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Posts tagged with 'qt'

mandel

How to send a {sv} over DBus with Qt

January 3, 2013
by mandel
Under c# , canonical , cpp , qt | Comment

I have recently been doing some work with Qt and DBus and I got stuck a little on how to correctly send a {sv} over DBus. Either my google-fu is terrible or there are not many examples on how to do this, therefore here is a small static method that will return a {sv} that can be send via DBus without getting a wrong parameters error:

dbus_helper.h
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#ifndef DBUS_HELPER_H
#define DBUS_HELPER_H
 
#include 
#include 
#include 
#include 
 
typedef QHash DBusStringHash;
class DBusHelper : public QObject
{
    Q_OBJECT
public:
    static int DBUS_STRING_MAP_ID;
 
    explicit DBusHelper(QObject *parent = 0);
 
    static class _init
    {
        public:
            _init()
            {
                // diff actions to init
                qRegisterMetaType("DBusStringHash");
                qDBusRegisterMetaType();
                DBUS_STRING_MAP_ID = QMetaType::type("DBusStringHash");
            }
    } _initializer;
 
    static QVariant getVariant(DBusStringHash hash);
 
};
 
Q_DECLARE_METATYPE(DBusStringHash)
#endif // DBUS_HELPER_H
dbus_helper.cpp
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// required for the init
int DBusHelper::DBUS_STRING_MAP_ID = 0;
DBusHelper::_init DBusHelper::_initializer;
 
DBusHelper::DBusHelper(QObject *parent) :
    QObject(parent)
{
}
 
QVariant DBusHelper::getVariant(DBusStringHash hash)
{
    return QVariant(DBUS_STRING_MAP_ID, &hash);
}

I added the init trick so that there is no need to manually register the types. I hope it helps!

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mandel

More py2exe fun!

April 6, 2011
by mandel
Under canonical , jpg , movetothread , py2exe , pyqt , python , qobject , qt | Comment

So far using py2exe has not been walk in the park with several issues so far and this time it could not be different…. The interesting issue brought to me by py2exe this time was during the runtime of a pyqt application in which the following was being print to stderr:

QObject::moveToThread: Current thread (0x21a3410) is not the object's thread (0x19af0d0).

Funny enough that error would not happen if the application was not froze (WTF!). After some help from ralsina and some googling we found the following:

In my case I was pretty scared that the actual issue was related to the that the operation of the QObject was taking place in a twisted deferred callback and that qtreactor might be doing something naughty. At the end it turned out that the issue was related to the use of a jpg image which requires to use an image plugin in Qt… I fixed the issue as per this. Nevertheless I have made the required changes so that such a hack is hidden in the Windows code and that the Qt UI can be used in Kubuntu without dirty code so if everything goes as planned, SSO should have a buggy t UI that runs on Kubuntu.

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mandel

PySide + PyQt and py2exe

April 4, 2011
by mandel
Under canonical , error , incompatible , py2exe , pyqt , pyside , python , qt , runtime | Comment

The following bug I have been faced with has made me loose more time that I would have expected and therefore I think is a good idea to describe it so that the rest of the internet can take advantage of my wasted time and also to keep a record of my stupidity.

After building the .exe file of the ubuntu-sso port to windows I was getting the following error at runtime:

Cannot mix incompatible Qt library (version 0x40701) with this library (version 0x40702)

Usually this means that you have two different version of Qt installed are you are mixing the libraries (.dll in this case because I was dealing with Windows). My initial reaction was to look at my Qt setup in the machine and compared the version installed in the system and that used by PyQt. Let me tell you that is a waste of time. The real reason behind this runtime error was the fact that I was using the qtreactor and I had PyQt and PySide installed in my system.

When not freezing the application, the fact that you have both packages installed is not a problem what so ever, but with py2exe it is. Py2exe bundles all the dependencies you app has and due to the fact hat qtreactor does the following:

try:
    from PyQt4.QtCore import QSocketNotifier, QObject, SIGNAL, QTimer, QCoreApplication
    from PyQt4.QtCore import QEventLoop
except ImportError:
    from PySide.QtCore import QSocketNotifier, QObject, SIGNAL, QTimer, QCoreApplication
    from PySide.QtCore import QEventLoop

both, PySide and PyQt were included in the frozen app. The problem arises due to this fact. When py2exe adds both libs, it copies the Qt dlls you depend on, and if PySide and PYQt depend on different versions (which is what was happening in my system) you might run into the issue of getting dlls from different versions because py2exe will override the already copied dlls without telling you.

In summary if you get the above runtime error, take a look to see if PySide and PyQt have ben included in your frozen app and if they depend in different versions of Qt.

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