<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- qtsensors-backend.qdoc -->
<title>Creating a sensor plugin | Qt Sensors 5.9</title>
<link rel="stylesheet" type="text/css" href="style/offline-simple.css" />
<script type="text/javascript">
document.getElementsByTagName("link").item(0).setAttribute("href", "style/offline.css");
// loading style sheet breaks anchors that were jumped to before
// so force jumping to anchor again
setTimeout(function() {
var anchor = location.hash;
// need to jump to different anchor first (e.g. none)
location.hash = "#";
setTimeout(function() {
location.hash = anchor;
}, 0);
}, 0);
</script>
</head>
<body>
<div class="header" id="qtdocheader">
<div class="main">
<div class="main-rounded">
<div class="navigationbar">
<table><tr>
<td >Qt 5.9</td><td ><a href="qtsensors-index.html">Qt Sensors</a></td><td >Creating a sensor plugin</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
</tr></table>
</div>
</div>
<div class="content">
<div class="line">
<div class="content mainContent">
<div class="sidebar">
<div class="toc">
<h3><a name="toc">Contents</a></h3>
<ul>
<li class="level1"><a href="#how-a-sensor-plugin-is-loaded">How a Sensor Plugin is Loaded</a></li>
</ul>
</div>
<div class="sidebar-content" id="sidebar-content"></div></div>
<h1 class="title">Creating a sensor plugin</h1>
<span class="subtitle"></span>
<!-- $$$creating-a-sensor-plugin.html-description -->
<div class="descr"> <a name="details"></a>
<a name="how-a-sensor-plugin-is-loaded"></a>
<h2 id="how-a-sensor-plugin-is-loaded">How a Sensor Plugin is Loaded</h2>
<p>Since sensor backends are created on demand, the sensor plugin is loaded and asked to register the sensor backends it handles. The plugin should implement <a href="qsensorplugininterface.html#registerSensors">QSensorPluginInterface::registerSensors</a>() and call <a href="qsensormanager.html#registerBackend">QSensorManager::registerBackend</a>() to register available backends. Typically the plugin will also inherit from <a href="qsensorbackendfactory.html">QSensorBackendFactory</a> and implement <a href="qsensorbackendfactory.html#createBackend">QSensorBackendFactory::createBackend</a>() in order to instantiate backends it has registered.</p>
<p>The simplest plugin will have just once sensor backend although there is no reason that multiple sensor backends cannot be in a plugin.</p>
<p>An example follows.</p>
<pre class="cpp">
<span class="keyword">class</span> MyPluginClass : <span class="keyword">public</span> <span class="type">QObject</span><span class="operator">,</span> <span class="keyword">public</span> <span class="type"><a href="qsensorplugininterface.html">QSensorPluginInterface</a></span><span class="operator">,</span> <span class="keyword">public</span> <span class="type"><a href="qsensorbackendfactory.html">QSensorBackendFactory</a></span>
{
Q_OBJECT
<span class="comment">//Q_PLUGIN_METADATA(IID "com.qt-project.Qt.QSensorPluginInterface/1.0" FILE "plugin.json")</span>
Q_INTERFACES(<span class="type"><a href="qsensorplugininterface.html">QSensorPluginInterface</a></span>)
<span class="keyword">public</span>:
<span class="type">void</span> registerSensors()
{
<span class="type"><a href="qsensormanager.html">QSensorManager</a></span><span class="operator">::</span>registerBackend(<span class="type"><a href="qaccelerometer.html">QAccelerometer</a></span><span class="operator">::</span>type<span class="operator">,</span> MyBackend<span class="operator">::</span>id<span class="operator">,</span> <span class="keyword">this</span>);
}
<span class="type"><a href="qsensorbackend.html">QSensorBackend</a></span> <span class="operator">*</span>createBackend(<span class="type"><a href="qsensor.html">QSensor</a></span> <span class="operator">*</span>sensor)
{
<span class="keyword">if</span> (sensor<span class="operator">-</span><span class="operator">></span>identifier() <span class="operator">=</span><span class="operator">=</span> MyBackend<span class="operator">::</span>id)
<span class="keyword">return</span> <span class="keyword">new</span> MyBackend(sensor);
<span class="keyword">return</span> <span class="number">0</span>;
}
};
</pre>
</div>
<!-- @@@creating-a-sensor-plugin.html -->
</div>
</div>
</div>
</div>
</div>
<div class="footer">
<p>
<acronym title="Copyright">©</acronym> 2017 The Qt Company Ltd.
Documentation contributions included herein are the copyrights of
their respective owners.<br> The documentation provided herein is licensed under the terms of the <a href="http://www.gnu.org/licenses/fdl.html">GNU Free Documentation License version 1.3</a> as published by the Free Software Foundation.<br> Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property
of their respective owners. </p>
</div>
</body>
</html>
