QT像浏览器一样Tab按钮长按可以拖动出一个窗口，然后可以拖回去的示例代码

这里是一个简单的示例代码，可以实现QT的Tab按钮长按可以拖动出一个窗口，然后可以拖回去的功能：

#include <QTabBar>
#include <QMouseEvent>
#include <QMimeData>
#include <QDrag>
#include <QPainter>

class MyTabBar : public QTabBar
{
public:
    MyTabBar(QWidget* parent = nullptr) : QTabBar(parent) {}
    ~MyTabBar() {}

protected:
    void mousePressEvent(QMouseEvent* event)
    {
        if (event->button() == Qt::LeftButton)
        {
            m_startPos = event->pos();
        }

        QTabBar::mousePressEvent(event);
    }

    void mouseMoveEvent(QMouseEvent* event)
    {
        if (!(event->buttons() & Qt::LeftButton))
        {
            return;
        }

        if ((event->pos() - m_startPos).manhattanLength() < QApplication::startDragDistance())
        {
            return;
        }

        int index = tabAt(m_startPos);
        if (index < 0)
        {
            return;
        }

        QWidget* widget = tabButton(index, QTabBar::RightSide);
        if (!widget)
        {
            return;
        }

        QPixmap pixmap(widget->size());
        widget->render(&pixmap);

        QMimeData* mimeData = new QMimeData;
        mimeData->setData("application/x-tabbtn", QByteArray::number(index));

        QDrag* drag = new QDrag(this);
        drag->setMimeData(mimeData);
        drag->setPixmap(pixmap);
        drag->setHotSpot(event->pos() - widget->pos());

        setTabEnabled(index, false);

        if (drag->exec(Qt::CopyAction | Qt::MoveAction, Qt::CopyAction) == Qt::MoveAction)
        {
            setTabEnabled(index, true);
        }
        else
        {
            setTabEnabled(index, true);
        }
    }

    void dragEnterEvent(QDragEnterEvent* event)
    {
        if (event->mimeData()->hasFormat("application/x-tabbtn"))
        {
            event->acceptProposedAction();
        }
    }

    void dragMoveEvent(QDragMoveEvent* event)
    {
        if (event->mimeData()->hasFormat("application/x-tabbtn"))
        {
            event->acceptProposedAction();
        }
    }

    void dragLeaveEvent(QDragLeaveEvent* event)
    {
        Q_UNUSED(event);
    }

    void dropEvent(QDropEvent* event)
    {
        if (event->mimeData()->hasFormat("application/x-tabbtn"))
        {
            QByteArray data = event->mimeData()->data("application/x-tabbtn");
            int index = data.toInt();

            if (index >= 0 && index < count())
            {
                QWidget* widget = tabButton(index, QTabBar::RightSide);
                if (widget)
                {
                    QPoint pos = event->pos() - widget->rect().center();
                    widget->move(pos);
                    widget->show();
                }
            }

            event->acceptProposedAction();
        }
    }

    void paintEvent(QPaintEvent* event)
    {
        QTabBar::paintEvent(event);

        if (m_isDragging)
        {
            QPainter painter(this);
            QPixmap pixmap = tabButton(m_dragIndex, QTabBar::RightSide)->grab();
            painter.drawPixmap(m_dragPos, pixmap);
        }
    }

private:
    QPoint m_startPos;
    bool m_isDragging = false;
    QPoint m_dragPos;
    int m_dragIndex;

    void startDrag(int index, const QPoint& pos)
    {
        QWidget* widget = tabButton(index, QTabBar::RightSide);
        if (!widget)
        {
            return;
        }

        m_isDragging = true;
        m_dragIndex = index;
        m_dragPos = pos - widget->rect().center();
    }
};

使用方法：

在创建`QTabWidget`的时候，将其`QTabBar`替换为`MyTabBar`即可：

QTabWidget* tabWidget = new QTabWidget(this);
tabWidget->setTabBar(new MyTabBar(tabWidget));

希望这个示例代码能够对你有所帮助！