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<title>Qt Widget Hierarchy (in-process)</title>
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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>Qt Widget Hierarchy (in-process)</h1>
The ActiveX control in this example is a <a href="qwidget.html">QWidget</a>
subclass with child widgets that are accessible as sub types.
<p>
<pre> class QParentWidget : public <a href="qwidget.html">QWidget</a>
{
<a href="metaobjects.html#Q_OBJECT">Q_OBJECT</a>
public:
QParentWidget( <a href="qwidget.html">QWidget</a> *parent = 0, const char *name = 0, WFlags f = 0 );
<a href="qsize.html">QSize</a> sizeHint() const;
public slots:
void createSubWidget( const <a href="qstring.html">QString</a> &name );
QSubWidget *subWidget( const <a href="qstring.html">QString</a> &name );
private:
<a href="qvboxlayout.html">QVBoxLayout</a> *vbox;
};
</pre>The <tt>QParentWidget</tt> class provides slots to create a widget
with a name, and to return a pointer to a named widget.
<p>
<pre> QParentWidget::QParentWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name, WFlags f )
: <a href="qwidget.html">QWidget</a>( parent, name, f )
{
vbox = new <a href="qvboxlayout.html">QVBoxLayout</a>( this );
<a name="x2649"></a> vbox-><a href="qlayout.html#setAutoAdd">setAutoAdd</a>( TRUE );
}
</pre>The constructor of QParentWidget creates a vertical box layout.
New child widgets are automatically added to the layout.
<p> <pre> void QParentWidget::createSubWidget( const <a href="qstring.html">QString</a> &name )
{
QSubWidget *sw = new QSubWidget( this, name );
sw->setLabel( name );
sw-><a href="qwidget.html#show">show</a>();
}
</pre>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> QSubWidget *QParentWidget::subWidget( const <a href="qstring.html">QString</a> &name )
{
return (QSubWidget*)<a href="qobject.html#child">child</a>( name, "QSubWidget" );
}
</pre>The <tt>subWidget</tt> slot uses the <a href="qobject.html#child">QObject::child</a>() function and
returns the first child of type <tt>QSubWidget</tt> that has the requested
name.
<p>
<pre> class QSubWidget : public <a href="qwidget.html">QWidget</a>
{
Q_OBJECT
Q_PROPERTY( QString label READ label WRITE setLabel )
public:
QSubWidget( <a href="qwidget.html">QWidget</a> *parent = 0, const char *name = 0, WFlags f = 0 );
void setLabel( const <a href="qstring.html">QString</a> &text );
<a href="qstring.html">QString</a> label() const;
<a href="qsize.html">QSize</a> sizeHint() const;
protected:
void paintEvent( <a href="qpaintevent.html">QPaintEvent</a> *e );
private:
<a href="qstring.html">QString</a> lbl;
};
</pre>The <tt>QSubWidget</tt> class has a single string-property <tt>label</tt>,
and implements the paintEvent to draw the label.
<p>
<pre> QSubWidget::QSubWidget( <a href="qwidget.html">QWidget</a> *parent, const char *name, WFlags f )
: <a href="qwidget.html">QWidget</a>( parent, name, f )
{
}
void QSubWidget::setLabel( const <a href="qstring.html">QString</a> &text )
{
lbl = text;
<a href="qobject.html#setName">setName</a>( text );
<a href="qwidget.html#update">update</a>();
}
QString QSubWidget::label() const
{
return lbl;
}
QSize QSubWidget::<a href="qwidget.html#sizeHint">sizeHint</a>() const
{
<a href="qfontmetrics.html">QFontMetrics</a> fm( <a href="qwidget.html#font">font</a>() );
return QSize( fm.<a href="qfontmetrics.html#width">width</a>(lbl), fm.<a href="qfontmetrics.html#height">height</a>() );
}
void QSubWidget::<a href="qwidget.html#paintEvent">paintEvent</a>( <a href="qpaintevent.html">QPaintEvent</a> * )
{
<a href="qpainter.html">QPainter</a> painter(this);
painter.<a href="qpainter.html#setPen">setPen</a>( <a href="qwidget.html#colorGroup">colorGroup</a>().text() );
painter.<a href="qpainter.html#drawText">drawText</a>( <a href="qwidget.html#rect">rect</a>(), AlignCenter, lbl );
}
</pre>The implementation of the QSubWidget class is self-explanatory.
