Qt Toolkit - application/application.cpp example file

# A Complete Application Window

This example program looks like a complete modern application. It has a menu bar, it has a tool bar, it has a status bar. It also illustrates use of QPrinter. Oh yes, and you can edit text with it.

    /****************************************************************************
    ** $Id: application.cpp,v 1.16.2.1 1999/02/01 19:58:21 hanord Exp $
    **
    ** Copyright (C) 1992-1998 Troll Tech 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 "application.h"

    #include <qpixmap.h>
    #include <qtoolbar.h>
    #include <qtoolbutton.h>
    #include <qpopupmenu.h>
    #include <qmenubar.h>
    #include <qkeycode.h>
    #include <qmultilinedit.h>
    #include <qfile.h>
    #include <qfiledialog.h>
    #include <qstatusbar.h>
    #include <qmessagebox.h>
    #include <qprinter.h>
    #include <qapplication.h>
    #include <qaccel.h>
    #include <qtextstream.h>
    #include <qpainter.h>
    #include <qpaintdevicemetrics.h>
    #include <qwhatsthis.h>

    #include "filesave.xpm"
    #include "fileopen.xpm"
    #include "fileprint.xpm"

    const char * fileOpenText = "Click this button to open a new file.\n\n"
    "You can also select the Open command from the File menu.";
    const char * fileSaveText = "Click this button to save the file you are "
    "editing.  You will be prompted for a file name.\n\n"
    "You can also select the Save command from the File menu.\n\n"
    "Note that implementing this function is left as an exercise for the reader.";
    const char * filePrintText = "Click this button to print the file you "
    "are editing.\n\n"
    "You can also select the Print command from the File menu.";

    ApplicationWindow::ApplicationWindow()
        : QMainWindow( 0, "example application main window" )
    {
        printer = new QPrinter;
        printer->setMinMax( 1, 10 );
        QPixmap openIcon, saveIcon, printIcon;

        fileTools = new QToolBar( this, "file operations" );

        openIcon = QPixmap( fileopen );
        QToolButton * fileOpen = new QToolButton( openIcon, "Open File", 0,
                                                  this, SLOT(load()),
                                                  fileTools, "open file" );

        saveIcon = QPixmap( filesave );
        QToolButton * fileSave = new QToolButton( saveIcon, "Save File", 0,
                                                  this, SLOT(save()),
                                                  fileTools, "save file" );

        printIcon = QPixmap( fileprint );
        QToolButton * filePrint = new QToolButton( printIcon, "Print File", 0,
                                                   this, SLOT(print()),
                                                   fileTools, "print file" );

        (void)QWhatsThis::whatsThisButton( fileTools );
        QWhatsThis::add( fileOpen, fileOpenText, FALSE );
        QWhatsThis::add( fileSave, fileSaveText, FALSE );
        QWhatsThis::add( filePrint, filePrintText, FALSE );

        QPopupMenu * file = new QPopupMenu();
        menuBar()->insertItem( "&File", file );

        file->insertItem( "New", this, SLOT(newDoc()), CTRL+Key_N );
        file->insertItem( openIcon, "Open", this, SLOT(load()), CTRL+Key_O );
        file->insertItem( saveIcon, "Save", this, SLOT(save()), CTRL+Key_S );
        file->insertSeparator();
        file->insertItem( printIcon, "Print", this, SLOT(print()), CTRL+Key_P );
        file->insertSeparator();
        file->insertItem( "Close", this, SLOT(closeDoc()), CTRL+Key_W );
        file->insertItem( "Quit", qApp, SLOT(quit()), CTRL+Key_Q );

        controls = new QPopupMenu();
        menuBar()->insertItem( "&Controls", controls );

        mb = controls->insertItem( "Menu bar", this, SLOT(toggleMenuBar()), CTRL+Key_M);
        // Now an accelerator for when the menubar is invisible!
        QAccel* a = new QAccel(this);
        a->connectItem( a->insertItem( CTRL+Key_M ), this, SLOT(toggleMenuBar()) );

        tb = controls->insertItem( "Tool bar", this, SLOT(toggleToolBar()), CTRL+Key_T);
        sb = controls->insertItem( "Status bar", this, SLOT(toggleStatusBar()), CTRL+Key_B);
        controls->setCheckable( TRUE );
        controls->setItemChecked( mb, TRUE );
        controls->setItemChecked( tb, TRUE );
        controls->setItemChecked( sb, TRUE );

        e = new QMultiLineEdit( this, "editor" );
        e->setFocus();
        setCentralWidget( e );
        statusBar()->message( "Ready", 2000 );
    }

    /*! Destroys the object and frees any allocated resources.

