<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<!-- qwebchannel.cpp -->
  <title>QWebChannel Class | Qt WebChannel 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="qtwebchannel-index.html">Qt WebChannel</a></td><td ><a href="qtwebchannel-module.html">C++ Classes</a></td><td >QWebChannel</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="#public-slots">Public Slots</a></li>
<li class="level1"><a href="#signals">Signals</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">QWebChannel Class</h1>
<!-- $$$QWebChannel-brief -->
<p>Exposes QObjects to remote HTML clients. <a href="#details">More...</a></p>
<!-- @@@QWebChannel -->
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign">   <span class="preprocessor">#include &lt;QWebChannel&gt;</span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += webchannel</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign">  Qt 5.4</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="../qtcore/qobject.html">QObject</a></td></tr></table></div><ul>
<li><a href="qwebchannel-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="qwebchannel.html#blockUpdates-prop">blockUpdates</a></b> : bool</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"> </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#QWebChannel">QWebChannel</a></b>(QObject *<i>parent</i> = Q_NULLPTR)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#dtor.QWebChannel">~QWebChannel</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> bool </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#blockUpdates-prop">blockUpdates</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#deregisterObject">deregisterObject</a></b>(QObject *<i>object</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#registerObject">registerObject</a></b>(const QString &amp;<i>id</i>, QObject *<i>object</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#registerObjects">registerObjects</a></b>(const QHash&lt;QString, QObject *&gt; &amp;<i>objects</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QHash&lt;QString, QObject *&gt; </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#registeredObjects">registeredObjects</a></b>() const</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#blockUpdates-prop">setBlockUpdates</a></b>(bool <i>block</i>)</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="public-slots"></a>
<h2 id="public-slots">Public Slots</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#connectTo">connectTo</a></b>(QWebChannelAbstractTransport *<i>transport</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#disconnectFrom">disconnectFrom</a></b>(QWebChannelAbstractTransport *<i>transport</i>)</td></tr>
</table></div>
<ul>
<li class="fn">1 public slot inherited from <a href="../qtcore/qobject.html#public-slots">QObject</a></li>
</ul>
<a name="signals"></a>
<h2 id="signals">Signals</h2>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qwebchannel.html#blockUpdates-prop">blockUpdatesChanged</a></b>(bool <i>block</i>)</td></tr>
</table></div>
<ul>
<li class="fn">2 signals inherited from <a href="../qtcore/qobject.html#signals">QObject</a></li>
</ul>
<h3>Additional Inherited Members</h3>
<ul>
<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>
<!-- $$$QWebChannel-description -->
<div class="descr">
<h2 id="details">Detailed Description</h2>
<p>Exposes QObjects to remote HTML clients.</p>
<p>The <a href="qwebchannel.html">QWebChannel</a> fills the gap between C++ applications and HTML/JavaScript applications. By publishing a <a href="../qtcore/qobject.html">QObject</a> derived object to a <a href="qwebchannel.html">QWebChannel</a> and using the <a href="qtwebchannel-javascript.html">qwebchannel.js</a> on the HTML side, one can transparently access properties and public slots and methods of the <a href="../qtcore/qobject.html">QObject</a>. No manual message passing and serialization of data is required, property updates and signal emission on the C++ side get automatically transmitted to the potentially remotely running HTML clients. On the client side, a JavaScript object will be created for any published C++ <a href="../qtcore/qobject.html">QObject</a>. It mirrors the C++ object's API and thus is intuitively useable.</p>
