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<h3><a name="toc">Contents</a></h3>
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<li class="level1"><a href="#mouse-elements">Mouse Elements</a></li>
<li class="level1"><a href="#mouse-event-handling">Mouse Event Handling</a></li>
<li class="level1"><a href="#defining-a-mouse-area">Defining a Mouse Area</a></li>
<li class="level1"><a href="#receiving-events">Receiving Events</a></li>
<li class="level1"><a href="#enabling-gestures">Enabling Gestures</a></li>
<li class="level1"><a href="#mouseevent-object">MouseEvent Object</a></li>
<li class="level2"><a href="#accepting-further-signals">Accepting Further Signals</a></li>
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<h1 class="title">QML Mouse Events</h1>
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<div class="descr"> <a name="details"></a>
<a name="mouse-elements"></a>
<h2>Mouse Elements</h2>
<ul>
<li><a href="qml-mousearea.html">MouseArea</a> Element</li>
<li><a href="qml-mouseevent.html">MouseEvent</a> Object</li>
</ul>
<a name="mouse-event-handling"></a>
<h2>Mouse Event Handling</h2>
<p>QML uses <a href="qmlevents.html">signals and handlers</a> to deliver mouse interactions. Specifically, the <a href="qml-mousearea.html">MouseArea</a> and <a href="qml-mouseevent.html">MouseEvent</a> elements provide QML components with signal handlers to accept mouse events within a defined area.</p>
<a name="defining-a-mouse-area"></a>
<h2>Defining a Mouse Area</h2>
<p>The <a href="qml-mousearea.html">MouseArea</a> element receives events within a defined area. One quick way to define this area is to anchor the <tt>MouseArea</tt> to its parent's area using the <tt>anchors.fill</tt> property. If the parent is a <a href="qml-rectangle.html">Rectangle</a> (or any <a href="qml-item.html">Item</a> component), then the <a href="qml-mousearea.html">MouseArea</a> will fill the area defined by the parent's dimensions. Alternatively, an area smaller or larger than the parent is definable.</p>
<pre class="qml"> <span class="type"><a href="qml-rectangle.html">Rectangle</a></span> {
<span class="name">id</span>: <span class="name">button1</span>
<span class="name">width</span>: <span class="number">100</span>; <span class="name">height</span>: <span class="number">100</span>
<span class="type"><a href="qml-mousearea.html">MouseArea</a></span> {
<span class="name">anchors</span>.fill: <span class="name">parent</span>
<span class="name">onClicked</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"button clicked"</span>)
}
<span class="type"><a href="qml-mousearea.html">MouseArea</a></span> {
<span class="name">width</span>:<span class="number">150</span>; <span class="name">height</span>: <span class="number">75</span>
<span class="name">onClicked</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"irregular area clicked"</span>)
}
}</pre>
<a name="receiving-events"></a>
<h2>Receiving Events</h2>
<p>The <a href="qml-mousearea.html">MouseArea</a> element provides <a href="qmlevents.html">signals and handlers</a> to detect different mouse events. The <a href="qml-mousearea.html">MouseArea</a> element documentation describes these gestures in greater detail:</p>
<ul>
<li>canceled</li>
<li>clicked</li>
<li>doubleClicked</li>
<li>entered</li>
<li>exited</li>
<li>positionChanged</li>
<li>pressAndHold</li>
<li>pressed</li>
<li>released</li>
</ul>
<p>These signals have signal handlers that are invoked when the signals are emitted.</p>
<pre class="qml"> <span class="type"><a href="qml-mousearea.html">MouseArea</a></span> {
<span class="name">anchors</span>.fill: <span class="name">parent</span>
<span class="name">onClicked</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"area clicked"</span>)
<span class="name">onDoubleClicked</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"area double clicked"</span>)
<span class="name">onEntered</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"mouse entered the area"</span>)
<span class="name">onExited</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"mouse left the area"</span>)
}</pre>
<a name="enabling-gestures"></a>
<h2>Enabling Gestures</h2>
<p>Some mouse gestures and button clicks need to be enabled before they send or receive events. Certain <a href="qml-mousearea.html">MouseArea</a> and <a href="qml-mouseevent.html">MouseEvent</a> properties enable these gestures.</p>
<p>To listen to (or explicitly ignore) a certain mouse button, set the appropriate mouse button to the <a href="qml-mousearea.html#acceptedButtons-prop">acceptedButtons</a> property.</p>
<p>Naturally, the mouse events, such as button presses and mouse positions, are sent during a mouse click. For example, the <tt>containsMouse</tt> property will only retrieve its correct value during a mouse press. The <a href="qml-mousearea.html#hoverEnabled-prop">hoverEnabled</a> will enable mouse events and positioning even when there are no mouse button presses. Setting the <tt>hoverEnabled</tt> property to <tt>true</tt>, in turn will enable the <tt>entered</tt>, <tt>exited</tt>, and <tt>positionChanged</tt> signal and their respective signal handlers.</p>
<pre class="qml"> <span class="type"><a href="qml-mousearea.html">MouseArea</a></span> {
<span class="name">hoverEnabled</span>: <span class="number">true</span>
<span class="name">acceptedButtons</span>: <span class="name">Qt</span>.<span class="name">LeftButton</span> <span class="operator">|</span> <span class="name">Qt</span>.<span class="name">RightButton</span>
<span class="name">onEntered</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"mouse entered the area"</span>)
<span class="name">onExited</span>: <span class="name">console</span>.<span class="name">log</span>(<span class="string">"mouse left the area"</span>)
}</pre>
<p>Additionally, to disable the whole mouse area, set the <tt>MouseArea</tt> element's <tt>enabled</tt> property to <tt>false</tt>.</p>
<a name="mouseevent-object"></a>
<h2>MouseEvent Object</h2>
<p>Signals and their handlers receive a <a href="qml-mouseevent.html">MouseEvent</a> object as a parameter. The <tt>mouse</tt> object contain information about the mouse event. For example, the mouse button that started the event is queried through the <a href="qml-mouseevent.html#button-prop">mouse.button</a> property.</p>
<p>The <tt>MouseEvent</tt> object can also ignore a mouse event using its <tt>accepted</tt> property.</p>
<a name="accepting-further-signals"></a>
<h3>Accepting Further Signals</h3>
<p>Many of the signals are sent multiple times to reflect various mouse events such as double clicking. To facilitate the classification of mouse clicks, the <a href="qml-mouseevent.html">MouseEvent</a> object has an <tt>accepted</tt> property to disable the event propagation.</p>
<p>To learn more about QML's event system, please read the <a href="qmlevents.html">QML Signal and Handler Event System</a> document.</p>
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