Launch a QWidget from a QMain window

I'm doing my first C++ - Qt4 application and I'm having some trouble "connecting" my different uis. I have a main window with several buttons and when I click on one, I want another window to open.

The MyMainWindowClass inherits from QMainWindow and the other from QWidget.

Here is the code I have written so far :

#include <iostream>
#include "MyWidgetClass.hpp"
#include "MyMainWindowClass.hpp"
#include "ui_MyMainWindowClassUi.h"


MyMainWindowClass::MyMainWindowClass(QWidget *parent) :
    QMainWindow(parent),
    m_ui(new Ui::MyMainWindowClassUi)
{
    m_ui->setupUi(this);
    initConnect();
}

void    MyMainWindowClass::initConnect()
{
  QObject::connect(m_ui->SomeBtn,
                   SIGNAL(clicked()),
                   this,
                   SLOT(SomeBtnClicked()));
  // Some other QObject::connect calls
  return;
}

void    MyMainWindowClass::SomeBtnClicked()
{
  std::cout << "Some Btn has been clicked" << std::endl;
  this->setEnabled(false);
  MyWidgetClass mwc(this);
  mwc.show();
  return;
}

This calls the Ctor and the Dtor from MyWidgetClass, disables the MyMainWindowClassUi, but doesn't开发者_StackOverflow社区 show my other GUI. What am I missing to have the window showed when I click on the button ?

Try this instead of your SomeBtnClicked method:

MyWidgetClass *mwc;

void MyMainWindowClass::SomeBtnClicked()
{
    std::cout << "Some Btn has been clicked" << std::endl;
    this->setEnabled(false);

    if (!mwc)
        mwc = new MyWidgetClass(this);
    mwc->show();
    mwc->raise();
    mwc->setActiveWindow();  // Qt 4: activateWindow()

    return;
}