General and Desktop

• 

  Unsolved Qt Creator suddenly says "No valid kits found."
  • Stokestack

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  Turns out this is a UI defect. Bug report filed: QTCREATORBUG-22353

• 

  Solved Building mqtt
  • FranciscoNC

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  It works, thanks :)

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  Unsolved Warnings
  • nammidd

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  What distribution are you running ?
  Are you using the Qt version it provides ?
  What filesystem are you using ?

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  Unsolved QAudioDeviceInfo::availableDevices does not detect USB audio headset
  • JoeCFD

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  How did you install that old version of Qt ? Is it the one provided by your distribution ?

  Note that Qt 5.5.1 is a bit outdated. The current version is 5.12.3 with 5.13 that is coming.

• 

  Unsolved A tree like Qt object architecture and QML
  • Bremenpl

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  It should be a tree of QObject and then you can use slots/Q_INVOKABLE methods/etc. to interact with them.

• 

  Solved Displaying a text in a QGraphicsScene
  • Sayanel

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  Well MyClass inherits from QWidget
  The idea I had was to have MyClass handle everything inside my 'graphicsView' -in order to not have it pollute the main windows-. This way I can interact with the scene using MyClass method and I can have it have slots.
  The idea is to crate a zone (foo.scene, displayed on the widget graphicsView) where I will be able to put all the object I want at the position I want.

  I found this example (https://doc.qt.io/qt-5/qtwidgets-graphicsview-chip-example.html) which I think does what I want (via its class 'View')

• 

  Unsolved application issues
  logo • • Sir_Moak

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  @Sir_Moak said in application issues:

  Am not really getting the doc at https://doc.qt.io/qt-5/layout.html. i just want someone to highlight how to go about it quickly as i have already built the app and wanna hook it up ASAP
  and for the errors as tool tip, it could be a notification alert which is fixed at the top left or right

  Hi and welcome to devnet,

  If you want more precise answer, you have to give more details about how your application should be looking.

• 

  Unsolved Choose between model/view or other approach
  • mix359

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  @mix359 said in Choose between model/view or other approach:

  It's not a matter of efficiency, because many of the data are simple data that can be represented with a derivation of QVariant, so I can probably put all of this data in a QList o QMap.

  You can use any storage/class/structure you want. It could be a database backend or anything. Also, you are not limited to using only the data() function. You could use that for a standard roles for listing things, but also define more getters/setters for the model object or another object if wanted. Use the index returned from the standard interface in getter/setter calls on that object to do more complex stuff. Just make sure you couch changes in the model that could affect what is shown in the views inside the correct begin/end data changed calls.

  We use qml for a lot or our work and it is common for there to be stuff we do outside the model if it makes sense. Like you might want to return a custom object to the qml interface we may have more methods defined on the model itself. I don't know if your using qml, but it is nice for doing complex interactions. I am sure you could do the same if your using widgets.

  The model/view code in Qt is really good at displaying lists and trees. No reason to reinvent that. Then add complex functionality if needed, where needed.

• 

  Solved How can I translate this openGL functions to Qt?
  • JesusM

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  @fcarney that's what I needed!.
  I had :

  protected QOpenGLFunctions

  but,as you said, some specific OpenGL functions are not there and I needed:

  protected QOpenGLFunctions_4_2_Core

  to use them.

  Thank you so much!

• 

  Solved A few questions about QWebsockets and packet order.
  • Hasan Al-Baghdadi

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  Thanks, that clears things up.

• 

  Unsolved NURBS SURFACE
  • Irodov

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  Hi,

  Then you should ask the QCustomPlot authors about that.

  It's not an official Qt module.

• 

  Unsolved I have some problems when using a select statement in the bindValue function
  • lso70

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  Locked as duplicate of https://forum.qt.io/topic/102044/i-have-some-problems-when-using-a-select-statement-in-the-bindvalue-function

• 

  Unsolved Building my own Qt and using it in Qt Creator
  • JonathanA

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  Sorry, it is 5.12.3. That's just the readme I used to jot down config notes from the first time I built it with 5.12.1

• 

  Unsolved Crash in QString destructor (while fetching reference count).
  • Bart_Vandewoestyne

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  I would guess you're deleting your class 'Bar' twice but it's only a guess without a reproducible minimal example.

