/usr/share/qt3/doc/html/qaxserver-example-hierarchy.html

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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> &amp;name );

        QSubWidget *subWidget( const <a href="qstring.html">QString</a> &amp;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-&gt;<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> &amp;name )
    {
        QSubWidget *sw = new QSubWidget( this, name );
        sw-&gt;setLabel( name );
        sw-&gt;<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> &amp;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> &amp;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> &amp;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> &amp;lib, const <a href="quuid.html">QUuid</a> &amp;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 &lt;&lt; "QParentWidget";
            list &lt;&lt; "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> &amp;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> &amp;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> &amp;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> &amp;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> &amp;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>    &lt;script language=javascript&gt;
    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;
    }
    &lt;/script&gt;

    &lt;p&gt;
    This widget can have many children!&lt;br&gt;
    &lt;object ID="ParentWidget" CLASSID="CLSID:d574a747-8016-46db-a07c-b2b4854ee75c"
    CODEBASE=http://www.trolltech.com/demos/hierarchy.cab&gt;
    [Object not available! Did you forget to build and register the server?]
    &lt;/object&gt;&lt;br&gt;
    &lt;form&gt;
    &lt;input type="edit" ID="nameEdit" value = "&lt;enter object name&gt;"&gt;
    &lt;input type="button" value = "Create" onClick="createSubWidget(this.form)"&gt;
    &lt;input type="edit" ID="labelEdit"&gt;
    &lt;input type="button" value = "Rename" onClick="renameSubWidget(this.form)"&gt;
    &lt;br&gt;
    &lt;input type="edit" ID="fontEdit" value = "MS Sans Serif"&gt;
    &lt;input type="button" value = "Set Font" onClick="setFont(this.form)"&gt;
    &lt;/form&gt;
</pre><p>See also <a href="qaxserver-examples.html">The QAxServer Examples</a>.

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