D-Bus Adaptor Example
The following example code shows how a D-Bus interface can be implemented using an adaptor.
A sample usage of QDBusAbstractAdaptor is as follows:
class MainApplicationAdaptor: public QDBusAbstractAdaptor
{
Q_OBJECT
Q_CLASSINFO("D-Bus Interface", "org.kde.DBus.MainApplication")
Q_PROPERTY(QString caption READ caption WRITE setCaption)
Q_PROPERTY(QString organizationName READ organizationName)
Q_PROPERTY(QString organizationDomain READ organizationDomain)
private:
QApplication *app;
public:
MainApplicationAdaptor(QApplication *application)
: QDBusAbstractAdaptor(application), app(application)
{
connect(application, SIGNAL(aboutToQuit()), SIGNAL(aboutToQuit()));
connect(application, SIGNAL(focusChanged(QWidget*, QWidget*)),
SLOT(focusChangedSlot(QWidget*, QWidget*)));
}
QString caption()
{
if (app->hasMainWindow())
return app->mainWindow()->caption();
return QString(""); // must not return a null QString
}
void setCaption(const QString &newCaption)
{
if (app->hasMainWindow())
app->mainWindow()->setCaption(newCaption);
}
QString organizationName()
{
return app->organizationName();
}
QString organizationDomain()
{
return app->organizationDomain();
}
public slots:
Q_NOREPLY void quit()
{ app->quit(); }
void reparseConfiguration()
{ app->reparseConfiguration(); }
QString mainWindowObject()
{
if (app->hasMainWindow())
return QString("/%1/mainwindow").arg(app->applicationName());
return QString();
}
void setSessionManagement(bool enable)
{
if (enable)
app->enableSessionManagement();
else
app->disableSessionManagement();
}
private slots:
void focusChangedSlot(QWidget *, QWidget *now)
{
if (now == app->mainWindow())
emit mainWindowHasFocus();
}
signals:
void aboutToQuit();
void mainWindowHasFocus();
};
The code above would create an interface that could be represented more or less in the following canonical representation:
interface org.kde.DBus.MainApplication
{
property readwrite STRING caption
property read STRING organizationName
property read STRING organizationDomain
method quit() annotation("org.freedesktop.DBus.Method.NoReply", "true")
method reparseConfiguration()
method mainWindowObject(out STRING)
method disableSessionManagement(in BOOLEAN enable)
signal aboutToQuit()
signal mainWindowHasFocus()
}
This adaptor could be used in the application's main function as follows
int main(int argc, char **argv)
{
// create the QApplication object
QApplication app(argc, argv);
// create the MainApplication adaptor:
new MainApplicationAdaptor(app);
// connect to D-Bus and register as an object:
QDBusConnection::sessionBus().registerObject("/MainApplication", app);
// add main window, etc.
[...]
app.exec();
}
Break-down analysis: