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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Free Documentation License
** Alternatively, this file may be used under the terms of the GNU Free
** Documentation License version 1.3 as published by the Free Software
** Foundation and appearing in the file included in the packaging of this
** file.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\class QDesignerTaskMenuExtension
\brief The QDesignerTaskMenuExtension class allows you to add custom
menu entries to Qt Designer's task menu.
\inmodule QtDesigner
QDesignerTaskMenuExtension provides an interface for creating
custom task menu extensions. It is typically used to create task
menu entries that are specific to a plugin in \QD.
\QD uses the QDesignerTaskMenuExtension to feed its task
menu. Whenever a task menu is requested, \QD will query
for the selected widget's task menu extension.
\image taskmenuextension-example-faded.png
A task menu extension is a collection of QActions. The actions
appear as entries in the task menu when the plugin with the
specified extension is selected. The image above shows the custom
\gui {Edit State...} action which appears in addition to \QD's
default task menu entries: \gui Cut, \gui Copy, \gui Paste etc.
To create a custom task menu extension, your extension class must
inherit from both QObject and QDesignerTaskMenuExtension. For
example:
\snippet doc/src/snippets/code/doc_src_qtdesigner.qdoc 9
Since we are implementing an interface, we must ensure that it
is made known to the meta-object system using the Q_INTERFACES()
macro. This enables \QD to use the qobject_cast() function to
query for supported interfaces using nothing but a QObject
pointer.
You must reimplement the taskActions() function to return a list
of actions that will be included in \QD task menu. Optionally, you
can reimplement the preferredEditAction() function to set the
action that is invoked when selecting your plugin and pressing
\key F2. The preferred edit action must be one of the actions
returned by taskActions() and, if it's not defined, pressing the
\key F2 key will simply be ignored.
In \QD, extensions are not created until they are required. A
task menu extension, for example, is created when you click the
right mouse button over a widget in \QD's workspace. For that
reason you must also construct an extension factory, using either
QExtensionFactory or a subclass, and register it using \QD's
\l {QExtensionManager}{extension manager}.
When a task menu extension is required, \QD's \l
{QExtensionManager}{extension manager} will run through all its
registered factories calling QExtensionFactory::createExtension()
for each until it finds one that is able to create a task menu
extension for the selected widget. This factory will then make an
instance of the extension.
There are four available types of extensions in \QD:
QDesignerContainerExtension, QDesignerMemberSheetExtension,
QDesignerPropertySheetExtension, and QDesignerTaskMenuExtension.
\QD's behavior is the same whether the requested extension is
associated with a container, a member sheet, a property sheet or a
task menu.
The QExtensionFactory class provides a standard extension factory,
and can also be used as an interface for custom extension
factories. You can either create a new QExtensionFactory and
reimplement the QExtensionFactory::createExtension() function. For
example:
\snippet doc/src/snippets/code/doc_src_qtdesigner.qdoc 10
Or you can use an existing factory, expanding the
QExtensionFactory::createExtension() function to make the factory
able to create a task menu extension as well. For example:
\snippet doc/src/snippets/code/doc_src_qtdesigner.qdoc 11
For a complete example using the QDesignerTaskMenuExtension class,
see the \l {designer/taskmenuextension}{Task Menu Extension
example}. The example shows how to create a custom widget plugin
for \QD, and how to to use the QDesignerTaskMenuExtension
class to add custom items to \QD's task menu.
\sa QExtensionFactory, QExtensionManager, {Creating Custom Widget
Extensions}
*/
/*!
\fn QDesignerTaskMenuExtension::~QDesignerTaskMenuExtension()
Destroys the task menu extension.
*/
/*!
\fn QAction *QDesignerTaskMenuExtension::preferredEditAction() const
Returns the action that is invoked when selecting a plugin with
the specified extension and pressing \key F2.
The action must be one of the actions returned by taskActions().
*/
/*!
\fn QList<QAction*> QDesignerTaskMenuExtension::taskActions() const
Returns the task menu extension as a list of actions which will be
included in \QD's task menu when a plugin with the specified
extension is selected.
The function must be reimplemented to add actions to the list.
*/
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