Multiple Window with C++ with Qt4

Question

I'm trying to build a GUI app, and I'm doing this through Qt. I also want to create a multi window application: I want that when I hit a button the other window shows up ("hiding" the previous one). Is that a GDI?

So far, I have create a .ui file for every window I want (currently 4), and I'm trying to connect them that way (the main window, with the other 3).

How could I do that?

I'm sending the file of the program in order to make my problema more undestandable:

main.cpp

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

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    StudyWindow s;

    QStackedWidget *stackedWidget = new QStackedWidget;
    stackedWidget->addWidget(w);
    stackedWidget->addWidget(s);

    QVBoxLayout *layout = new QVBoxLayout;
    layout->addWidget(stackedWidget);
    setLayout(layout);

    w.show();
    return a.exec();
}

mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    ConnectStuff();
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::ConnectStuff()
{
}

mainwindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include <QPushButton>
#include <QLayout>
#include <QStackedWidget>
#include "study.h"
namespace Ui {
    class MainWindow;
}
class MainWindow : public QMainWindow
{
    Q_OBJECT
public:
    void ConnectStuff();
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
private:
    Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H

study.h

#ifndef STUDYWINDOW_H
#define STUDYWINDOW_H

#include <QMainWindow>
#include <QPushButton>

namespace Ui {
    class StudyWindow;
}

class StudyWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit StudyWindow(QWidget *parent = 0);
    ~StudyWindow();

private:
    Ui::StudyWindow *ui;
};

#endif // STUDYWINDOW_H

ui_Study.h

/********************************************************************************
** Form generated from reading UI file 'Study.ui'
**
** Created: Tue 20. Mar 20:10:56 2012
**      by: Qt User Interface Compiler version 4.7.4
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_STUDY_H
#define UI_STUDY_H

#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QHeaderView>
#include <QtGui/QMainWindow>
#include <QtGui/QMenu>
#include <QtGui/QMenuBar>
#include <QtGui/QPushButton>
#include <QtGui/QStatusBar>
#include <QtGui/QTreeWidget>
#include <QtGui/QWidget>

QT_BEGIN_NAMESPACE

class Ui_StudyWindow
{
public:
    QAction *actionVoltar;
    QAction *actionSair;
    QWidget *centralwidget;
    QTreeWidget *treeWidget;
    QPushButton *pushButton;
    QMenuBar *menubar;
    QMenu *menuVoltar;
    QStatusBar *statusbar;

    void setupUi(QMainWindow *MainWindow)
    {
        if (MainWindow->objectName().isEmpty())
            MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
        MainWindow->resize(800, 600);
        actionVoltar = new QAction(MainWindow);
        actionVoltar->setObjectName(QString::fromUtf8("actionVoltar"));
        actionSair = new QAction(MainWindow);
        actionSair->setObjectName(QString::fromUtf8("actionSair"));
        centralwidget = new QWidget(MainWindow);
        centralwidget->setObjectName(QString::fromUtf8("centralwidget"));
        treeWidget = new QTreeWidget(centralwidget);
        QFont font;
        font.setPointSize(8);
        font.setBold(true);
        font.setWeight(75);
        QTreeWidgetItem *__qtreewidgetitem = new QTreeWidgetItem();
        __qtreewidgetitem->setFont(0, font);
        treeWidget->setHeaderItem(__qtreewidgetitem);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        new QTreeWidgetItem(treeWidget);
        treeWidget->setObjectName(QString::fromUtf8("treeWidget"));
        treeWidget->setGeometry(QRect(0, 110, 161, 451));
        pushButton = new QPushButton(centralwidget);
        pushButton->setObjectName(QString::fromUtf8("pushButton"));
        pushButton->setGeometry(QRect(0, 0, 75, 23));
        MainWindow->setCentralWidget(centralwidget);
        menubar = new QMenuBar(MainWindow);
        menubar->setObjectName(QString::fromUtf8("menubar"));
        menubar->setGeometry(QRect(0, 0, 800, 21));
        menuVoltar = new QMenu(menubar);
        menuVoltar->setObjectName(QString::fromUtf8("menuVoltar"));
        MainWindow->setMenuBar(menubar);
        statusbar = new QStatusBar(MainWindow);
        statusbar->setObjectName(QString::fromUtf8("statusbar"));
        MainWindow->setStatusBar(statusbar);

        menubar->addAction(menuVoltar->menuAction());
        menuVoltar->addAction(actionVoltar);
        menuVoltar->addSeparator();
        menuVoltar->addAction(actionSair);

        retranslateUi(MainWindow);

