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Qt 6

This is where all Qt 6 related questions belong

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  • Read before posting in this category!

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    SGaistS
    And now (incomplete at the time of this post): https://wiki.qt.io/New_Features_in_Qt_6.2
  • How to update CmakeLists.txt for android build from qt5 to qt6?

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  • Qt Graphs. Building 2d plot using c++ only.

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    BugSleeperB
    @Christian-Ehrlicher Ok! @everyone Another question is , how to remove one line from current list in C++? Some App such as process monitor will frequently add or remove lines in the middle of current list. However, I notice that QML List operations can only add or remove objects from the end. //qqmllist.h AppendFunction append = nullptr; CountFunction count = nullptr; AtFunction at = nullptr; ClearFunction clear = nullptr; ReplaceFunction replace = nullptr; RemoveLastFunction removeLast = nullptr; At this moment, we can clear the graph, and re-add lines. But this is not a nice solution. May be a "removeAt" function or "removeOne" can be adopted for this usage in future. There seems to be extra works for QScatterSeries and other classes from QtCharts to QtGraphs, new class has fewer functions and properties than old one. And, Will multi-Y Axises be supported in future ? For example, we can bind a line series to left axis in Kg or right axis in Meters.
  • Apple Liquid Glass on Qt

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    @raulgd said in Apple Liquid Glass on Qt: Apple Liquid Glass on Qt Unsolved Qt 6 5 posts 4 posters 530 views 2 watching Mark unread Not Watching Oldest to Newest Reply ROffline raulgd wrote on 19 Jun 2025, 20:31 last edited by #1 Hi all, How hard would it be to get Qt 6 to use the native liquid glass UI on Qt? If it's QML I guess a whole new Qt Quick Controls theme would be needed, and also won't take advantage of all the little details and nuances the original liquid glass has, and Qt Widgets also is its own thing right? it's not just a wrapper to call the OS native controls. Qt 6 doesn’t come with Apple’s Liquid Glass UI built in, so you’d need to design a custom Qt Quick Controls theme in QML to get the look. Even then, it won’t perfectly match all the little details of the real thing. Qt Widgets also don’t just use the OS’s native controls, so they’d need their own custom styling too.
  • Installation issues of Qt on Windows Server 2022

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    @SGaist It should normally be like the following: [image: ef0e01c8-280c-4a6e-bada-881e471b2fba.jpg]
  • How to disable linking with Qt6EntryPoint in qmake ?

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    W
    Could anybody provide an example possibly for a project with MFC, msvc and vcproj? How to override the qmake settings from the Qt Tools?
  • Facing issue in installing QT

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    now its failing due to: FAILED: v8_context_snapshot_generator "<>/python-3.8.1-rh7/bin/python3" "<>/qtwebengine/src/3rdparty/chromium/build/toolchain/gcc_link_wrapper.py" --output="./v8_context_snapshot_generator" -- <>/gcc-10.3.0-rocky8/bin/g++ -Wl,--build-id=sha1 -fPIC -Wl,-z,noexecstack -Wl,-z,relro -Wl,-z,now -m64 -Wl,-O2 -Wl,--gc-sections -Wl,-z,defs -Wl,--as-needed -rdynamic -pie -Wl,--disable-new-dtags -L<>/rocky8/harfbuzz-11.3.3/lib64 -o "./v8_context_snapshot_generator" -Wl,--start-group @"./v8_context_snapshot_generator.rsp" -Wl,--end-group -latomic -ldl -lpthread -lrt -lsmime3 -lnss3 -lnssutil3 -lplds4 -lplc4 -lnspr4 -lresolv -ljpeg -lpng16 -lz -lxml2 -lxslt -lm -lexpat -lfreetype -lfontconfig -lharfbuzz-subset -lharfbuzz -ldbus-1 -ldrm -lasound -ludev -Wl,--start-group -Wl,--end-group <>/qt/build/qtwebengine/src/core/Release/x86_64/obj/third_party/blink/renderer/modules/app_banner/libapp_banner.a: error adding symbols: Malformed archive collect2: error: ld returned 1 exit status
  • button on top QVideoWidget

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    DeSGuND
    @JonB read post more once and did through qml thanks an answer
  • Qt5 is better than Qt6

