Qt Reference Documentation

# mainwindow.cpp Example File

webkit/previewer/mainwindow.cpp

     /****************************************************************************
     **
     ** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
     ** All rights reserved.
     ** Contact: Nokia Corporation (qt-info@nokia.com)
     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
     ** You may use this file under the terms of the BSD license as follows:
     **
     ** "Redistribution and use in source and binary forms, with or without
     ** modification, are permitted provided that the following conditions are
     ** met:
     **   * Redistributions of source code must retain the above copyright
     **     notice, this list of conditions and the following disclaimer.
     **   * Redistributions in binary form must reproduce the above copyright
     **     notice, this list of conditions and the following disclaimer in
     **     the documentation and/or other materials provided with the
     **     distribution.
     **   * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
     **     the names of its contributors may be used to endorse or promote
     **     products derived from this software without specific prior written
     **     permission.
     **
     ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
     ** $QT_END_LICENSE$
     **
     ****************************************************************************/

     #include <QtGui>
     #include <QtWebKit>
     #include "mainwindow.h"

     MainWindow::MainWindow()
     {
         createActions();
         createMenus();
         centralWidget = new Previewer(this);
         setCentralWidget(centralWidget);

         connect(centralWidget->webView, SIGNAL(loadFinished(bool)),
             this, SLOT(updateTextEdit()));
         setStartupText();
     }

     void MainWindow::createActions()
     {
         openAct = new QAction(tr("&Open..."), this);
         openAct->setShortcuts(QKeySequence::Open);
         openAct->setStatusTip(tr("Open an existing HTML file"));
         connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

         openUrlAct = new QAction(tr("&Open URL..."), this);
         openUrlAct->setShortcut(tr("Ctrl+U"));
         openUrlAct->setStatusTip(tr("Open a URL"));
         connect(openUrlAct, SIGNAL(triggered()), this, SLOT(openUrl()));

         saveAct = new QAction(tr("&Save"), this);
         saveAct->setShortcuts(QKeySequence::Save);
         saveAct->setStatusTip(tr("Save the HTML file to disk"));
         connect(saveAct, SIGNAL(triggered()), this, SLOT(save()));

         exitAct = new QAction(tr("E&xit"), this);
         exitAct->setStatusTip(tr("Exit the application"));
         exitAct->setShortcuts(QKeySequence::Quit);
         connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

         aboutAct = new QAction(tr("&About"), this);
         aboutAct->setStatusTip(tr("Show the application's About box"));
         connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

         aboutQtAct = new QAction(tr("About &Qt"), this);
         aboutQtAct->setStatusTip(tr("Show the Qt library's About box"));
         connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
     }

     void MainWindow::createMenus()
     {
         fileMenu = menuBar()->addMenu(tr("&File"));
         fileMenu->addAction(openAct);
         fileMenu->addAction(openUrlAct);
         fileMenu->addAction(saveAct);
         fileMenu->addSeparator();
         fileMenu->addAction(exitAct);

         menuBar()->addSeparator();

         helpMenu = menuBar()->addMenu(tr("&Help"));
         helpMenu->addAction(aboutAct);
         helpMenu->addAction(aboutQtAct);
     }

     void MainWindow::about()
     {
         QMessageBox::about(this, tr("About Previewer"),
             tr("The <b>Previewer</b> example demonstrates how to "
                "view HTML documents using a QWebView."));
     }

     void MainWindow::open()
     {
         QString fileName = QFileDialog::getOpenFileName(this);
         if (!fileName.isEmpty()) {
             // read from file
             QFile file(fileName);

             if (!file.open(QIODevice::ReadOnly)) {
                 QMessageBox::information(this, tr("Unable to open file"),
                     file.errorString());
                 return;
             }

             QTextStream out(&file);
             QString output = out.readAll();

             // display contents
             centralWidget->plainTextEdit->setPlainText(output);
             centralWidget->setBaseUrl(QUrl::fromLocalFile(fileName));
         }
     }

     void MainWindow::openUrl()
     {
         bool ok;
         QString url = QInputDialog::getText(this, tr("Enter a URL"),
                       tr("URL:"), QLineEdit::Normal, "http://", &ok);

         if (ok && !url.isEmpty()) {
             centralWidget->webView->setUrl(url);
         }
     }

     void MainWindow::save()
     {
         QString content = centralWidget->plainTextEdit->toPlainText();
         QString fileName = QFileDialog::getSaveFileName(this);

         if (!fileName.isEmpty()) {
             // save to file
             QFile file(fileName);

             if (!file.open(QIODevice::WriteOnly)) {
                 QMessageBox::information(this, tr("Unable to open file"),
                     file.errorString());
                 return;
             }

             QTextStream in(&file);
             in << content;
         }
     }

     void MainWindow::updateTextEdit()
     {
         QWebFrame *mainFrame = centralWidget->webView->page()->mainFrame();
         QString frameText = mainFrame->toHtml();
         centralWidget->plainTextEdit->setPlainText(frameText);
     }

     void MainWindow::setStartupText()
     {
         QString string = "<html><body><h1>HTML Previewer</h1>"
                          " <p>This example shows you how to use QWebView to"
                          " preview HTML data written in a QPlainTextEdit.</p>"
                          " </body></html>";
         centralWidget->webView->setHtml(string);
     }