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.
265
questions with no upvoted or accepted answers
1
vote
0
answers
5k
views
Not finding QT4 QWidget after update
Updated from buntu 11.0 to 12.04. I use to have QT4 ver 4.7.4, now I have 4.8.1.
My project is failing to build because it can't find #include <QWidget>. A search of the disk tells me there is ...
- 73
1
vote
1
answer
221
views
QT creator tutorial: Itemstyle invalid
Running the Currencyconverter tutorial "itemstyle" in the following line is underlined with red:
ItemStyle.class: "title"
with an error "invalid property name"
How to fix this error?
- 11
1
vote
1
answer
2k
views
How do I install libqt4.7.4?
I need to use libqt4.7.4 (or .3) on the latest build of Ubuntu. Is there any easy way to revert to that version. Will it break anything?
sudo apt-get install qt4-dev-tools=4.7.4 errors with 'Version ...
1
vote
1
answer
1k
views
Qt-sdk Setup causes Segmentation Fault
Immediately after I start the ./qt-sdk-linux-x86-opensource-2010.05.1.bin setup and press submit, I get a "Segmentation fault" in the Terminal. What should I do?
NekitoSP
1
vote
1
answer
323
views
Broken RStudio, VLC, and other apps because of Qt incompatibility on Ubuntu 20.04
I updated my system to use the lastest RStudio version, which required to install Qt from Qt's website (https://d13lb3tujbc8s0.cloudfront.net/onlineinstallers/qt-unified-linux-x64-4.2.0-online.run), ...
- 179
1
vote
1
answer
184
views
Ubuntu Phone - detect system type Desktop or Mobile
Is there a way to detect platform from QML or Qt C++ classes? I have Qt/QML project supplied to Linux/Android/Windows at one time, I see it's possible to deploy it to Ubuntu Phone. Is there a way to ...
- 727
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 ...
- 11
0
votes
0
answers
273
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
...
- 101
0
votes
0
answers
165
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
0
answers
42
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 ...
- 711
0
votes
0
answers
77
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,...
- 1
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 ...
- 213
0
votes
0
answers
57
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
245
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 ...
- 101
0
votes
0
answers
123
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 -...
- 343
0
votes
1
answer
638
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 ...
0
votes
0
answers
75
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-...
- 43
0
votes
0
answers
351
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.
- 21
0
votes
0
answers
113
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.
0
votes
1
answer
375
views
Rescale a QT app to fit a smaller screen
I have to use a QT app developed by a third party. Unfortunately, it does not fit the screen(s) of the computer that I use (with Ubuntu 22). I cannot access all the features of this app simply because ...
- 131
0
votes
1
answer
930
views
How do I install Qt6 QtWebEngineProcess in Ubuntu 22.04?
I installed the following packages: qt6-base-dev, qt6-webengine-dev and libqt6webenginecore6. But my application still returns an error: "Could not find QtWebEngineProcess". I can only find /...
- 998
0
votes
1
answer
90
views
ns3 please I have a qst about the instalation of ns3 I had this erreur , and I dont know how I can
youx@youx:~$ sudo apt install build-essential autoconf automake libxmu-dev python-pygraphviz cvs mercurial bzr git cmake p7zip-full python-matplotlib python-tk python-dev python-kiwi python-gnome2 ...
0
votes
0
answers
313
views
Is it possible to cross-compile among different Ubuntu relases?
Real case scenario: I have a dev machine that runs Ubuntu 22.04. Most of my customers have a dedicated remote machine that run Ubuntu as well, but with different releases - 20.04, 21.04, etc...
I ...
- 517
0
votes
0
answers
58
views
Hard reboot corrupted/removed my Qt library. Couldn't run GUI apps
A little over a week ago I had an issue. My monitor didn't detect my system (Ubuntu 22.04), so I did a hard restart. Unfortunately this caused a problem:
Konsole terminal closes immediately because it ...
- 343
0
votes
0
answers
550
views
Installing an older version of QT
I am using Ubuntu 20.04 x64 desktop. I installed qt using the command sudo apt-get install qt5-default. All went well except I need QT 5.9.5. I see under the build and run tab the following
QT 5.12.8 ...
- 1
0
votes
1
answer
399
views
Problem with QNetwork request - Error creating SSL context
I have an application which has a feature to display an overlay on a Google Maps display. In order to display a map overlay, my application has a dialog which downloads an xml file describing the map. ...
0
votes
0
answers
541
views
Cool Retro Term not displaying
I'm trying to start up cool retro term, and am running into an issue. When I run it using "cool-retro-term" in the terminal, the new window pops up, but it's see-through, as in you can see ...
0
votes
0
answers
536
views
WSL2 seems to change network configuration or DISPLAY variable on start-up. Where can I see what happens?
I'm using WSL2 with Ubuntu 20.04, and I have a problem trying to run Qt apps, currently discussed in this question. The gist of it is that Qt calls a plugin, xcb, that tries to connect to a display. ...
- 33
0
votes
0
answers
187
views
PCManFM-QT, Dolphin, FTP, and upload/overwrite prompts
In the previous version of ubuntu, PCManFM-QT would not prompt to upload/overwrite remote files when editing in VSCode using PCManFM-QT as my FTP client. I've updated to Ubuntu Studio 22.04 LTS, and ...
0
votes
1
answer
645
views
Fix font size for high-resolution screen
I have a high-resolution monitor. The font and cursor are too small for various applications. As you can see in the screenshot the font for PGAdmin is much smaller than VS code and Chrome. I thought ...
