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<td >Qt 5.9</td><td ><a href="qtmultimedia-index.html">Qt Multimedia</a></td><td ><a href="qtmultimedia-modules.html">C++ Classes</a></td><td >QMetaDataReaderControl</td></tr></table><table class="buildversion"><tr>
<td id="buildversion" width="100%" align="right">Qt 5.9.4 Reference Documentation</td>
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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#public-functions">Public Functions</a></li>
<li class="level1"><a href="#signals">Signals</a></li>
<li class="level1"><a href="#protected-functions">Protected Functions</a></li>
<li class="level1"><a href="#macros">Macros</a></li>
<li class="level1"><a href="#details">Detailed Description</a></li>
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<h1 class="title">QMetaDataReaderControl Class</h1>
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<p>The <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a> class provides read access to the meta-data of a <a href="qmediaservice.html">QMediaService</a>'s media. <a href="#details">More...</a></p>
<!-- @@@QMetaDataReaderControl -->
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<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QMetaDataReaderControl></span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += multimedia</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="qmediacontrol.html">QMediaControl</a></td></tr></table></div><ul>
<li><a href="qmetadatareadercontrol-members.html">List of all members, including inherited members</a></li>
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<a name="public-functions"></a>
<h2 id="public-functions">Public Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#dtor.QMetaDataReaderControl">~QMetaDataReaderControl</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QStringList </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#availableMetaData">availableMetaData</a></b>() const = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual bool </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#isMetaDataAvailable">isMetaDataAvailable</a></b>() const = 0</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual QVariant </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#metaData">metaData</a></b>(const QString &<i>key</i>) const = 0</td></tr>
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<a name="signals"></a>
<h2 id="signals">Signals</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#metaDataAvailableChanged">metaDataAvailableChanged</a></b>(bool <i>available</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#metaDataChanged">metaDataChanged</a></b>()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#metaDataChanged-1">metaDataChanged</a></b>(const QString &<i>key</i>, const QVariant &<i>value</i>)</td></tr>
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<a name="protected-functions"></a>
<h2 id="protected-functions">Protected Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#QMetaDataReaderControl">QMetaDataReaderControl</a></b>(QObject *<i>parent</i> = Q_NULLPTR)</td></tr>
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<a name="macros"></a>
<h2 id="macros">Macros</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qmetadatareadercontrol.html#QMetaDataReaderControl_iid">QMetaDataReaderControl_iid</a></b></td></tr>
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<a name="details"></a>
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<h2 id="details">Detailed Description</h2>
<p>The <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a> class provides read access to the meta-data of a <a href="qmediaservice.html">QMediaService</a>'s media.</p>
<p>If a <a href="qmediaservice.html">QMediaService</a> can provide read or write access to the meta-data of its current media it will implement <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a>. This control provides functions for both retrieving and setting meta-data values. Meta-data may be addressed by the keys defined in the <a href="qmediametadata.html">QMediaMetaData</a> namespace.</p>
<p>The functionality provided by this control is exposed to application code by the meta-data members of <a href="qmediaobject.html">QMediaObject</a>, and so meta-data access is potentially available in any of the media object classes. Any media service may implement <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a>.</p>
<p>The interface name of <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a> is <code>org.qt-project.qt.metadatareadercontrol/5.0</code> as defined in <a href="qmetadatareadercontrol.html#QMetaDataReaderControl_iid">QMetaDataReaderControl_iid</a>.</p>
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<p><b>See also </b><a href="qmediaservice.html#requestControl-1">QMediaService::requestControl</a>() and <a href="qmediaobject.html">QMediaObject</a>.</p>
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<h2>Member Function Documentation</h2>
<!-- $$$QMetaDataReaderControl[overload1]$$$QMetaDataReaderControlQObject* -->
<h3 class="fn" id="QMetaDataReaderControl"><a name="QMetaDataReaderControl"></a><code>[protected] </code>QMetaDataReaderControl::<span class="name">QMetaDataReaderControl</span>(<span class="type">QObject</span> *<i>parent</i> = Q_NULLPTR)</h3>
<p>Construct a <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a> with <i>parent</i>. This class is meant as a base class for service specific meta data providers so this constructor is protected.</p>
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<!-- $$$~QMetaDataReaderControl[overload1]$$$~QMetaDataReaderControl -->
<h3 class="fn" id="dtor.QMetaDataReaderControl"><a name="dtor.QMetaDataReaderControl"></a>QMetaDataReaderControl::<span class="name">~QMetaDataReaderControl</span>()</h3>
