Questions tagged [qt]

Qt is an application framework originally created by Trolltech and currently managed by Digia. The KDE desktop uses the Qt framework for its applications.

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1 answer
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Touchscreen is being recognized as a mouse

I plugged in a 3M touchscreen to my Linux PC. It appears as it recognizes it as a mouse. Here's my xinput output: xinput ⎡ Virtual core pointer id=2 [master pointer (3)] ⎜ ↳...
3 votes
1 answer
5k views

Struggling to build Qt due to missing OpenGL libraries

I'm trying to build an executable Qt-based program for Linux, and link Qt statically in the binary. According to the Qt docs, to do this I'm going to need to build Qt from source, starting with the ...
1 vote
1 answer
6k views

Where are Qt Charts and Qt Data Visualization located in Ubuntu repository

I'm trying to install Qt Charts and Qt Data Visualization modules from Ubuntu repository, but I cannot find them. Are they available in the repository? Ubuntu: Zesty (17.04) I get the following ...
0 votes
2 answers
4k views

How to update qt version to 5.15.1

i have on kubuntu qt version to 5.12.8, and i need to update it to 5.15.1 i tried to manually install it..the installation folder installs it in /home/Qt. but when i check the qt version is still 5.12....
0 votes
1 answer
75 views

QT Applications Not Adhering to GTK Theme After Upgrading to Ubuntu 23.10

Hello Ubuntu community, I recently upgraded my system from Ubuntu 22.04 to 23.10 and encountered an issue with QT applications. Despite installing Kvantum and attempting to change the theme, these ...
5 votes
3 answers
23k views

This application failed to start because no Qt platform plugin could be initialized

I wanted to install Systemback on my ubuntu 20.04 and found this page. When I ran systemback, I get this error message. ckim@ckim-ubuntu:~$ sudo systemback& [1] 220231 ckim@ckim-ubuntu:~$ No ...
4 votes
1 answer
653 views

Creating a Debian package for a Qt application built using CMake

I would like to create a .deb installation package for a GUI based Qt5 application. Most of the links available for this problem are pretty old, so I'm curious if there are more up-to-date solutions ...
3 votes
1 answer
1k views

Qtcreator freezes after few minutes of use

I just installed Qt 4.1.0 Based on Qt 5.7.0 (GCC 4.9.1 20140922 (Red Hat 4.9.1-10), 64 bit) And every time I run it after a few minutes of use it freezes. I have Ubuntu 16.04.1 LTS, on a laptop (...
4 votes
1 answer
9k views

Cannot open qcreator qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in ""

I am on Ubuntu. When I type qtcreator on terminal, I get: QFactoryLoader::QFactoryLoader() checking directory path "/usr/bin/plugins/platforms" ... QFactoryLoader::QFactoryLoader() looking at "/usr/...
0 votes
1 answer
1k views

Spyder fails to start: Could not find the Qt platform plugin "xcb" in ""

Error description I have an existing Conda environment with Python 3.8.16, and I have tried to install Spyder with: conda install spyder as well as with conda install -c conda-forge spyder, (not ...
1 vote
0 answers
26 views

Why camera not showing on Qt app using libvlc on virtualbox

My camera is not showing up on the Qt app by using the libvlc on the Virtualbox. I'm getting the below error when I debug that the camera can't show on the Qt app. [00007fe3b8098480] main video output ...
0 votes
0 answers
21 views

Okular - apt and snap cannot resize

I have been a long-time user of Okular, but after a recent fresh installation, I've noticed the absence of the maximize button. My main issue is the inability to resize the windows, as I can only ...
1 vote
0 answers
43 views

QT apps do not respect file-chooser bookmarks

background In ubuntu files app (Nautilus), a user can create bookmarks to folders in the left pane: most apps respect these bookmarks; I assume this is just by virtue of them using a ~ system file-...
6 votes
1 answer
9k views

Ubuntu 22.04 with Qt6 - qmake: could not find a Qt installation of ''

In Ubuntu 22.04 after installing Qt6 using sudo apt install qt6-base-dev calling qmake results in an error message: qmake: could not find a Qt installation of '' or qmake: could not exec '/usr/lib/...
3 votes
1 answer
23k views

Cmake error: -- Configuring incomplete, errors occurred!

I have an error when I run cmake ... Could you please help me? Thanks so much I want to build my project. I use mkdir build, cd build/ and cmake ...Then I got this error: CMake Error at /usr/share/...
0 votes
0 answers
216 views

Cannot launch Plasma in Wayland

I am completely unable to launch plasma in wayland, and I am completely lost at this point. Steps I have tried: Specify QT_QPA_PLUGIN="xcb;wayland-org.kde.kwin.qpa" in /etc/environment ...
22 votes
5 answers
118k views

Qt5 installation and path configuration

I have installed Qt5 from the Qt5 project site, to the following directory /opt/Qt5 I would also like to mention that I had Qt4 installed previously, I have removed all instances of Qt4 through ...
0 votes
0 answers
142 views

Newly deployed Ubuntu 22.04.3 LTS, experiencing a non-showstopper nuisance error Qt: Session management error: networkIdsList argument is NULL?

