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<h1 class="title">KeyboardFilter Class Reference</h1>
<span class="small-subtitle">(QWSServer::KeyboardFilter)<br/></span>
<!-- $$$KeyboardFilter-brief -->
<p>The KeyboardFilter class is a base class for global keyboard event filters in Qt for Embedded Linux. <a href="#details">More...</a></p>
<!-- @@@KeyboardFilter -->
<pre class="cpp"> <span class="preprocessor">#include <<a href="qwsserver.html">QWSServer</a>></span></pre><ul>
<li><a href="qwsserver-keyboardfilter-members.html">List of all members, including inherited members</a></li>
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<h2>Public Functions</h2>
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<tr><td class="memItemLeft rightAlign topAlign"> virtual </td><td class="memItemRight bottomAlign"><b><a href="qwsserver-keyboardfilter.html#dtor.KeyboardFilter">~KeyboardFilter</a></b> ()</td></tr>
<tr><td class="memItemLeft rightAlign topAlign"> virtual bool </td><td class="memItemRight bottomAlign"><b><a href="qwsserver-keyboardfilter.html#filter">filter</a></b> ( int <i>unicode</i>, int <i>keycode</i>, int <i>modifiers</i>, bool <i>isPress</i>, bool <i>autoRepeat</i> ) = 0</td></tr>
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<!-- $$$KeyboardFilter-description -->
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<h2>Detailed Description</h2>
<p>The KeyboardFilter class is a base class for global keyboard event filters in Qt for Embedded Linux.</p>
<p>Note that this class is only available in <a href="qt-embedded-linux.html">Qt for Embedded Linux</a>.</p>
<p>In <a href="qt-embedded-linux.html">Qt for Embedded Linux</a>, all system generated events, including keyboard events, are passed to the server application which then propagates the event to the appropriate client. The KeyboardFilter class is used to implement a global, low-level filter on the server side. The server applies the filter to all keyboard events before passing them on to the clients:</p>
<p class="centerAlign"><img src="images/qwsserver_keyboardfilter.png" alt="" /></p><p>This feature can, for example, be used to filter things like APM (advanced power management) suspended from a button without having to filter for it in all applications.</p>
<p>To add a new keyboard filter you must first create the filter by deriving from this class, reimplementing the pure virtual <a href="qwsserver-keyboardfilter.html#filter">filter</a>() function. Then you can install the filter on the server using <a href="qwsserver.html">QWSServer</a>'s <a href="qwsserver.html#addKeyboardFilter">addKeyboardFilter()</a> function. <a href="qwsserver.html">QWSServer</a> also provides a <a href="qwsserver.html#removeKeyboardFilter">removeKeyboardFilter()</a> function.</p>
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<p><b>See also </b><a href="qt-embedded-architecture.html">Qt for Embedded Linux Architecture</a>, <a href="qwsserver.html">QWSServer</a>, and <a href="qwsinputmethod.html">QWSInputMethod</a>.</p>
<!-- @@@KeyboardFilter -->
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<h2>Member Function Documentation</h2>
<!-- $$$~KeyboardFilter[overload1]$$$~KeyboardFilter -->
<h3 class="fn"><a name="dtor.KeyboardFilter"></a>KeyboardFilter::<span class="name">~KeyboardFilter</span> ()<tt> [virtual]</tt></h3>
<p>Destroys the keyboard filter.</p>
<!-- @@@~KeyboardFilter -->
<!-- $$$filter[overload1]$$$filterintintintboolbool -->
<h3 class="fn"><a name="filter"></a><span class="type">bool</span> KeyboardFilter::<span class="name">filter</span> ( <span class="type">int</span> <i>unicode</i>, <span class="type">int</span> <i>keycode</i>, <span class="type">int</span> <i>modifiers</i>, <span class="type">bool</span> <i>isPress</i>, <span class="type">bool</span> <i>autoRepeat</i> )<tt> [pure virtual]</tt></h3>
<p>Implement this function to return true if a given key event should be stopped from being processed any further; otherwise it should return false.</p>
<p>A key event can be identified by the given <i>unicode</i> value and the <i>keycode</i>, <i>modifiers</i>, <i>isPress</i> and <i>autoRepeat</i> parameters.</p>
<p>The <i>keycode</i> parameter is the Qt keycode value as defined by the <a href="qt.html#Key-enum">Qt::Key</a> enum. The <i>modifiers</i> is an OR combination of <a href="qt.html#KeyboardModifier-enum">Qt::KeyboardModifier</a> values, indicating whether <b>Shift/Alt/Ctrl</b> keys are pressed. The <i>isPress</i> parameter is true if the event is a key press event and <i>autoRepeat</i> is true if the event is caused by an auto-repeat mechanism and not an actual key press.</p>
<!-- @@@filter -->
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