/****************************************************************************
**
** 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.
** $QT_END_LICENSE$
**
****************************************************************************/

/*!
    \example weatherinfo
    \title Weather Info (C++/QML)

    \brief The Weather Info example shows how to use the user's current position
           to retrieve local content from a web service in a C++ plugin for QML.

    \ingroup qtpositioning-examples

    Key \l{Qt Positioning} classes used in this example:

    \list
    \li \l{QGeoPositionInfo}
    \li \l{QGeoPositionInfoSource}
    \endlist

    \image ../images/example-weatherinfo.png

    \include examples-run.qdocinc

    The key part of this example is the application's data model, contained
    in the WeatherData and AppModel classes. WeatherData represents the weather
    information taken from the HTTP service. It is a simple data class, but we
    give it Q_PROPERTies to expose it nicely to QML, later.

    \snippet weatherinfo/appmodel.h 0
    \snippet weatherinfo/appmodel.h 1

    AppModel models the state of the entire application. At startup, the
    application first begins by waiting for network connectivity. We do
    this using the QNetworkConfigurationManager and QNetworkSession family
    of C++ APIs.

    \snippet weatherinfo/appmodel.cpp 0
    \snippet weatherinfo/appmodel.cpp 1

    Once the network session is open, we proceed to get the platform's
    default position source using QGeoPositionInfo::createDefaultSource()

    \snippet weatherinfo/appmodel.cpp 2

    If no default source is available, we take a static position and fetch
    weather for that. If, however, we do have a position source, we connect
    its positionUpdated() signal to a slot on the AppModel and call
    startUpdates(), which begins regular updates of device position.

    When a position update is received, we use the longitude and latitude
    of the returned coordinate to retrieve the current "city" name for use
    in the weather lookup.

    \snippet weatherinfo/appmodel.cpp 3

    To inform the UI about this process, the cityChanged() signal is emitted
    when a new city is used, and the weatherChanged() signal whenever a
    weather update occurs.

    \snippet weatherinfo/appmodel.h 2
    \snippet weatherinfo/appmodel.h 3
    \snippet weatherinfo/appmodel.h 4

    We use a QQmlListProperty for the weather forecast information,
    which contains the next 4 days of forecast weather. This makes it
    easy to access from QML.

    To expose these to the QML UI layer, we use the qmlRegisterType()
    function. We call this once for each type we wish to register, before
    loading the actual QML file.

    \snippet weatherinfo/main.cpp 0
    \snippet weatherinfo/main.cpp 1

    Finally, in the actual QML, we instantiate the AppModel.

    \snippet weatherinfo/weatherinfo.qml 0
    \snippet weatherinfo/weatherinfo.qml 1
    \snippet weatherinfo/weatherinfo.qml 2

    Once instantiated like this, we can use its properties elsewhere in the
    QML document:

    \snippet weatherinfo/weatherinfo.qml 3
    \snippet weatherinfo/weatherinfo.qml 4

*/
