source: trunk/src/declarative/qml/qdeclarativeextensionplugin.cpp@ 1107

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#include "qdeclarativeextensionplugin.h"

QT_BEGIN_NAMESPACE

/*!
    \since 4.7
    \class QDeclarativeExtensionPlugin
    \brief The QDeclarativeExtensionPlugin class provides an abstract base for custom QML extension plugins.

    \ingroup plugins

    QDeclarativeExtensionPlugin is a plugin interface that makes it possible to
    create QML extensions that can be loaded dynamically into QML applications.
    These extensions allow custom QML types to be made available to the QML engine. 
    
    To write a QML extension plugin:
    
    \list
    \o Subclass QDeclarativeExtensionPlugin, implement registerTypes() method
    to register types using qmlRegisterType(), and export the class using the Q_EXPORT_PLUGIN2() macro
    \o Write an appropriate project file for the plugin
    \o Create a \l{Writing a qmldir file}{qmldir file} to describe the plugin
    \endlist

    QML extension plugins can be used to provide either application-specific or
    library-like plugins. Library plugins should limit themselves to registering types,
    as any manipulation of the engine's root context may cause conflicts
    or other issues in the library user's code.


    \section1 An example

    Suppose there is a new \c TimeModel C++ class that should be made available
    as a new QML element. It provides the current time through \c hour and \c minute 
    properties, like this:

    \snippet examples/declarative/cppextensions/plugins/plugin.cpp 0
    \dots

    To make this class available as a QML type, create a plugin that registers
    this type with a specific \l {QML Modules}{module} using qmlRegisterType(). For this example the plugin
    module will be named \c com.nokia.TimeExample (as defined in the project
    file further below).

    \snippet examples/declarative/cppextensions/plugins/plugin.cpp plugin
    \codeline
    \snippet examples/declarative/cppextensions/plugins/plugin.cpp export

    This registers the \c TimeModel class with the 1.0 version of this 
    plugin library, as a QML type called \c Time. The Q_ASSERT statement 
    ensures the module is imported correctly by any QML components that use this plugin.

    The project file defines the project as a plugin library and specifies 
    it should be built into the \c com/nokia/TimeExample directory:

    \code
    TEMPLATE = lib
    CONFIG += qt plugin
    QT += declarative

    DESTDIR = com/nokia/TimeExample
    TARGET = qmlqtimeexampleplugin
    ...
    \endcode    

    Finally, a \l{Writing a qmldir file}{qmldir file} is required in the \c com/nokia/TimeExample directory