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    goldenhawkingG
    @DevWinDemon I also use msys2 ucrt64 qt6, may be you can make things better follow these approaches. Copy your exe file into a release directory. Make and run msys2qtdeployplus under the same env, such as mingw64 bash or ucrt64 bash, everything will be ok. the msys2qtdeployplus will do : (1) Call windeployqt5/6 for every exe and dlls in the release dir, and, extra dep dir as needed. (2) Repeatly call ldd/ntldd for each dlls in the release dir, copy extra dependcies from msys64/ucrt64 bin dirs to the release dir. (3) If there were no more extra dlls be copied, goto (4), else, repeat , goto (2) (4) Finished. Before this approach, please make sure that ldd /ntldd, windeployqt5 or 6 has been installed by pacman -S, in your env, such as ucrt64. Repeatly calling ldd/ntldd is very important, for example, Qt SQL psql plugin need libpq, but libpq also has its' own deps, libcrypto.dll and so on. [image: f22d9cd9-76c2-494c-9742-8f8b6efd1078.png] Call upx tool with "find -exec", for every dll and exe in release dir, using lzma and deep trim switchers, that can significantly reduce the files size. upx can be installed by pacman -S.
  • Raspberry CM 5 Boot2Qt 6.9.1 - no text and incorrect colors

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    jsulmJ
    @Volodymyr-Mudryk Boot2Qt is commercial software, so you can ask QtCompany directly for support
  • QTableView setSpan + moveSection causes selection mismatch

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    @Christian-Ehrlicher Added a link and a quote in the commentary to the report
  • 50 signal/slots

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    JonBJ
    @servant-0 said in 50 signal/slots: I setup the 50 signals to emit their object name as a QString and call findChild on it to update the text on a label in the slot All as @J.Hilk has written about findChild(). Also it depends hugely on whether your target widget is "close" in the hierarchy to the widget you call findChild() on. If that is "high up" it has a lot of searching to do if there are a lot of descendent widgets. It sounds like you have a backend data layer which emits a signal when it changes and passes the value of what will be used as a widget's objectName() to indicate which widget to update? If so that is not ideal for decoupling data from UI. You might like to look at QDataWidgetMapper for a means of tying widgets to data values (works in both directions, though you may only need data->widget direction). For that you would store your data values in anything derived from a QAbstractItemModel and any time that data changes internally a signal is sent and the corresponding widget is updated (without lookup).
  • Missing DLLs in QT6....I think

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    Christian EhrlicherC
    These dlls are installed in the same directory as the release dlls - <QTDIR>\version<compiler_type>\bin
  • Stack widget setCurrentWidget does not change the widget

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    J
    Hello, before using ->setCurrentWidget(), you can check if that widget is already contained in that stack widget or not. you can m_centralStackedWidget->indexOf(m_windowSplitter) to find out if the widget is present in the stackwidget or not, it will return "-1" if the widget is not present in stackwidget
  • How to use QProcess with QtConcurrent?

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    JonBJ
    @Teg-Miles It's not so much that QProcess "wasn't created for threading", it's that there is no need (and only added complexity) to use threads to run the the processes since another process is asynchronous anyway. It won't even use any calling threads you might create anyway, as soon as a sub-process runs it is in its own thread/process anyway, not the one which ran it. No, ps will not be faster than, say, reading from /proc yourself as that is what it will be doing anyway --- it's not magic, it has to be written in C/C++ itself anyway. OTOH there is an overhead inherent in creating and running another process, plus whatever IPC or I/O you do to get its data back. That will be true on Windows too. I assume Get-Process is a PowerShell command a bit like ps? So again that is just one way you could call it. There will also be Windows own system calls to get information about other processes, and calling those yourself from C/C++ will get better performance. But finding out how to do this in Linux/Windows/MacOS may be something you don't want to do and you find running some command on each OS and reading its output is what you prefer for a simple, non-commercial program.
  • Qt 6.8.3 or higher Font displays incorrectly on systems with Japanese language.

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    SGaistS
    You can use qDebug to print your application's font information.
  • Qt Applications Font doesn't look right.

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    T
    @Cruzmatt22 I do have WinAero Tweaker installed but System Font is set to default. Also the command line parameter did work. I was hoping there was some sort global fix.
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    Christian EhrlicherC
    @DevWinDemon said in The code execution cannot proceed because Qt6Core.dll was not found. Reinstalling the program may fix this problem.: I work 2 years like this on qt 5.15.16 Nobody hinders you to make it work the same with Qt6 - simply put it in the PATH env var as you did for Qt5. Please stop insulting people for things neither we nor Qt can do against - that's how a library search path on windows works (and also on linux there is a similar thing). So learn on how library search is working on your platform. But maybe your russia os has a better solution for this...
  • Install Qt6StateMachine with aqt install-qt

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    S
    Thanks @Paul-Colby This was helpful.
  • Qt6 + GStreamer

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    SGaistS
    Are you setting the CMAKE_PREFIX_PATH variable to point to the Qt version you want to use ?