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QWebPage Class Reference
[QtWebKit module]

The QWebPage class provides an object to view and edit web documents. More...

 #include <QWebPage>

This class is not part of the Qt GUI Framework Edition.

Inherits QObject.

This class was introduced in Qt 4.4.

• List of all members, including inherited members

Public Types

Properties

• 1 property inherited from QObject

Public Functions

Reimplemented Public Functions

• 29 public functions inherited from QObject

Public Slots

• 1 public slot inherited from QObject

Signals

• 1 signal inherited from QObject

Protected Functions

• 7 protected functions inherited from QObject

Additional Inherited Members

• 5 static public members inherited from QObject

Detailed Description

The QWebPage class provides an object to view and edit web documents.

QWebPage holds a main frame responsible for web content, settings, the history of navigated links and actions. This class can be used, together with QWebFrame, to provide functionality like QWebView in a widget-less environment.

QWebPage's API is very similar to QWebView, as you are still provided with common functions like action() (known as pageAction() in QWebView), triggerAction(), findText() and settings(). More QWebView-like functions can be found in the main frame of QWebPage, obtained via QWebPage::mainFrame(). For example, the load(), setUrl() and setHtml() unctions for QWebPage can be accessed using QWebFrame.

The loadStarted() signal is emitted when the page begins to load.The loadProgress() signal, on the other hand, is emitted whenever an element of the web page completes loading, such as an embedded image, a script, etc. Finally, the loadFinished() signal is emitted when the page has loaded completely. Its argument, either true or false, indicates whether or not the load operation succeeded.

Using QWebPage in a Widget-less Environment

Before you begin painting a QWebPage object, you need to set the size of the viewport by calling setViewportSize(). Then, you invoke the main frame's render function (QWebFrame::render()). An example of this is shown in the code snippet below.

Suppose we have a Thumbnail class as follows:

 class Thumbnailer : public QObject
 {
     Q_OBJECT

 public:
     Thumbnailer(const QUrl &url);

 signals:
     void finished();

 private slots:
     void render();

 private:
     QWebPage page;

 };

The Thumbnail's constructor takes in a url. We connect our QWebPage object's loadFinished() signal to our private slot, render().

 Thumbnailer::Thumbnailer(const QUrl &url)
 {
     page.mainFrame()->load(url);
     connect(&page, SIGNAL(loadFinished(bool)),
         this, SLOT(render()));
 }

The render() function shows how we can paint a thumbnail using a QWebPage object.

 void Thumbnailer::render()
 {
     page.setViewportSize(page.mainFrame()->contentsSize());
     QImage image(page.viewportSize(), QImage::Format_ARGB32);
     QPainter painter(&image);

     page.mainFrame()->render(&painter);
     painter.end();

     QImage thumbnail = image.scaled(400, 400);
     thumbnail.save("thumbnail.png");

     emit finished();
 }

We begin by setting the viewportSize and then we instantiate a QImage object, image, with the same size as our viewportSize. This image is then sent as a parameter to painter. Next, we render the contents of the main frame and its subframes into painter. Finally, we save the scaled image.

See also QWebFrame.

Member Type Documentation

enum QWebPage::Extension

This enum describes the types of extensions that the page can support. Before using these extensions, you should verify that the extension is supported by calling supportsExtension().

(introduced in Qt 4.6)

enum QWebPage::FindFlag
flags QWebPage::FindFlags

This enum describes the options available to QWebPage's findText() function. The options can be OR-ed together from the following list:

The FindFlags type is a typedef for QFlags<FindFlag>. It stores an OR combination of FindFlag values.

enum QWebPage::LinkDelegationPolicy

This enum defines the delegation policies a webpage can have when activating links and emitting the linkClicked() signal.

enum QWebPage::NavigationType

This enum describes the types of navigation available when browsing through hyperlinked documents.

enum QWebPage::WebAction

This enum describes the types of action which can be performed on the web page.

Actions only have an effect when they are applicable. The availability of actions can be be determined by checking isEnabled() on the action returned by action().

One method of enabling the text editing, cursor movement, and text selection actions is by setting contentEditable to true.

enum QWebPage::WebWindowType

Property Documentation

contentEditable : bool

This property holds whether the content in this QWebPage is editable or not.

