Qt Documentation

Contents

QDBusInterface Class

The QDBusInterface class is a proxy for interfaces on remote objects. More...

Header: #include <QDBusInterface>
qmake: QT += dbus
Since: Qt 4.2
Inherits: QDBusAbstractInterface

This class was introduced in Qt 4.2.

Public Functions

QDBusInterface(const QString &service, const QString &path, const QString &interface = QString(), const QDBusConnection &connection = QDBusConnection::sessionBus(), QObject *parent = nullptr)
virtual ~QDBusInterface()

Detailed Description

QDBusInterface is a generic accessor class that is used to place calls to remote objects, connect to signals exported by remote objects and get/set the value of remote properties. This class is useful for dynamic access to remote objects: that is, when you do not have a generated code that represents the remote interface.

Calls are usually placed by using the call() function, which constructs the message, sends it over the bus, waits for the reply and decodes the reply. Signals are connected to by using the normal QObject::connect() function. Finally, properties are accessed using the QObject::property() and QObject::setProperty() functions.

The following code snippet demonstrates how to perform a mathematical operation of "2 + 2" in a remote application called com.example.Calculator, accessed via the session bus.

QDBusInterface remoteApp( "com.example.Calculator", "/Calculator/Operations",
                          "org.mathematics.RPNCalculator" );
remoteApp.call( "PushOperand", 2 );
remoteApp.call( "PushOperand", 2 );
remoteApp.call( "ExecuteOperation", "+" );
QDBusReply<int> reply = remoteApp.call( "PopOperand" );

if ( reply.isValid() )
    printf( "%d", reply.value() );          // prints 4

See also Qt D-Bus XML compiler (qdbusxml2cpp).

Member Function Documentation

QDBusInterface::QDBusInterface(const QString &service, const QString &path, const QString &interface = QString(), const QDBusConnection &connection = QDBusConnection::sessionBus(), QObject *parent = nullptr)

Creates a dynamic QDBusInterface object associated with the interface interface on object at path path on service service, using the given connection. If interface is an empty string, the object created will refer to the merging of all interfaces found in that object.

parent is passed to the base class constructor.

If the remote service service is not present or if an error occurs trying to obtain the description of the remote interface interface, the object created will not be valid (see isValid()).

[virtual] QDBusInterface::~QDBusInterface()

Destroy the object interface and frees up any resource used.

© 2020 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.