Qt/Widgets/WidgetInsideMainWindow

main.cpp

#include <QApplication>
 
#include "filemenu.h"
 
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    MyForm form;
 
    form.show();
    return app.exec();
}

filemenu.h

#ifndef FILEMENUFORM_H
#define FILEMENUFORM_H
 
#include "ui_filemenu.h"
 
class MyForm : public QMainWindow, private Ui::FileMenuForm
{
	Q_OBJECT
public:
    MyForm(QWidget *parent = 0);
 
public slots:
    void mnuOpenInnerForm_triggered();
};
 
#endif

filemenu.cpp

#include "filemenu.h"
#include "InsideForm.h"
 
#include <iostream>
 
MyForm::MyForm(QWidget *parent)
{
  setupUi(this);
  connect( this->mnuOpenInnerForm, SIGNAL( triggered() ), this, SLOT(mnuOpenInnerForm_triggered()) );
 
}
 
void MyForm::mnuOpenInnerForm_triggered()
{
  std::cout << "Inner form." << std::endl;
  MyInsideForm* insideForm = new MyInsideForm(this);
  this->setCentralWidget(insideForm);
}

InsideForm.h

#ifndef INSIDEFORM_H
#define INSIDEFORM_H
 
#include "ui_InsideForm.h"
 
class MyInsideForm : public QWidget, private Ui::InsideForm
{
	Q_OBJECT
public:
    MyInsideForm(QWidget *parent = 0);
 
public slots:
    void btnButton_clicked();
};
 
#endif

InsideForm.cpp

#include "InsideForm.h"
 
#include <iostream>
 
MyInsideForm::MyInsideForm(QWidget *parent)
{
  setupUi(this);
  connect( this->btnButton, SIGNAL( clicked() ), this, SLOT(btnButton_clicked()) );
}
 
void MyInsideForm::btnButton_clicked()
{
  this->lblLabel->setText("Clicked");
}

filemenu.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>FileMenuForm</class>
 <widget class="QMainWindow" name="FileMenuForm">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>800</width>
    <height>600</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>MainWindow</string>
  </property>
  <widget class="QWidget" name="centralwidget"/>
  <widget class="QMenuBar" name="menubar">
   <property name="geometry">
    <rect>
     <x>0</x>
     <y>0</y>
     <width>800</width>
     <height>25</height>
    </rect>
   </property>
   <widget class="QMenu" name="menuFile">
    <property name="title">
     <string>File</string>
    </property>
    <addaction name="mnuOpenInnerForm"/>
   </widget>
   <addaction name="menuFile"/>
  </widget>
  <widget class="QStatusBar" name="statusbar"/>
  <action name="mnuOpenInnerForm">
   <property name="text">
    <string>Create Int Form</string>
   </property>
  </action>
  <action name="mnuDoubleForm">
   <property name="text">
    <string>CreateDoubleForm</string>
   </property>
  </action>
 </widget>
 <resources/>
 <connections/>
</ui>

InsideForm.ui

<?xml version="1.0" encoding="UTF-8"?>
<ui version="4.0">
 <class>InsideForm</class>
 <widget class="QWidget" name="InsideForm">
  <property name="geometry">
   <rect>
    <x>0</x>
    <y>0</y>
    <width>400</width>
    <height>300</height>
   </rect>
  </property>
  <property name="windowTitle">
   <string>Form</string>
  </property>
  <widget class="QPushButton" name="btnButton">
   <property name="geometry">
    <rect>
     <x>150</x>
     <y>90</y>
     <width>92</width>
     <height>27</height>
    </rect>
   </property>
   <property name="text">
    <string>Click me</string>
   </property>
  </widget>
  <widget class="QLabel" name="lblLabel">
   <property name="geometry">
    <rect>
     <x>180</x>
     <y>140</y>
     <width>59</width>
     <height>17</height>
    </rect>
   </property>
   <property name="text">
    <string>TextLabel</string>
   </property>
  </widget>
 </widget>
 <resources/>
 <connections/>
</ui>

CMakeLists.txt

cmake_minimum_required(VERSION 2.6)
 
PROJECT(WidgetInsideMainWindow)
 
FIND_PACKAGE(Qt4 REQUIRED)
INCLUDE(${QT_USE_FILE})
 
QT4_WRAP_UI(UISrcs filemenu.ui InsideForm.ui)
QT4_WRAP_CPP(MOCSrcs filemenu.h InsideForm.h)
 
include_directories(${include_directories} ${CMAKE_CURRENT_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR})
 
ADD_EXECUTABLE(WidgetInsideMainWindow main.cpp filemenu.cpp InsideForm.cpp ${MOCSrcs} ${UISrcs})
TARGET_LINK_LIBRARIES(WidgetInsideMainWindow ${QT_LIBRARIES})