If this property is enabled the contents of the page can be edited by the user through a visible cursor. If disabled (the default) only HTML elements in the web page with their contenteditable attribute set are editable.

This property was introduced in Qt 4.5.

Access functions:

forwardUnsupportedContent : bool

This property holds whether QWebPage should forward unsupported content.

If enabled, the unsupportedContent() signal is emitted with a network reply that can be used to read the content.

If disabled, the download of such content is aborted immediately.

By default unsupported content is not forwarded.

Access functions:

linkDelegationPolicy : LinkDelegationPolicy

This property holds how QWebPage should delegate the handling of links through the linkClicked() signal.

The default is to delegate no links.

Access functions:

modified : const bool

This property holds whether the page contains unsubmitted form data.

By default, this property is false.

Access functions:

palette : QPalette

This property holds the page's palette.

The base brush of the palette is used to draw the background of the main frame.

By default, this property contains the application's default palette.

Access functions:

preferredContentsSize : QSize

This property holds the size of the fixed layout.

The size affects the layout of the page in the viewport. If set to a fixed size of 1024x768 for example then webkit will layout the page as if the viewport were that size rather than something different.

This property was introduced in Qt 4.6.

Access functions:

selectedText : const QString

This property holds the text currently selected.

By default, this property contains an empty string.

Access functions:

See also selectionChanged().

viewportSize : QSize

This property holds the size of the viewport.

The size affects for example the visibility of scrollbars if the document is larger than the viewport.

By default, for a newly-created Web page, this property contains a size with zero width and height.

Access functions:

Member Function Documentation

QWebPage::QWebPage ( QObject * parent = 0 )

Constructs an empty QWebPage with parent parent.

QWebPage::~QWebPage ()

Destroys the web page.

bool QWebPage::acceptNavigationRequest ( QWebFrame * frame, const QNetworkRequest & request, NavigationType type )   [virtual protected]

This function is called whenever WebKit requests to navigate frame to the resource specified by request by means of the specified navigation type type.

If frame is a null pointer then navigation to a new window is requested. If the request is accepted createWindow() will be called.

The default implementation interprets the page's linkDelegationPolicy and emits linkClicked accordingly or returns true to let QWebPage handle the navigation itself.

See also createWindow().

QAction * QWebPage::action ( WebAction action ) const

Returns a QAction for the specified WebAction action.

The action is owned by the QWebPage but you can customize the look by changing its properties.

QWebPage also takes care of implementing the action, so that upon triggering the corresponding action is performed on the page.

See also triggerAction().

quint64 QWebPage::bytesReceived () const

Returns the number of bytes that were received from the network to render the current page.

See also totalBytes().

QString QWebPage::chooseFile ( QWebFrame * parentFrame, const QString & suggestedFile )   [virtual protected]

This function is called when the web content requests a file name, for example as a result of the user clicking on a "file upload" button in a HTML form.

A suggested filename may be provided in suggestedFile. The frame originating the request is provided as parentFrame.

void QWebPage::contentsChanged ()   [signal]

This signal is emitted whenever the text in form elements changes as well as other editable content.

This function was introduced in Qt 4.5.

See also contentEditable, QWebFrame::toHtml(), and QWebFrame::toPlainText().

QObject * QWebPage::createPlugin ( const QString & classid, const QUrl & url, const QStringList & paramNames, const QStringList & paramValues )   [virtual protected]

This function is called whenever WebKit encounters a HTML object element with type "application/x-qt-plugin". The classid, url, paramNames and paramValues correspond to the HTML object element attributes and child elements to configure the embeddable object.

QMenu * QWebPage::createStandardContextMenu ()

This function creates the standard context menu which is shown when the user clicks on the web page with the right mouse button. It is called from the default contextMenuEvent() handler. The popup menu's ownership is transferred to the caller.

This function was introduced in Qt 4.5.

QWebPage * QWebPage::createWindow ( WebWindowType type )   [virtual protected]

This function is called whenever WebKit wants to create a new window of the given type, for example when a JavaScript program requests to open a document in a new window.

If the new window can be created, the new window's QWebPage is returned; otherwise a null pointer is returned.

If the view associated with the web page is a QWebView object, then the default implementation forwards the request to QWebView's createWindow() function; otherwise it returns a null pointer.

See also acceptNavigationRequest().

QWebFrame * QWebPage::currentFrame () const

Returns the frame currently active.

