#ifndef WIDGET_H
#define WIDGET_H

#include <QtGui/QWidget>
#include <QPushButton>

class Widget : public QWidget
{
    Q_OBJECT
private:
    QPushButton Btn1;
    QPushButton Btn2;
    QPushButton Btn3;
    QPushButton Btn4;
    void initControl();
private slots:
    void outtime();
public:
    Widget(QWidget *parent = 0);
    ~Widget();
};

#endif // WIDGET_H

#include "Widget.h"
#include <QStackedLayout>
#include <QHBoxLayout>
#include <QTimer>

Widget::Widget(QWidget *parent)
    : QWidget(parent), Btn1(this), Btn2(this), Btn3(this), Btn4(this)
{
    initControl();
}

void Widget::initControl()
{
    Btn1.setText("Btn1");
    Btn2.setText("Btn2");
    Btn3.setText("Btn3");
    Btn4.setText("Btn4");

    QStackedLayout* slayout = new QStackedLayout();



    QHBoxLayout* hlayout = new QHBoxLayout();//通过间接的方法来嵌套布局管理器
    QWidget* widget = new QWidget();
    Btn2.setParent(widget);
    Btn3.setParent(widget);
    hlayout->addWidget(&Btn2);
    hlayout->addWidget(&Btn3);
    widget->setLayout(hlayout);



    slayout->addWidget(&Btn1);//0
    slayout->addWidget(widget);//1
    slayout->addWidget(&Btn4);//2

    slayout->setCurrentIndex(0);//设置初始要显示的按钮

    setLayout(slayout);

    //计时器的使用
    QTimer* timer = new QTimer();//1.定义对象
    connect(timer, SIGNAL(timeout()), this, SLOT(outtime()));//3.连接信号与槽
    timer->start(2000);//4.启动定时器

}

void Widget::outtime()//2.编写槽函数
{
    QStackedLayout* sLayout = dynamic_cast<QStackedLayout*>(layout());

    if(sLayout != NULL)
    {
        int index = (sLayout->currentIndex() + 1) % sLayout->count();//防止溢出，故取余
        sLayout->setCurrentIndex(index);
    }

}

Widget::~Widget()
{
    
}

#include <QtGui/QApplication>
#include "Widget.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    
    return a.exec();
}