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<li class="level1"><a href="#public-functions">Public Functions</a></li>
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<h1 class="title">QQmlApplicationEngine Class</h1>
<!-- $$$QQmlApplicationEngine-brief -->
<p>QQmlApplicationEngine provides a convenient way to load an application from a single QML file. <a href="#details">More...</a></p>
<!-- @@@QQmlApplicationEngine -->
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<tr><td class="memItemLeft rightAlign topAlign"> Header:</td><td class="memItemRight bottomAlign"> <span class="preprocessor">#include <QQmlApplicationEngine></span>
</td></tr><tr><td class="memItemLeft rightAlign topAlign"> qmake:</td><td class="memItemRight bottomAlign"> QT += qml</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Since:</td><td class="memItemRight bottomAlign"> Qt 5.1</td></tr><tr><td class="memItemLeft rightAlign topAlign"> Inherits:</td><td class="memItemRight bottomAlign"> <a href="qqmlengine.html">QQmlEngine</a></td></tr></table></div><p>This class was introduced in Qt 5.1.</p>
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<li><a href="qqmlapplicationengine-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>
<div class="table"><table class="alignedsummary">
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#QQmlApplicationEngine-2">QQmlApplicationEngine</a></b>(const QString &<i>filePath</i>, QObject *<i>parent</i> = nullptr)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#QQmlApplicationEngine-1">QQmlApplicationEngine</a></b>(const QUrl &<i>url</i>, QObject *<i>parent</i> = nullptr)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#QQmlApplicationEngine">QQmlApplicationEngine</a></b>(QObject *<i>parent</i> = nullptr)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#dtor.QQmlApplicationEngine">~QQmlApplicationEngine</a></b>() override</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> QList<QObject *> </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#rootObjects">rootObjects</a></b>() const</td></tr>
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<a name="public-slots"></a>
<h2 id="public-slots">Public Slots</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#load-1">load</a></b>(const QString &<i>filePath</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#load">load</a></b>(const QUrl &<i>url</i>)</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#loadData">loadData</a></b>(const QByteArray &<i>data</i>, const QUrl &<i>url</i> = QUrl())</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> void </td><td class="memItemRight bottomAlign"><b><a href="qqmlapplicationengine.html#setInitialProperties">setInitialProperties</a></b>(const QVariantMap &<i>initialProperties</i>)</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="qqmlapplicationengine.html#objectCreated">objectCreated</a></b>(QObject *<i>object</i>, const QUrl &<i>url</i>)</td></tr>
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<a name="details"></a>
<!-- $$$QQmlApplicationEngine-description -->
<div class="descr">
<h2 id="details">Detailed Description</h2>
<p>This class combines a <a href="qqmlengine.html">QQmlEngine</a> and <a href="qqmlcomponent.html">QQmlComponent</a> to provide a convenient way to load a single QML file. It also exposes some central application functionality to QML, which a C++/QML hybrid application would normally control from C++.</p>
<p>It can be used like so:</p>
<pre class="cpp">
<span class="preprocessor">#include <QGuiApplication></span>
<span class="preprocessor">#include <QQmlApplicationEngine></span>
<span class="type">int</span> main(<span class="type">int</span> argc<span class="operator">,</span> <span class="type">char</span> <span class="operator">*</span>argv<span class="operator">[</span><span class="operator">]</span>)
{
<span class="type"><a href="../qtgui/qguiapplication.html">QGuiApplication</a></span> app(argc<span class="operator">,</span> argv);
<span class="type"><a href="qqmlapplicationengine.html#QQmlApplicationEngine">QQmlApplicationEngine</a></span> engine(<span class="string">"main.qml"</span>);
<span class="keyword">return</span> app<span class="operator">.</span>exec();
}
</pre>
