QDockWidget设置为tab切换形式

QDockWidget设置为tab切换形式的，其实就是调用一下

void QMainWindow::tabifyDockWidget(QDockWidget *first, QDockWidget *second)的此方法即可实现。

/********************************************************************************
** Form generated from reading UI file 'guitest.ui'
**
** Created by: Qt User Interface Compiler version 5.12.2
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_GUITEST_H
#define UI_GUITEST_H

#include <QtCore/QVariant>
#include <QtWidgets/QApplication>
#include <QtWidgets/QDockWidget>
#include <QtWidgets/QMainWindow>
#include <QtWidgets/QMenuBar>
#include <QtWidgets/QStatusBar>
#include <QtWidgets/QToolBar>
#include <QtWidgets/QWidget>

QT_BEGIN_NAMESPACE

class Ui_GUITestClass
{
public:
    QWidget *centralWidget;
    QMenuBar *menuBar;
    QToolBar *mainToolBar;
    QStatusBar *statusBar;
    QDockWidget *dockWidget;
    QWidget *dockWidgetContents;
    QDockWidget *dockWidget_2;
    QWidget *dockWidgetContents_2;

    void setupUi(QMainWindow *GUITestClass)
    {
        if (GUITestClass->objectName().isEmpty())
            GUITestClass->setObjectName(QString::fromUtf8("GUITestClass"));
        GUITestClass->resize(933, 671);
        centralWidget = new QWidget(GUITestClass);
        centralWidget->setObjectName(QString::fromUtf8("centralWidget"));
        GUITestClass->setCentralWidget(centralWidget);
        menuBar = new QMenuBar(GUITestClass);
        menuBar->setObjectName(QString::fromUtf8("menuBar"));
        menuBar->setGeometry(QRect(0, 0, 933, 26));
        GUITestClass->setMenuBar(menuBar);
        mainToolBar = new QToolBar(GUITestClass);
        mainToolBar->setObjectName(QString::fromUtf8("mainToolBar"));
        GUITestClass->addToolBar(Qt::TopToolBarArea, mainToolBar);
        statusBar = new QStatusBar(GUITestClass);
        statusBar->setObjectName(QString::fromUtf8("statusBar"));
        GUITestClass->setStatusBar(statusBar);
        dockWidget = new QDockWidget(GUITestClass);
        dockWidget->setObjectName(QString::fromUtf8("dockWidget"));
        dockWidget->setAutoFillBackground(true);
        dockWidgetContents = new QWidget();
        dockWidgetContents->setObjectName(QString::fromUtf8("dockWidgetContents"));
        dockWidget->setWidget(dockWidgetContents);
        dockWidget->setStyleSheet("border:1px solid #ccc;");
        GUITestClass->addDockWidget(static_cast<Qt::DockWidgetArea>(1), dockWidget);

        dockWidget_2 = new QDockWidget(GUITestClass);
        dockWidget_2->setObjectName(QString::fromUtf8("dockWidget_2"));
        dockWidgetContents_2 = new QWidget();
        dockWidgetContents_2->setObjectName(QString::fromUtf8("dockWidgetContents_2"));
        dockWidget_2->setStyleSheet("border:1px solid #ccc;");
        //dockWidgetContents_2->setLayoutDirection(Qt::LeftToRight);
        dockWidget_2->setWidget(dockWidgetContents_2);
        GUITestClass->addDockWidget(static_cast<Qt::DockWidgetArea>(1), dockWidget_2);

        GUITestClass->tabifyDockWidget(dockWidget, dockWidget_2);
        retranslateUi(GUITestClass);

        QMetaObject::connectSlotsByName(GUITestClass);
    } // setupUi

    void retranslateUi(QMainWindow *GUITestClass)
    {
        GUITestClass->setWindowTitle(QApplication::translate("GUITestClass", "GUITest", nullptr));
        dockWidget->setWindowTitle(QApplication::translate("GUITestClass", "BBB", nullptr));
        dockWidget_2->setWindowTitle(QApplication::translate("GUITestClass", "AAA", nullptr));
    } // retranslateUi

};

namespace Ui {
    class GUITestClass: public Ui_GUITestClass {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_GUITEST_H