DBus reply data accessed via QString

micland

@amonR2
out of curiousity I was looking for a solution (I didn't know before that maps and structs are supported by DBus). And I found a way - using Qt 5.6, but should work with Qt 4.8 as well:

    // first the same code as you did already
    QDBusInterface *iface_Clementine = new QDBusInterface("org.mpris.clementine", "/Player", "org.freedesktop.MediaPlayer", QDBusConnection::sessionBus());
    if(iface_Clementine->isValid()) {
        QDBusMessage replyClementine = iface_Clementine->call("GetMetadata");
        qDebug() << replyClementine;
        // there is just one argument and this argument is a map
        QList<QVariant> args = replyClementine.arguments();
        const QDBusArgument &arg = args[0].value<QDBusArgument>();
        // the map has to be extracted entry by entry which is a tuple of key and value
        // in this case, the key is a string but the type of the value depends on the key (string, int, ...)
        arg.beginMap();
        while (!arg.atEnd()) {
            QString key;
            QDBusVariant value;
            arg.beginMapEntry();
            arg >> key >> value;
            arg.endMapEntry();
            qDebug() << "Key:" << key << "\t\tValue:" << value.variant();
        }
        arg.endMap();
    }

You still have to inspect the type of the value (depends on what the entry represents: album or track number, or whatever). And the argument parsing can be wrapped in a stream operator, see http://doc.qt.io/qt-5/qdbusargument.html#beginMap-1

Some further helpul information can be found here: http://stackoverflow.com/questions/20206376/how-do-i-extract-the-returned-data-from-qdbusmessage-in-a-qt-dbus-call

I have no clue why the qdbusviewer of Qt 5.6 is unable to call the DBus method but the code snippet above is working fine.

amonR2

@micland

WOOW!!! Thank you sooo much micland!! It works!!!
I tried a code similar to yours but some data were missing. Just needed to do a very tiny modification on your code:

qDebug() << key << value.variant().toString();

or directly

qDebug() << value.variant().toString();

Except it, it is perfect! Thank you again.
@micland said:

I have no clue why the qdbusviewer of Qt 5.6 is unable to call the DBus method but the code snippet above is working fine.

I hope it is going to change as I intend to use it or the 5.7 version very soon.

Cheers again.