Skip to content

General and Desktop

This is where all the desktop OS and general Qt questions belong.
83.5k Topics 457.1k Posts
  • QWidget - the drawn image is erased

    Unsolved
    7
    0 Votes
    7 Posts
    497 Views
    SGaistS
    Hi, Keep the QPixmap rather than execute the conversion each time.
  • Save number with high decimal

    Unsolved
    15
    0 Votes
    15 Posts
    2k Views
    kshegunovK
    Use a stable solver. Your matrix is quite close to singular. QR comes to mind, eigen already provides it out of the box.
  • QTableView field (related to other db table) does not get refreshed

    Unsolved
    1
    0 Votes
    1 Posts
    86 Views
    No one has replied
  • Example of calling a function to parent?

    Unsolved
    38
    0 Votes
    38 Posts
    5k Views
    M
    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 ?
  • Qt5 default text encoding has chaged

    Solved
    10
    0 Votes
    10 Posts
    1k Views
    Christian EhrlicherC
    @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.
  • What causes error " called on pointer returned from a mismatched allocation function"

    Unsolved
    7
    0 Votes
    7 Posts
    5k Views
    ocgltdO
    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)
  • How do you re configure a Qt build from source?

    Solved
    3
    0 Votes
    3 Posts
    858 Views
    R
    Thanks - I was following some internal documentation which is probably not the best idea. Your answer makes sense.
  • This topic is deleted!

    Unsolved
    25
    0 Votes
    25 Posts
    26 Views
  • Update qml value dynamically in C++ using thread

    Solved
    15
    0 Votes
    15 Posts
    2k Views
    P
    It was a great help for running threads. Running in QtConcurrent::run([=], really solved all the issues of my UI non responsive ness.. Thanks a lot for your help
  • Find public IP of my internet connection

    Solved
    11
    0 Votes
    11 Posts
    836 Views
    Christian EhrlicherC
    @markolino_it Then please mark the topic as solved.
  • qt.qpa.xcb: could not connect to display

    Unsolved
    2
    0 Votes
    2 Posts
    787 Views
    jsulmJ
    @overfl0w said in qt.qpa.xcb: could not connect to display: which is still ROOT privilege uid/gid of 0), it fails about the 3rd of 4th plugin loading (XCB) Usually, root cannot access X server when running from other user account. Do you really have to start your app as root? Regarding plug-ins: set QT_DEBUG_PLUGINS=1 in a terminal and start your app there: there should be much more output providing more details why exactly the plug-in isn't loaded, please post it.
  • Minimum width and height not working on QDockWidget

    Unsolved
    2
    0 Votes
    2 Posts
    519 Views
    SGaistS
    Hi, If memory serves well, you should do that to the widget inside the QDockWidget.
  • macOS and Qt set-up

    Solved
    6
    0 Votes
    6 Posts
    524 Views
    SPlattenS
    @SGaist , I think the actual problem was low resources ( disk space ), I've cleaned up and removed a lot of junk, now installing again.
  • Intermittent crash passing QVariantMap from QML to C++ worker thread

    Unsolved
    1
    0 Votes
    1 Posts
    215 Views
    No one has replied
  • How to update parents QTableView

    Solved
    7
    0 Votes
    7 Posts
    531 Views
    P
    Ok it works! In the constructor: positionsForm::positionsForm(QSqlRelationalTableModel *parentmodel, QWidget *parent) : QDialog(parent), ui(new Ui::positionsForm) this->parentmodel = parentmodel; connect(ui->positionsTable->model(), SIGNAL(dataChanged(QModelIndex,QModelIndex)), this, SLOT(updateParent())); And the function: void positionsForm::updateParent(){ qDebug() << "updateParent called!!"; this->parentmodel->select(); }
  • Setting QProxyStyle on TabBar, overrides Palette

    Unsolved tabbar palette setstyle
    12
    0 Votes
    12 Posts
    2k Views
    SGaistS
    Looks likes there might be a bug that has crept in. I have a related but different issue with the macOS style.
  • tabbar scrollbuttons?

    Unsolved
    10
    0 Votes
    10 Posts
    654 Views
    SGaistS
    Are you sure that it is not just related to the fact that you are at the far left of the tab list ? The same happens with macOS. The left button is transparent but as soon as you start moving the tabs with the right arrow, the left one fully appears and becomes usable. It becomes again transparent when full left is reached again.
  • connection with google on Qt

    Unsolved
    12
    0 Votes
    12 Posts
    2k Views
    SGaistS
    Did you saw this updated version of the example code you likely used for your application: https://appfluence.com/productivity/how-to-authenticate-qt-google-sso/ ?
  • This topic is deleted!

    Unsolved
    1
    0 Votes
    1 Posts
    5 Views
    No one has replied
  • Get Mouse local position on key press event

    3
    0 Votes
    3 Posts
    4k Views
    F
    @RiccardoTurati Could use mapFromGlobal.