General and Desktop

• 

  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 ]

• 

  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.

• 

  Unsolved OpenCV VideoCapture Failure from QThread
  opencv videocapture qthread crash gui • • rtavakko

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  Hi,

  Are you subclassing QThread ?

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  Unsolved Why console prompt: QEventLoop: Cannot be used without QApplication?
  • canid

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  Hi and welcome to devnet,

  Can you show the code you are using ?

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  Unsolved Handle mouse swipe in SwipeDelegate of ListView
  • cristeab

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  No one has replied

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  Unsolved Problem to run QT-Webassembly Examples
  examples building error webassembly • • davidMus

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  No one has replied

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  Unsolved No widget is shown, strangely
  • tomy

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  By container widget I meant "a widget made to contain other widgets". Unrelated to QVector and friends.

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  Unsolved Starting process detached exit upon parent exit
  • SherifOmran

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  Hi,

  What version of Qt ?
  What OS ?
  What application ?
  Do you realize you are leaking QProcess objects ?

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  Unsolved Saving space on small displays
  • l3u_

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  @l3u_ said in Saving space on small displays:

  So how does being invisible block triggering the QAction while being hidden?

  Apparently it just does?... It was probably a design decision that actions don't apply to hidden windows, since they cannot have an active user context while hidden.

  Maybe attach your action to the menu bar's owning window instead of the bar itself.

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  Unsolved Use QStandardItemModel with QTreeView
  • rmam

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  https://doc.qt.io/qt-5/qstandarditemmodel.html#details - there is a short example on how to build a tree, so yes it's possible to use it in a QTreeView.
  See also https://doc.qt.io/qt-5/qstandarditem.html#appendRow and https://doc.qt.io/qt-5/qstandarditem.html#appendRow-1

• 

  Solved QDateTime fromString () does not work
  • Samuel Ives

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  @Gerd it worked, but it's strange that the result of the query is with a 'T' in the timestamp while the server is not present

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  Unsolved How to center a column with a checkbox in QTableView?
  • Robert Hairgrove

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  And how to you set the value from the model? Using setIndexWidget is definitely no way to go.
  @gurpal2000 : fell free to provide a patch to Qt so it gets integrated... you can add me as reviewer.

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  Unsolved It is factible to create standalone internet softwares?
  • U7Development

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  Hi
  Should be feasible, however, web technologies have an edge with that sort of media.
  I wonder if qtwebengine would be enough for the viewing part so we could avoid
  too much code to render the elements.

• 

  Unsolved Add checkbox to QFileDialog
  • krzysieklfc

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  How to you execute the dialog? You have to use exec(), not one of the static functions...

• 

  Unsolved How use QGraphicsScene::itemAt ?
  • Mikeeeeee

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  @Mikeeeeee said in How use QGraphicsScene::itemAt ?:

  In this class I draw on QGraphicsScene.

  ...and you display the scene using a QGraphicsView, right?

  And I need to get information about the drawn object under the mouse

  QGraphicsScene does not understand mouse coordinates. QGraphicsView transforms mouse coordinates into scene coordinates.

  You have two options to get the item under your mouse:

  Use QGraphicsView::itemAt(), OR Call QGraphicsView::mapToScene() followed by QGraphicsScene::itemAt().

  More info: https://doc.qt.io/qt-5/graphicsview.html#coordinate-mapping

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  Solved How to make a SVG at tab Widget ?
  • RiceBall

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  @mrjj
  Thank you very much.
  I did it.
  I will learn hardly.

• 

  Solved Handling delayed dbus method
  dbus delayed method qvariant qmlextplugin error • • blacky_i

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  I've solved it.

  To handle long I did not have to send immediately reply (even though tutorial said that we have to). And delayed reply will be send.

  Also in extension, QDBusPendingReply<QString, QByteArray> reply = *call; setting expecting signature to \"say\" and not looking to xml interface.

