Question

This examples shows how to write a very simple, but complete application using an addressbook as the example.

---

Header file of the mainwindow:

/****************************************************************************
** $Id:  qt/mainwindow.h   3.0.5   edited Oct 12 2001 $
**
** Copyright ( C ) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#ifndef AB_MAINWINDOW_H
#define AB_MAINWINDOW_H

#include <qmainwindow.h>
#include <qstring.h>

class QToolBar;
class QPopupMenu;
class ABCentralWidget;

class ABMainWindow: public QMainWindow
{
    Q_OBJECT

public:
    ABMainWindow();
    ~ABMainWindow();

protected slots:
    void fileNew();
    void fileOpen();
    void fileSave();
    void fileSaveAs();
    void filePrint();
    void closeWindow();

protected:
    void setupMenuBar();
    void setupFileTools();
    void setupStatusBar();
    void setupCentralWidget();

    QToolBar *fileTools;
    QString filename;
    ABCentralWidget *view;

};


#endif

---

Implementation of the mainwindow:

/****************************************************************************
** $Id:  qt/mainwindow.cpp   3.0.5   edited Oct 12 2001 $
**
** Copyright ( C ) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#include "mainwindow.h"
#include "centralwidget.h"

#include <qtoolbar.h>
#include <qtoolbutton.h>
#include <qpopupmenu.h>
#include <qmenubar.h>
#include <qstatusbar.h>
#include <qapplication.h>
#include <qfiledialog.h>

ABMainWindow::ABMainWindow()
    : QMainWindow( 0, "example addressbook application" ),
      filename( QString::null )
{
    setupMenuBar();
    setupFileTools();
    setupStatusBar();
    setupCentralWidget();
}


ABMainWindow::~ABMainWindow()
{
}

void ABMainWindow::setupMenuBar()
{
    QPopupMenu *file = new QPopupMenu( this );
    menuBar()->insertItem( "&File", file );

    file->insertItem( "New", this, SLOT( fileNew() ), CTRL + Key_N );
    file->insertItem( QPixmap( "fileopen.xpm" ), "Open", this, SLOT( fileOpen() ), CTRL + Key_O );
    file->insertSeparator();
    file->insertItem( QPixmap( "filesave.xpm" ), "Save", this, SLOT( fileSave() ), CTRL + Key_S );
    file->insertItem( "Save As...", this, SLOT( fileSaveAs() ) );
    file->insertSeparator();
    file->insertItem( QPixmap( "fileprint.xpm" ), "Print...", this, SLOT( filePrint() ), CTRL + Key_P );
    file->insertSeparator();
    file->insertItem( "Close", this, SLOT( closeWindow() ), CTRL + Key_W );
    file->insertItem( "Quit", qApp, SLOT( quit() ), CTRL + Key_Q );
}

void ABMainWindow::setupFileTools()
{
    //fileTools = new QToolBar( this, "file operations" );
}

void ABMainWindow::setupStatusBar()
{
    //statusBar()->message( "Ready", 2000 );
}

void ABMainWindow::setupCentralWidget()
{
    view = new ABCentralWidget( this );
    setCentralWidget( view );
}

void ABMainWindow::closeWindow()
{
    close();
}

void ABMainWindow::fileNew()
{
}

void ABMainWindow::fileOpen()
{
    QString fn = QFileDialog::getOpenFileName( QString::null, QString::null, this );
    if ( !fn.isEmpty() ) {
        filename = fn;
        view->load( filename );
    }
}

void ABMainWindow::fileSave()
{
    if ( filename.isEmpty() ) {
        fileSaveAs();
        return;
    }

    view->save( filename );
}

void ABMainWindow::fileSaveAs()
{
    QString fn = QFileDialog::getSaveFileName( QString::null, QString::null, this );
    if ( !fn.isEmpty() ) {
        filename = fn;
        fileSave();
    }
}

void ABMainWindow::filePrint()
{
}

---

Header file of the centralwidget:

/****************************************************************************
** $Id:  qt/centralwidget.h   3.0.5   edited Oct 12 2001 $
**
** Copyright ( C ) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#ifndef AB_CENTRALWIDGET_H
#define AB_CENTRALWIDGET_H

