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Breadcrumbs go here --> <li><a href="all-examples.html">Examples</a></li> <li>Hierarchy Example (ActiveQt)</li> </ul> </div> <div class="toolbuttons toolblock"> <ul> <li id="smallA" class="t_button">A</li> <li id="medA" class="t_button active">A</li> <li id="bigA" class="t_button">A</li> <li id="print" class="t_button"><a href="javascript:this.print();"> <span>Print</span></a></li> </ul> </div> </div> <div class="content mainContent"> <h1 class="title">Hierarchy Example (ActiveQt)</h1> <span class="subtitle"></span> <!-- $$$activeqt/hierarchy-description --> <div class="descr"> <a name="details"></a> <p>Files:</p> <ul> <li><a href="activeqt-hierarchy-objects-cpp.html">activeqt/hierarchy/objects.cpp</a></li> <li><a href="activeqt-hierarchy-objects-h.html">activeqt/hierarchy/objects.h</a></li> <li><a href="activeqt-hierarchy-main-cpp.html">activeqt/hierarchy/main.cpp</a></li> <li><a href="activeqt-hierarchy-hierarchy-pro.html">activeqt/hierarchy/hierarchy.pro</a></li> </ul> <p>The Hierarchy example is shows how to write an in-process ActiveX control. The control is a <a href="qwidget.html">QWidget</a> subclass with child widgets that are accessible as sub-types.<pre class="cpp"> <span class="keyword">class</span> <span class="type">QParentWidget</span> : <span class="keyword">public</span> <span class="type"><a href="qwidget.html">QWidget</a></span> { Q_OBJECT Q_CLASSINFO(<span class="string">"ClassID"</span><span class="operator">,</span> <span class="string">"{d574a747-8016-46db-a07c-b2b4854ee75c}"</span>); Q_CLASSINFO(<span class="string">"InterfaceID"</span><span class="operator">,</span> <span class="string">"{4a30719d-d9c2-4659-9d16-67378209f822}"</span>); Q_CLASSINFO(<span class="string">"EventsID"</span><span class="operator">,</span> <span class="string">"{4a30719d-d9c2-4659-9d16-67378209f823}"</span>); <span class="keyword">public</span>: <span class="type">QParentWidget</span>(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span>); <span class="type"><a href="qsize.html">QSize</a></span> sizeHint() <span class="keyword">const</span>; <span class="keyword">public</span> <span class="keyword">slots</span>: <span class="type">void</span> createSubWidget( <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name ); <span class="type">QSubWidget</span> <span class="operator">*</span>subWidget( <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name ); <span class="keyword">private</span>: <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span> <span class="operator">*</span>vbox; };</pre> <p>The <tt>QParentWidget</tt> class provides slots to create a widget with a name, and to return a pointer to a named widget. The class declaration uses <tt>Q_CLASSINFO()</tt> to provide the COM identifiers for this class.</p> <pre class="cpp"> <span class="type">QParentWidget</span><span class="operator">::</span><span class="type">QParentWidget</span>(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent) : <span class="type"><a href="qwidget.html">QWidget</a></span>(parent) { vbox <span class="operator">=</span> <span class="keyword">new</span> <span class="type"><a href="qvboxlayout.html">QVBoxLayout</a></span>(<span class="keyword">this</span>); }</pre> <p>The constructor of QParentWidget creates a vertical box layout. New child widgets are automatically added to the layout.</p> <pre class="cpp"> <span class="type">void</span> <span class="type">QParentWidget</span><span class="operator">::</span>createSubWidget(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name) { <span class="type">QSubWidget</span> <span class="operator">*</span>sw <span class="operator">=</span> <span class="keyword">new</span> <span class="type">QSubWidget</span>(<span class="keyword">this</span><span class="operator">,</span> name); vbox<span class="operator">-</span><span class="operator">></span>addWidget(sw); sw<span class="operator">-</span><span class="operator">></span>setLabel(name); sw<span class="operator">-</span><span class="operator">></span>show(); }</pre> <p>The <tt>createSubWidget</tt> slot creates a new <tt>QSubWidget</tt> with the name provided in the parameter, and sets the label to that name. The widget is also shown explicitly.