• 

  Unsolved How to connect Risip in Qt
  • Mikeeeeee

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  @Mikeeeeee said in How to connect Risip in Qt:

  But PJSIP does not have dll and lib files.

  @mrjj is right. As I said in my previous post:

  build a version of the library that is compatible with your compiler.

  Here, "build" means use your compiler to create .dll/.lib files from the library's source code.

• 

  Unsolved Why QDoc don't work, it's really confusing.
  qdoc • • Stephen INF

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  Re: [Why QDoc don't work](it's really confusing.)
  I have the same issue with Qt5.12.0 on Windows. Does anyone have the solution for this?
  Some notes - the enumerators was processed without problems:

  class MyClass
  {
  public:
  enum Type
  {
  }
  void foo();
  }

  /*!
  \enum MyClass::Type - parsed without errors
  \value …
  */

  /*!
  \fn void MyClass::foo() - error: use of undeclared identifier 'MyClass' why???
  */

• 

  Unsolved Can't edit text in cell in a dynamic QTable model
  • jss193

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  Hi
  Besides i very much agree with @VRonin about using QStandardItemModel
  Your current issue is that you use 2 vectors now

  bool ModelTable::setData(const QModelIndex & index, const QVariant & value, int role)
  {
  m_gridData = new QVector<QVector<QString>>; // this is a new one, you add to
  ...

  so
  the one you make
  ModelTable::ModelTable(QObject *parent):QAbstractTableModel (parent)
  {
  m_gridData = new QVector<QVector<QString>>;

  Might not be used at all and just leak memory or be used in
  bool ModelTable::insertRows where its empty and still gives index out of bounds for that reason.

• 

  Unsolved how to change "OK" to my custom text on QDialogButtonBox?
  • opengpu

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  Hi
  You can use
  https://doc.qt.io/qt-5/qmessagebox.html#addButton
  to add custom buttons.

• 

  QAction cannot setStyleSheet?
  • opengpu

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  Hi
  What is it you are trying to archive ?

• 

  Unsolved convert interlockedincrement to atomic
  • SherifOmran

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  @SherifOmran
  Hi
  mingw should be able to use useInterlockedDecrement
  https://docs.microsoft.com/en-us/windows/desktop/api/winnt/nf-winnt-interlockeddecrement
  if you link against Kernel32
  so try wtih
  LIBS += -lkernel32
  in .pro file ( qmake + run rebuild all)
  and see if it will use it then.

• 

  Solved Switch off "Take a UI Tour" window appearing at start of Qt Creator. How?
  • bogong

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  @ehblan said in Switch off "Take a UI Tour" window appearing at start of Qt Creator. How?:

  I have the same problem . please where to switch it off in setting ? or change a file in system ?
  hi :
  after setting the sessions restore . the TakeTour dialog disappear .
  file > sessions > manage > select the " restore last session on startup " . done .

  it works on my Mac .

• 

  Unsolved how to debug Qt sources on mac
  • davecotter

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  Since you ran macdeployqt and install_name_tools, you like have everything loaded from your application bundle rather than from your Qt installation.

  Note that you have the -use-debug-libs option for macdeploqt that should help.

• 

  Solved Spout / OpenGL GL_RGBA to QImage
  spout opengl • • rtavakko

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  Just to sum up this thread for anyone else having this issue, this would be the correct way to do it:

  QImage img; unsigned char* data; data = new unsigned char[4*width*height*sizeof(unsigned char)]; img = QImage((uchar*)(data),width,height,QImage::Format_RGBA8888);

  Make sure you allocate the appropriate space needed. E.g. if image format is RGB, size of the data array will be 3 * width * height * sizeof(unsigned char) and the QImage format will be QImage::Format_RGB888.

  Thanks all for your help.