#include <qwidget.h>
#include <qstring.h>

class QTabWidget;
class QListView;
class QGridLayout;
class QLineEdit;
class QPushButton;
class QListViewItem;
class QCheckBox;

class ABCentralWidget : public QWidget
{
    Q_OBJECT

public:
    ABCentralWidget( QWidget *parent, const char *name = 0 );

    void save( const QString &filename );
    void load( const QString &filename );

protected slots:
    void addEntry();
    void changeEntry();
    void itemSelected( QListViewItem* );
    void selectionChanged();
    void toggleFirstName();
    void toggleLastName();
    void toggleAddress();
    void toggleEMail();
    void findEntries();

protected:
    void setupTabWidget();
    void setupListView();

    QGridLayout *mainGrid;
    QTabWidget *tabWidget;
    QListView *listView;
    QPushButton *add, *change, *find;
    QLineEdit *iFirstName, *iLastName, *iAddress, *iEMail,
        *sFirstName, *sLastName, *sAddress, *sEMail;
    QCheckBox *cFirstName, *cLastName, *cAddress, *cEMail;

};

#endif

---

Implementation of the centralwidget:

/****************************************************************************
** $Id:  qt/centralwidget.cpp   3.0.5   edited Apr 3 15:01 $
**
** Copyright ( C ) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#include "centralwidget.h"

#include <qtabwidget.h>
#include <qlistview.h>
#include <qlayout.h>
#include <qwidget.h>
#include <qlabel.h>
#include <qpushbutton.h>
#include <qlineedit.h>
#include <qlabel.h>
#include <qcheckbox.h>
#include <qfile.h>
#include <qtextstream.h>

ABCentralWidget::ABCentralWidget( QWidget *parent, const char *name )
    : QWidget( parent, name )
{
    mainGrid = new QGridLayout( this, 2, 1, 5, 5 );

    setupTabWidget();
    setupListView();

    mainGrid->setRowStretch( 0, 0 );
    mainGrid->setRowStretch( 1, 1 );
}

void ABCentralWidget::save( const QString &filename )
{
    if ( !listView->firstChild() )
        return;

    QFile f( filename );
    if ( !f.open( IO_WriteOnly ) )
        return;

    QTextStream t( &f );

    QListViewItemIterator it( listView );

    for ( ; it.current(); ++it )
        for ( unsigned int i = 0; i < 4; i++ )
            t << it.current()->text( i ) << "\n";

    f.close();
}

void ABCentralWidget::load( const QString &filename )
{
    listView->clear();

    QFile f( filename );
    if ( !f.open( IO_ReadOnly ) )
        return;

    QTextStream t( &f );

    while ( !t.atEnd() ) {
        QListViewItem *item = new QListViewItem( listView );
        for ( unsigned int i = 0; i < 4; i++ )
            item->setText( i, t.readLine() );
    }

    f.close();
}

void ABCentralWidget::setupTabWidget()
{
    tabWidget = new QTabWidget( this );

    QWidget *input = new QWidget( tabWidget );
    QGridLayout *grid1 = new QGridLayout( input, 2, 5, 5, 5 );

    QLabel *liFirstName = new QLabel( "First &Name", input );
    liFirstName->resize( liFirstName->sizeHint() );
    grid1->addWidget( liFirstName, 0, 0 );

    QLabel *liLastName = new QLabel( "&Last Name", input );
    liLastName->resize( liLastName->sizeHint() );
    grid1->addWidget( liLastName, 0, 1 );

    QLabel *liAddress = new QLabel( "Add&ress", input );
    liAddress->resize( liAddress->sizeHint() );
    grid1->addWidget( liAddress, 0, 2 );

    QLabel *liEMail = new QLabel( "&E-Mail", input );
    liEMail->resize( liEMail->sizeHint() );
    grid1->addWidget( liEMail, 0, 3 );

    add = new QPushButton( "A&dd", input );
    add->resize( add->sizeHint() );
    grid1->addWidget( add, 0, 4 );
    connect( add, SIGNAL( clicked() ), this, SLOT( addEntry() ) );

    iFirstName = new QLineEdit( input );
    iFirstName->resize( iFirstName->sizeHint() );
    grid1->addWidget( iFirstName, 1, 0 );
    liFirstName->setBuddy( iFirstName );

    iLastName = new QLineEdit( input );
    iLastName->resize( iLastName->sizeHint() );
    grid1->addWidget( iLastName, 1, 1 );
    liLastName->setBuddy( iLastName );

