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+
+/*!
+ \example webkit/previewer
+ \title Previewer Example
+
+ The Previewer example shows how to use QtWebKit's QWebView to preview
+ HTML data written in a QPlainTextEdit.
+
+ \image previewer-example.png
+
+ \section1 The User Interface
+
+ Before we begin, we create a user interface using \QD. Two QGroupBox
+ objects - the editor group box and the previewer group box are separated
+ by a QSplitter. In the editor group box, we have a QPlainTextEdit object,
+ \c plainTextEdit, and two QPushButton objects. In the previewer group box,
+ we have a QWebView object, \c webView.
+
+ \image previewer-ui.png
+
+ \section1 Previewer Class Definition
+
+ The \c Previewer class is a subclass of both QWidget and Ui::Form.
+ We subclass Ui::Form in order to embed the \QD user interface form
+ created earlier. This method of embedding forms is known as the
+ \l{The Multiple Inheritance Approach}{multiple inheritance approach}.
+
+ In our \c previewer.h file, we have a constructor and a slot,
+ \c on_previewButton_clicked().
+
+ \snippet examples/webkit/previewer/previewer.h 0
+
+ \section1 Previewer Class Implementation
+
+ The \c{Previewer}'s constructor is only responsible for setting up the
+ user interface.
+
+ \snippet examples/webkit/previewer/previewer.cpp 0
+
+ The \c on_previewButton_clicked() is a slot corresponding to the
+ \c{previewButton}'s \l{QPushButton::}{clicked()} signal. When the
+ \c previewButton is clicked, we extract the contents of \c plainTextEdit,
+ and then invoke the \l{QWebView::}{setHtml()} function to display our
+ contents as HTML.
+
+ \snippet examples/webkit/previewer/previewer.cpp 1
+
+ \section1 MainWindow Class Definition
+
+ The \c MainWindow class for the Previewer example is a subclass of
+ QMainWindow with a constructor and five private slots: \c open(),
+ \c openUrl(), \c save(), \c about() and \c updateTextEdit().
+
+ \snippet examples/webkit/previewer/mainwindow.h 0
+
+ The private objects in \c MainWindow are \c centralWidget, which is
+ a \c Previewer object, \c fileMenu, \c helpMenu and the QAction objects
+ \c openAct, \c openUrlAct, \c saveAct, \c exitAct, \c aboutAct and
+ \c aboutQtAct.
+
+ \snippet examples/webkit/previewer/mainwindow.h 1
+
+ There are three private functions: \c createActions(), \c createMenus()
+ and \c setStartupText(). The \c createActions() and \c createMenus()
+ functions are necessary to set up the main window's actions and
+ assign them to the \gui File and \gui Help menus. The \c setStartupText()
+ function, on the other hand, displays a description about the example
+ in its HTML Previewer window.
+
+ \section1 MainWindow Class Implementation
+
+ The \c{MainWindow}'s constructor invokes \c createActions() and
+ \c createMenus() to set up the \gui File menu and \gui Help menu. Then,
+ the \c Previewer object, \c centralWidget, is set to the main window's
+ central widget. Also, we connect \c webView's
+ \l{QWebView::}{loadFinished()} signal to our \c updateTextEdit() slot.
+ Finally, we call the \c setStartupText() function to display the
+ description of the example.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 0
+
+ Within the \c createActions() function, we instantiate all our private
+ QAction objects which we declared in \c{mainwindow.h}. We set the
+ short cut and status tip for these actions and connect their
+ \l{QAction::}{triggered()} signal to appropriate slots.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 1
+ \dots
+
+ The \c createMenus() function instantiates the QMenu items, \c fileMenu
+ and \c helpMenu and adds them to the main window's
+ \l{QMainWindow::menuBar()}{menu bar}.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 2
+
+ The example also provides an \c about() slot to describe its purpose.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 3
+
+ The \c MainWindow class provides two types of \gui Open functions:
+ \c open() and \c openUrl(). The \c open() function opens an HTML file
+ with \c fileName, and reads it with QTextStream. The function then
+ displays the output on \c plainTextEdit. The file's name is obtained
+ using QFileDialog's \l{QFileDialog::}{getOpenFileName()} function.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 4
+
+ The \c openUrl() function, on the other hand, displays a QInputDialog
+ to obtain a URL, and displays it on \c webView.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 5
+
+ In order to save a HTML file, the \c save() function first extracts the
+ contents of \c plainTextEdit and displays a QFileDialog to obtain
+ \c fileName. Then, we use a QTextStream object, \c in, to write to
+ \c file.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 6
+
+ Earlier, in \c{MainWindow}'s constructor, we connected \c{webView}'s
+ \l{QWebView::}{loadFinished()} signal to our private \c updateTextEdit()
+ slot. This slot updates the contents of \c plainTextEdit with the HTML
+ source of the web page's main frame, obtained using \l{QWebFrame}'s
+ \l{QWebFrame::}{toHtml()} function.
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 7
+
+ To provide a description about the Previewer example, when it starts up,
+ we use the \c setStartupText() function, as shown below:
+
+ \snippet examples/webkit/previewer/mainwindow.cpp 8
+
+
+ \section1 The \c{main()} Function
+
+ The \c main() function instantiates a \c MainWindow object, \c mainWindow,
+ and displays it with the \l{QWidget::}{show()} function.
+
+ \snippet examples/webkit/previewer/main.cpp 0
+
+*/
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