75
votes
“Failed to load platform plugin ”xcb“ ” while launching qt5 app on linux without qt installed
I had this error message when trying to run "Stellarium".
With strace I found that the missing file was libxcb-xinerama.so.0.
I had to reinstall libxcb-xinerama0 to make it work:
sudo apt-get ...
- 851
69
votes
What package do I need to build a Qt 5 & CMake application?
I just stumbled upon this question while trying to compile KeePassX 2.0.
What helped me was to use apt-file to search for the missing packages:
For example running this:
apt-file search Qt5CoreConfig....
- 851
69
votes
“Failed to load platform plugin ”xcb“ ” while launching qt5 app on linux without qt installed
To any future readers who come across this - before you start (dangerously) messing around with symlinks to shared libraries, I strongly suggest that you run
export QT_DEBUG_PLUGINS=1
and then run ...
- 961
49
votes
Accepted
qt5-default not in Ubuntu 21.04
The 21.04 is based on Debian bullseye, which does not have qt5-default package in the repository. I reported a bug to launchpad about missed qt5-default package.
There is a way is to install all ...
- 98.3k
33
votes
Accepted
How do you install qt on ubuntu22.04
You need to install packages:
sudo apt install -y qtcreator qtbase5-dev qt5-qmake cmake
And you need to manually change the Qt version:
screenshot how to manually change Qt version
Then you need to ...
- 446
24
votes
“Failed to load platform plugin ”xcb“ ” while launching qt5 app on linux without qt installed
Try to install libqt5x11extras5 package with command:
sudo apt-get install libqt5x11extras5
The name may be different. You can figure it out by searching:
sudo apt-cache search qt5 | grep 'X11 extras'...
- 341
24
votes
Accepted
Qt apps stopped inheriting GTK themes
On Ubuntu 17.10 Qt4 apps do inherit the global GTK theme, while Qt5 don't. Since libqt5libqgtk2 isn't available in the official Ubuntu repositories anymore, we have to use another workaround:
Install ...
- 824
19
votes
Debug Qt application on ubuntu with root permission using qt creator
Go to Tools-> Options-> Environment
In the Tab General under **System** Group there is a Terminal Option.
The default value is set to/usr/bin/xterm -e. Replace it with /usr/bin/xterm -e sudo or /...
- 191
17
votes
Accepted
Qt/KDE camera app alternative to Cheese in Kubuntu 18.04?
According to the description in apt show kamoso, it's a "tool to take pictures and videos from your webcam".
If you want to read about it before installing, the man page for 18.04 is here: http://...
- 41.8k
16
votes
“Failed to load platform plugin ”xcb“ ” while launching qt5 app on linux without qt installed
The correct solution is running the following comand onto a terminal:
sudo ln -sf /usr/lib/x86_64-linux-gnu/qt5/plugins/platforms/ /usr/bin/
It creates the symbolic link it's missed.
- 285
16
votes
Ubuntu 18.04: "Add to Favorites" missing for certain qt-based applications?
A convenient workaround for me was adding it to my favorites from the omnibar.
- 281
14
votes
Accepted
How to update Qt from 5.5.1 to 5.9.5 on Ubuntu 16.04
A second option is to add Qt using a PPA. The example below installs Qt 5.11.1. There are PPA's for other versions if required.
Add the PPA
sudo add-apt-repository ppa:beineri/opt-qt-5.11.1-xenial
...
- 1,370
14
votes
qt4 / libqt4-* in Ubuntu 20.04
Adding this PPA repository to your system may solve.
sudo add-apt-repository ppa:rock-core/qt4
sudo apt-get update
Then run to install qt4.
sudo apt-get install libqtcore4
- 151
14
votes
Accepted
How to install Qt6 on Ubuntu 21.10
libqt6network6 is indeed part of the qt6-base-dev meta-package and you can install it like so:
sudo apt install qt6-base-dev
However, unfortunately, this meta-package is not available for Ubuntu 21....
- 28.4k
13
votes
Accepted
Ubuntu 22.04 with Qt6 - qmake: could not find a Qt installation of ''
In Ubuntu 22.04 there is currently an open bug QtChooser doesnt support
qt6.
So even if Qt6 has been installed using sudo apt install qt6-base-dev, qtchooser -l does not list a
qt6 option and qmake ...
- 406
12
votes
Accepted
What is the default icon set in Ubuntu 16.04?
