@lolcocks Thanks! I had to add "sudo" at the begining of the command line to make it work on my raspberry Pi 3B+.

Hi and welcome to devnet, Rather than just posting code, you should also explain exactly what you want to achieve.

Awesome, thanks. I'll keep that in mind and put in some checks just to make sure.

@Denni-0 you are right sir I am completely doing it in wrong manner and no doubt I have to correct it. Actually I am developing a billing system. So how can we set a QTableWidget and the user select the values from Comobox and in the other columns it should calculate whatever mathematics formula we set on it. Afterwards we will store it in database. Also we should be able to add multiple rows. This will surely help me.

@KIMIA said in QPainter::begin: Paint device returned engine == 0, type: 1: Not my area, but your code is run inside some paintEvent(), right? I think your error message comes from QPainter::isActive() returning false. After one of painter = QPainter(obj) or painter.begin(obj) it needs to return true, but you're saying it's still false?

If you want to use it like that, you have to write: from PySide2 import QtCharts

This work project responde to many problems How to integrate matplotlib in Pyqt5 include : Open file to read and write (read data , save data to .txt file) by pyqt5 how to use QlistWidget how to use figureCanva to Both plot 2D ,3D

@younglegend Help with what exactly? I thought you had copied Denni's stuff or whatever? I thought you were going to implemented what i suggested about keeping your comment in a "shadow" file for each file? Just to be 100% clear again. If you want a "proper" program for managing file versions + comments, you don't want to write it yourself, you should use a VCS out there like git or github. If however you want to knock up something to learn Qt, you could follow my simple suggestion, or you could get (a lot) more involved by doing it via a database from Qt....

Depending on what your image is, you can create a custom QAbstractSlider that will draw the image and then the cursor on top of it.

@JonB I have no idea how to use it please give me some practical example . I guess my class skeleton is completely wrong.

@a_person Find out what it is about your environment that does make it find PyQt5 when from the terminal or wherever (e.g. maybe you have a virtual environment, I don't know), and then compare that environment to the one being used inside Qt Creator at run time which does not locate it?

@denni-0 said in Qt for Python crashes accessing QObject::property: Okay unless PySide2 is doing some interesting naming conventions this code will not work because MyModelProvider() is not supplied The provider is not necessary to the example so I deleted it. Anyway, the solution was that I was assigning the properties as QObjects while Python expected strings or int. So changing @QtCore.Property(QtCore.QObject, constant=True) to @QtCore.Property(str, constant=True) worked.

This is my experience with "Ravi, Robbie" and whoever is running things at goslicd. I interviewed over a skype call and in my oppinion it went very smoothly and it was a good interview. He knows I'm at least qualified if not over qualified for this job. He said over skype that he would send me the coder agreement that I could read over and then get back to him on it. He never sent the agreement. It's been 2-3 days. It was supposed to be sent right after the skype call. No email from him. I sent an email asking about it. No response was returned. I said I was open about how much I would get paid per milestone. That would be an employer's wet dream, right? There is no hourly wage, it's jut pay-by-milestone + equity (so they say). Another horror story from the dishonest, fake, unfair job market. This post has no business in the Qt forums, with such disrespect shown from the hiring party. Well, they do have about a 20% chance of success as 80% of startups fail. Good luck to them! I could have finished all of the project milestones in less than half the timeline stated. Their loss. Thinking of applying? Don't waste your time.

@nekitamtip what I would do is not rely on the call stack as @Kent-Dorfman points out its unreliable at best and not available due to threading issues (now that does not mean it cannot be just means it would take a lot of work and time to figure it out if it is even possible). So with that said and a much easier methodology for handling this in code regardless of the coding language you use here is what I do. Any place you plan to "raise" an error or handle an exception include enough information so that you can easily determine where that error occurred along with what that error was. In your example I would change the raise to read: raise Exception('MyTreadWorker.job_with_exception_raised :' + error_message) This basically (at a glance) tells you where the error occurred in detail and if the error was dynamic what that error was -- note if the error is static then simply replace [ ' + error_message ] with [ Description of Error ' ] again do this any place you raise an error and/or use a try except -- further I would actually call an error_handler routine in case I want to switch from live debugging to production debugging and want those errors posted to an error-log of some sort. Basically it is considered quality programming that when you raise an error or handle an exception that you report enough information back so that with that error message you (1) Know exactly where the error occurred (2) Know exactly what the error was (3) and include any extra information that might be available that would make fixing that error much easier If you do this as a standard within all your code you will soon find out that tracking done bugs becomes a trivial task.

First off regardless of the coding language you should follow the MVC (Model-View-Controller) methodology of coding which basically divorces the front-end (View) from the back-end (Model) by putting in a middle interpreter layer (Controller). Why do this well first it has the benefit of separating functionality and focusing each element on what it does best. The GUI (View) is best for handling the user interface and not very good with dealing with the data, while the Database (Model) is best for handling the data and is not very good with handling the user interface. The Controller is just the method for moving the data from the View to Model. This also has a secondary benefit if you ever change the back-end with a different database engine the only thing that is effected is the Model and maybe a bit of the Controller the GUI is essentially untouched and vice-versa if you wish to change the front-end the only thing that really changes is the front-end since all the API calls to the middle-tier would essentially remain the same. Further should the business logic affecting the data occur that is generally dealt with within the Controller or the Database depending on the implementation of the business logic. For instance data validation and manipulation generally takes place within the Controller layer making sure that no bad-data gets into the database which is always a nightmare and something that happens often if you directly tie the front-end into the back-end. So in short use pyqt5 to handle your front-end GUI and use python to handle your interface to your database (validating and moving the data to the database) and let the database do what its best at doing - handling the data with storage and stored-procedures, triggers, etc... I hope that helps