        QMetaObject::connectSlotsByName(MainWindow);
    } // setupUi

    void retranslateUi(QMainWindow *MainWindow)
    {
        MainWindow->setWindowTitle(QApplication::translate("MainWindow", "MainWindow", 0, QApplication::UnicodeUTF8));
        actionVoltar->setText(QApplication::translate("MainWindow", "Voltar", 0, QApplication::UnicodeUTF8));
        actionSair->setText(QApplication::translate("MainWindow", "Sair", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem = treeWidget->headerItem();
        ___qtreewidgetitem->setText(1, QApplication::translate("MainWindow", "Items", 0, QApplication::UnicodeUTF8));
        ___qtreewidgetitem->setText(0, QApplication::translate("MainWindow", "Mat\303\251ria", 0, QApplication::UnicodeUTF8));

        const bool __sortingEnabled = treeWidget->isSortingEnabled();
        treeWidget->setSortingEnabled(false);
        QTreeWidgetItem *___qtreewidgetitem1 = treeWidget->topLevelItem(0);
        ___qtreewidgetitem1->setText(0, QApplication::translate("MainWindow", "Portugu\303\252s", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem2 = treeWidget->topLevelItem(1);
        ___qtreewidgetitem2->setText(0, QApplication::translate("MainWindow", "Reda\303\247\303\243o", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem3 = treeWidget->topLevelItem(2);
        ___qtreewidgetitem3->setText(0, QApplication::translate("MainWindow", "Matem\303\241tica", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem4 = treeWidget->topLevelItem(3);
        ___qtreewidgetitem4->setText(0, QApplication::translate("MainWindow", "Biologia", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem5 = treeWidget->topLevelItem(4);
        ___qtreewidgetitem5->setText(0, QApplication::translate("MainWindow", "F\303\255sica", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem6 = treeWidget->topLevelItem(5);
        ___qtreewidgetitem6->setText(0, QApplication::translate("MainWindow", "Qu\303\255mica", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem7 = treeWidget->topLevelItem(6);
        ___qtreewidgetitem7->setText(0, QApplication::translate("MainWindow", "Hist\303\263ria", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem8 = treeWidget->topLevelItem(7);
        ___qtreewidgetitem8->setText(0, QApplication::translate("MainWindow", "Geografia", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem9 = treeWidget->topLevelItem(8);
        ___qtreewidgetitem9->setText(0, QApplication::translate("MainWindow", "Ingl\303\252s", 0, QApplication::UnicodeUTF8));
        QTreeWidgetItem *___qtreewidgetitem10 = treeWidget->topLevelItem(9);
        ___qtreewidgetitem10->setText(0, QApplication::translate("MainWindow", "Espanhol", 0, QApplication::UnicodeUTF8));
        treeWidget->setSortingEnabled(__sortingEnabled);

        pushButton->setText(QApplication::translate("MainWindow", "Cansei!", 0, QApplication::UnicodeUTF8));
        menuVoltar->setTitle(QApplication::translate("MainWindow", "Arquivo", 0, QApplication::UnicodeUTF8));
    } // retranslateUi

};

namespace Ui {
    class StudyWindow: public Ui_StudyWindow {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_STUDY_H

ui_mainwindow.h

/********************************************************************************
** Form generated from reading UI file 'mainwindow.ui'
**
** Created: Tue 20. Mar 20:10:56 2012
**      by: Qt User Interface Compiler version 4.7.4
**
** WARNING! All changes made in this file will be lost when recompiling UI file!
********************************************************************************/

#ifndef UI_MAINWINDOW_H
#define UI_MAINWINDOW_H

#include <QtCore/QVariant>
#include <QtGui/QAction>
#include <QtGui/QApplication>
#include <QtGui/QButtonGroup>
#include <QtGui/QGroupBox>
#include <QtGui/QHeaderView>
#include <QtGui/QLabel>
#include <QtGui/QMainWindow>
#include <QtGui/QMenu>
#include <QtGui/QMenuBar>
#include <QtGui/QPlainTextEdit>
#include <QtGui/QPushButton>
#include <QtGui/QStatusBar>
#include <QtGui/QWidget>