<p>The C++ <a href="qwebchannel.html">QWebChannel</a> API makes it possible to talk to any HTML client, which could run on a local or even remote machine. The only limitation is that the HTML client supports the JavaScript features used by <code>qwebchannel.js</code>. As such, one can interact with basically any modern HTML browser or standalone JavaScript runtime, such as node.js.</p>
<p>There also exists a declarative <a href="qtwebchannel-qmlmodule.html">WebChannel API</a>.</p>
</div>
<p><b>See also </b><a href="qtwebchannel-standalone-example.html">Qt WebChannel Standalone Example</a> and <a href="qtwebchannel-javascript.html">JavaScript API</a>.</p>
<!-- @@@QWebChannel -->
<div class="prop">
<h2>Property Documentation</h2>
<!-- $$$blockUpdates-prop$$$blockUpdates$$$setBlockUpdatesbool$$$blockUpdatesChangedbool -->
<h3 class="fn" id="blockUpdates-prop"><a name="blockUpdates-prop"></a><span class="name">blockUpdates</span> : <span class="type">bool</span></h3>
<p>When set to true, updates are blocked and remote clients will not be notified about property changes.</p>
<p>The changes are recorded and sent to the clients once updates become unblocked again by setting this property to false. By default, updates are not blocked.</p>
<p><b>Access functions:</b></p>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft topAlign rightAlign"> bool </td><td class="memItemRight bottomAlign"><span class="name"><b>blockUpdates</b></span>() const</td></tr>
<tr><td class="memItemLeft topAlign rightAlign"> void </td><td class="memItemRight bottomAlign"><span class="name"><b>setBlockUpdates</b></span>(bool <i>block</i>)</td></tr>
</table></div>
<p><b>Notifier signal:</b></p>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft topAlign rightAlign"> void </td><td class="memItemRight bottomAlign"><span class="name"><b>blockUpdatesChanged</b></span>(bool <i>block</i>)</td></tr>
</table></div>
<!-- @@@blockUpdates -->
</div>
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QWebChannel[overload1]$$$QWebChannelQObject* -->
<h3 class="fn" id="QWebChannel"><a name="QWebChannel"></a>QWebChannel::<span class="name">QWebChannel</span>(<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>parent</i> = Q_NULLPTR)</h3>
<p>Constructs the <a href="qwebchannel.html">QWebChannel</a> object with the given <i>parent</i>.</p>
<p>Note that a <a href="qwebchannel.html">QWebChannel</a> is only fully operational once you connect it to a <a href="qwebchannelabstracttransport.html">QWebChannelAbstractTransport</a>. The HTML clients also need to be setup appropriately using <a href="qtwebchannel-javascript.html"><code>qwebchannel.js</code></a>.</p>
<!-- @@@QWebChannel -->
<!-- $$$~QWebChannel[overload1]$$$~QWebChannel -->
<h3 class="fn" id="dtor.QWebChannel"><a name="dtor.QWebChannel"></a><code>[virtual] </code>QWebChannel::<span class="name">~QWebChannel</span>()</h3>
<p>Destroys the <a href="qwebchannel.html">QWebChannel</a>.</p>
<!-- @@@~QWebChannel -->
<!-- $$$connectTo[overload1]$$$connectToQWebChannelAbstractTransport* -->
<h3 class="fn" id="connectTo"><a name="connectTo"></a><code>[slot] </code><span class="type">void</span> QWebChannel::<span class="name">connectTo</span>(<span class="type"><a href="qwebchannelabstracttransport.html">QWebChannelAbstractTransport</a></span> *<i>transport</i>)</h3>
<p>Connects the <a href="qwebchannel.html">QWebChannel</a> to the given <i>transport</i> object.</p>
<p>The transport object then handles the communication between the C++ application and a remote HTML client.</p>
<p><b>See also </b><a href="qwebchannelabstracttransport.html">QWebChannelAbstractTransport</a> and <a href="qwebchannel.html#disconnectFrom">QWebChannel::disconnectFrom</a>().</p>
<!-- @@@connectTo -->
<!-- $$$deregisterObject[overload1]$$$deregisterObjectQObject* -->
<h3 class="fn" id="deregisterObject"><a name="deregisterObject"></a><span class="type">void</span> QWebChannel::<span class="name">deregisterObject</span>(<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>object</i>)</h3>
<p>Deregisters the given <i>object</i> from the <a href="qwebchannel.html">QWebChannel</a>.</p>
<p>Remote clients will receive a <code>destroyed</code> signal for the given object.</p>
<p><b>Note: </b>This function can be invoked via the meta-object system and from QML. See <a href="../qtcore/qobject.html#Q_INVOKABLE">Q_INVOKABLE</a>.</p>
