容器窗口 <QTabWidget>

//////////////////////////////////////////
   #include "test9_2a.h"
#include "M_win.h"

Test9_2A::Test9_2A(QWidget *parent)
    : QMainWindow(parent)
{

    ui.setupUi(this);

    M_win *page = new M_win();

    ui.stackedWidget->insertWidget(0,page);

    connect(ui.BtnFirst,  SIGNAL(clicked()), this, SLOT(OnBtnFirst()));
    connect(ui.BtnSecond, SIGNAL(clicked()), this, SLOT(OnBtnSecond()));
    connect(ui.BtnThird,  SIGNAL(clicked()), this, SLOT(OnBtnthird()));

}

Test9_2A::~Test9_2A()
{

}

int Test9_2A::OnBtnFirst()
{
    ui.stackedWidget->setCurrentIndex(0);
    return 0;
}

int Test9_2A::OnBtnSecond()
{
    ui.stackedWidget->setCurrentIndex(1);
    return 0;
}

int Test9_2A::OnBtnthird()
{
    ui.stackedWidget->setCurrentIndex(2);
    return 0;
}