<p>Unlike <a href="../qtquick/qquickview.html">QQuickView</a>, QQmlApplicationEngine does not automatically create a root window. If you are using visual items from Qt Quick, you will need to place them inside of a <a href="../qtquick/qml-qtquick-window-window.html">Window</a>.</p>
<p>You can also use <a href="../qtcore/qcoreapplication.html">QCoreApplication</a> with QQmlApplicationEngine, if you are not using any QML modules which require a <a href="../qtgui/qguiapplication.html">QGuiApplication</a> (such as <code>QtQuick</code>).</p>
<p>List of configuration changes from a default <a href="qqmlengine.html">QQmlEngine</a>:</p>
<ul>
<li>Connecting Qt.<a href="qqmlengine.html#quit">quit</a>() to <a href="../qtcore/qcoreapplication.html#quit">QCoreApplication::quit</a>()</li>
<li>Automatically loads translation files from an i18n directory adjacent to the main QML file.<ul>
<li>Translation files must have "<a href="../qtdoc/whatsnew53.html#qml">qml_</a>" prefix e.g. qml_ja_JP.qm.</li>
</ul>
</li>
<li>Translations are reloaded when the <code>QJSEngine::uiLanguage</code> / <code>Qt.uiLanguage</code> property is changed.</li>
<li>Automatically sets an incubation controller if the scene contains a <a href="../qtquick/qquickwindow.html">QQuickWindow</a>.</li>
<li>Automatically sets a <code>QQmlFileSelector</code> as the url interceptor, applying file selectors to all QML files and assets.</li>
</ul>
<p>The engine behavior can be further tweaked by using the inherited methods from <a href="qqmlengine.html">QQmlEngine</a>.</p>
</div>
<!-- @@@QQmlApplicationEngine -->
<div class="func">
<h2>Member Function Documentation</h2>
<!-- $$$QQmlApplicationEngine$$$QQmlApplicationEngineconstQString&QObject* -->
<h3 class="fn" id="QQmlApplicationEngine-2"><a name="QQmlApplicationEngine-2"></a>QQmlApplicationEngine::<span class="name">QQmlApplicationEngine</span>(const <span class="type"><a href="../qtcore/qstring.html">QString</a></span> &<i>filePath</i>, <span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>parent</i> = nullptr)</h3>
<p>Create a new QQmlApplicationEngine and loads the QML file at the given <i>filePath</i>, which must be a local file path. If a relative path is given then it will be interpreted as relative to the working directory of the application.</p>
<p>This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.</p>
<!-- @@@QQmlApplicationEngine -->
<!-- $$$QQmlApplicationEngine$$$QQmlApplicationEngineconstQUrl&QObject* -->
<h3 class="fn" id="QQmlApplicationEngine-1"><a name="QQmlApplicationEngine-1"></a>QQmlApplicationEngine::<span class="name">QQmlApplicationEngine</span>(const <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> &<i>url</i>, <span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>parent</i> = nullptr)</h3>
<p>Create a new QQmlApplicationEngine and loads the QML file at the given <i>url</i>. This is provided as a convenience, and is the same as using the empty constructor and calling load afterwards.</p>
<!-- @@@QQmlApplicationEngine -->
<!-- $$$QQmlApplicationEngine[overload1]$$$QQmlApplicationEngineQObject* -->
<h3 class="fn" id="QQmlApplicationEngine"><a name="QQmlApplicationEngine"></a>QQmlApplicationEngine::<span class="name">QQmlApplicationEngine</span>(<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>parent</i> = nullptr)</h3>
<p>Create a new QQmlApplicationEngine with the given <i>parent</i>. You will have to call <a href="qqmlapplicationengine.html#load">load</a>() later in order to load a QML file.</p>
<!-- @@@QQmlApplicationEngine -->
<!-- $$$load$$$loadconstQString& -->
<h3 class="fn" id="load-1"><a name="load-1"></a><code>[slot] </code><span class="type">void</span> QQmlApplicationEngine::<span class="name">load</span>(const <span class="type"><a href="../qtcore/qstring.html">QString</a></span> &<i>filePath</i>)</h3>
<p>Loads the root QML file located at <i>filePath</i>. <i>filePath</i> must be a path to a local file. If <i>filePath</i> is a relative path, it is taken as relative to the application's working directory. The object tree defined by the file is instantiated immediately.</p>
<p>If an error occurs, error messages are printed with <a href="../qtcore/qtglobal.html#qWarning">qWarning</a>.</p>
<!-- @@@load -->
<!-- $$$load[overload1]$$$loadconstQUrl& -->
<h3 class="fn" id="load"><a name="load"></a><code>[slot] </code><span class="type">void</span> QQmlApplicationEngine::<span class="name">load</span>(const <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> &<i>url</i>)</h3>