- 111
0
votes
0
answers
336
views
Installing the fcitx5-frontend-qt5 package
I am trying to install the fcitx5-frontend-qt5 package so that I can use it on qt applications. Unfortunately, this error comes up every time:
Reading package lists... Done
Building dependency tree ...
0
votes
0
answers
233
views
Syntax Error on accessing JSON data in QML data from python youtube_dl
I have a simple youtube_dl function to access the youtube download links here,
@QtCore.Slot(str, result=str)
def getDownloadLinks(self, url):
try:
with youtube_dl.YoutubeDL({}) as ydl:
...
0
votes
0
answers
144
views
suddenly unable to boot into Kubuntu
I am suddenly unable to boot into Kubuntu, I didn't do anything weird to my system yesterday, and suddenly it does not boot, it gets stuck on the motherboards logo.
I've figured out already that when ...
0
votes
0
answers
303
views
Lags in many apps (but not the others) when the GPU is 100% busy
I'm using Ubuntu 20.04 (default desktop install, i.e. with Gnome I suppose) and NVIDIA GeForce RTX 2080 GPU. When the GPU is 100% busy with a background process, some apps start lagging. Namely, those ...
- 292
0
votes
0
answers
184
views
How can I make text in dialog windows selectable (for copying)?
Well, I mean more all windows rather than just dialog windows, but I can't think of a better term to start pointing in the direction of what I mean.
To be more concrete:
kdialog --title '...
- 361
0
votes
1
answer
3k
views
Matplotlib complains about not finding Qt platform plugin "wayland"
I have trouble getting Matplotlib to work on Ubuntu 21.04. Whenever I want to plot something I'm getting the following error message:
qt.qpa.plugin: Could not find the Qt platform plugin "wayland&...
- 205
0
votes
0
answers
118
views
mate-session warns about not finding a desktop file
Getting similar warnings in the system logs:
Jul 14 09:11:18 precision-7510 mate-session[5184]: WARNING: Unable to find desktop file 'keepassxc.desktop': V složkách hledání nelze najít platný soubor ...
- 1
0
votes
1
answer
598
views
Crazy virtual onscreen keyboard on Kubuntu
I am on Kubuntu with a 2:1 laptop. Everything works apart the default on-screen keyboard. It appears when I click inside some document with the mouse, not with my fingers. It is getting really really ...
- 11
0
votes
1
answer
3k
views
Where did QT install to?
I am trying to set up a qt project in CLION. I installed qt using these commands
sudo apt-get install qtcreator
and
sudo apt-get install qtdeclarative5-dev
When you create a qt application in clion ...
- 1
0
votes
0
answers
363
views
Qt5 installer does not find debugger
I installed Qt5.15.2 with the online community-version installer on Ubuntu 20.04. In QtCreator I find the compilers but not the debugger. On my system I also have GDB:
$apt policy gdb
gdb:
Installed:...
- 517
0
votes
0
answers
116
views
qt3dwindow.h missing in focal and xenial
The way dev package for Qt are designed in ubuntu is extremly disturbing to me.
Lets take a simple example, QForwardRenderer include file for instance:
It is part of bionic: https://packages.ubuntu....
- 101
0
votes
1
answer
814
views
Ubuntu 20.04 Deemix launching error
I get the following error when I try to open an executable file with ./deemix-pyweb:
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
This ...
- 1
0
votes
1
answer
602
views
Qt Upgrade Problems, Cmake still looking in /usr/lib/x86_64-linux-gnu
I think I'm missing some basic understanding of how to appropriately upgrade Qt via a .run file from qt.io, and how to reference it appropriately when trying to build some code with CMake. Here's what ...
0
votes
1
answer
822
views
qtcreator doesn't launch on ubunu 20.04
I don't know why it doesn't launch. The last time I used it, it was perfect. I tried to run it using the terminal, then it gives:
Bus error (core dumped)
I tried to update and upgrade, then tried to ...
- 163
0
votes
0
answers
244
views
I have an error when loading lock screen theme when starting Kubuntu
When I select a theme on Kubuntu, it's apply the theme but after restarting Kubuntu and loading the lock this error appear:
I already tried the other themes, but it still didn't work even after I ...
- 390
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
2
answers
274
views
QT Apps like GRSYNC and VLC starts slowly on Ubuntu 20.4 (since some time)
i'm on Ubuntustudio 20.4 and i'm using grsync to backup my data. This was working fine since I installed Ubuntu, but now grsync takes over 30s to start. I tried via the terminal and from the start ...
- 103
0
votes
0
answers
908
views
Reset bottom panel in Lubuntu 20 (restore default)?
I tried to setup hotspot (and failed, leading to How can I create a hotspot in Lubuntu 20? ), but I managed to somehow delete wifi panel from my bottom panel.
What worse it is not appearing list of ...
- 1,083
0
votes
0
answers
454
views
Qt error when trying to use GPU rendering for a robotics simulator on headless machine
I'm trying to get a robotics simulator (https://github.com/stepjam/PyRep) working on a remote headless machine with GPU rendering. I've followed the installation instructions, and can run an example ...
- 11
0
votes
0
answers
2k
views
wireshark problem while loading or opening wireshark qt.qpa.plugin
av_acharya@AnoxBotox:/$ wireshark
qt.qpa.plugin: Could not find the Qt platform plugin "xcb" in "path/to/plugins"
This application failed to start because no Qt platform plugin ...
