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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:FDL$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see http://www.qt.io/terms-conditions. For further
** information use the contact form at http://www.qt.io/contact-us.
**
** GNU Free Documentation License Usage
** 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. Please review the following information to ensure
** the GNU Free Documentation License version 1.3 requirements
** will be met: http://www.gnu.org/copyleft/fdl.html.
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\page positioning-cpp-qml.html
\title Interfaces between C++ and QML Code in Qt Positioning
\brief Some of the providing QtPositioning QML types providing interfaces to access and modify properties in C++.
\section1 Overview
Depending on the type of C++ class QtPositioning utilizes two methods to simplify
exchange of position data between C++ and QML code.
\target Cpp_value_integration_positioning
\section1 Direct C++ Value Integration in QtPositioning
Starting with Qt 5.5, it has become much easier to integrate non-QObject based
data types into QML. This is achieved by adding \l Q_GADGET support to QtQml.
The macro converts classes into a light-weight
version of a QObject without the required \l QObject inheritance. At the same time
it retains the reflection capabilities of \l QMetaObject. As a result they can be directly
exposed to QML and do not require any further wrapper classes.
A significant number of Position and Location
related data types were converted to Q_GADGETs. They retain their API and value
type character but have become introspectable via \l QMetaObject. This conversion
was done to the following classes:
\list
\li \l QGeoCircle
\li \l QGeoCoordinate
\li \l QGeoRectangle
\li \l QGeoShape
\endlist
Using \l QGeoCoordinate as an example, the C++ types are directly exposed to the
QML environment via its meta type:
\code
qRegisterMetaType<QGeoCoordinate>();
QMetaType::registerEqualsComparator<QGeoCoordinate>();
\endcode
The above registration of \l QGeoCoordinate is automatically done once by the
QtPositioning QML plugin. The \l{Plane Spotter (QML)}{Plane Spotter} example demonstrates
this feature.
\section1 QVariant Based integration
This section provides information on how to integrate QGeoAddress and QGeoLocation.
\section2 Address - QGeoAddress
The \l {QtPositioning::Address::address} {Address.address} property is used to provide an interface between C++ and QML code. First a pointer to a
Address object must be obtained from C++, then use the \l {QObject::property()}{property()} and
\l {QObject::setProperty()}{setProperty()} functions to get and set the \c address property.
The following gets the QGeoAddress representing this object from C++:
\snippet cpp/cppqml.cpp Address get
The following sets the properties of this object based on a QGeoAddress object from C++:
\snippet cpp/cppqml.cpp Address set
\section2 Location - QGeoLocation
The \l {Location::location} {Location.location} property is used to provide an interface between C++ and QML code. First a pointer to a
Location object must be obtained from C++, then use the \l {QObject::property()}{property()} and
\l {QObject::setProperty()}{setProperty()} functions to get and set the \c location property.
The following gets the QGeoLocation representing this object from C++:
\snippet cpp/cppqml.cpp Location get
The following sets the properties of this object based on a QGeoLocation object from C++:
\snippet cpp/cppqml.cpp Location set
*/
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