</p> <pre class="cpp"> <span class="type">QSubWidget</span> <span class="operator">*</span><span class="type">QParentWidget</span><span class="operator">::</span>subWidget(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name) { <span class="keyword">return</span> findChild<span class="operator"><</span><span class="type">QSubWidget</span><span class="operator">*</span><span class="operator">></span>(name); }</pre> <p>The <tt>subWidget</tt> slot uses the <tt>QObject::child()</tt> function and returns the first child of type <tt>QSubWidget</tt> that has the requested name.</p> <pre class="cpp"> <span class="keyword">class</span> <span class="type">QSubWidget</span> : <span class="keyword">public</span> <span class="type"><a href="qwidget.html">QWidget</a></span> { Q_OBJECT Q_PROPERTY( <span class="type"><a href="qstring.html">QString</a></span> label READ label WRITE setLabel ) Q_CLASSINFO(<span class="string">"ClassID"</span><span class="operator">,</span> <span class="string">"{850652f4-8f71-4f69-b745-bce241ccdc30}"</span>); Q_CLASSINFO(<span class="string">"InterfaceID"</span><span class="operator">,</span> <span class="string">"{2d76cc2f-3488-417a-83d6-debff88b3c3f}"</span>); Q_CLASSINFO(<span class="string">"ToSuperClass"</span><span class="operator">,</span> <span class="string">"QSubWidget"</span>); <span class="keyword">public</span>: <span class="type">QSubWidget</span>(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent <span class="operator">=</span> <span class="number">0</span><span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name <span class="operator">=</span> <span class="type"><a href="qstring.html">QString</a></span>()); <span class="type">void</span> setLabel( <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>text ); <span class="type"><a href="qstring.html">QString</a></span> label() <span class="keyword">const</span>; <span class="type"><a href="qsize.html">QSize</a></span> sizeHint() <span class="keyword">const</span>; <span class="keyword">protected</span>: <span class="type">void</span> paintEvent( <span class="type"><a href="qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span>e ); <span class="keyword">private</span>: <span class="type"><a href="qstring.html">QString</a></span> lbl; };</pre> <p>The <tt>QSubWidget</tt> class has a single string-property <tt>label</tt>, and implements the paintEvent to draw the label. The class uses again <tt>Q_CLASSINFO</tt> to provide the COM identifiers, and also sets the <i>ToSuperClass</i> attribute to <i>QSubWidget</i>, to ensure that only no slots of any superclasses (i.e. <a href="qwidget.html">QWidget</a>) are exposed.</p> <pre class="cpp"> <span class="type">QSubWidget</span><span class="operator">::</span><span class="type">QSubWidget</span>(<span class="type"><a href="qwidget.html">QWidget</a></span> <span class="operator">*</span>parent<span class="operator">,</span> <span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>name) : <span class="type"><a href="qwidget.html">QWidget</a></span>(parent) { setObjectName(name); } <span class="type">void</span> <span class="type">QSubWidget</span><span class="operator">::</span>setLabel(<span class="keyword">const</span> <span class="type"><a href="qstring.html">QString</a></span> <span class="operator">&</span>text) { lbl <span class="operator">=</span> text; setObjectName(text); update(); } <span class="type"><a href="qstring.html">QString</a></span> <span class="type">QSubWidget</span><span class="operator">::</span>label() <span class="keyword">const</span> { <span class="keyword">return</span> lbl; } <span class="type"><a href="qsize.html">QSize</a></span> <span class="type">QSubWidget</span><span class="operator">::</span>sizeHint() <span class="keyword">const</span> { <span class="type"><a href="qfontmetrics.html">QFontMetrics</a></span> fm(font()); <span class="keyword">return</span> <span class="type"><a href="qsize.html">QSize</a></span>(fm<span class="operator">.