在QT项目中，窗口设置 setWindowFlags(Qt::FramelessWindowHint) 之后，就无法拖动；所以会自定义一个menubar控件，并实现窗口拖动；

效果如上图，上代码：

#include <QMainWindow>


class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = 0);
    ~MainWindow();

protected:
    bool eventFilter(QObject *, QEvent *);

private:
    QWidget *m_menu;
   
};

cpp:

#include "mainwindow.h"
#include <QMouseEvent>

MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent)
{
    setWindowFlags(Qt::FramelessWindowHint);
    this->setFixedSize(500,300);
    m_menu = new QWidget(this);
    m_menu->setFixedSize(this->width(), 50);
    m_menu->setStyleSheet("background-color:lightblue;");

    m_menu->installEventFilter(this);
}

MainWindow::~MainWindow()
{

}

bool MainWindow::eventFilter(QObject *watched, QEvent *eve)
{
    static QPoint mousePoint;
    static bool mousePressed = false;
    QMouseEvent *event = static_cast<QMouseEvent *>(eve);
    if(watched == m_menu)
    {
        if(event->type() == QEvent::MouseButtonPress)
        {
            if(event->button() == Qt::LeftButton)
            {
                mousePressed = true;
                mousePoint = event->globalPos() - this->pos();
                return true;
            }
        }
        else if(event->type() == QEvent::MouseButtonRelease)
        {
            mousePressed = false;
            return true;
        }
        else if(event->type() == QEvent::MouseMove)
        {
            this->move(event->globalPos() - mousePoint);
            return true;
        }
    }

    return QWidget::eventFilter(watched, eve);
}

 

两点注意：

1.m_menu->installEventFilter(this); 

本代码中，需要拖动的控件是自定义的m_menu，注册监测对象；

 

2.eventFilter;

在这个事件中，处理目标对象的事件；所以代码中先判断 (watched == m_menu);

 

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