General and Desktop

@ocgltd said in Sorting with MVC and database. Row number confusion - conceptual question: Does the QSFPM translate view row numbers to QAIM row numbers as read from the DB? Yes. And note that QSortFilterProxyModel has a bunch of map...() methods for converting QModelIndexes between it and the source model when these are needed. Or I have to have the QAIM perform SQL Selects using a different 'sort by' order based on the View's sort order? Noooo :) And note that any model could be used by multiple views, each with different sorting/filtering, so the model never needs to do anything about, or know anything about, what views might do with its data.

Resolved the problem: supportedpixelformat method need more formats: return QList<QVideoFrame::PixelFormat>() << QVideoFrame::Format_RGB32 << QVideoFrame::Format_ARGB32 << QVideoFrame::Format_ARGB32_Premultiplied << QVideoFrame::Format_RGB565 << QVideoFrame::Format_RGB555;

@apalomer said in Selected QLabel?: You have to imagine that label1 lives in two different UI files that end up composed in the same GUI Then you need to use the UI file/class somewhere in the selector to distinguish. (To be clear: you can use your own class names in the selector, not just Qt inbuilt ones like QFrame or QLabel.) Anyway, I have tried the descendant selector but I would like to have the name of the ascendant. Something like this: The available facilities are in the reference I gave, and that does not include "ascendant" direction, only "descendent", as per CSS too. I guess I will have to change the names at the end.... I don't see why. Presumably the different .ui's classes are different, and that should be usable in the selector. There is also a supplementary way of distinguishing your labels which may suit. In that same reference page see Property Selector QPushButton[flat="false"] and https://doc.qt.io/qt-5/stylesheet-examples.html#customizing-using-dynamic-properties. You can add your own dynamic properties even in Designer on a widget, there is some "add property plus-button" on the properties on any widget.

@JonB Thank you for clarification

@ChrisW67 Yes, that's what i thought at first but when I STDOUT QByteArray, then i realized that serializing data to stream is causing those extra bytes.

In general, you cannot connect to a database that does not already exist: as a file in the case of Access, or a service for MySql/Oracle etc. Sqlite is unusual in that it will create the file referenced if it does not exist (that can also fail). You can programmatically create an Access database by automating Access (ActiveQt) and probably a bunch of other ways, including copying an "empty" template.

Hi, If you want to use a member function, the array you pass to the map method must contain items of that class.

@Christian-Ehrlicher sorry. that's true, that doesn't make sense. I was thinking about it in a different way ( a wrong way btw). Using the regular qpushbutton does the job.

@Pepijn There is a https://doc.qt.io/qt-5/qprocess.html#CreateProcessArgumentModifier-typedef for Windows only. The Qt docs don't seem to state what its members are. From https://code.woboq.org/qt5/qtbase/src/corelib/io/qprocess_win.cpp.html#_ZN15QProcessPrivate17callCreateProcessEPi there should be a cpargs->inheritHandles you could set/override? However from line https://code.woboq.org/qt5/qtbase/src/corelib/io/qprocess_win.cpp.html#564 I already see true being passed for that. So.... are you really sure this does not already work? I know the bug you referenced says inheritance was switched off, but that was from 2012..... Ah, I now see it talks about DuplicateHandle. I don't know what the Qt code does about that perhaps prior to calling CreateProcess? You should also read https://docs.microsoft.com/en-us/windows/win32/sysinfo/handle-inheritance. I suggest you look in the code at what you claim is happening. You state As far as I can tell from this issue at some point sockets were made to be not inheritable, meaning it would no longer be possible to access the open socket in the child process. but I have yet to find that definitively. Are you sure, have you tested? You claim a "change" and an "old default" but have not mentioned anything about Qt versions, which you might compare/read about for this change?

C++ basics - in your second example the temporary is deleted after the usage. Simply said: Temporaries are deleted when the ; is processed.

Hi, Keep the QPixmap rather than execute the conversion each time.

Use a stable solver. Your matrix is quite close to singular. QR comes to mind, eigen already provides it out of the box.

This code looks strange ... class positionsForm *form = new class positionsForm(model, this); The class name doesn't start with a capital letter and looking like a function, confusing. Why are you using class , obviously positionsForm is a class. and finally: connect(ui->positionsTable->model(), SIGNAL(dataChanged(QModelIndex,QModelIndex)), this, SLOT(emitSignal())); since model is defined in ArticlesWindow why not make the connection straight away in that class ?

@hskoglund said in Qt5 default text encoding has chaged: Utils.h:173: error: C2440: 'return': cannot convert from 'const char8_t [4]' to 'QString' Because of QT_NO_CAST_FROM_ASCII which should be enabled for all projects by default - a QString and a char* are two completely different types which should not implicitly convert into each other.

I'm using GCC 64 bit I found a bug report about this, so I think it's a known error (to compensate for an MSVC issues). I am ignoring it and all seems to work (though I don't like such scary messages suggesting I'm going to free memory incorrectly)

Thanks - I was following some internal documentation which is probably not the best idea. Your answer makes sense.