See also mainFrame() and frameCreated().

void QWebPage::databaseQuotaExceeded ( QWebFrame * frame, QString databaseName )   [signal]

This signal is emitted whenever the web site shown in frame is asking to store data to the database databaseName and the quota allocated to that web site is exceeded.

This function was introduced in Qt 4.5.

void QWebPage::downloadRequested ( const QNetworkRequest & request )   [signal]

This signal is emitted when the user decides to download a link. The url of the link as well as additional meta-information is contained in request.

See also unsupportedContent().

bool QWebPage::event ( QEvent * ev )   [virtual]

Reimplemented from QObject::event().

bool QWebPage::extension ( Extension extension, const ExtensionOption * option = 0, ExtensionReturn * output = 0 )   [virtual]

This virtual function can be reimplemented in a QWebPage subclass to provide support for extensions. The option argument is provided as input to the extension; the output results can be stored in output.

The behavior of this function is determined by extension.

You can call supportsExtension() to check if an extension is supported by the page.

Returns true if the extension was called successfully; otherwise returns false.

See also supportsExtension() and Extension.

bool QWebPage::findText ( const QString & subString, FindFlags options = 0 )

Finds the specified string, subString, in the page, using the given options.

If the HighlightAllOccurrences flag is passed, the function will highlight all occurrences that exist in the page. All subsequent calls will extend the highlight, rather than replace it, with occurrences of the new string.

If the HighlightAllOccurrences flag is not passed, the function will select an occurrence and all subsequent calls will replace the current occurrence with the next one.

To clear the selection, just pass an empty string.

Returns true if subString was found; otherwise returns false.

bool QWebPage::focusNextPrevChild ( bool next )

Similar to QWidget::focusNextPrevChild it focuses the next focusable web element if next is true; otherwise the previous element is focused.

Returns true if it can find a new focusable element, or false if it can't.

QWebFrame * QWebPage::frameAt ( const QPoint & pos ) const

Returns the frame at the given point pos.

This function was introduced in Qt 4.6.

See also mainFrame() and currentFrame().

void QWebPage::frameCreated ( QWebFrame * frame )   [signal]

This signal is emitted whenever the page creates a new frame.

void QWebPage::geometryChangeRequested ( const QRect & geom )   [signal]

This signal is emitted whenever the document wants to change the position and size of the page to geom. This can happen for example through JavaScript.

QWebHistory * QWebPage::history () const

Returns a pointer to the view's history of navigated web pages.

QVariant QWebPage::inputMethodQuery ( Qt::InputMethodQuery property ) const

This method is used by the input method to query a set of properties of the page to be able to support complex input method operations as support for surrounding text and reconversions.

property specifies which property is queried.

See also QWidget::inputMethodEvent(), QInputMethodEvent, and QInputContext.

void QWebPage::javaScriptAlert ( QWebFrame * frame, const QString & msg )   [virtual protected]

This function is called whenever a JavaScript program running inside frame calls the alert() function with the message msg.

The default implementation shows the message, msg, with QMessageBox::information.

bool QWebPage::javaScriptConfirm ( QWebFrame * frame, const QString & msg )   [virtual protected]

This function is called whenever a JavaScript program running inside frame calls the confirm() function with the message, msg. Returns true if the user confirms the message; otherwise returns false.

The default implementation executes the query using QMessageBox::information with QMessageBox::Yes and QMessageBox::No buttons.

void QWebPage::javaScriptConsoleMessage ( const QString & message, int lineNumber, const QString & sourceID )   [virtual protected]

This function is called whenever a JavaScript program tries to print a message to the web browser's console.

For example in case of evaluation errors the source URL may be provided in sourceID as well as the lineNumber.

The default implementation prints nothing.

bool QWebPage::javaScriptPrompt ( QWebFrame * frame, const QString & msg, const QString & defaultValue, QString * result )   [virtual protected]

This function is called whenever a JavaScript program running inside frame tries to prompt the user for input. The program may provide an optional message, msg, as well as a default value for the input in defaultValue.

If the prompt was cancelled by the user the implementation should return false; otherwise the result should be written to result and true should be returned.

The default implementation uses QInputDialog::getText.

void QWebPage::linkClicked ( const QUrl & url )   [signal]

This signal is emitted whenever the user clicks on a link and the page's linkDelegationPolicy property is set to delegate the link handling for the specified url.