    iAddress = new QLineEdit( input );
    iAddress->resize( iAddress->sizeHint() );
    grid1->addWidget( iAddress, 1, 2 );
    liAddress->setBuddy( iAddress );

    iEMail = new QLineEdit( input );
    iEMail->resize( iEMail->sizeHint() );
    grid1->addWidget( iEMail, 1, 3 );
    liEMail->setBuddy( iEMail );

    change = new QPushButton( "&Change", input );
    change->resize( change->sizeHint() );
    grid1->addWidget( change, 1, 4 );
    connect( change, SIGNAL( clicked() ), this, SLOT( changeEntry() ) );

    tabWidget->addTab( input, "&Add/Change Entry" );

    // --------------------------------------

    QWidget *search = new QWidget( this );
    QGridLayout *grid2 = new QGridLayout( search, 2, 5, 5, 5 );

    cFirstName = new QCheckBox( "First &Name", search );
    cFirstName->resize( cFirstName->sizeHint() );
    grid2->addWidget( cFirstName, 0, 0 );
    connect( cFirstName, SIGNAL( clicked() ), this, SLOT( toggleFirstName() ) );

    cLastName = new QCheckBox( "&Last Name", search );
    cLastName->resize( cLastName->sizeHint() );
    grid2->addWidget( cLastName, 0, 1 );
    connect( cLastName, SIGNAL( clicked() ), this, SLOT( toggleLastName() ) );

    cAddress = new QCheckBox( "Add&ress", search );
    cAddress->resize( cAddress->sizeHint() );
    grid2->addWidget( cAddress, 0, 2 );
    connect( cAddress, SIGNAL( clicked() ), this, SLOT( toggleAddress() ) );

    cEMail = new QCheckBox( "&E-Mail", search );
    cEMail->resize( cEMail->sizeHint() );
    grid2->addWidget( cEMail, 0, 3 );
    connect( cEMail, SIGNAL( clicked() ), this, SLOT( toggleEMail() ) );

    sFirstName = new QLineEdit( search );
    sFirstName->resize( sFirstName->sizeHint() );
    grid2->addWidget( sFirstName, 1, 0 );

    sLastName = new QLineEdit( search );
    sLastName->resize( sLastName->sizeHint() );
    grid2->addWidget( sLastName, 1, 1 );

    sAddress = new QLineEdit( search );
    sAddress->resize( sAddress->sizeHint() );
    grid2->addWidget( sAddress, 1, 2 );

    sEMail = new QLineEdit( search );
    sEMail->resize( sEMail->sizeHint() );
    grid2->addWidget( sEMail, 1, 3 );

    find = new QPushButton( "F&ind", search );
    find->resize( find->sizeHint() );
    grid2->addWidget( find, 1, 4 );
    connect( find, SIGNAL( clicked() ), this, SLOT( findEntries() ) );

    cFirstName->setChecked( TRUE );
    sFirstName->setEnabled( TRUE );
    sLastName->setEnabled( FALSE );
    sAddress->setEnabled( FALSE );
    sEMail->setEnabled( FALSE );

    tabWidget->addTab( search, "&Search" );

    mainGrid->addWidget( tabWidget, 0, 0 );
}

void ABCentralWidget::setupListView()
{
    listView = new QListView( this );
    listView->addColumn( "First Name" );
    listView->addColumn( "Last Name" );
    listView->addColumn( "Address" );
    listView->addColumn( "E-Mail" );

    listView->setSelectionMode( QListView::Single );

    connect( listView, SIGNAL( clicked( QListViewItem* ) ), this, SLOT( itemSelected( QListViewItem* ) ) );

    mainGrid->addWidget( listView, 1, 0 );
    listView->setAllColumnsShowFocus( TRUE );
}

void ABCentralWidget::addEntry()
{
    if ( !iFirstName->text().isEmpty() || !iLastName->text().isEmpty() ||
         !iAddress->text().isEmpty() || !iEMail->text().isEmpty() ) {
        QListViewItem *item = new QListViewItem( listView );
        item->setText( 0, iFirstName->text() );
        item->setText( 1, iLastName->text() );
        item->setText( 2, iAddress->text() );
        item->setText( 3, iEMail->text() );
    }