<p>Loads the root QML file located at <i>url</i>. The object tree defined by the file is created immediately for local file urls. Remote urls are loaded asynchronously, listen to the <a href="qqmlapplicationengine.html#objectCreated">objectCreated</a> signal to determine when the object tree is ready.</p>
<p>If an error occurs, the <a href="qqmlapplicationengine.html#objectCreated">objectCreated</a> signal is emitted with a null pointer as parameter and error messages are printed with <a href="../qtcore/qtglobal.html#qWarning">qWarning</a>.</p>
<!-- @@@load -->
<!-- $$$loadData[overload1]$$$loadDataconstQByteArray&constQUrl& -->
<h3 class="fn" id="loadData"><a name="loadData"></a><code>[slot] </code><span class="type">void</span> QQmlApplicationEngine::<span class="name">loadData</span>(const <span class="type"><a href="../qtcore/qbytearray.html">QByteArray</a></span> &<i>data</i>, const <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> &<i>url</i> = QUrl())</h3>
<p>Loads the QML given in <i>data</i>. The object tree defined by <i>data</i> is instantiated immediately.</p>
<p>If a <i>url</i> is specified it is used as the base url of the component. This affects relative paths within the data and error messages.</p>
<p>If an error occurs, error messages are printed with <a href="../qtcore/qtglobal.html#qWarning">qWarning</a>.</p>
<!-- @@@loadData -->
<!-- $$$objectCreated[overload1]$$$objectCreatedQObject*constQUrl& -->
<h3 class="fn" id="objectCreated"><a name="objectCreated"></a><code>[signal] </code><span class="type">void</span> QQmlApplicationEngine::<span class="name">objectCreated</span>(<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *<i>object</i>, const <span class="type"><a href="../qtcore/qurl.html">QUrl</a></span> &<i>url</i>)</h3>
<p>This signal is emitted when an object finishes loading. If loading was successful, <i>object</i> contains a pointer to the loaded object, otherwise the pointer is NULL.</p>
<p>The <i>url</i> to the component the <i>object</i> came from is also provided.</p>
<p><b>Note: </b>If the path to the component was provided as a <a href="../qtcore/qstring.html">QString</a> containing a relative path, the <i>url</i> will contain a fully resolved path to the file.</p>
<!-- @@@objectCreated -->
<!-- $$$setInitialProperties[overload1]$$$setInitialPropertiesconstQVariantMap& -->
<h3 class="fn" id="setInitialProperties"><a name="setInitialProperties"></a><code>[slot] </code><span class="type">void</span> QQmlApplicationEngine::<span class="name">setInitialProperties</span>(const <span class="type"><a href="../qtcore/qvariant.html#QVariantMap-typedef">QVariantMap</a></span> &<i>initialProperties</i>)</h3>
<p>Sets the <i>initialProperties</i> with which the QML component gets initialized after it gets loaded.</p>
<p>This function was introduced in Qt 5.14.</p>
<p><b>See also </b><a href="qqmlcomponent.html#setInitialProperties">QQmlComponent::setInitialProperties</a>, <a href="qqmlapplicationengine.html#load">QQmlApplicationEngine::load</a>, and <a href="qqmlapplicationengine.html#loadData">QQmlApplicationEngine::loadData</a>.</p>
<!-- @@@setInitialProperties -->
<!-- $$$~QQmlApplicationEngine[overload1]$$$~QQmlApplicationEngine -->
<h3 class="fn" id="dtor.QQmlApplicationEngine"><a name="dtor.QQmlApplicationEngine"></a><code>[override virtual] </code>QQmlApplicationEngine::<span class="name">~QQmlApplicationEngine</span>()</h3>
<p>Destroys the <a href="qqmlapplicationengine.html">QQmlApplicationEngine</a> and all QML objects it loaded.</p>
<!-- @@@~QQmlApplicationEngine -->
<!-- $$$rootObjects[overload1]$$$rootObjects -->
<h3 class="fn" id="rootObjects"><a name="rootObjects"></a><span class="type"><a href="../qtcore/qlist.html">QList</a></span><<span class="type"><a href="../qtcore/qobject.html#QObject">QObject</a></span> *> QQmlApplicationEngine::<span class="name">rootObjects</span>() const</h3>
<p>Returns a list of all the root objects instantiated by the <a href="qqmlapplicationengine.html">QQmlApplicationEngine</a>. This will only contain objects loaded via <a href="qqmlapplicationengine.html#load">load</a>() or a convenience constructor.</p>
<p><b>Note: </b>In Qt versions prior to 5.9, this function is marked as non-<code>const</code>.</p>
<!-- @@@rootObjects -->
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