By default no links are delegated and are handled by QWebPage instead.

See also linkHovered().

void QWebPage::linkHovered ( const QString & link, const QString & title, const QString & textContent )   [signal]

This signal is emitted when the mouse hovers over a link.

link contains the link url. title is the link element's title, if it is specified in the markup. textContent provides text within the link element, e.g., text inside an HTML anchor tag.

When the mouse leaves the link element the signal is emitted with empty parameters.

See also linkClicked().

void QWebPage::loadFinished ( bool ok )   [signal]

This signal is emitted when a load of the page is finished. ok will indicate whether the load was successful or any error occurred.

See also loadStarted().

void QWebPage::loadProgress ( int progress )   [signal]

This signal is emitted when the global progress status changes. The current value is provided by progress and scales from 0 to 100, which is the default range of QProgressBar. It accumulates changes from all the child frames.

See also bytesReceived().

void QWebPage::loadStarted ()   [signal]

This signal is emitted when a new load of the page is started.

See also loadFinished().

QWebFrame * QWebPage::mainFrame () const

Returns the main frame of the page.

The main frame provides access to the hierarchy of sub-frames and is also needed if you want to explicitly render a web page into a given painter.

See also currentFrame().

void QWebPage::menuBarVisibilityChangeRequested ( bool visible )   [signal]

This signal is emitted whenever the visibility of the menubar in a web browser window that hosts QWebPage should be changed to visible.

void QWebPage::microFocusChanged ()   [signal]

This signal is emitted when for example the position of the cursor in an editable form element changes. It is used inform input methods about the new on-screen position where the user is able to enter text. This signal is usually connected to QWidget's updateMicroFocus() slot.

QNetworkAccessManager * QWebPage::networkAccessManager () const

Returns the QNetworkAccessManager that is responsible for serving network requests for this QWebPage.

See also setNetworkAccessManager().

QWebPluginFactory * QWebPage::pluginFactory () const

Returns the QWebPluginFactory that is responsible for creating plugins embedded into this QWebPage. If no plugin factory is installed a null pointer is returned.

See also setPluginFactory().

void QWebPage::printRequested ( QWebFrame * frame )   [signal]

This signal is emitted whenever the page requests the web browser to print frame, for example through the JavaScript window.print() call.

See also QWebFrame::print() and QPrintPreviewDialog.

void QWebPage::repaintRequested ( const QRect & dirtyRect )   [signal]

This signal is emitted whenever this QWebPage should be updated and no view was set. dirtyRect contains the area that needs to be updated. To paint the QWebPage get the mainFrame() and call the render(QPainter*, const QRegion&) method with the dirtyRect as the second parameter.

See also mainFrame() and view().

void QWebPage::restoreFrameStateRequested ( QWebFrame * frame )   [signal]

This signal is emitted when the load of frame is finished and the application may now update its state accordingly.

This function was introduced in Qt 4.5.

void QWebPage::saveFrameStateRequested ( QWebFrame * frame, QWebHistoryItem * item )   [signal]

This signal is emitted shortly before the history of navigated pages in frame is changed, for example when navigating back in the history.

The provided QWebHistoryItem, item, holds the history entry of the frame before the change.

A potential use-case for this signal is to store custom data in the QWebHistoryItem associated to the frame, using QWebHistoryItem::setUserData().

This function was introduced in Qt 4.5.

void QWebPage::scrollRequested ( int dx, int dy, const QRect & rectToScroll )   [signal]

This signal is emitted whenever the content given by rectToScroll needs to be scrolled dx and dy downwards and no view was set.

See also view().

void QWebPage::selectionChanged ()   [signal]

This signal is emitted whenever the selection changes.

See also selectedText().

void QWebPage::setNetworkAccessManager ( QNetworkAccessManager * manager )

Sets the QNetworkAccessManager manager responsible for serving network requests for this QWebPage.

Note: It is currently not supported to change the network access manager after the QWebPage has used it. The results of doing this are undefined.

See also networkAccessManager().

void QWebPage::setPluginFactory ( QWebPluginFactory * factory )

Sets the QWebPluginFactory factory responsible for creating plugins embedded into this QWebPage.

Note: The plugin factory is only used if the QWebSettings::PluginsEnabled attribute is enabled.