• 

  This topic is deleted!
  • Dariusz

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• 

  Solved Showing data from multiple SQLite tables
  database model-view sqlite view • • Pl45m4

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  @Christian-Ehrlicher

  Hm ok... That's not what I wanted to hear :D
  Thank you anyway.
  I think, I will subclass QSqlQueryModel then and write functions to make the model writable...

• 

  Unsolved How to set the right method
  • Zunneh

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  @Pl45m4
  Just a little mistake xD.

• 

  Unsolved -lglut not found after upgrading from Qt 5.11 to 5.12 on Windows
  • Vadi2

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  Can't even see the first error, not even the full logs from appveyor show it :(

  I'm using the Qt version provided by AppVeyor - I don't think they compiled it themselves, but I can't be sure. I'll ask.

• 

  Unsolved QOpenGLShader::link: Vertex info error: must write to gl_Position
  • JesusM

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• 

  Solved Problem loading an image with QImage
  qimage error qopengltexture path image • • JesusM

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  @KillerSmath That solved my problem. Thanks!

• 

  This topic is deleted!
  • tungsteno

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• 

  Unsolved Drag & Drop inside of a ListView
  • WeWon44

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  Thanks, that was very useful, I still have doubts on how to implement this correctly (mainly how to get the correct position) since I never manipulated events but I’ll give this a try and share the results in a few hours

• 

  Unsolved QDebug & QFlags - pretty text?
  qflag qflags qdebug • • Dariusz

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  @Dariusz said in QDebug & QFlags - pretty text?:

  I cant have 100+ flags :- (

  Why do you want to have so many flags in one property?
  "do I need to number each item in my enum 1/2/4/8/16" - yes, if you want to combine several flags in one variable. Flags use OR to set a flag, AND to unset the flag. This is why each flag must have its own bit in a the integer value:

  // Set flag 0x01 with some other flags already set 01010000 OR 00000001 = 01010001 // Unset same flag keeping other flags 01010001 AND 11111110 = 01010000

  "but I'm getting weird flags" - what do you mean by that?

• 

  Solved QTcpServer::newConnection() does not work when realized in another class
  • gaosiy

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  @gaosiy said in QTcpServer::newConnection() does not work when realized in another class:

  but when I want to use TCP communication with UI, the same way of my method does not work

  You should not do it same way in a UI application: your UI application will already have an event loop.
  Doing the connect in MainWindow constructor (or its init() method) is perfectly valid and the right thing to do. Your server should not know anything about your UI, so it can't do the connect to UI as it does not know anything about it :-)

• 

  Unsolved How to configure Qt Creator with emscripten compiler?
  • Jose Bento

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  I have follow the instruction from https://gist.github.com/blockspacer/698fbca13c01ab977256849daa6cc084
  Compiled folder for my Qt-Wasm : ~/qt5
  and emscripten: ~/emsdk/emscripten/1.38.30
  for sample project : ~/qt-webassembly-examples
  And everything work well.

  I use fedora 29 and Qt 5.12. And for Qt Creator I use these configuration:

  Option->CMake , add the new configuration :
  Name: System Make at /usr/bin/make
  Path: /usr/bin/make

  Option->Compilers, Add->Custom->C and C++
  For C
  Name: EMCC
  Compiler Path: ~/emsdk/emscripten/1.38.30/emcc
  Make Path: /usr/bin/make
  ABI: x86 - linux - generic - elf - 64bit

  For C++
  Name: EMCC
  Compiler Path: ~/emsdk/emscripten/1.38.30/em++
  Make Path: /usr/bin/make
  ABI: x86 - linux - generic - elf - 64bit

  Option->Qt Versions, Add new configuration
  Version name: Qt %{Qt:Version} (qt5) wasm-emscripten
  qmake location: ~/qt5/qtbase/bin/qmake

  Option->Kits, Add new configuration
  Name: emscripten
  File system name: leave empty
  Compiler: C: EMCC, C++: EM++
  Qt Version: choose from we filled before (Qt %{Qt:Version} (qt5) wasm-emscripten), in my system is : Qt 5.12.3 (qt5) wasm-emscripten
  Qt mkspec: leave empty
  CMake Tool: System Make at /usr/bin/make

  Now try "Run qmake" on project than "Build"
  The project builder maybe at build- {project_name}-emscripten-Debug/Profile/Release.
  Go to that folder from terminal, and run using "python -mSimpleHTTPServer"

  don't forget to set kit Build&Run Setting into "emscripten"
  for test project i use the project "gui_multicanvas", u can open it from qt creator.