I built a new server instance on Kamatera cloud. The release was stripped to the core, yet the install was superbly clean. Installed Firefox $ sudo apt install firefox Attempted to install NoMachine ...
0 votes
2 answers
5k views

How do I check whether I'm using two different version of cmake?

I've been having some problems with Qt not being able to use the newest version of cmake. I recently upgraded the version using apt-get cmake --version cmake version 3.2.2 But Qt somehow still ...
0 votes
1 answer
6k views

qmake- No Such File or Directory after Installing QT5

OS: Ubuntu 22.04.1 KDE Plasma: 5.24.6 KDE Frameworks: 5.92.0 QT: 5.15.3 I installed QT5 from their website. Downloaded the installer and ran it. It installed QT in my Home directory and the qmake ...
2 votes
1 answer
7k views

How do I build a project with qmake-qt4?

I'm new user of Ubuntu, so excuse me if my question is very obvious. I have a 32-bit Ubuntu 11.10 installed in VirtualBox, and I want to build a project using qmake-qt4, the problem is that I don't ...
0 votes
0 answers
39 views

How can I let the file date be formatted according to ISO 8601 also in load/store dialogues

I am using Xubuntu 22.04. I have added a line alias date='date -Iseconds' to /etc/bash.bashrc in order to let file dates be formatted according to ISO 8601 (YYYY-MM-DDThh:mm:ss) Further I have ...
13 votes
6 answers
41k views

Debug Qt application on ubuntu with root permission using qt creator

It is possible to run my application with root priviliges using sudo, like this: sudo ./MyApp Is it possible to debug my Qt application using root priviliges using QtCreator? How can I do this on an ...
2 votes
1 answer
477 views

Spectacle no longer launches

I've tried uninstalling & reinstalling Spectacle, rebooting, but no dice -- it doesn't launch from the Plasma (3.24.7) launcher, nor the command line. Some potentially useful info here though: ➜ ~...
1 vote
0 answers
95 views

When opening Git Giu on Ubuntu 22.04 Virtual Box the screen does not show the graphics correctly

When opening Git Giu on Ubuntu 22.04 Virtual Box the screen does not show the graphics correctly. I have recently used the same functionality a couple days ago and I had no problem with it. I really ...
1 vote
0 answers
35 views

RaySession theming goes crazy if I press the canvas

I'm facing a problem I have no idea how could I tackle. My main concern is with RaySession, which opens fine, but if I press the wrong place (the canvas), the theming goes crazy, and I'm not able to ...
0 votes
0 answers
73 views

qt 6.6.0 help document went wrong

Ubuntu 22.04 At first, I can use qt help documents in qt creator, that means I can search a class name in help mode and I can press F1 in edit mode to get help. But after I upgrade qt to 6.6.0 version,...
7 votes
2 answers
33k views

Could not load the Qt platform plugin "xcb" in "" even though it was found

First of all I would like to say that I'm not an experienced Linux user, so please, don't be too 'techy' with me. I'm trying to install XnViewMP package on Xubuntu 20.04, but I'm getting this error: ...
0 votes
0 answers
52 views

Receiving "appliction not responding" error

THANKS HAL I started receiving this error after upgrading Ubuntu: I receive this periodically after some functions are activated. I honestly do not recall exactly when this started, but I am ...
0 votes
0 answers
218 views

How to get debug symbols for QT5 in Ubuntu 20.04?

I have the following stack trace from QT. I want to get more detail, but apparently I need some kind of debug symbols for QT5 to see more. However, I have not been able to figure out how. There is ...
0 votes
1 answer
786 views

Cannot mix incompatible Qt library (5.15.3) with this library (5.15.2) - Ubuntu 22.04

Trying to run Nsight Compute 2022.4.0.15 gui using ncu-ui but get this error. $ ncu-ui Cannot mix incompatible Qt library (5.15.3) with this library (5.15.2) I think these were the libraries that ...
0 votes
2 answers
4k views

cmake: error while loading shared libraries: libidn.so.11: cannot open shared object file: No such file or directory

I'm trying to build the qt-gstreamer-1.2.0 package listed here. But when I run cmake .. -DCMAKE_INSTALL_PREFIX=/path/to/installation/ according to the README file I encounter the cmake: error while ...
0 votes
1 answer
224 views

Is there a current version of PCManFM-Qt that's ready to go?