    iFirstName->setText( "" );
    iLastName->setText( "" );
    iAddress->setText( "" );
    iEMail->setText( "" );
}

void ABCentralWidget::changeEntry()
{
    QListViewItem *item = listView->currentItem();

    if ( item &&
         ( !iFirstName->text().isEmpty() || !iLastName->text().isEmpty() ||
           !iAddress->text().isEmpty() || !iEMail->text().isEmpty() ) ) {
        item->setText( 0, iFirstName->text() );
        item->setText( 1, iLastName->text() );
        item->setText( 2, iAddress->text() );
        item->setText( 3, iEMail->text() );
    }
}

void ABCentralWidget::selectionChanged()
{
    iFirstName->setText( "" );
    iLastName->setText( "" );
    iAddress->setText( "" );
    iEMail->setText( "" );
}

void ABCentralWidget::itemSelected( QListViewItem *item )
{
    if ( !item )
        return;
    item->setSelected( TRUE );
    item->repaint();

    iFirstName->setText( item->text( 0 ) );
    iLastName->setText( item->text( 1 ) );
    iAddress->setText( item->text( 2 ) );
    iEMail->setText( item->text( 3 ) );
}

void ABCentralWidget::toggleFirstName()
{
    sFirstName->setText( "" );

    if ( cFirstName->isChecked() ) {
        sFirstName->setEnabled( TRUE );
        sFirstName->setFocus();
    }
    else
        sFirstName->setEnabled( FALSE );
}

void ABCentralWidget::toggleLastName()
{
    sLastName->setText( "" );

    if ( cLastName->isChecked() ) {
        sLastName->setEnabled( TRUE );
        sLastName->setFocus();
    }
    else
        sLastName->setEnabled( FALSE );
}

void ABCentralWidget::toggleAddress()
{
    sAddress->setText( "" );

    if ( cAddress->isChecked() ) {
        sAddress->setEnabled( TRUE );
        sAddress->setFocus();
    }
    else
        sAddress->setEnabled( FALSE );
}

void ABCentralWidget::toggleEMail()
{
    sEMail->setText( "" );

    if ( cEMail->isChecked() ) {
        sEMail->setEnabled( TRUE );
        sEMail->setFocus();
    }
    else
        sEMail->setEnabled( FALSE );
}

void ABCentralWidget::findEntries()
{
    if ( !cFirstName->isChecked() &&
         !cLastName->isChecked() &&
         !cAddress->isChecked() &&
         !cEMail->isChecked() ) {
        listView->clearSelection();
        return;
    }

    QListViewItemIterator it( listView );

    for ( ; it.current(); ++it ) {
        bool select = TRUE;

        if ( cFirstName->isChecked() ) {
            if ( select && it.current()->text( 0 ).contains( sFirstName->text() ) )
                select = TRUE;
            else
                select = FALSE;
        }
        if ( cLastName->isChecked() ) {
            if ( select && it.current()->text( 1 ).contains( sLastName->text() ) )
                select = TRUE;
            else
                select = FALSE;
        }
        if ( cAddress->isChecked() ) {
            if ( select && it.current()->text( 2 ).contains( sAddress->text() ) )
                select = TRUE;
            else
                select = FALSE;
        }
        if ( cEMail->isChecked() ) {
            if ( select && it.current()->text( 3 ).contains( sEMail->text() ) )
                select = TRUE;
            else
                select = FALSE;
        }

        if ( select )
            it.current()->setSelected( TRUE );
        else
            it.current()->setSelected( FALSE );
        it.current()->repaint();
    }
}

---

Main:

/****************************************************************************
** $Id:  qt/main.cpp   3.0.5   edited Oct 12 2001 $
**
** Copyright ( C ) 1992-2000 Trolltech AS.  All rights reserved.
**
** This file is part of an example program for Qt.  This example
** program may be used, distributed and modified without limitation.
**
*****************************************************************************/

#include <qapplication.h>

#include "mainwindow.h"

int main( int argc, char ** argv )
{
    QApplication a( argc, argv );

    ABMainWindow *mw = new ABMainWindow();
    mw->setCaption( "Qt Example - Addressbook" );
    a.setMainWidget( mw );
    mw->show();

    a.connect( &a, SIGNAL( lastWindowClosed() ), &a, SLOT( quit() ) );
    int result = a.exec();
    delete mw;
    return result;
}

See also Examples.