<p>Destroy the meta-data object.</p>
<!-- @@@~QMetaDataReaderControl -->
<!-- $$$availableMetaData[overload1]$$$availableMetaData -->
<h3 class="fn" id="availableMetaData"><a name="availableMetaData"></a><code>[pure virtual] </code><span class="type">QStringList</span> QMetaDataReaderControl::<span class="name">availableMetaData</span>() const</h3>
<p>Returns a list of keys there is meta-data available for.</p>
<!-- @@@availableMetaData -->
<!-- $$$isMetaDataAvailable[overload1]$$$isMetaDataAvailable -->
<h3 class="fn" id="isMetaDataAvailable"><a name="isMetaDataAvailable"></a><code>[pure virtual] </code><span class="type">bool</span> QMetaDataReaderControl::<span class="name">isMetaDataAvailable</span>() const</h3>
<p>Identifies if meta-data is available from a media service.</p>
<p>Returns true if the meta-data is available and false otherwise.</p>
<!-- @@@isMetaDataAvailable -->
<!-- $$$metaData[overload1]$$$metaDataconstQString& -->
<h3 class="fn" id="metaData"><a name="metaData"></a><code>[pure virtual] </code><span class="type">QVariant</span> QMetaDataReaderControl::<span class="name">metaData</span>(const <span class="type">QString</span> &<i>key</i>) const</h3>
<p>Returns the meta-data for the given <i>key</i>.</p>
<!-- @@@metaData -->
<!-- $$$metaDataAvailableChanged[overload1]$$$metaDataAvailableChangedbool -->
<h3 class="fn" id="metaDataAvailableChanged"><a name="metaDataAvailableChanged"></a><code>[signal] </code><span class="type">void</span> QMetaDataReaderControl::<span class="name">metaDataAvailableChanged</span>(<span class="type">bool</span> <i>available</i>)</h3>
<p>Signal the availability of meta-data has changed, <i>available</i> will be true if the multimedia object has meta-data.</p>
<!-- @@@metaDataAvailableChanged -->
<!-- $$$metaDataChanged[overload1]$$$metaDataChanged -->
<h3 class="fn" id="metaDataChanged"><a name="metaDataChanged"></a><code>[signal] </code><span class="type">void</span> QMetaDataReaderControl::<span class="name">metaDataChanged</span>()</h3>
<p>Signal the changes of meta-data.</p>
<p>If multiple meta-data elements are changed, metaDataChanged(const QString &key, const QVariant &value) signal is emitted for each of them with metaDataChanged() changed emitted once.</p>
<p><b>Note:</b> Signal <i>metaDataChanged</i> is overloaded in this class. To connect to this one using the function pointer syntax, you must specify the signal type in a static cast, as shown in this example:<pre class="cpp">
connect(metaDataReaderControl<span class="operator">,</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">void</span>(<span class="type"><a href="qmetadatareadercontrol.html#QMetaDataReaderControl">QMetaDataReaderControl</a></span><span class="operator">::</span><span class="operator">*</span>)()<span class="operator">></span>(<span class="operator">&</span><span class="type"><a href="qmetadatareadercontrol.html#QMetaDataReaderControl">QMetaDataReaderControl</a></span><span class="operator">::</span>metaDataChanged)<span class="operator">,</span>
<span class="operator">[</span><span class="operator">=</span><span class="operator">]</span>(){ <span class="comment">/* ... */</span> });
</pre>
<!-- @@@metaDataChanged -->
<!-- $$$metaDataChanged$$$metaDataChangedconstQString&constQVariant& -->
<h3 class="fn" id="metaDataChanged-1"><a name="metaDataChanged-1"></a><code>[signal] </code><span class="type">void</span> QMetaDataReaderControl::<span class="name">metaDataChanged</span>(const <span class="type">QString</span> &<i>key</i>, const <span class="type">QVariant</span> &<i>value</i>)</h3>
<p>Signal the changes of one meta-data element <i>value</i> with the given <i>key</i>.</p>
<p><b>Note:</b> Signal <i>metaDataChanged</i> is overloaded in this class. To connect to this one using the function pointer syntax, you must specify the signal type in a static cast, as shown in this example:<pre class="cpp">
connect(metaDataReaderControl<span class="operator">,</span> <span class="keyword">static_cast</span><span class="operator"><</span><span class="type">void</span>(<span class="type"><a href="qmetadatareadercontrol.html#QMetaDataReaderControl">QMetaDataReaderControl</a></span><span class="operator">::</span><span class="operator">*</span>)(<span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span><span class="operator">,</span> <span class="keyword">const</span> <span class="type">QVariant</span> <span class="operator">&</span>)<span class="operator">></span>(<span class="operator">&</span><span class="type"><a href="qmetadatareadercontrol.html#QMetaDataReaderControl">QMetaDataReaderControl</a></span><span class="operator">::</span>metaDataChanged)<span class="operator">,</span>
<span class="operator">[</span><span class="operator">=</span><span class="operator">]</span>(<span class="keyword">const</span> <span class="type">QString</span> <span class="operator">&</span>key<span class="operator">,</span> <span class="keyword">const</span> <span class="type">QVariant</span> <span class="operator">&</span>value){ <span class="comment">/* ... */</span> });
</pre>
<!-- @@@metaDataChanged -->
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<div class="macros">
<h2>Macro Documentation</h2>
<!-- $$$QMetaDataReaderControl_iid[overload1]$$$QMetaDataReaderControl_iid -->
<h3 class="fn" id="QMetaDataReaderControl_iid"><a name="QMetaDataReaderControl_iid"></a><span class="name">QMetaDataReaderControl_iid</span></h3>
<p><code>org.qt-project.qt.metadatareadercontrol/5.0</code></p>
<p>Defines the interface name of the <a href="qmetadatareadercontrol.html">QMetaDataReaderControl</a> class.</p>
<!-- @@@QMetaDataReaderControl_iid -->
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