General and Desktop

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  How to create the plugin of MYSQL for Qt
  • BlackStar  

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  @flydragon Do not duplicate posting because you do not get an answer immendiately. [edit:koahnig see https://forum.qt.io/topic/82629/why-qsqlquery-exec-exit-failed ]
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  Reporting inappropriate content on the forums
  spam • • Eddy  

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  Thank you for the report. I have banned the user, which got rid of the spam posting. Not a loss, as this user did not post any other content on the site. Just deleting this one posting was not possible. Thanks for reporting this.
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  UNSOLVED Problems launching a QProgressDialog after main window is made visible
  • JCBaraza  

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  UNSOLVED Regarding Projector Programming using QT
  • Prath  

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  @Prath said in Regarding Projector Programming using QT: after running the above programme which program? The Serial Terminal example I suggested before? Have you tested managing the projector using any other terminal application? Just to validate it works fine...
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  UNSOLVED Successfully loaded .qm files, but translator remained empty
  • QTLeearn  

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  UNSOLVED How to normalization the tick value of QCustomPlot?
  • cyberpunker  

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  Then you might want to contact its authors. They might be faster to answer than here.
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  UNSOLVED Error during uninstalling Qt application from MacOS
  • aliks-os  

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  In the app container ? What do you mean by that ? Did you check the user permissions ?
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  UNSOLVED Layered Views
  • Folling  

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  UNSOLVED Best way to process cv::Mat 's in threads? intell tbb & QThread with event messaging or QThrealPoll ?
  • RahibeMeryem  

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  @SGaist I am trying signal slot connection to distribute frames :) little stupid. one idea is the putting a shared QQueue and pulling frames from threads to process What is the best approach to wait Queue is not empty without wasting cpu time ?
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  UNSOLVED Font size paint by QPainter do not looks consistent under different resolution
  • tham  

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  Hi, Do you mean the text should grow depending on the size of the widget ?
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  UNSOLVED Opening a window behind main window
  windows mainwindow pixmap graphicsview raises window • • hodahle  

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  UNSOLVED is it possible to use QtConcurrent::mapped inside a QThread ?
  • RahibeMeryem  

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  Hi, AFAIK, yes you can. You have to benchmark the processings you need before designing a pipeline for your video application.
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  UNSOLVED How to detect Drops outside of the target
  • sandro4912  

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  My question was more - how do you begin the drag operation? Normally you call QDrag::exec() or something similar which returns the drop action used.
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  UNSOLVED stop a loop in object that has been moved to a QThread?
  qthread loop movetothread stop • • pauledd  

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  @pauledd said in stop a loop in object that has been moved to a QThread?: Worker::doWork() As shown, at no time is this function checking the Qt Event loop. public slots: void doWork(){ ... while(m_running){ // process server UA_Server_run_iterate(m_server, true); // process events like signals QCoreApplication::processEvents(); } ... } void stopWork(){ m_running = false; } There are signals connected to the slots above to control my server.
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  SOLVED OpenCV VideoCapture Failure from QThread
  qthread gui crash opencv videocapture • • rtavakko  

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  @JKSH This is how I emit the OpenCV mat data: emit processedImage(2, videoFrameOut.ptr(0,0),videoFrameOut.cols, videoFrameOut.rows, videoFrameOut.step); The first parameter is just used to determine which display should draw the image and the rest are dimensions and stride which I think are ok. @SGaist You are correct, I changed the line below to make a copy: displayImage = QImage(imageData, width, height, step, QImage::Format_RGBA8888).copy(0,0,width,height); I think this fixed the issue. I got a couple of crashes in 'memcpy' but that was when loading files a little too quickly. I think most likey resizing the data quickly was the issue. I will do more testing this week and post the results. Thanks!
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  UNSOLVED Trying to Build Qt 5.13.2 for Windows
  • DragonOsman  

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  I've decided to give up trying to build it and am now installing the 5.13.2 binaries directly. I have the GnuWin32 stuff needed for Qt WebKit, though, and I'm wondering if I'm still going to need to build that or if the prebuilt binaries come with it already.
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  UNSOLVED QMediaPlayer stream data from a self signed https server
  qmediaplayer streaming https • • Vagabond  

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  @Vagabond Could it be possible you connect QNetworkAccesManager::sslErrors() signal to some slot where you can inspect what may be going on, in particular look for QSslError::SelfSignedCertificate which you can ignore... see snippet in QNetworkReply::ignoreSslErrors() documentation.
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  UNSOLVED SIGNAL and SLOT....
  • bricedorsey  

