When you use custom types, it's pretty usual to register them all before building any of the widgets that will use them as part of your application startup sequence after you created your QApplication object.

@Christian-Ehrlicher Yup, it worked! Thanks a lot.

@CJha said in How to write entire QVector to a binary file?: If it's a copy then I assume it is always going to be the data No, because Qt containers use copy-on-write. See https://doc.qt.io/qt-5/implicit-sharing.html

Now I realized I have to set QDataStream::setVersion to QDataStream::Qt_4_7. I think the problem is solved.

Maybe that QByteArray is the culprit, you could try rewrite into more vanilla standard: ... { QByteArray block; QBuffer buffer(&block); buffer.open(QIODevice::WriteOnly); QDataStream out(&buffer); ... at least you would expose more stuff to the debugger :-)

@jsulm said in QDataStream an openCV::mat serialisation...: @Dariusz What is stream here? Is it QDataStream? "Any idea what did I mess up with this ?" - well, what is not working? Yep :- ) I think I might "got it". Naturally 5 min after asking question... elemSize1() return incorrect number of channels. Looks like I need elemSize() instead. still testing. Yep it was wrong element number. Hope it helps other "serializers" out here : -)

Adding typedef typename Container::value_type valType; to the loop helped with this issue . Thank you very much .

@raven-worx @mrjj @Wieland @Pablo-J-Rogina Thank you guys ! It worked perfectly. I'm now able to read and write a XML file and load items to my drawing. Thank you again Happy coding !

Thanks @karlheinzreichel Originaly I have data called Sample, to save it I save it as a QVector<double> const Value. for(int iSamples=0;iSamples<_pSampleProcessing->getRawDataVector().size();iSamples++) { xDataVector.append(_pSampleProcessing->getRawDataVector().at(iSamples).getX()); yDataVector.append(_pSampleProcessing->getRawDataVector().at(iSamples).getY()); } I dont think so, because If it would be overloaded I might get an error, because I tried it to save it as a Sample before. So saving as a double seems possible.

I've posted an answer how to know if you have read everything here: https://stackoverflow.com/a/46162082/969016

Another solution: Store all your data as key-value pairs in QMap<QString, QVariant> and write it to QDataStream. Next, applications will read full QMap contents from stream, then access needed values by their names.

@VRonin, division by 2, really? I know you can do much better ;) while (data) { const quint8 byte = data & 1; // data % 2 data >>= 1; // data / 2 myStream.writeRawData(&byte, 1); }

Hi, There's no ready made code to dump your model since only you know what make sense to dump. So yes you'll have to write the dumper and loader yourself. QDataStream comes to mind for that task. Hope it helps

Ok guy thank you for that much replies :P! I solved the issue by myself anyway. In case sombebody has a similar problem here comes the solution: What I did wrong was that I connected a time consuming function to the UpdateClient::tcpReady() slot. In this function I did some stuff which also lead to the emission of UpdateClient::tcpReady(). This broke the QEventQueue. So to what I had to chance was to skip the direct signal slot connection an do this in the UpdateClient::tcpReady(): QTimer::singleShot(0, this, SIGNAL(updateAvailable())); No everything is working fine ;).

I am not sure I completely understand the problem since I do not see any structure in your read/write code. But normal way to deal with structures (the same as with classes) is to write/read every member separate in their natural form with provided by QDataStream functionality. And you certainly need to know type of the data written to the file to read it properly. Your problem (as far as I can understand) is related to using wrong function to read integer data, cause you read it as char data,