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diff --git a/doc/src/declarative/extending-examples.qdoc b/doc/src/declarative/extending-examples.qdoc new file mode 100644 index 0000000..17bef4e --- /dev/null +++ b/doc/src/declarative/extending-examples.qdoc @@ -0,0 +1,309 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the documentation of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** 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 either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +/*! +\example declarative/extending/adding +\title Extending QML - Adding Types Example + +The Adding Types Example shows how to add a new element type, \c Person, to QML. +The \c Person type can be used from QML like this: + +\snippet examples/declarative/extending/adding/example.qml 0 + +\section1 Declare the Person class + +All QML elements map to C++ types. Here we declare a basic C++ Person class +with the two properties we want accessible on the QML type - name and shoeSize. +Although in this example we use the same name for the C++ class as the QML +element, the C++ class can be named differently, or appear in a namespace. + +\snippet examples/declarative/extending/adding/person.h 0 + +Following the class declaration, we include the QML_DECLARE_TYPE() macro. This +is necessary to declare the type to QML. It also includes the logic necessary +to expose the class to Qt's meta system - that is, it includes the +Q_DECLARE_METATYPE() functionality. + +\section1 Define the Person class + +\snippet examples/declarative/extending/adding/person.cpp 0 + +The Person class implementation is quite basic. The property accessors simply +return members of the object instance. + +The implementation must also include the QML_DEFINE_TYPE() macro. This macro +registers the Person class with QML as a type in the People library version 1.0, +and defines the mapping between the C++ and QML class names. + +\section1 Running the example + +The main.cpp file in the example includes a simple shell application that +loads and runs the QML snippet shown at the beginning of this page. +*/ + +/*! +\example declarative/extending/properties +\title Extending QML - Object and List Property Types Example + +This example builds on: +\list +\o \l {Extending QML - Adding Types Example} +\endlist + +The Object and List Property Types example shows how to add object and list +properties in QML. This example adds a BirthdayParty element that specifies +a birthday party, consisting of a celebrant and a list of guests. People are +specified using the People QML type built in the previous example. + +\snippet examples/declarative/extending/properties/example.qml 0 + +\section1 Declare the BirthdayParty + +The BirthdayParty class is declared like this: + +\snippet examples/declarative/extending/properties/birthdayparty.h 0 +\snippet examples/declarative/extending/properties/birthdayparty.h 1 +\snippet examples/declarative/extending/properties/birthdayparty.h 2 +\snippet examples/declarative/extending/properties/birthdayparty.h 3 + +The class contains a member to store the celebrant object, and also a +QmlConcreteList<Person *> member. + +In QML, the type of a list properties - and the guests property is a list of +people - are all of type QmlList<T *>*. QmlList is an abstract list interface +that allows a developer to react to QML accessing and modifying the contents of +the list. This is useful for implementing "virtual lists" or other advanced +scenarios, but can't be used directly for the common case of just wanting a +regular list of things. For this a concrete implementation, QmlConcreteList, is +provided and that is used here. + +\section2 Define the BirthdayParty + +The implementation of BirthdayParty property accessors is straight forward. + +\snippet examples/declarative/extending/properties/birthdayparty.cpp 0 + +\section1 Running the example + +The main.cpp file in the example includes a simple shell application that +loads and runs the QML snippet shown at the beginning of this page. +*/ + +/*! +\example declarative/extending/coercion +\title Extending QML - Inheritance and Coercion Example + +This example builds on: +\list +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +The Inheritance and Coercion Example shows how to use base classes to assign +elements of more than one type to a property. It specializes the Person element +developed in the previous examples into two elements - a \c Boy and a \c Girl. + +\snippet examples/declarative/extending/coercion/example.qml 0 + +\section1 Declare Boy and Girl + +\snippet examples/declarative/extending/coercion/person.h 0 + +The Person class remains unaltered in this example and the Boy and Girl C++ +classes are trivial extensions of it. As an example, the inheritance used here +is a little contrived, but in real applications it is