QT_BEGIN_NAMESPACE

class Ui_MainWindow
{
public slots:
public:
    QAction *actionAjuda;
    QAction *actionLista_de;
    QAction *actionSair;
    QWidget *centralwidget;
    QPushButton *pshBStudy;
    QPushButton *pshBSimulator;
    QPushButton *pshBExamCalen;
    QPushButton *pshBReadOfDay;
    QLabel *labelTitle;
    QPlainTextEdit *plainTextNews;
    QLabel *labelNews;
    QGroupBox *groupBox;
    QLabel *labelCollege;
    QLabel *labelCourse;
    QLabel *labelMemSince;
    QLabel *labelLoggedWith;
    QLabel *labelBP;
    QStatusBar *statusbar;
    QMenuBar *menuBar;
    QMenu *menuArquivo;


    void setupUi(QMainWindow *MainWindow)
    {
        if (MainWindow->objectName().isEmpty())
            MainWindow->setObjectName(QString::fromUtf8("MainWindow"));
        MainWindow->resize(800, 600);
        QSizePolicy sizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred);
        sizePolicy.setHorizontalStretch(0);
        sizePolicy.setVerticalStretch(0);
        sizePolicy.setHeightForWidth(MainWindow->sizePolicy().hasHeightForWidth());
        MainWindow->setSizePolicy(sizePolicy);
        actionAjuda = new QAction(MainWindow);
        actionAjuda->setObjectName(QString::fromUtf8("actionAjuda"));
        actionLista_de = new QAction(MainWindow);
        actionLista_de->setObjectName(QString::fromUtf8("actionLista_de"));
        actionSair = new QAction(MainWindow);
        actionSair->setObjectName(QString::fromUtf8("actionSair"));
        centralwidget = new QWidget(MainWindow);
        centralwidget->setObjectName(QString::fromUtf8("centralwidget"));
        pshBStudy = new QPushButton(centralwidget);
        pshBStudy->setObjectName(QString::fromUtf8("pshBStudy"));
        pshBStudy->setGeometry(QRect(140, 120, 161, 81));
        pshBStudy->setDefault(true);
        pshBSimulator = new QPushButton(centralwidget);
        pshBSimulator->setObjectName(QString::fromUtf8("pshBSimulator"));
        pshBSimulator->setGeometry(QRect(530, 120, 161, 81));
        pshBExamCalen = new QPushButton(centralwidget);
        pshBExamCalen->setObjectName(QString::fromUtf8("pshBExamCalen"));
        pshBExamCalen->setGeometry(QRect(140, 260, 161, 81));
        pshBReadOfDay = new QPushButton(centralwidget);
        pshBReadOfDay->setObjectName(QString::fromUtf8("pshBReadOfDay"));
        pshBReadOfDay->setGeometry(QRect(530, 260, 161, 81));
        labelTitle = new QLabel(centralwidget);
        labelTitle->setObjectName(QString::fromUtf8("labelTitle"));
        labelTitle->setGeometry(QRect(200, 10, 431, 71));
        QFont font;
        font.setPointSize(23);
        labelTitle->setFont(font);
        plainTextNews = new QPlainTextEdit(centralwidget);
        plainTextNews->setObjectName(QString::fromUtf8("plainTextNews"));
        plainTextNews->setGeometry(QRect(610, 440, 181, 111));
        plainTextNews->setReadOnly(true);
        labelNews = new QLabel(centralwidget);
        labelNews->setObjectName(QString::fromUtf8("labelNews"));
        labelNews->setGeometry(QRect(610, 420, 81, 16));
        groupBox = new QGroupBox(centralwidget);
        groupBox->setObjectName(QString::fromUtf8("groupBox"));
        groupBox->setGeometry(QRect(0, 460, 431, 91));
        labelCollege = new QLabel(groupBox);
        labelCollege->setObjectName(QString::fromUtf8("labelCollege"));
        labelCollege->setGeometry(QRect(230, 50, 111, 16));
        labelCourse = new QLabel(groupBox);
        labelCourse->setObjectName(QString::fromUtf8("labelCourse"));
        labelCourse->setGeometry(QRect(230, 30, 111, 16));
        labelMemSince = new QLabel(groupBox);
        labelMemSince->setObjectName(QString::fromUtf8("labelMemSince"));
        labelMemSince->setGeometry(QRect(10, 50, 111, 16));
        labelLoggedWith = new QLabel(groupBox);
        labelLoggedWith->setObjectName(QString::fromUtf8("labelLoggedWith"));
        labelLoggedWith->setGeometry(QRect(10, 30, 111, 16));
        labelBP = new QLabel(groupBox);
        labelBP->setObjectName(QString::fromUtf8("labelBP"));
        labelBP->setGeometry(QRect(10, 70, 111, 16));
        MainWindow->setCentralWidget(centralwidget);
        statusbar = new QStatusBar(MainWindow);
        statusbar->setObjectName(QString::fromUtf8("statusbar"));
        MainWindow->setStatusBar(statusbar);
        menuBar = new QMenuBar(MainWindow);
        menuBar->setObjectName(QString::fromUtf8("menuBar"));
        menuBar->setGeometry(QRect(0, 0, 800, 21));
        menuArquivo = new QMenu(menuBar);
        menuArquivo->setObjectName(QString::fromUtf8("menuArquivo"));
        MainWindow->setMenuBar(menuBar);
        QWidget::setTabOrder(pshBStudy, pshBSimulator);
        QWidget::setTabOrder(pshBSimulator, pshBExamCalen);
        QWidget::setTabOrder(pshBExamCalen, pshBReadOfDay);
        QWidget::setTabOrder(pshBReadOfDay, plainTextNews);

