Cross-Platform Accessibility Support in Qt 4

Example Code

The first example illustrates how to provide accessibility information for a custom widget. We can use QAccessibleWidget as a base class and reimplement various functions:

 class MyWidgetInterface : public QAccessibleWidget
 {
 public:
     MyWidgetInterface(QWidget *widget, Role role);

     QString text(Text text, int child) const;
     State state(int child) const;
     QString actionText(int action, Text text, int child) const;
     bool doAction(int action, int child, const QVariantList &params);
     ...
 };

Here's how we would implement the doAction() function to call a function named click() on the wrapped MyWidget object when the user invokes the object's default action or "presses" it.

 bool MyWidgetInterface::doAction(int action, int child,
                                  const QVariantList &params)
 {
     if (child || !widget()->isEnabled())
         return false;

     switch (action) {
     case DefaultAction:
     case Press:
         {
             MyWidget *widget = qobject_cast<MyWidget *>(object());
             if (widget)
                 widget->click();
         }
         return true;
     }
     return QAccessibleWidget::doAction(action, child, params);
 }

To export the widget interface as a plugin, we must subclass QAccessibleFactory:

 QStringList MyFactory::keys() const
 {
     return QStringList() << "MyWidget" << "MyOtherWidget";
 }

 QAccessibleInterface *MyFactory::create(const QString &className,
                                         QObject *object)
 {
     if (classname == "MyWidget")
         return new MyWidgetInterface(object);
     if (classname == "MyOtherWidget")
         return new MyOtherWidgetInterface(object);
     return 0;
 }

 Q_EXPORT_PLUGIN2(MyFactory)

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