General and Desktop

Just because you create a plugin for the Qt Designer / QtCreator doesn't mean you need the sources (or the library) with the plugins widget.

@Dummie1138 said in Is there a way of reading the previous value of a QSpinbox?: I'm wondering whether this function exists If you are talking about something like aboutToChange(int oldVal), unfortunately not (for QSpinBox at least). ContextMenus have an aboutToShow signal before they are shown, but QSpinBox doesn't . As soon as you get your valueChanged signal, the widget itself forgets about the old value, if you haven't saved it.

Oh great, thanks for your answer !

@jsulm It worked. Thanks.

@serkan_tr i solved the problem i added to environment variables System Variables -> new -> PKG_CONFIG_PATH -> C:\gstreamer\1.0\msvc_x86_64\lib\gstreamer-1.0\pkgconfig; C:\gstreamer\1.0\msvc_x86_64\lib\pkgconfig

If you nest several widget you might also want to reduce the content margins (at least of some widgets) to 0. When you scroll down in the object properties widgets at the bottom you will find (in red) the settings for the widgets layout. QTabWidget is a little tricky here as you need to make one tab current and then click on the QTabWidget (instead of the single page) to see the layout of the page.

Hallo Karl-Heinz, ohne es ganz genau zu wissen: Listen sind in Python integrierte Typen, daher gibt's die QList nicht. Du kannst das Ergebnis von self.w.katTWKategorien.selectedItems() einer Variablen zuweisen und bekommst mit myList[0]das erste Element (wenn es ein solches gibt). LG Axel

@jsulm never mind, i solved it with removing setWindowModality(Qt::ApplicationModal); and adding setWindowFlags(Qt::WindowStaysOnTopHint|Qt::FramelessWindowHint); it. It still works like modal window and its possible to interact with keyboard since i added WindowStaysOnTopHint flag to keyboard too.

Such call helped me from functools import partial image_import_btn.clicked.connect(partial(display_image, grid_image_detect)) Maybe is more professional call?

Then the links I posted is what you should read and use.

I wonder if in a opengl widget what will be used is the gpu? It depends on what you do with it. If you just upload the image as a texture and display it as a quad then yes, the work is done mostly by the GPU. If you modify the image and need to re-upload it often then both CPU and GPU will be involved. Widgets are rendered on the CPU, so the load in case of animation is expected, especially if the image is large or the widget is big. Widgets are not generally suited for animations, rather for static UIs. If you're interested in animated UIs you might also want to take a look at QtQuick. It is backed by OpenGL (or Vulkan or Direct3D depending on your platform) but has a easier and higher level declarative syntax.

@Chris-Kawa said in QMake precompiled headers in *.pri files. How?: It has nothing to do with CMake or qmake. #pragma once is a compiler extension that replaces include guards i.e. in a standard C++ That's interesting about #pragma once. Never been using it. For the more than 10 years of Qt developing got it from you for the first time. Definetly need to refresh reading of compiler reference. Thanks a lot for explanation. Issue closed.

@tim-hilt Can you describe verbally which palette should be changed? The application palette? A specific widget’s palette? Something else? We’ll find it out!

Solved by creating QTableWidget. I transmited data from database in QTableWidget one query in a column and then row by row added data from QTableWidget to QString value to export it later to CSV.

@MyNick-0 said in Qt6, save TableView record in the database: How can I consider the data from the model You set data with setData() and retrieve it with data() as you should already know - if not please read the documentation about Qt's model/view framework can you bring the code? I don't write code for others when they don't provide code by themself in the first place so I see that they thought about the problem and tried things out by themself.

Well, I just found how to solve this. As stated in the output I posted above, the problem it's basically Qt being unable to find libqsqlmysql.so, but thanks to ChatGPT and google searches I found a workaround: Make sure that you have installed the MySQL client library on your system. You can check if it is installed by running the command locate libmysqlclient.so.21 (in case you are using Linux). Make sure that the MySQL driver library is in a location where your Qt application can find it. You can try adding the directory where the MySQL driver library is located to the LD_LIBRARY_PATH environment variable, by running the command: export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/path/to/mysql/lib Then, run Qt from terminal. For example, I do it with this command: ~/Qt/Tools/QtCreator/bin/qtcreator Thats it, now it should work. If you don't want to execute the export LD_LIBRARY_PATH=... command everytime before opening Qt, you can set LD_LIBRARY_PATH under environment (Where you add environment variables) . Example: [image: 0219fe83-192b-400b-acbe-db93587f7e35.png] After your default values in LD_LIBRARY_PATH, add ::/path/to/mysql/lib. If you do this, It's not necessary to open Qt from terminal anymore.

@ChrisW67 said in How to add new widgets between spacers in a QGridLayout?: ou are asking the grid layout to add a new widget at the far right (index+1), and that is what it is doing. At index 0 is the left spacer, and at index 1 the right spacer, when I add the first button at index 1, it is added before or after the right spacer? The strange is that only one button gets to the middle. I also tried gridLayout->addWidget(btn, 2, index); and resulted on this: [image: 6d347ba3-c39a-4cfb-8eff-d3896bde3d42.png] I don't think adding a QHBoxLayout at the bottom is necessary for this task.