<p>
<pre> class ActiveQtFactory : public <a href="qaxfactory.html">QAxFactory</a>
{
public:
ActiveQtFactory( const <a href="quuid.html">QUuid</a> &lib, const <a href="quuid.html">QUuid</a> &app )
: <a href="qaxfactory.html">QAxFactory</a>( lib, app )
{}
<a href="qstringlist.html">QStringList</a> featureList() const
{
<a href="qstringlist.html">QStringList</a> list;
list << "QParentWidget";
list << "QSubWidget";
return list;
}
</pre>The <tt>ActiveQtFactory</tt> class implements a <a href="qaxfactory.html">QAxFactory</a>. It returns
the class names of all supported types, <tt>QParentWidget</tt> and
<tt>QSubWidget</tt>, from the <tt>featureList()</tt> reimplementation.
<p> <pre> <a href="qwidget.html">QWidget</a> *create( const <a href="qstring.html">QString</a> &key, QWidget *parent, const char *name )
{
if ( key == "QParentWidget" )
return new QParentWidget( parent, name );
return 0;
}
</pre>The factory can however only create objects of the <tt>QParentWidget</tt>
type directly - objects of subtypes can only be created through the
interface of <tt>QParentWidget</tt> objects.
<p> <pre> <a href="quuid.html">QUuid</a> classID( const <a href="qstring.html">QString</a> &key ) const
{
if ( key == "QParentWidget" )
return QUuid( "{d574a747-8016-46db-a07c-b2b4854ee75c}" );
if ( key == "QSubWidget" )
return QUuid( "{850652f4-8f71-4f69-b745-bce241ccdc30}" );
return QUuid();
}
<a href="quuid.html">QUuid</a> interfaceID( const <a href="qstring.html">QString</a> &key ) const
{
if ( key == "QParentWidget" )
return QUuid( "{4a30719d-d9c2-4659-9d16-67378209f822}" );
if ( key == "QSubWidget" )
return QUuid( "{2d76cc2f-3488-417a-83d6-debff88b3c3f}" );
return QUuid();
}
<a href="quuid.html">QUuid</a> eventsID( const <a href="qstring.html">QString</a> &key ) const
{
if ( key == "QParentWidget" )
return QUuid( "{aac9f855-c3dc-4cae-b747-c77f4d509f4c}" );
if ( key == "QSubWidget" )
return QUuid( "{25fac47e-c723-4696-8c74-6185903bdf65}" );
return QUuid();
}
</pre>COM however requires the IDs for the interfaces of the sub types as
well to be able to marshal calls correctly.
<p> <pre> <a href="qstring.html">QString</a> exposeToSuperClass( const <a href="qstring.html">QString</a> &key ) const
{
if ( key == "QSubWidget" )
return key;
return QAxFactory::exposeToSuperClass(key);
}
};
</pre>Objects of the <tt>QSubWidget</tt> type should not expose the full
functionality of e.g. <a href="qwidget.html">QWidget</a>. Only those properties and slots
explicitly declared in the type are accessible.
<p> <pre> QAXFACTORY_EXPORT( ActiveQtFactory, "{9e626211-be62-4d18-9483-9419358fbb03}", "{75c276de-1df5-451f-a004-e4fa1a587df1}" )
</pre>The factory is then exported using the <a href="qaxfactory.html#QAXFACTORY_EXPORT">QAXFACTORY_EXPORT</a>
macro.
<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/multiple</tt>.
<p> <hr>
<p> The <a href="qaxserver-demo-hierarchy.html">demonstration</a> requires your
WebBrowser to support ActiveX controls, and scripting to be enabled.
<p>
<pre> <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!<br>
<object ID="ParentWidget" CLASSID="CLSID:d574a747-8016-46db-a07c-b2b4854ee75c"
CODEBASE=http://www.trolltech.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 = "<enter object name>">
<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><p>See also <a href="qaxserver-examples.html">The QAxServer Examples</a>.
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