I'm currently running 0.17.0, but on GitHub the latest version is 1.3 - so I'm wayyy behind. However, when I try apt, it tells me I have the latest version. Snap doesn't have it, neither does Flatpak. ...
12 votes
2 answers
53k views

How to install Qt6 on Ubuntu 21.10

When trying to open a program that requires Qt6, it gives error while loading shared libraries: libQt6Network.so.6: cannot open shared object file: No such file or directory. I tried installing Qt6 by ...
2 votes
2 answers
1k views

Rstudio does not launch in Ubuntu 21.04

I have installed R 4 $ R R version 4.1.1 (2021-08-10) -- "Kick Things" and then Rstudio from the installer. The software centre shows the installation as correct, I have the icon on the ...
0 votes
0 answers
113 views

How to reset Qt package on 22.04?

(Not an advanced Linux user) My GUI apps requiring the Qt library (Konsole, Wireshark, P4V etc) suddenly started seg faulting on start-up. I tried sudo apt reinstall '~i' I tried sudo apt-get install -...
4 votes
3 answers
37k views

Qt (headers and libraries) not found

I'm trying to install a program and i used the following command: ./configure But, an error occurred: checking for Qt... configure: error: Qt (>= Qt 3.2) (headers and libraries) not found. ...
2 votes
1 answer
1k views

Scrollbar width in Qt applications

I have made the scrollbar width for Gtk applications wider, Create a file called ~/.config/gtk-3.0/gtk.css Containing scrollbar slider { /* size of the slider / min-width: 20px; min-height: ...
0 votes
1 answer
588 views

unable to launch virtualbox using SSH (Qt FATAL: This application failed to start because no Qt platform plugin could be initialized)

I have a Home Assistant virtual machine in Virtual Box. I typically access it using GUI, but now i'm using the device in a headless setup, so i'm trying to open it using ssh access. The issue I ...
2 votes
1 answer
2k views

Qt5 - how to use Free? Asking for money

I need to use Qt5 till i release my final version, my client wont pay until he see the whole application is stable and not having any issue. But Qt5 is asking money before even i get a client. In ...
0 votes
0 answers
70 views

Polychromatic Error: Wrong Qt Library Version (Ubuntu 22.04)

I got a new Razer mouse, and I'm trying to use Polychromatic to alter colors/DPI. I installed openrazer and Polychromatic as specified on their websites for Ubuntu 22.04, but when I run polychromatic-...
0 votes
1 answer
148 views

QT6 strange widget rendering when 'XDG_CURRENT_DESKTOP' is defined

~~(Note: This question was originally asked on QT's forum, without much help)~~ We recently upgraded to Ubutnu 22.04, with QT 6.5.1 installed using the online installer. When porting some of our older ...
4 votes
1 answer
165 views

How can I keep bookmarks synchronised between Qt and GTK applications?

Does anyone know a solution to keeping the same bookmarks (red rectangle in the screenshots) between Qt-based and GTK-based applications? Qt-based applications: GTK-based applications:
0 votes
0 answers
331 views

error ; qt.qpa.xcb: could not connect to display while running gnuplot

I have tried many solutions but I am not able to start gnuplot or any program that needs display using qt. I am using ubuntu extension in windows WSL.
1 vote
1 answer
2k views

Wireshark crash

While starting wireshark, I am getting following error: sudo wireshark This application failed to start because it could not find or load the Qt platform plugin "xcb". Available platform plugins ...
0 votes
0 answers
103 views

How I can increase the qt version in Ubuntu 22.04?

I need to update the latest qt version supported by the Ubuntu 22.04, the default version is 5.15.3. Please help me out to increase the qt version. Thanks in advance.
3 votes
1 answer
2k views

downgrade spyder

I have just upgraded ubuntu. As a result, spyder is not working anymore. This the error: Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway. ...
2 votes
1 answer
2k views

How do I install libqwt-qt4-dev on ubuntu 20.04?

I'm trying to compile gplates from source, since there isn't currently a .deb file for 20.04 fossa yet, but it requires using qt4 and subsequently qwt for qt4. Is there any way I can install the ...
1 vote
1 answer
21 views

Why is "sip" missing when I run bzr?

When I run a bzr command such as: bzr config launchpad_username I get a strange error message: Unable to load plugin 'qbrz' from '/usr/lib/python3/dist-packages/breezy/plugins/qbrz': No module named '...
1 vote
1 answer
2k views

Lubuntu 20.04 windows too big for the screen

I've had a problem with recent installs of Lubuntu 20.04 on laptops with lower resolution screens. Specifically 2 laptops both with screens 1366 x 768 pixels. One is an Acer with stock Intel graphics ...

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