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 Qt Custom control. Problem with Q_PROPERTY() and QConicalGradient
  • oxoocoffee

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  Unsolved Thread ownership of object when subclassing QThread
  • kengineer

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  @kengineer said in Thread ownership of object when subclassing QThread:

  Race condition how? I'm not planning on accessing the serial port object outside of the context of the newly created thread, I just desire to use it within other private helper functions I create in my class that are only used within the new thread. If I was then yes I should use signals and slots.

  QThread is not a thread, it never was and is not ever going to be. The thread is the QThread::run function, nothing more, nothing less - a root of a stack. Anything you put in your QThread class can be used from the thread that created that QThread instance, everything else is abusing it and begging for trouble. I mean you can do it if you know what you're doing, but it's not good, and you run the risk of shooting yourself in the foot.

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  Unsolved Casting QVector<int> to QVector<double>
  • dovahin

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  @dovahin said in Casting QVector<int> to QVector<double>:

  I know I could iterate through both of them, but looking for something better

  What @SGaist wrote. Also there's nothing better. QVector<int> and QVector<double> are two different and distinct classes, you can't just cast from one to the other.

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  Unsolved How should post data to API that has ContentTypeHeader:"text/plain; charset=utf-8" ?
  • zhmh

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  @SGaist but I post the same format data that I use in postman

  POST /api/PatData/ HTTP/1.1 Host: site.com Content-Type: application/json Cache-Control: no-cache Postman-Token: c31beda7-12bf-d5b8-4945-88895d0727a0 "102,2019/02/21,23:31:21"
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  Unsolved OpenStreetMaps with QtWidgets/C++
  • MuratUrsavas

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  It doesn't find the OpenSSL version matching the one used when building Qt. A v1.1 VS v1.0 classic issue. Which version of Qt are you using ?
  On what platform ?

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  Unsolved Qt software debugging techniques
  • Cobra91151

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  @SGaist

  Ok. I will check it and reply later. Thanks.

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  Unsolved QItemDelegate for editing questions
  • JonB

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  @Christian-Ehrlicher
  You're a hero :)
  Here we go https://doc.qt.io/qt-5/qabstractitemdelegate.html:

  The returned editor widget should have Qt::StrongFocus; otherwise, QMouseEvents received by the widget will propagate to the view.

  What do you think of that? Do I need to take any action on the QWidget I am returning?

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  Unsolved Circular image area
  • tovikonioput

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  @tovikonioput

  Hi! You need to reimplement the paintEvent of QLabel class to have circular image.

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  Unsolved QWindowsContext::windowsProc: No Qt Window found for event
  • Dagginio

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  Since both have the same behavior, that's likely the case.

  You should take a look at the bug report system to see if it's something known. If not, please open a new report providing a minimal complete example project.

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  Unsolved Smooth scaling QPixmap
  • patrickkidd

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  @SGaist

  @SGaist said in Smooth scaling QPixmap:

  What are the parameters of the animation ?

  Just this:

  self.expandAnimation = QPropertyAnimation(self, b'size') self.expandAnimation.setDuration(util.ANIM_DURATION_MS) self.expandAnimation.setEasingCurve(util.ANIM_EASING)
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  Unsolved upgrade SDK on macOs Qt version
  • AmirAbbasi

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  You're welcome !

  Since you have it working now, please mark the thread as solved using the "Topic Tools" button so that other forum users may know a solution has been found :)

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  Unsolved why no findXmlElement functions?
  • fryn3

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  QtXml is in 'done' state - this doesn't mean it will be removed. It just will not gain any major updates anymore.

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  Unsolved update qsqlite and qtableview
  • Mogli123

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  @Mogli123
  Provided I understand you right:

  It looks like that it is very impractical to do this for all cells

  I believe you're saying you have some array of data (from a TCP socket). You want to update the database to change the TOOLNR value of a bunch of rows to a variety of values in your input data,

  It cannot be helped that this requires a distinct SQL statement to be sent to the database for each input value (array element). If you have a 100 rows of data you will be executing 100 SQL statements. That's how it is.

  At the code side, as @SGaist says you do not have to write 100 lines of code, one for each row. You use a loop to produce the statements, like:

  for (int i = 0; i < arrayToolChangeWarnings.size(); i++ { queryToolChangeWarnings->prepare("UPDATE ToolChangeWarnings SET TOOLNR = :TOOLNR WHERE ID = " + QString::number(i)); queryToolChangeWarnings->bindValue(":TOOLNR", arrayToolChangeWarnings[i]); queryToolChangeWarnings->exec(); }

  There may be a way of sending the multiple statements as a single batch efficiently, I don't know (but then you'd have to deal with the bindings somehow).

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  Unsolved How to compile Qt5Websockets and install it on my Qt folder installation?
  • lucaszanella

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  @lucaszanella

  In qmake, you would have to add QT += websockets to your .pro file. I really don't know how the CMake equivalent is.

  https://forum.qt.io/topic/60975/what-do-i-have-to-add-for-the-qt-websockets-module-in-cmake already discusses this topic, but has not been marked as SOLVED. Therefore I don't know if the solution has been found.

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  Unsolved Qt Creator stops on a line but no fault or message reported
  • SPlatten

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  No one has replied

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  Solved Strange behavior of .toStdString()
  • HaHoHSO

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  Got it! Thanks a lot!

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  Unsolved QChart to QByteArray
  • HaoXiang

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  @HaoXiang
  I think you'll have to be a bit more specific about what you want: QChart is a visual widget object, so what do you actually mean by "convert" it to a QByteArray? Maybe you mean the series data it is plotting? Or do you want to (somehow) capture all its attributes too? Or what?

