窗体即可.*/
        this->move(m_windowPoint + relativePos );
    }
}

void Window::mouseReleaseEvent(QMouseEvent *event)
{
    if (event->button() == Qt::LeftButton)
    {
        /*改变移动状态.*/
        m_move = false;
    }
}