<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE html> <html lang="en"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <!-- qsensor.cpp --> <title>QSensorReading Class | Qt Sensors 5.11</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 ><a href="../qtdoc/index.html">Qt 5.11</a></td><td ><a href="qtsensors-index.html">Qt Sensors</a></td><td ><a href="qtsensors-module.html">C++ Classes</a></td><td >QSensorReading</td></tr></table><table class="buildversion"><tr> <td id="buildversion" width="100%" align="right">Qt 5.11.2 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="#properties">Properties</a></li> <li class="level1"><a href="#public-functions">Public Functions</a></li> <li class="level1"><a href="#macros">Macros</a></li> <li class="level1"><a href="#details">Detailed Description</a></li> </ul> </div> <div class="sidebar-content" id="sidebar-content"></div></div> <h1 class="title">QSensorReading Class</h1> <!-- $$$QSensorReading-brief --> <p>The <a href="qsensorreading.html">QSensorReading</a> class holds the readings from the sensor. <a href="#details">More...</a></p> <!-- @@@QSensorReading --> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QSensorReading></span> </td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += sensors</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="../qtcore/qobject.html">QObject</a></td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherited By:</td><td class="memItemRight bottomAlign"> <p><a href="qaccelerometerreading.html">QAccelerometerReading</a>, <a href="qaltimeterreading.html">QAltimeterReading</a>, <a href="qambientlightreading.html">QAmbientLightReading</a>, <a href="qambienttemperaturereading.html">QAmbientTemperatureReading</a>, <a href="qcompassreading.html">QCompassReading</a>, <a href="qdistancereading.html">QDistanceReading</a>, <a href="qgyroscopereading.html">QGyroscopeReading</a>, <a href="qholsterreading.html">QHolsterReading</a>, <a href="qhumidityreading.html">QHumidityReading</a>, <a href="qirproximityreading.html">QIRProximityReading</a>, <a href="qlidreading.html">QLidReading</a>, <a href="qlightreading.html">QLightReading</a>, <a href="qmagnetometerreading.html">QMagnetometerReading</a>, <a href="qorientationreading.html">QOrientationReading</a>, <a href="qpressurereading.html">QPressureReading</a>, <a href="qproximityreading.html">QProximityReading</a>, <a href="qrotationreading.html">QRotationReading</a>, <a href="qtapreading.html">QTapReading</a>, and <a href="qtiltreading.html">QTiltReading</a></p> </td></tr></table></div><ul> <li><a href="qsensorreading-members.html">List of all members, including inherited members</a></li> </ul> <a name="properties"></a> <h2 id="properties">Properties</h2> <ul> <li class="fn"><b><a href="qsensorreading.html#timestamp-prop">timestamp</a></b> : const quint64</li> </ul> <ul> <li class="fn">1 property inherited from <a href="../qtcore/qobject.html#properties">QObject</a></li> </ul> <a name="public-functions"></a> <h2 id="public-functions">Public Functions</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#setTimestamp">setTimestamp</a></b>(quint64 <i>timestamp</i>)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> quint64 </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#timestamp">timestamp</a></b>() const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> QVariant </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#value">value</a></b>(int <i>index</i>) const</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> int </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#valueCount">valueCount</a></b>() const</td></tr> </table></div> <ul> <li class="fn">34 public functions inherited from <a href="../qtcore/qobject.html#public-functions">QObject</a></li> </ul> <a name="macros"></a> <h2 id="macros">Macros</h2> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#DECLARE_READING">DECLARE_READING</a></b>(<i>classname</i>)</td></tr> <tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qsensorreading.html#IMPLEMENT_READING">IMPLEMENT_READING</a></b>(<i>classname</i>)</td></tr> </table></div> <h3>Additional