Ambiance GTK is the default theme and Ubuntu Mono (dark) is the default iconset
(Ubuntu tweak tool can be used to change it if you want to match Ubuntu with your QT)
- 297k
12
votes
Cannot install Qt-4 on Ubuntu 20.04 - Quite Universal Circuit Simulator (QUCS)
The Qt4 framework has been removed from Ubuntu 20.04 main repository.
You can still get Qt4 libraries, adding the PPA rock-core/qt4
Run in a terminal:
sudo add-apt-repository ppa:rock-core/qt4
sudo ...
- 15.2k
11
votes
Accepted
Installing Qt 5.5.1 on Ubuntu 14.04 - throws qt.network.ssl error on terminal
Now OpenSSL in Ubuntu is compiled without sslv2 because it’s insecure, but Qt 5.5.x still requires it. In order to enable sslv2 the package needs to be re-configued without the no-sslv2 flag.
...
- 3,935
10
votes
How to install libqt4-core and libqt4-gui on Ubuntu 16.04 LTS?
These libqt4-core and libqt4-gui packages don't exist anymore in Ubuntu 16.04 LTS and newer. They were dummy packages with dependencies to other packages. The following procedure will modify the Vidyo ...
- 742
10
votes
Accepted
What happened to the qtbase5-dbg package in Zesty?
I submitted this question to the ubuntu-devel-discuss mailing list and Mattia Rizzolo responded with the following reply:
Debian is slowly dropping manual debug symbol packages (-dbg) in favour
...
- 32.1k
10
votes
Accepted
"qmake" is not recognized
The solution lies in using update-alternatives(8). For more information on the reasoning behind it, refer to What exactly does `update-alternatives` do?
sudo update-alternatives --install /usr/bin/...
- 746
10
votes
Accepted
Virtualbox not launching on Ubuntu 18.04 - Qt lib problem
Thanks cmak.fr for pointing me towards the solution. I had to reinstall the the libqt5core5a and libdouble-conversion1 packages. Note that this also removed virtualbox-qt, which had to be reinstalled:...
10
votes
Accepted
Ubuntu 18.04 - Unable to locate package qt-sdk
The qt-sdk package included the development libraries for Qt4. You can install these in 18.04 using the following:
sudo apt install libqt4-dev
- 1,370
10
votes
Accepted
epson-printer-utility error loading shared libraries
Ubuntu 20.04 LTS no longer has Qt4 libraries on purpose. See this question, for instance. Your best bet is compiling from source, or setting up a virtual machine with an older Ubuntu version as the ...
- 337
10
votes
Accepted
Could not load the Qt platform plugin "xcb" in "" even though it was found
I was able to resolve the issue by installing missing packages. Those are the steps I performed:
I set the QT_DEBUG_PLUGINS to 1 with export QT_DEBUG_PLUGINS=1 command and ran xnview from the same ...
- 173
9
votes
How can I get Qt5 applications to use the GTK theme in Ubuntu 17.04?
Apart from qt5ct you also need to install qt5-style-plugins package, then you should get the 'gtk2' theme in qt5ct
sudo apt-get install qt5-style-plugins
And, as per the qt5ct documentation, don't ...
- 211
9
votes
Where I find mimeapps.list?
It should be in below directory:
/usr/share/applications/mimeapps.list
If its not be exists, you can create it, and put that line into this file:
sudo nano /usr/share/applications/mimeapps.list
...
- 5,748
9
votes
Accepted
Cant find Qt5Designer, qt5svg and qt5x11extras
To anyone else having the issue with qttools5-dev-tools not installing Qt Designer stuff try
sudo apt install qttools5-dev
instead (note there is no -tools at the end).
I was also lacking qt5svg ...
- 141
9
votes
Accepted
QtCreator not recognizing linked libraries after upgrading Ubuntu to 20.04
Same issue here, same solution as @nou. QtCreator 4.11 still relies on clang-8, but on Ubuntu 20.04 apt will install clang-10. The following solved the problem for me:
Install clang 8
sudo apt ...
- 106
9
votes
Accepted
qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found. in ubuntu 20.04
First do this:
$ export DISPLAY=:1.0
The newest version of opencv-python that I had installed was causing the problem with pyqt5. So I uninstalled it and installed the following version:
$ pip ...
- 4,429
Only top scored, non community-wiki answers of a minimum length are eligible