• 

  Unsolved Qt Static Build with SQL plugins/libs
  • dalishi

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  IIRC, you would have to put the whole path to the file that needs to get linked.

• 

  Unsolved Item of QAbstractListModel changes type after beeing updated
  • Slash200

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  @SGaist No they don't point to the same address.
  I want to visualize a single item.

• 

  Unsolved How to connect IP camera to QT ?
  • indrajeet_janyu

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  Hi and welcome to devnet,

  What kind of camera is that ?
  What kind of connection are you going to use ?
  What is the use case of this application ?

• 

  Unsolved Best approach to process frames in) a Queue (producer) and consuming from a thread pool ? (consumer
  • RahibeMeryem

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  Also for all the image processing ?

  Are you using Qt only for displaying the final result ?

• 

  Solved How do I make #defines in a header file visible to the whole project?
  • Stokestack

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  @Stokestack said in How do I make #defines in a header file visible to the whole project?:

  and called it a day.

  If your issue is solved, please don't forget to mark your post as such. Thanks.

• 

  Unsolved Different styles for qtreewidgetitem 's of the same qtreewidget
  • Black Imp

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  @JonB thank you. I think I'll try to manage different look just with background and foreground colors, via code.

• 

  Solved What should I be replacing foreach with?
  foreach iterators • • mmikeinsantarosa

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  @mmikeinsantarosa
  FWIW, I used parameters: static constexpr int scale = 10000, iterations = 100 * scale;
  And the non-detaching iterator was 24 times faster
  Detaching: 1247
  Non-detaching: 51

  So this is a good thing to know!

• 

  Unsolved DYLD_LIBRARY_PATH equivilant for Windows?
  • kitfox

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  @kitfox On Windows, the normal PATH is searched for DLLs also, plus the current directory (and IIRC some hardcoded like Windows\system32)

  Regards

• 

  Solved Deploying Qt app in Windows
  • xtingray

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  Not for the dlls - but it's up to you where to put your own dlls and data. Fiddling around with some batch files is crying for problems.

• 

  Unsolved QImage and TGA support in c++
  • dokif

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  @KillerSmath May be i got happy to soon.. that function only loads correctly for me 24 bit compressed tga.. but it fails with 32 bits (and does not support 16 bit). Also, i think it does not support transparency.

• 

  Solved mouse press event on everything?
  • legitnameyo

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  @legitnameyo
  I dont know other ways. event filter can allow pass through so it don't suffer nearly the same but
  since you consume the click to close the Frame, then most solutions will suffer this.
  Why not just tone the overlay widget with some transparent color its clear to user that Frame is in foreground.
  Then he click to remove and then click on what he wants.

  You could also try making with changing focus. When you pop Frame, you set focus to it.
  if something else gets focus then close it.
  https://doc.qt.io/qt-5/qapplication.html#focusWidget
  But that only works if user clicks on something that can have focus.

  so if you dont want to use
  https://doc.qt.io/qt-5/qapplication.html#widgetAt
  and select it for focus after first close click then im afraid im
  out of ideas.

• 

  Unsolved Qt 5.11+ : How to use Qt Quick Compiler? (Qt Open Source Version)
  • Ibrahim

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  @Ibrahim said in Qt 5.11+ : How to use Qt Quick Compiler? (Qt Open Source Version):

  Well, how can I understand that is QtQuickCompiler running?

  Since I think, that this is still not properly answered, here is a way to test, if your build used the Qt Quick compiler:

  A benefit of the Qt Quick compiler, is that syntax errors are checked during compilation.

  So you can just put some invalid QML syntax in your qml file and test if the build finds the error during compilation (then you are using the compiler) or if the error is only found when running the application (then you are using the interpreter).

  So. e.g. put the following at the top of your main.qml and see what happens:

  imports asdf

  This trick worked fine for me. In my case my problem was that I was still using in my compilation options Qt5.10, after that I have to configure CONFIG += qtquickcompiler in the build steps inside qt.

  I added CONFIG += qtquickcompiler parameter to .pro file but I get this error message when I compile my app:

  I think that this was your error, you should not define it on .pro but in the compile options steps for qmake. I can even see checkbox that indicates me if the compiler is enabled or not.
  Th

• 

  Unsolved Missing Android SDK Packages
  • tomy

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  Unsolved 3D world coords to 2D screen coords
  • TontonLeon

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  Unsolved Is declaring functions as slot still needed/meaningful with the new function reference connect?
  • l3u_

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  Thanks for the info!