• 

  Solved How to make files preview like in native file manager?
  • Tundra

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  Upd: Be careful ─ code in http://www.cplusplus.com/forum/windows/100661/ conteins an error. There should be resource releasing:

  pIExtract->Release();
• 

  Unsolved How to break QGraphicsScene into fragments?
  • Mikeeeeee

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  Quoting myself:
  @SGaist said in How to break QGraphicsScene into fragments?:

  Then you'll have to implement that yourself. The render method won't do that for you.

• 

  Solved How to get QLineEdit to elide and align left?
  • patrickkidd

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  @Christian-Ehrlicher said in How to get QLineEdit to elide and align left?:

  It's working fine for me here:

  Are you sure you call it after your set the text?

  I can verify that setting the cursor position works using the following simple example, which means that my problem is somewhere else in my code:

  def test_QLineEdit_alignment(): app = QApplication(sys.argv) w = QLineEdit() w.setReadOnly(True) w.resize(50, 20) w.setText('1234567890 1234567890') w.setCursorPosition(0) w.show() app.exec() test_QLineEdit_alignment()

  Thanks!

• 

  Unsolved QOpenGLWidget no longer "paintGl"...
  qopenglwidget • • Dariusz

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  What do you mean by "slowly" ?

• 

  Unsolved Full uninstall Qt 5.*
  • GMAA

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  Hi and welcome to devnet,

  You can check their content. Based on what you wrote, I would say it is safe to delete these two folders.

• 

  Solved qtreeview item text too long
  • user4592357

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  @VRonin
  yes i just realized it's the displayText() method. thank you. and also can you please format the code so it's better readable? :)

• 

  Unsolved Manual loop
  • Mehodin

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  @Mehodin said in Manual loop:

  I uhh, i actually managed to find what i need by simply calling QApplication::processEvents() in a while loop, somehow that was enough so the UI would keep running and wouldn't deadlock

  Please don‘t, with each call to processEvents() a fairy dies !

• 

  Unsolved The correct way of instantiating the main widget in main.cpp
  • tomy

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  @J.Hilk said in The correct way of instantiating the main widget in main.cpp:

  it gets destroyed once app.exec returns and therefore deletes the object its pointing to

  it gets destroyed once after app.exec returns and therefore deletes the object its pointing to.

  So if ~QSuperClass calls deleteLater on some object that is not a child (or grandchild, etc) of this it will be leaked as correctly pointed out bu Christian

• 

  Unsolved how to edit specific column of QTreeWidgetItem, not all column editable but just some column editable
  • opengpu

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  @opengpu

  Did u look at this https://stackoverflow.com/questions/2801959/making-only-one-column-of-a-qtreewidgetitem-editable/2802379#2802379 ?

• 

  Unsolved Qt can protocol on windows desktop ?
  • Nouman

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  @Nouman

  Please see https://doc.qt.io/qt-5/qtcanbus-backends.html#can-bus-plugins for supported Hardware.

  Regards

• 

  Unsolved QTModbus
  • __vnv__

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  I have meet the same problem as you. And I solved it by using function sendRawRequest which can set different function code.

• 

  Unsolved Get target Object for drag and drop in QTreeWidget
  • clementNg

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  This was already answered correctly in another forum: https://www.qtcentre.org/threads/70302-Get-target-Object-for-drag-and-drop-in-QTreeWidget

• 

  Unsolved qtvirtualkeyboard jetsontx2
  • tyggylpp

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  No one has replied

• 

  Solved Problem compiling projects within solutions in MSVC 2017
  • MateoAero

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  @MateoAero said in Problem compiling projects within solutions in MSVC 2017:

  I was generating a separate DLL called "NetUtils.dll". Guess what: there is a DLL named exactly the same as part of windows. Therefore, it seems that during the DLL lookup, whenever qt5core.dll called the NetApiBufferFree function, in the end it was trying to find it in my DLL instead of in the one located in Windows files...

  I gotta say, this is the first time I've seen DLL Hell happen this way :-D

  Anyway, I'm glad you've resolved your issue. Happy coding!