    */

    ApplicationWindow::~ApplicationWindow()
    {
        delete printer;
    }

    void ApplicationWindow::newDoc()
    {
        ApplicationWindow *ed = new ApplicationWindow;
        ed->resize( 400, 400 );
        ed->show();
    }

    void ApplicationWindow::load()
    {
        QString fn = QFileDialog::getOpenFileName(0,0,this);
        if ( !fn.isEmpty() )
            load( fn );
        else
            statusBar()->message( "Loading aborted", 2000 );
    }

    void ApplicationWindow::load( const char *fileName )
    {
        QFile f( fileName );
        if ( !f.open( IO_ReadOnly ) )
            return;

        e->setAutoUpdate( FALSE );
        e->clear();

        QTextStream t(&f);
        while ( !t.eof() ) {
            QString s = t.readLine();
            e->append( s );
        }
        f.close();

        e->setAutoUpdate( TRUE );
        e->repaint();
        setCaption( fileName );
        QString s;
        s.sprintf( "Loaded document %s", fileName );
        statusBar()->message( s, 2000 );
    }

    void ApplicationWindow::save()
    {
        statusBar()->message( "File->Save is not implemented" );
        QMessageBox::message( "Note", "Left as an exercise for the user." );
    }

    void ApplicationWindow::print()
    {
        const int MARGIN = 10;
        int pageNo = 1;

        if ( printer->setup(this) ) {               // printer dialog
            statusBar()->message( "Printing..." );
            QPainter p;
            p.begin( printer );                     // paint on printer
            p.setFont( e->font() );
            int yPos        = 0;                    // y position for each line
            QFontMetrics fm = p.fontMetrics();
            QPaintDeviceMetrics metrics( printer ); // need width/height
                                                     // of printer surface
            for( int i = 0 ; i < e->numLines() ; i++ ) {
                if ( MARGIN + yPos > metrics.height() - MARGIN ) {
                    QString msg;
                    msg.sprintf( "Printing (page %d)...", ++pageNo );
                    statusBar()->message( msg );
                    printer->newPage();             // no more room on this page
                    yPos = 0;                       // back to top of page
                }
                p.drawText( MARGIN, MARGIN + yPos,
                            metrics.width(), fm.lineSpacing(),
                            ExpandTabs | DontClip,
                            e->textLine( i ) );
                yPos = yPos + fm.lineSpacing();
            }
            p.end();                                // send job to printer
            statusBar()->message( "Printing completed", 2000 );
        } else {
            statusBar()->message( "Printing aborted", 2000 );
        }

    }

    void ApplicationWindow::closeDoc()
    {
        close( TRUE ); // close AND DELETE!
    }

    void ApplicationWindow::toggleMenuBar()
    {
        if ( menuBar()->isVisible() ) {
            menuBar()->hide();
            controls->setItemChecked( mb, FALSE );
        } else {
            menuBar()->show();
            controls->setItemChecked( mb, TRUE );
        }
    }

    void ApplicationWindow::toggleToolBar()
    {
        if ( fileTools->isVisible() ) {
            fileTools->hide();
            controls->setItemChecked( tb, FALSE );
        } else {
            fileTools->show();
            controls->setItemChecked( tb, TRUE );
        }
    }

    void ApplicationWindow::toggleStatusBar()
    {
        if ( statusBar()->isVisible() ) {
            statusBar()->hide();
            controls->setItemChecked( sb, FALSE );
        } else {
            statusBar()->show();
            controls->setItemChecked( sb, TRUE );
        }
    }