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  Solved How can I get a parent from child in treeView?
  • vale88

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  @VRonin thanks..it works

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  Solved QThread: msleep doesn't work when system time is changed
  • CP71

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  @J.Hilk
  Thank you very much.
  It is very very interesting reading and I’ll take into consideration for future.

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  Unsolved migrate old application
  • aminemaar

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  @mrjj thanks I will try that , may be it works
  @kamel100 I find other solution, I will load links in webview , But I still have other problem, how to load DLL files for windows or so files for linux dynamically regardless of the target platform (linux or windwos).

  [It was simply spam. ~kshegunov]

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  Solved How to output to console
  • Alex Williams

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  That's it. Thank you very much for a quick response.

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  Unsolved How to close Message Box Window
  • saurabh162

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  No one has replied

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  Unsolved QTextBrowser detect image deletion
  • shaun2344

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  @shaun2344 what about having a copy of the text before the user change(s) and doing a comparison on contentsChange signal?

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  Unsolved Know data sent with QSslSocket
  • cfdev

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  @cfdev If you are in another thread, you can use the waitFor... functions. But then you cannot use the signals. Please stick to one of them.

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  Unsolved QDockWidget - how to tell if it is tabbed under or closed
  • gde23

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  @SGaist Here is a zip file with a minimal working example.
  To test it just drag all three Docks to a DockWidgetArea so they get tabbed.
  Then drag one widget back to floating.

  Now tabifiedDockWidgets() will return no widgets for the floating one (see qDebug() output). This is how it should be.

  However, tabifiedDockWidgets() will return the floating widget when called for one of the other widgets. This is wrong in my opinion.

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  Unsolved Http post
  • satyanarayana143

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  @satyanarayana143 maybe using Wireshark to capture the actual network traffic is better to see what is actually being sent...

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  Unsolved Remove Parts of a String
  • meikelneit

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  @meikelneit

  This is depending on the complexity of text between curled braces. However, I would try first with QRegularExpression.

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  Unsolved how to insert an image in a QFile generated file using HTML
  • ManiRon

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  @ManiRon
  Like @jsulm I am still at a loss about what you are asking. I don't know what your code is about either, it opens files (for read/write at that), then doesn't use them....

  All you can do is if your HTML contains

  <img src="Logo1.png" alt="Test" >

  then there needs to be a file named Logo1.png in the directory where that HTML is executed from. How it gets there is irrelevant: it might be something already there, you might create it from code, I don't know, but that's what you need. QFile is not needed, and cannot somehow be "passed" to HTML.

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  Solved TaskBar-Icon hidden when MainWindow hidden
  • Toby

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  @Toby Yes, in general it is a good idea to decouple UI and logic.

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  Unsolved Qt3D: Draw Grid/Axis Lines?
  • oblivioncth

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  @zespy
  This is absolutely brilliant explanation and example.
  I know the topic is old now, but still a valid reference. Hence i thought to share the correction i had to do on buffer type [I assume its deprecated now], respectively :

  auto *buf = new Qt3DRender::QBuffer(Qt3DRender::QBuffer::VertexBuffer, geometry); auto *indexBuffer = new Qt3DRender::QBuffer(Qt3DRender::QBuffer::IndexBuffer, geometry);

  Mine is Qt 5.9 on Win 10.

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  Unsolved Dynamically fit QComboBox popup height to the (dynamically changing) count of items
  qcombobox view resize qlistview item • • AloyseTech

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  @AloyseTech IIRC hidePop() will reset the Popupwidget, so maybe hijack the add/remove process.
  Call hidePopup before adding are removing item and call showPopup afterwards?

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  Unsolved Mingw32 undefined reference
  • Dre4m

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  for mingw 32
  
  for mingw 64

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  Class problem
  • Nafab213

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  @Nafab213 said in Class problem:

  I want to learn so help me a little

  That's why I only pointed you to the relevant part but wanted you to find the actual mistake by yourself. You're using different names for the variable.

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  Focus problems when embedding a native window
  win32 desktop • • Zylann

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  This thread is 4 years old, but I want to give a solution anyway.
  I spent the past 2 months trying to figure out how to do this, and all the threads I found are talking about issues but nobody gave me a solution.

  Actually, the QWidget you create has its own focus but is not "parent" of the HWND you are embedding on it, so you have to make the keyboard focus by yourself.

  The best way to do that is by using the SetFocus function of the winuser library (WinUser.h):
  https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-setfocus

  Like, in example:

  m_qwindow = QWindow::fromWinId(m_handle); m_widget = QWidget::createWindowContainer(m_qwindow, this); // tell the os to focus the viewport window SetFocus(m_handle);

  with m_handle being the HWND (or WId) used to create the QWindow.

  Unfortunately, this solution works only on windows (but maybe there are equivalents on another os).
  It also doesn't work when clicking on the embedded window, because it isn't owned by Qt.
  maybe you can try to mess with QFocusFrame (I haven't tried this at all, but it should be a way to use it as a fix by putting it over the embedded window)
  or, if the window you are embedding is one of your creations, put the SetFocus() function in its code, as a callback when clicked.

  I hope that even with 4 years late, this solution is still helping the desperate developers like who I was the past two months.

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  Solved Polymorphism didn't work
  • Zunneh

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  thank you guys , it work :)

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  Solved QFileDialog::getOpenFileName
  • meikelneit

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  Thank you very mutch, that is what i was looking for.

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  Solved QPixmap::scaled: Pixmap is a null pixmap
  • Stan Huang

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  @Stan-Huang Sorry, I found the path parameter for QPixMap() is null.

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  Unsolved Timer Cannot Stop..?
  • PrAnit

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  until the op actually shows the function where he calls stop(), it may just as well be variable shadowing.