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  @bricedorsey said in SIGNAL and SLOT....: i havewrite it correct.. Your connect statement is wrong - I already told you why.
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  UNSOLVED Trying to implement QChart, get error undefined reference to 'qt_version_tag@Qt_5.9'
  qchart qtversiontag • • markd  

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  @markd said in Trying to implement QChart, get error undefined reference to 'qt_version_tag@Qt_5.9': As noted above, if I comment out the 'new QChart(); line I get the following: $ ldd LTSD | grep -i libQt5 libQt5Widgets.so.5 => /opt/Qt5.9.1/5.9.1/gcc_64/lib/libQt5Widgets.so.5 (0x00007f2451f3d000) libQt5Gui.so.5 => /opt/Qt5.9.1/5.9.1/gcc_64/lib/libQt5Gui.so.5 (0x00007f245178f000) libQt5Core.so.5 => /opt/Qt5.9.1/5.9.1/gcc_64/lib/libQt5Core.so.5 (0x00007f2451055000 As soon as I add the line " QChart *slagchart = new QChart();" to my code, I get the error. The linker doesn't build an executable so I can't check ldd to see where it is trying to get the library.
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  SOLVED Linking error with zlib library - LNK2019: unresolved external symbol _deflate referenced in function
  • rajendrasp79  

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  I got the fix, the problem was that the kit I was using was VS 2015 and the lib was probably built using VS 2017. I switched to VS 2017 and it is working fine
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  UNSOLVED Smooth out gps path on map (QLocation), how to ?
  • Marek  

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  @Marek said in Smooth out gps path on map (QLocation), how to ?: I would like to display this route on a QML map and make it smooth Have you try your app displaying a live GPS feed? If so then you may want to use your log file as source, take a look at this article.
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  SOLVED Mac OS Mojave privacy prompt not appearing in notarized builds.
  • Joshua Parmenter  

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  I finally got this working. The info plist needs to have a string in place to ask for permissions (as mentioned already) and the app, when signed, needs to have entitlements attached that include: <key>com.apple.security.device.audio-input</key> <true/> <key>com.apple.security.device.microphone</key> <true/> Hope that helps someone else in the future!
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  UNSOLVED How to communicate with a BLE device?
  • SietseAchterop  

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  UNSOLVED Scxml: sending external event from a state
  • vladzouth  

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  SOLVED How to open a KDE konsole app via QProcess?
  • SandyLocke  

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  @SandyLocke said in How to open a KDE konsole app via QProcess?: worked so please mark your post as solved then. Thanks.
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  UNSOLVED currentChanged fires immediately upon initialization?
  • SRaD  

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  @SRaD you may want to think of connect, signal and slot as wiring, switch and bulb respectively. With connect() you wire the switch to the bulb, then when you emit a signal is like actuating the switch so the electricity ends up in the bulb (the slot) where you carry on things (light your room).
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  UNSOLVED how to upload images taken from QTapp to Cloud Server
  qcamera api google drive • • vinaygopal  

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  @jsulm sorry for the late reply, i am trying to implement this on a desktop, i am able to take a picture using the camera and also able to store it on to my local desktop is there a way i can take access to my google drive stroge server and upload the image directly to the server?
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  UNSOLVED How to manage incoming serial data to avoid data loss
  • Ketank16  

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  @VRonin void serial::framesAvailable() { qDebug() << "serialport.isTransactionStarted() = " << serialport.isTransactionStarted(); //QTextStream stream(serial); if(serialport.isTransactionStarted() == false) { for(;;) { serialport.startTransaction(); if(stream.readLineInto(&tempLine)) { if(tempLine != '\0' && tempLine.size() == 1) { //qDebug() << "tempLine " << tempLine << tempLine.size(); line.append(tempLine); serialport.commitTransaction(); } } else { serialport.rollbackTransaction(); break; } } //qDebug()<< "line " << line; if(line.size() == 192 && line.startsWith("CH")) { divided_line = line; line.clear(); //qDebug()<< "line " << divided_line; emit linereceived(divided_line); } } }
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  SOLVED HiDPI and SVG icon resolution
  svg icons resolution hidpi • • cle1109  

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  Turns out there is a simple solution: app.setAttribute(Qt.AA_UseHighDpiPixmaps)
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  UNSOLVED Is there any way to block the keyPressEvent event on the keyboard?Is there a switch method?
  • canid  