        menuBar->addAction(menuArquivo->menuAction());
        menuArquivo->addAction(actionSair);


        retranslateUi(MainWindow);

        QMetaObject::connectSlotsByName(MainWindow);
    } // setupUi

    void retranslateUi(QMainWindow *MainWindow)
    {
        MainWindow->setWindowTitle(QApplication::translate("MainWindow", "MainWindow", 0, QApplication::UnicodeUTF8));
        actionAjuda->setText(QApplication::translate("MainWindow", "Sobre...", 0, QApplication::UnicodeUTF8));
        actionLista_de->setText(QApplication::translate("MainWindow", "Lista de Provas", 0, QApplication::UnicodeUTF8));
        actionSair->setText(QApplication::translate("MainWindow", "Sair...", 0, QApplication::UnicodeUTF8));
        pshBStudy->setText(QApplication::translate("MainWindow", "Estudar!", 0, QApplication::UnicodeUTF8));
        pshBSimulator->setText(QApplication::translate("MainWindow", "Simulado", 0, QApplication::UnicodeUTF8));
        pshBExamCalen->setText(QApplication::translate("MainWindow", "Calend\303\241rio de Provas", 0, QApplication::UnicodeUTF8));
        pshBReadOfDay->setText(QApplication::translate("MainWindow", "Leitura do Dia", 0, QApplication::UnicodeUTF8));
        labelTitle->setText(QApplication::translate("MainWindow", "Escolha o que quer fazer hoje: ", 0, QApplication::UnicodeUTF8));
        labelNews->setText(QApplication::translate("MainWindow", "Novidades:", 0, QApplication::UnicodeUTF8));
        groupBox->setTitle(QApplication::translate("MainWindow", "Informa\303\247\303\265es", 0, QApplication::UnicodeUTF8));
        labelCollege->setText(QApplication::translate("MainWindow", "Faculdade:", 0, QApplication::UnicodeUTF8));
        labelCourse->setText(QApplication::translate("MainWindow", "Curso Pretendido:", 0, QApplication::UnicodeUTF8));
        labelMemSince->setText(QApplication::translate("MainWindow", "Membro desde:", 0, QApplication::UnicodeUTF8));
        labelLoggedWith->setText(QApplication::translate("MainWindow", "Voc\303\252 esta logado com: ", 0, QApplication::UnicodeUTF8));
        labelBP->setText(QApplication::translate("MainWindow", "BP: ", 0, QApplication::UnicodeUTF8));
        menuArquivo->setTitle(QApplication::translate("MainWindow", "Arquivo", 0, QApplication::UnicodeUTF8));
    } // retranslateUi

};

namespace Ui {
    class MainWindow: public Ui_MainWindow {};
} // namespace Ui

QT_END_NAMESPACE

#endif // UI_MAINWINDOW_H

Answer 1

well, after some patience and study of the Qt Architecture I did it. I just added that line in Ui_MainWindow::SetupUI(blablabla)

studyWindow = new StudyWindow(MainWindow);
QObject::connect(pshBStudy, SIGNAL(clicked()), studyWindow, SLOT(show()));

And the respective attribute to Ui_MainWindow Class. And now it's working alright.

Answer 2

So you have one window A which "controls" the others W1, W2, ...., Wn?

One way is to do :

• Associate each of the 3 buttons Bi to their respective window Wi (like a map where a key is a button and the value the QMainWindow)
  
• Create a custom slot in window A and connect the clicked() signals of each of the buttons to this slot.
  
• In this slot you find which button Bi sent the signal using sender(). You find the associated window Wi and you call show(). In the meanwhile you call hide() for all other windows Wj, j!=i

All the methods cited above are either in the doc of QWidget or Qobject, so you should read it.

Answer 3

You can use the signal and slot mechanism, for that please go through the following documentation..

http://qt-project.org/doc/qt-4.8/signalsandslots.html

Now you can connect the signal of one window to the another and in the slot of the other window you show the other window and hide the previous one.