<p><b>See also </b><a href="qwebchannel.html#registerObjects">QWebChannel::registerObjects</a>(), <a href="qwebchannel.html#registerObject">QWebChannel::registerObject</a>(), and <a href="qwebchannel.html#registeredObjects">QWebChannel::registeredObjects</a>().</p>
<!-- @@@deregisterObject -->
<!-- $$$disconnectFrom[overload1]$$$disconnectFromQWebChannelAbstractTransport* -->
<h3 class="fn" id="disconnectFrom"><a name="disconnectFrom"></a><code>[slot] </code><span class="type">void</span> QWebChannel::<span class="name">disconnectFrom</span>(<span class="type"><a href="qwebchannelabstracttransport.html">QWebChannelAbstractTransport</a></span> *<i>transport</i>)</h3>
<p>Disconnects the <a href="qwebchannel.html">QWebChannel</a> from the <i>transport</i> object.</p>
<p><b>See also </b><a href="qwebchannel.html#connectTo">QWebChannel::connectTo</a>().</p>
<!-- @@@disconnectFrom -->
<!-- $$$registerObject[overload1]$$$registerObjectconstQString&QObject* -->
<h3 class="fn" id="registerObject"><a name="registerObject"></a><span class="type">void</span> QWebChannel::<span class="name">registerObject</span>(const <span class="type"><a href="../qtcore/qstring.html">QString</a></span> &amp;<i>id</i>, <span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>object</i>)</h3>
<p>Registers a single object to the <a href="qwebchannel.html">QWebChannel</a>.</p>
<p>The properties, signals and public methods of the <i>object</i> are published to the remote clients. There, an object with the identifier <i>id</i> is then constructed.</p>
<p><b>Note: </b>A current limitation is that objects must be registered before any client is initialized.</p><p><b>Note: </b>This function can be invoked via the meta-object system and from QML. See <a href="../qtcore/qobject.html#Q_INVOKABLE">Q_INVOKABLE</a>.</p>
<p><b>See also </b><a href="qwebchannel.html#registerObjects">QWebChannel::registerObjects</a>(), <a href="qwebchannel.html#deregisterObject">QWebChannel::deregisterObject</a>(), and <a href="qwebchannel.html#registeredObjects">QWebChannel::registeredObjects</a>().</p>
<!-- @@@registerObject -->
<!-- $$$registerObjects[overload1]$$$registerObjectsconstQHash<QString,QObject*>& -->
<h3 class="fn" id="registerObjects"><a name="registerObjects"></a><span class="type">void</span> QWebChannel::<span class="name">registerObjects</span>(const <span class="type"><a href="../qtcore/qhash.html">QHash</a></span>&lt;<span class="type"><a href="../qtcore/qstring.html">QString</a></span>, <span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *&gt; &amp;<i>objects</i>)</h3>
<p>Registers a group of objects to the <a href="qwebchannel.html">QWebChannel</a>.</p>
<p>The properties, signals and public invokable methods of the objects are published to the remote clients. There, an object with the identifier used as key in the <i>objects</i> map is then constructed.</p>
<p><b>Note: </b>A current limitation is that objects must be registered before any client is initialized.</p><p><b>See also </b><a href="qwebchannel.html#registerObject">QWebChannel::registerObject</a>(), <a href="qwebchannel.html#deregisterObject">QWebChannel::deregisterObject</a>(), and <a href="qwebchannel.html#registeredObjects">QWebChannel::registeredObjects</a>().</p>
<!-- @@@registerObjects -->
<!-- $$$registeredObjects[overload1]$$$registeredObjects -->
<h3 class="fn" id="registeredObjects"><a name="registeredObjects"></a><span class="type"><a href="../qtcore/qhash.html">QHash</a></span>&lt;<span class="type"><a href="../qtcore/qstring.html">QString</a></span>, <span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *&gt; QWebChannel::<span class="name">registeredObjects</span>() const</h3>
<p>Returns the map of registered objects that are published to remote clients.</p>
<p><b>See also </b><a href="qwebchannel.html#registerObjects">QWebChannel::registerObjects</a>(), <a href="qwebchannel.html#registerObject">QWebChannel::registerObject</a>(), and <a href="qwebchannel.html#deregisterObject">QWebChannel::deregisterObject</a>().</p>
<!-- @@@registeredObjects -->
</div>
        </div>
       </div>
   </div>
   </div>
</div>
<div class="footer">
   <p>
   <acronym title="Copyright">&copy;</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>