likely that the two +extensions would add additional properties or modify the Person classes +behavior. + +\section2 Define People as a base class + +The implementation of the People class itself has not changed since the the +previous example. However, as we have repurposed the People class as a common +base for Boy and Girl, we want to prevent it from being instantiated from QML +directly - an explicit Boy or Girl should be instantiated instead. + +\snippet examples/declarative/extending/coercion/person.cpp 0 + +While we want to disallow instantiating Person from within QML, it still needs +to be registered with the QML engine, so that it can be used as a property type +and other types can be coerced to it. To register a type, without defining a +named mapping into QML, we use the QML_DEFINE_NOCREATE_TYPE() macro instead of +the QML_DEFINE_TYPE() macro used previously. + +\section2 Define Boy and Girl + +The implementation of Boy and Girl are trivial. + +\snippet examples/declarative/extending/coercion/person.cpp 1 + +All that is necessary is to implement the constructor, and to register the types +and their QML name with the QML engine. + +\section1 Running the example + +The BirthdayParty element has not changed since the previous example. The +celebrant and guests property still use the People type. + +\snippet examples/declarative/extending/coercion/birthdayparty.h 0 + +However, as all three types, Person, Boy and Girl, have been registered with the +QML system, on assignment QML automatically (and type-safely) converts the Boy +and Girl objects into a Person. + +The main.cpp file in the example includes a simple shell application that +loads and runs the QML snippet shown at the beginning of this page. +*/ + +/*! +\example declarative/extending/default +\title Extending QML - Default Property Example + +This example builds on: +\list +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +The Default Property Example is a minor modification of the +\l {Extending QML - Inheritance and Coercion Example} that simplifies the +specification of a BirthdayParty through the use of a default property. + +\snippet examples/declarative/extending/default/example.qml 0 + +\section1 Declaring the BirthdayParty class + +The only difference between this example and the last, is the addition of the +\c DefaultProperty class info annotation. + +\snippet examples/declarative/extending/default/birthdayparty.h 0 + +The default property specifies the property to assign to whenever an explicit +property is not specified, in the case of the BirthdayParty element the guest +property. It is purely a syntactic simplification, the behavior is identical +to specifying the property by name, but it can add a more natural feel in many +situations. The default property must be either an object or list property. + +\section1 Running the example + +The main.cpp file in the example includes a simple shell application that +loads and runs the QML snippet shown at the beginning of this page. +*/ + +/*! +\example declarative/extending/grouped +\title Extending QML - Grouped Properties Example + +This example builds on: +\list +\o \l {Extending QML - Default Property Example} +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +*/ + +/*! +\example declarative/extending/grouped +\title Extending QML - Attached Properties Example + +This example builds on: +\list +\o \l {Extending QML - Grouped Properties Example} +\o \l {Extending QML - Default Property Example} +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +*/ + +/*! +\example declarative/extending/signal +\title Extending QML - Signal Support Example + +This example builds on: +\list +\o \l {Extending QML - Attached Properties Example} +\o \l {Extending QML - Grouped Properties Example} +\o \l {Extending QML - Default Property Example} +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +*/ + +/*! +\example declarative/extending/valuesource +\title Extending QML - Property Value Source Example + +This example builds on: +\list +\o \l {Extending QML - Signal Support Example} +\o \l {Extending QML - Attached Properties Example} +\o \l {Extending QML - Grouped Properties Example} +\o \l {Extending QML - Default Property Example} +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +*/ + +/*! +\example declarative/extending/binding +\title Extending QML - Binding Example + +This example builds on: +\list +\o \l {Extending QML - Property Value Source Example} +\o \l {Extending QML - Signal Support Example} +\o \l {Extending QML - Attached Properties Example} +\o \l {Extending QML - Grouped Properties Example} +\o \l {Extending QML - Default Property Example} +\o \l {Extending QML - Inheritance and Coercion Example} +\o \l {Extending QML - Object and List Property Types Example} +\o \l {Extending QML - Adding Types Example} +\endlist + +*/ |