Father.h

#ifndef FATHER_H
#define FATHER_H

#include <QtGui/QMainWindow>
#include "ui_Father.h"

#include "Son.h"

class Father : public QMainWindow
{
    Q_OBJECT

public:
    Father(QWidget *parent = 0, Qt::WFlags flags = 0);
    ~Father();

protected:
    Son *m_son;

protected slots:
    void SonWindowEventClicked();       //子視窗呼叫的父視窗槽函式
    void on_pushButton_Father_clicked();//開啟子視窗

private:
    Ui::FatherClass m_FatherUi;
};

#endif // FATHER_H
 

#include "stdafx.h"
#include "Father.h"

#include <QMessageBox>

Father::Father(QWidget *parent, Qt::WFlags flags)
    : QMainWindow(parent, flags)
{
    m_FatherUi.setupUi(this);    
}

Father::~Father()
{

}

void Father::SonWindowEventClicked()
{
    QMessageBox::information(0, tr(""), tr(""));//檢測函式呼叫是否成功
}

void Father::on_pushButton_Father_clicked()
{
    m_son = new Son;
    m_son->show();
    connect(m_son, SIGNAL(SonWindowEvent()),this,SLOT(SonWindowEventClicked()));//連線子視窗的訊號和父視窗的槽
}
 

#ifndef SON_H
#define SON_H

#include <QWidget>
#include "ui_Son.h"

class Son : public QWidget
{
    Q_OBJECT

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

signals:
    void SonWindowEvent();           //子視窗的訊號

protected slots:
    void on_pushButton_Son_clicked();//子視窗呼叫父視窗的槽函式

private:
    Ui::Son m_SonUi;
};

#endif // SON_H
 

#include "StdAfx.h"
#include "Son.h"

Son::Son(QWidget *parent)
    : QWidget(parent)
{
    m_SonUi.setupUi(this);
}

Son::~Son()
{

}

void Son::on_pushButton_Son_clicked()
{
    emit SonWindowEvent();
}