Inherited Members</h3> <ul> <li class="fn">1 public slot inherited from <a href="../qtcore/qobject.html#public-slots">QObject</a></li> <li class="fn">2 signals inherited from <a href="../qtcore/qobject.html#signals">QObject</a></li> <li class="fn">1 public variable inherited from <a href="../qtcore/qobject.html#public-variables">QObject</a></li> <li class="fn">10 static public members inherited from <a href="../qtcore/qobject.html#static-public-members">QObject</a></li> <li class="fn">9 protected functions inherited from <a href="../qtcore/qobject.html#protected-functions">QObject</a></li> <li class="fn">2 protected variables inherited from <a href="../qtcore/qobject.html#protected-variables">QObject</a></li> </ul> <a name="details"></a> <!-- $$$QSensorReading-description --> <div class="descr"> <h2 id="details">Detailed Description</h2> <p>The <a href="qsensorreading.html">QSensorReading</a> class holds the readings from the sensor.</p> <p>Note that <a href="qsensorreading.html">QSensorReading</a> is not particularly useful by itself. The interesting data for each sensor is defined in a sub-class of <a href="qsensorreading.html">QSensorReading</a>.</p> </div> <!-- @@@QSensorReading --> <div class="prop"> <h2>Property Documentation</h2> <!-- $$$timestamp-prop$$$timestamp --> <h3 class="fn" id="timestamp-prop"><a name="timestamp-prop"></a><span class="name">timestamp</span> : const <span class="type"><a href="../qtcore/qtglobal.html#quint64-typedef">quint64</a></span></h3> <p>This property holds the timestamp of the reading.</p> <p>Timestamps values are microseconds since a fixed point. You can use timestamps to see how far apart two sensor readings are.</p> <p>Note that sensor timestamps from different sensors may not be directly comparable (as they may choose different fixed points for their reference).</p> <p><b>Note that some platforms do not deliver timestamps correctly</b>. Applications should be prepared for occasional issues that cause timestamps to jump backwards.</p> <p><b>Access functions:</b></p> <div class="table"><table class="alignedsummary"> <tr><td class="memItemLeft topAlign rightAlign"> quint64 </td><td class="memItemRight bottomAlign"><span class="name"><b><a href="qsensorreading.html#timestamp">timestamp</a></b></span>() const</td></tr> </table></div> <!-- @@@timestamp --> </div> <div class="func"> <h2>Member Function Documentation</h2> <!-- $$$setTimestamp[overload1]$$$setTimestampquint64 --> <h3 class="fn" id="setTimestamp"><a name="setTimestamp"></a><span class="type">void</span> QSensorReading::<span class="name">setTimestamp</span>(<span class="type"><a href="../qtcore/qtglobal.html#quint64-typedef">quint64</a></span> <i>timestamp</i>)</h3> <p>Sets the <i>timestamp</i> of the reading.</p> <p><b>See also </b><a href="qsensorreading.html#timestamp">timestamp</a>().</p> <!-- @@@setTimestamp --> <!-- $$$timestamp --> <h3 class="fn" id="timestamp"><a name="timestamp"></a><span class="type"><a href="../qtcore/qtglobal.html#quint64-typedef">quint64</a></span> QSensorReading::<span class="name">timestamp</span>() const</h3> <p>Returns the timestamp of the reading.</p> <p><b>Note:</b> Getter function for property <a href="qsensorreading.html#timestamp-prop">timestamp</a>. </p><p><b>See also </b><a href="qsensorreading.html#setTimestamp">setTimestamp</a>().</p> <!-- @@@timestamp --> <!-- $$$value[overload1]$$$valueint --> <h3 class="fn" id="value"><a name="value"></a><span class="type"><a href="../qtcore/qvariant.html">QVariant</a></span> QSensorReading::<span class="name">value</span>(<span class="type">int</span> <i>index</i>) const</h3> <p>Returns the value of the property at <i>index</i>.</p> <p>Note that this function is slower than calling the data function directly.</p> <p>Here is an example of getting a property via the different mechanisms available.</p> <p>Accessing directly provides the best performance but requires compile-time knowledge of the data you are accessing.</p> <pre class="cpp"> <span class="type"><a href="qaccelerometerreading.html">QAccelerometerReading</a></span> <span class="operator">*</span>reading <span class="operator">=</span> <span class="operator">.