See also pluginFactory().

void QWebPage::setView ( QWidget * view )

Sets the view that is associated with the web page.

See also view().

QWebSettings * QWebPage::settings () const

Returns a pointer to the page's settings object.

See also QWebSettings::globalSettings().

bool QWebPage::shouldInterruptJavaScript ()   [slot]

This function is called when a JavaScript program is running for a long period of time.

If the user wanted to stop the JavaScript the implementation should return true; otherwise false.

The default implementation executes the query using QMessageBox::information with QMessageBox::Yes and QMessageBox::No buttons.

Warning: Because of binary compatibility constraints, this function is not virtual. If you want to provide your own implementation in a QWebPage subclass, reimplement the shouldInterruptJavaScript() slot in your subclass instead. QtWebKit will dynamically detect the slot and call it.

This function was introduced in Qt 4.6.

void QWebPage::statusBarMessage ( const QString & text )   [signal]

This signal is emitted when the statusbar text is changed by the page.

void QWebPage::statusBarVisibilityChangeRequested ( bool visible )   [signal]

This signal is emitted whenever the visibility of the statusbar in a web browser window that hosts QWebPage should be changed to visible.

bool QWebPage::supportsExtension ( Extension extension ) const   [virtual]

This virtual function returns true if the web page supports extension; otherwise false is returned.

See also extension().

bool QWebPage::swallowContextMenuEvent ( QContextMenuEvent * event )

Filters the context menu event, event, through handlers for scrollbars and custom event handlers in the web page. Returns true if the event was handled; otherwise false.

A web page may swallow a context menu event through a custom event handler, allowing for context menus to be implemented in HTML/JavaScript. This is used by Google Maps, for example.

void QWebPage::toolBarVisibilityChangeRequested ( bool visible )   [signal]

This signal is emitted whenever the visibility of the toolbar in a web browser window that hosts QWebPage should be changed to visible.

quint64 QWebPage::totalBytes () const

Returns the total number of bytes that were received from the network to render the current page, including extra content such as embedded images.

See also bytesReceived().

void QWebPage::triggerAction ( WebAction action, bool checked = false )   [virtual]

This function can be called to trigger the specified action. It is also called by QtWebKit if the user triggers the action, for example through a context menu item.

If action is a checkable action then checked specified whether the action is toggled or not.

See also action().

QUndoStack * QWebPage::undoStack () const

Returns a pointer to the undo stack used for editable content.

void QWebPage::unsupportedContent ( QNetworkReply * reply )   [signal]

This signals is emitted when webkit cannot handle a link the user navigated to.

At signal emissions time the meta data of the QNetworkReply reply is available.

Note: This signal is only emitted if the forwardUnsupportedContent property is set to true.

See also downloadRequested().

void QWebPage::updatePositionDependentActions ( const QPoint & pos )

Updates the page's actions depending on the position pos. For example if pos is over an image element the CopyImageToClipboard action is enabled.

QString QWebPage::userAgentForUrl ( const QUrl & url ) const   [virtual protected]

This function is called when a user agent for HTTP requests is needed. You can reimplement this function to dynamically return different user agents for different URLs, based on the url parameter.

The default implementation returns the following value:

"Mozilla/5.0 (%Platform%; %Security%; %Subplatform%; %Locale%) AppleWebKit/%WebKitVersion% (KHTML, like Gecko) %AppVersion Safari/%WebKitVersion%"

In this string the following values are replaced at run-time:

• %Platform% and %Subplatform% are expanded to the windowing system and the operation system.
• %Security% expands to U if SSL is enabled, otherwise N. SSL is enabled if QSslSocket::supportsSsl() returns true.
• %Locale% is replaced with QLocale::name(). The locale is determined from the view of the QWebPage. If no view is set on the QWebPage, then a default constructed QLocale is used instead.
• %WebKitVersion% is the version of WebKit the application was compiled against.
• %AppVersion% expands to QCoreApplication::applicationName()/QCoreApplication::applicationVersion() if they're set; otherwise defaulting to Qt and the current Qt version.

QWidget * QWebPage::view () const

Returns the view widget that is associated with the web page.

See also setView().

void QWebPage::windowCloseRequested ()   [signal]

This signal is emitted whenever the page requests the web browser window to be closed, for example through the JavaScript window.close() call.