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  @canid I dont know / tested if it works but you could try to install an event filter and ignore some key events on your form and let other keys through
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  This topic is deleted!
  • SenltonGomes  

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  UNSOLVED modify QTableWidget row contents
  • russjohn834  

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  @Christian-Ehrlicher Thanks. @Christian-Ehrlicher said in modify QTableWidget row contents: btw: why are you creating the xml reader on the heap - now you're leaking it. I do this at the end. // close reader and flush file xmlReader->clear(); xmlFile->close(); // Delete delete xmlFile; delete xmlReader; @Christian-Ehrlicher said in modify QTableWidget row contents: And what's the exact problem now? This is im looking forward to implement: Click of particular row on QTablewidget AND modify should open a dialog with defualt some default values (read from that particular xml entry). it will be really helpful if some can show this with some pseudocodes. Thank you
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  UNSOLVED QPainter reset Transformation Does not work.
  • Sebastian  

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  UNSOLVED Qt3DCore - High CPU Usage
  • webzoid  

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  @webzoid said in Qt3DCore - High CPU Usage: @JKSH I'm assuming that you replaced "my_model.obj" with an alternative? Ah, no I didn't notice that your code needs my_model.obj. (Suggestion: When you want others to reproduce a problem that you're seeing, it's best to use examples that don't require others to create their own resource files) I've just run the Basic Shapes example and my current CPU usage is at 52.1%!!! Yikes! OK, since you can reproduce your problem on an official example, let's stick to this. Use this example when you submit a bug report. My machine is an Intel Core i5-2500 @ 3.30GHz + dual AMD Radeon HD 7500 graphics cards + 16GB RAM. That should certainly be enough to run the Basic Shapes example comfortably. Ok, so one thing I didn't highlight is that I'm running 3 displays from those dual graphics cards. Interestingly, if I have the Qt example application running on the primary display, the CPU usage is high. If I move the Qt window to one of the other displays then the CPU usage drops by about 30% to around the 24% region. Weirdness! 24% still seems quite high. What happens if you only have a single display connected to your GPU? I just noticed this on a different machine: Specs: Intel i7-7770 3.6 GHz 16 GB DDR4 RAM 3071MB NVIDIA GeForce GTX 1080 Ti 1920 x 1080 display Qt 5.13.1 for MSVC 2017 32-bit Behaviour for the Basic Shapes example when idle: Mode CPU Usage Debug mode 4% Release mode 17% Would you be happy to open a report at https://bugreports.qt.io/ ? (Provide as much details as you can, using an official example)
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  UNSOLVED General questions about Model in Qt (docs)
  • Xilit  

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  @J-Hilk Still don't work.( But as I've mentioned above I've already found in Woboq code browser. On this link). Interesting. I download Sources to make MySQL work, but it doesn't. Maybe that's why? Because Sqlite does. But I'm not sure what does Target path means.
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  UNSOLVED Mainwindow content gets vignetted at border
  • gde23  

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  UNSOLVED Reopen MainWindow
  • vel1024  

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  If your "myWindow" is just a window belong to the application you want to shut down. I'm afraid that we can hardly achieve that. We can't restart a window in a shuted down application.
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  UNSOLVED Refresh entire form upon pressing a button
  • russjohn834  

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  UNSOLVED QComboBox item model with ItemIsUserCheckable and ItemIsSelectable
  • Alvein  

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  @JonB ItemIsSelectable seems to have precedence over ItemIsUserCheckable. So, mixing the two flags, does not show the checkboxes. The problem with not using ItemIsSelectable is that the clicks over the items text are not being registered. So there's no way of knowing when the click wasn't over the check boxes. BTW, I don't think this behavior is so rare. I'm pretty sure a lot of applications register clicks on a check box text as if they were in the check box itself. It's a pity that it's not possible to add widgets inside combo boxes. I'll have to either implement a drop-down list widget or forget the dual behavior and just add a selectable "Done" item at the end of the list (and annoy the user in the process, because of the lack of clicks registering over the other items text).
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  UNSOLVED Change QComboBox popup highlighted item background color
  • qt.1234  

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  @qt-1234 Not sure what you tried. If it was what @qwasder85 typed in above, ComboBox will be wrong, you'll need to try with QComboBox .... I don't know exactly what you will want, you'll have to play and read. But I would start by verifying that from the docs page you can indeed get some of those samples to work, soi you know you're doing stylesheet right, and then move on to exactly what you need.