</span><span class="operator">.</span><span class="operator">.</span>; <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> x <span class="operator">=</span> reading<span class="operator">-</span><span class="operator">></span>x(); </pre> <p>You can also access a property by name. To do this you must call <a href="../qtcore/qobject.html#property">QObject::property</a>().</p> <pre class="cpp"> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> x <span class="operator">=</span> reading<span class="operator">-</span><span class="operator">></span>property(<span class="string">"x"</span>)<span class="operator">.</span>value<span class="operator"><</span><span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">></span>(); </pre> <p>Finally, you can access values via numeric index.</p> <pre class="cpp"> <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> x <span class="operator">=</span> reading<span class="operator">-</span><span class="operator">></span>value(<span class="number">0</span>)<span class="operator">.</span>value<span class="operator"><</span><span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span><span class="operator">></span>(); </pre> <p>Note that value() can only access properties declared with <a href="../qtcore/qobject.html#Q_PROPERTY">Q_PROPERTY</a>() in sub-classes of <a href="qsensorreading.html">QSensorReading</a>.</p> <p><b>See also </b><a href="qsensorreading.html#valueCount">valueCount</a>() and <a href="../qtcore/qobject.html#property">QObject::property</a>().</p> <!-- @@@value --> <!-- $$$valueCount[overload1]$$$valueCount --> <h3 class="fn" id="valueCount"><a name="valueCount"></a><span class="type">int</span> QSensorReading::<span class="name">valueCount</span>() const</h3> <p>Returns the number of extra properties that the reading has.</p> <p>Note that this does not count properties declared in <a href="qsensorreading.html">QSensorReading</a>.</p> <p>As an example, this returns 3 for <a href="qaccelerometerreading.html">QAccelerometerReading</a> because there are 3 properties defined in that class.</p> <!-- @@@valueCount --> </div> <div class="macros"> <h2>Macro Documentation</h2> <!-- $$$DECLARE_READING[overload1]$$$DECLARE_READING --> <h3 class="fn" id="DECLARE_READING"><a name="DECLARE_READING"></a><span class="name">DECLARE_READING</span>(<i>classname</i>)</h3> <p>The DECLARE_READING macro adds some required methods to a reading class.</p> <p>This macro should be used for all reading classes. Pass the <i>classname</i> of your reading class.</p> <pre class="cpp"> <span class="keyword">class</span> MyReading : <span class="keyword">public</span> <span class="type"><a href="qsensorreading.html">QSensorReading</a></span> { Q_OBJECT Q_PROPERTY(<span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> myprop READ myprop) DECLARE_READING(MyReading) <span class="keyword">public</span>: <span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> myprop() <span class="keyword">const</span>; vod setMyprop(<span class="type"><a href="../qtcore/qtglobal.html#qreal-typedef">qreal</a></span> myprop); }; </pre> <p><b>See also </b><a href="qsensorreading.html#IMPLEMENT_READING">IMPLEMENT_READING</a>().</p> <!-- @@@DECLARE_READING --> <!-- $$$IMPLEMENT_READING[overload1]$$$IMPLEMENT_READING --> <h3 class="fn" id="IMPLEMENT_READING"><a name="IMPLEMENT_READING"></a><span class="name">IMPLEMENT_READING</span>(<i>classname</i>)</h3> <p>The IMPLEMENT_READING macro implements the required methods for a reading class.</p> <p>This macro should be used for all reading classes. It should be placed into a single compilation unit (source file), not into a header file. Pass the <i>classname</i> of your reading class.</p> <pre class="cpp"> IMPLEMENT_READING(MyReading) </pre> <p><b>See also </b><a href="qsensorreading.html#DECLARE_READING">DECLARE_READING</a>().</p> <!-- @@@IMPLEMENT_READING --> </div> </div> </div> </div> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2018 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>