General and Desktop

@Christian-Ehrlicher Debugger was not even necessary because the problem was just student's inexperience: i just needed to find QSqlQuery::at() in documentation and replace this piece of stupidity: QString DataProcessor::getValue(QString tableName, int recordNum, int colNum) { QSqlQuery query = selectAll(tableName); QStringList colTypes = getColTypes(tableName); QString value = ""; int i = 0; while( i <= 0) { if (query.next() == recordNum) { value = query.value(colNum).toString(); i++; } } return value; } by this: QString DataProcessor::getValue(QString tableName, int recordNum, int colNum) { QSqlQuery query = selectAll(tableName); QStringList colTypes = getColTypes(tableName); QString value = ""; while(query.next()) { if (query.at() == recordNum) { value = query.value(colNum).toString(); } } return value; }

I finally solved this. It's actually kind stupid: name cannnot be used as Q_PROPERTY name. After I change the property name, it works.

@donquibeats said in Passing control+keypress instructions from one form to another: works immediately. great, so don't forget to mark your post as solved then!

@TomNow99 But there isn't, for the same reason. QDataStream operator << needs to know the type at compile time, just the same question as before. Because we are C++ and that is a strongly typed language. Unless you're willing to stream it as a QVariant, which is not what you want. At the end of the day you can write a method just like you've shown just with the necessary ifs/switch for all the QVariant types you want to handle, which might be a dozen? Once you've written the method once, it's done.

@learnist said in How to edit a QListwidgetItem by using custom context menu ? need some corrections: but for point 3 ,which edit trigger should i use ?? can you please elaborate If you don't want double clicking or any key pressing to trigger the editing, just set it to QAbstractItemView::NoEditTriggers.

@YuChao-Hsu That's Objective C++. The code need to be in a *.mm file.

@Bonnie I see. I got it to work now. Thanks.

Yes, I just figured that out. So this works for those interested. //Slot to force a plot widget to always be on top or not - alwaysOnTopFlag = true means always on top void MainWindow::getAlwaysOnTopFlag(int widgetID, bool alwaysOnTopFlag) { if(alwaysOnTopFlag == true) { dialogue->setWindowFlags(windowFlags() | Qt::WindowSystemMenuHint | Qt::WindowTitleHint); dialogue->setParent(NULL); //allow the plotWidget not to go behind the main window dialogue->setWindowFlags(windowFlags() & ~Qt::CustomizeWindowHint); dialogue->setWindowFlags(windowFlags() | Qt::WindowSystemMenuHint | Qt::WindowTitleHint); dialogue->setWindowFlags(windowFlags() | Qt::WindowMinimizeButtonHint | Qt::WindowCloseButtonHint); //add a minimize button dialogue->setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint); //always on top dialogue->show(); } else { dialogue->setWindowFlags(windowFlags() & ~Qt::CustomizeWindowHint); dialogue->setWindowFlags(windowFlags() | Qt::WindowSystemMenuHint | Qt::WindowTitleHint); dialogue->setParent(NULL); //allow the plotWidget to go behind the main window dialogue->setWindowFlags(windowFlags() | Qt::WindowMinimizeButtonHint | Qt::WindowCloseButtonHint); //add a minimize button dialogue->setWindowFlags(windowFlags() & ~Qt::WindowStaysOnTopHint); //not on top dialogue->show(); } } Would a pin be easier or better? If so is there an easy way to implement?

@JonB Thank you that worked great

@MuratUrsavas said in QProcess output lines are truncated to 80 columns: If I debug the process (a standard Linux command) and try to get the output with readAllOutputStandard(), I see that each line has been truncated to 80 characters. ??? That should be sufficient description of the issue. My current usage "shows " almost 200 characters. In my search I found QProcess has inherited form QIODevice and this note qint64 QIODevice::peek(char * data, qint64 maxSize) Reads at most maxSize bytes from the device into data, without side effects (i.e., if you call read() after peek(), you will get the same data). Returns the number of bytes read. If an error occurs, such as when attempting to peek a device opened in WriteOnly mode, this function returns -1. Perhaps further search for "maxSize" could answer the question.

@JonB As I've said, I dont know what OP is trying to do with his long later ( sounds wrong... :-D ). If it's somehow important for the value to be higher than 0, this would definitely crash then... Just my thoughts. And I didnt mentioned any pointer :)

@AnneRanch If you would have deleted this stuff here, @KH-219Design wouldn't be able reply to your post. You've deleted your original post only and not the whole thread (which will indeed remove everything, so that nobody, except admins and moderators - I guess, can read it anymore). You can delete / remove everything by using the topic-tools... The menu with the three vertical dots below your first post will just delete your very first question.

Sorry for the late reply. I did a reinstall and with this a switch to msvc. Now it works. I was on mingw before. Best regards Holger

@Merlino said in QRegExp to parse a CSV file: simple CSV file If the file conforms to such format, you should have one and only one marker as field separator. Originally a comma (so the name) but later on some other character (that obviously cannot be part of the field values...) @Gojir4 Can't you simply use line.split(";") ? Yes you can. @Gojir4 provided the right answer I guess. From you data example, in your case it seems to be a SCSV file indeed: a semi-colon separated values. @Merlino about 2 hours ago no because the string fields can contain punctuation and quotation marks so the simple split would be fooled. Yes, you'll have punctation and quotation marks in the string fields, but I bet none of such characters will be a semi-colon (;) It looks like you're over-complicating your use case.

@Alfie-Anil said in Opening txt files in qt c++ and writing to it.: QFile file("urlfile.txt"); This file will be relative to whatever the current directory happens to be in your application at the time the line is executed. Which may or may not be correct. Safer would be to use an absolute path. the same location as the directory that the project is saved in I don't know what "the directory that the project is saved in" is. There will not be any Qt methods to retrieve such a thing. There will be for, say, where the executable is being run from. Writing to such a location at runtime is not a good idea anyway. Look through https://doc.qt.io/qt-5/qstandardpaths.html#StandardLocation-enum to find a suitable one for where you want to save the file, and use that to build the absolute path.

Ok this worked: self.setSizePolicy(QtWidgets.QSizePolicy.Maximum, QtWidgets.QSizePolicy.Expanding)