</span>width(lbl)<span class="operator">,</span> fm<span class="operator">.</span>height()); } <span class="type">void</span> <span class="type">QSubWidget</span><span class="operator">::</span>paintEvent(<span class="type"><a href="qpaintevent.html">QPaintEvent</a></span> <span class="operator">*</span>) { <span class="type"><a href="qpainter.html">QPainter</a></span> painter(<span class="keyword">this</span>); painter<span class="operator">.</span>setPen(palette()<span class="operator">.</span>text()<span class="operator">.</span>color()); painter<span class="operator">.</span>drawText(rect()<span class="operator">,</span> <span class="type"><a href="qt.html">Qt</a></span><span class="operator">::</span>AlignCenter<span class="operator">,</span> lbl); }</pre> <p>The implementation of the QSubWidget class is self-explanatory.</p> <pre class="cpp"> <span class="preprocessor">#include "objects.h"</span> <span class="preprocessor">#include <QAxFactory></span> <a href="qaxfactory.html#QAXFACTORY_BEGIN">QAXFACTORY_BEGIN</a>(<span class="string">"{9e626211-be62-4d18-9483-9419358fbb03}"</span><span class="operator">,</span> <span class="string">"{75c276de-1df5-451f-a004-e4fa1a587df1}"</span>) <a href="qaxfactory.html#QAXCLASS">QAXCLASS</a>(<span class="type">QParentWidget</span>) <a href="qaxfactory.html#QAXTYPE">QAXTYPE</a>(<span class="type">QSubWidget</span>) <a href="qaxfactory.html#QAXFACTORY_END">QAXFACTORY_END</a>()</pre> <p>The classes are then exported using a <a href="qaxfactory.html">QAxFactory</a>. <tt>QParentWidget</tt> is exported as a full class (which can be created ), while <tt>QSubWidget</tt> is only exported as a type, which can only be created indirectly through APIs of <tt>QParentWidget</tt>.</p> <p>To build the example you must first build the <a href="qaxserver.html">QAxServer</a> library. Then run qmake and your make tool in <tt>examples/activeqt/hierarchy</tt>.</p> <p>The <a href="qaxserver-demo-hierarchy.html">demonstration</a> requires your WebBrowser to support ActiveX controls, and scripting to be enabled.</p> <pre class="cpp"> <script language="javascript"> function createSubWidget( form ) { ParentWidget.createSubWidget( form.nameEdit.value ); } function renameSubWidget( form ) { var SubWidget = ParentWidget.subWidget( form.nameEdit.value ); if ( !SubWidget ) { alert( "No such widget " + form.nameEdit.value + "!" ); return; } SubWidget.label = form.labelEdit.value; form.nameEdit.value = SubWidget.label; } function setFont( form ) { ParentWidget.font = form.fontEdit.value; } </script> <p> This widget can have many children! </p> <object ID="ParentWidget" CLASSID="CLSID:d574a747-8016-46db-a07c-b2b4854ee75c" CODEBASE="http://qt.nokia.com/demos/hierarchy.cab"> [Object not available! Did you forget to build and register the server?] </object><br /> <form> <input type="edit" ID="nameEdit" value="&lt;enter object name&gt;" /> <input type="button" value="Create" onClick="createSubWidget(this.form)" /> <input type="edit" ID="labelEdit" /> <input type="button" value="Rename" onClick="renameSubWidget(this.form)" /> <br /> <input type="edit" ID="fontEdit" value="MS Sans Serif" /> <input type="button" value = "Set Font" onClick="setFont(this.form)" /> </form></pre> </div> <!-- @@@activeqt/hierarchy --> </div> </div> </div> <div class="ft"> <span></span> </div> </div> <div class="footer"> <p> <acronym title="Copyright">©</acronym> 2013 Digia Plc and/or its subsidiaries. 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