Hierarchy Example (ActiveQt)Files:
The Hierarchy example is shows how to write an in-process ActiveX control. The control is a QWidget subclass with child widgets that are accessible as sub-types. class QParentWidget : public QWidget { Q_OBJECT Q_CLASSINFO("ClassID", "{d574a747-8016-46db-a07c-b2b4854ee75c}"); Q_CLASSINFO("InterfaceID", "{4a30719d-d9c2-4659-9d16-67378209f822}"); Q_CLASSINFO("EventsID", "{4a30719d-d9c2-4659-9d16-67378209f823}"); public: QParentWidget(QWidget *parent = 0); QSize sizeHint() const; public slots: void createSubWidget( const QString &name ); QSubWidget *subWidget( const QString &name ); private: QVBoxLayout *vbox; }; The QParentWidget class provides slots to create a widget with a name, and to return a pointer to a named widget. The class declaration uses Q_CLASSINFO() to provide the COM identifiers for this class. QParentWidget::QParentWidget(QWidget *parent) : QWidget(parent) { vbox = new QVBoxLayout(this); } The constructor of QParentWidget creates a vertical box layout. New child widgets are automatically added to the layout. void QParentWidget::createSubWidget(const QString &name) { QSubWidget *sw = new QSubWidget(this, name); vbox->addWidget(sw); sw->setLabel(name); sw->show(); } The createSubWidget slot creates a new QSubWidget with the name provided in the parameter, and sets the label to that name. The widget is also shown explicitly. QSubWidget *QParentWidget::subWidget(const QString &name) { return qFindChild<QSubWidget*>(this, name); } The subWidget slot uses the QObject::child() function and returns the first child of type QSubWidget that has the requested name. class QSubWidget : public QWidget { Q_OBJECT Q_PROPERTY( QString label READ label WRITE setLabel ) Q_CLASSINFO("ClassID", "{850652f4-8f71-4f69-b745-bce241ccdc30}"); Q_CLASSINFO("InterfaceID", "{2d76cc2f-3488-417a-83d6-debff88b3c3f}"); Q_CLASSINFO("ToSuperClass", "QSubWidget"); public: QSubWidget(QWidget *parent = 0, const QString &name = QString()); void setLabel( const QString &text ); QString label() const; QSize sizeHint() const; protected: void paintEvent( QPaintEvent *e ); private: QString lbl; }; The QSubWidget class has a single string-property label, and implements the paintEvent to draw the label. The class uses again Q_CLASSINFO to provide the COM identifiers, and also sets the ToSuperClass attribute to QSubWidget, to ensure that only no slots of any superclasses (i.e. QWidget) are exposed. QSubWidget::QSubWidget(QWidget *parent, const QString &name) : QWidget(parent) { setObjectName(name); } void QSubWidget::setLabel(const QString &text) { lbl = text; setObjectName(text); update(); } QString QSubWidget::label() const { return lbl; } QSize QSubWidget::sizeHint() const { QFontMetrics fm(font()); return QSize(fm.width(lbl), fm.height()); } void QSubWidget::paintEvent(QPaintEvent *) { QPainter painter(this); painter.setPen(palette().text().color()); painter.drawText(rect(), Qt::AlignCenter, lbl); } The implementation of the QSubWidget class is self-explanatory. #include "objects.h" #include <QAxFactory> QAXFACTORY_BEGIN("{9e626211-be62-4d18-9483-9419358fbb03}", "{75c276de-1df5-451f-a004-e4fa1a587df1}") QAXCLASS(QParentWidget) QAXTYPE(QSubWidget) QAXFACTORY_END() The classes are then exported using a QAxFactory. QParentWidget is exported as a full class (which can be created ), while QSubWidget is only exported as a type, which can only be created indirectly through APIs of QParentWidget. To build the example you must first build the QAxServer library. Then run qmake and your make tool in examples/activeqt/hierarchy. The demonstration requires your WebBrowser to support ActiveX controls, and scripting to be enabled. <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="<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> |