Questions[qt5](ubuntu)

Ubuntu 20.04 dropped qt4 and all libqt4-* dependencies in its official repos. My knowledge about version conflict and install-breaking actions is limited, so before any unthoughtful action is taken, I would want the community's take about this.

Would it be possible to get qt4 to install on Ubuntu 20.04, and if so, which source would not end up breaking the install?

Alternatively, what container method would be the lightest for apps relying on qt4? My usecase for qt4 is solely for some Xilinx ISE components, nothing else, so the lightweight criteria is really important.

I have loads of programs that require Qt4 and I need to install programs that require Qt5. When I try to install Qt5 things start off dodgy and then proceed to insanity. I request friendly guidance. It's probably easiest for you to look at the terminal output directly:

$ sudo apt update
Ign:1 http://linux.dropbox.com/ubuntu wily InRelease
Ign:2 http://repo.ubports.com xenial InRelease                                                                  
Hit:3 http://linux.dropbox.com/ubuntu wily Release                                                              
Hit:4 http://gb.archive.ubuntu.com/ubuntu xenial InRelease                                                      
Ign:5 http://repo.ubports.com xenial_-_mir26 InRelease                                                          
Hit:6 http://ppa.launchpad.net/deadsnakes/ppa/ubuntu xenial InRelease                                           
Hit:8 http://gb.archive.ubuntu.com/ubuntu xenial-updates InRelease                                              
Hit:9 http://repo.ubports.com xenial Release                                                                    
Hit:10 http://security.ubuntu.com/ubuntu xenial-security InRelease                                              
Hit:11 http://gb.archive.ubuntu.com/ubuntu xenial-backports InRelease                                           
Hit:12 http://repo.ubports.com xenial_-_mir26 Release                                          
Hit:13 http://ppa.launchpad.net/maarten-baert/simplescreenrecorder/ubuntu xenial InRelease
Hit:14 https://repo.nordvpn.com/deb/nordvpn/debian stable InRelease          
Hit:15 http://ppa.launchpad.net/nextcloud-devs/client/ubuntu xenial InRelease
Hit:17 http://ppa.launchpad.net/numix/ppa/ubuntu xenial InRelease             
Hit:19 http://ppa.launchpad.net/otto-kesselgulasch/gimp/ubuntu xenial InRelease
Hit:20 http://ppa.launchpad.net/ubuntu-toolchain-r/test/ubuntu xenial InRelease
Hit:21 https://updates.signal.org/desktop/apt xenial InRelease
Hit:22 https://riot.im/packages/debian xenial InRelease
Reading package lists... Done 
Building dependency tree       
Reading state information... Done
23 packages can be upgraded. Run 'apt list --upgradable' to see them.

$ sudo apt install qt5-default
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies.
 protonmail-bridge : Depends: libqt5designer5 but it is not going to be installed
                     Depends: libqt5multimediawidgets5 but it is not going to be installed
 qt5-default : Depends: qtbase5-dev
               Depends: qtchooser (>= 55-gc9562a1-1~)
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

$ sudo apt install qtbase5-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
You might want to run 'apt-get -f install' to correct these:
The following packages have unmet dependencies.
 protonmail-bridge : Depends: qt5-default but it is not going to be installed
                     Depends: libqt5designer5 but it is not going to be installed
                     Depends: libqt5multimediawidgets5 but it is not going to be installed
 qtbase5-dev : Depends: libgles2-mesa-dev but it is not going to be installed or
                        libgles2-dev but it is not installable
               Depends: libqt5concurrent5 (= 5.9.5+dfsg-0ubports2) but it is not going to be installed
               Depends: qt5-qmake (= 5.9.5+dfsg-0ubports2)
               Depends: qtbase5-dev-tools (= 5.9.5+dfsg-0ubports2)
               Depends: qtchooser
               Recommends: libqt5opengl5-dev (= 5.9.5+dfsg-0ubports2)
E: Unmet dependencies. Try 'apt-get -f install' with no packages (or specify a solution).

$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Correcting dependencies... Done
The following packages were automatically installed and are no longer required:
  audacity-data libflac++6v5 liblilv-0-0 libportsmf0v5 libqscintilla2-l10n libqt4-declarative libqt4-network
  libqt4-script libqt4-sql libqt4-sql-mysql libqt4-sql-sqlite libqt4-xml libqt4-xmlpatterns libqtcore4
  libqtdbus4 libqtgui4 libsbsms10 libserd-0-0 libsord-0-0 libsratom-0-0 libunibreak1 libvamp-hostsdk3v5
  libzlcore-data libzlcore0.13 libzltext-data libzltext0.13 linux-headers-4.15.0-42
  linux-headers-4.15.0-42-generic linux-image-4.15.0-42-generic linux-modules-4.15.0-42-generic
  linux-modules-extra-4.15.0-42-generic simplescreenrecorder-lib sqliteman-doc
Use 'sudo apt autoremove' to remove them.
The following packages will be REMOVED
  audacity fbreader libqscintilla2-12v5 libqt4-designer libqt4-opengl libqt4-svg libsuil-0-0 libzlui-qt4
  protonmail-bridge simplescreenrecorder sqliteman vidyodesktop
0 to upgrade, 0 to newly install, 12 to remove and 23 not to upgrade.
1 not fully installed or removed.
After this operation, 45.6 MB disk space will be freed.
Do you want to continue? [Y/n] n

The final suggestion of my attempt would remove some core things I need, so this is not an option. How might I proceed, kindly stranger?

I have made my laptop double boot a few months again, with Ubuntu 18.04.1 . I have been working with okular to open pdf files (for the commenting option) but suddenly okular doesn't work anymore. When trying to open okular I get the following error:

Unable to find the Okular component: Cannot load library /snap/okular/39/usr/lib/x86_64-linux-gnu/qt5/plugins/okularpart.so: (libKF5JSApi.so.5: cannot open shared object file: No such file or directory)

I don't understand how to solve this problem. Okular was working fine until today and I didn't change anything to my ubuntu system in the mean time. Perhaps the problem comes from the fact that I have been working on windows the last few days and also used the windows ubuntu app.

How can I make okular work again?

I have Ubuntu 18.04.

While launching virtual box I am getting an error

$ virtualbox
VirtualBox: supR3HardenedMainGetTrustedMain: dlopen("/usr/lib/virtualbox/VirtualBox.so",) failed: libQt5Core.so.5: cannot open shared object file: No such file or directory

$ ldd /usr/lib/virtualbox/VirtualBox.so | grep Qt
libQt5X11Extras.so.5 => /usr/lib/x86_64-linux-gnu/libQt5X11Extras.so.5 (0x00007f7dcec8e000)
libQt5Core.so.5 => not found
libQt5Gui.so.5 => not found
libQt5Widgets.so.5 => not found
libQt5PrintSupport.so.5 => /usr/lib/x86_64-linux-gnu/libQt5PrintSupport.so.5 (0x00007f7dcea1f000)
libQt5OpenGL.so.5 => /usr/lib/x86_64-linux-gnu/libQt5OpenGL.so.5 (0x00007f7dce7c8000)
libQt5Gui.so.5 => not found
libQt5Core.so.5 => not found
libQt5Widgets.so.5 => not found
libQt5Gui.so.5 => not found
libQt5Core.so.5 => not found
libQt5Widgets.so.5 => not found
libQt5Gui.so.5 => not found
libQt5Core.so.5 => not found

$ apt-file search libQt5Gui.so.5
libqt5gui5: /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
libqt5gui5: /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.9
libqt5gui5: /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5.9.5

The system has libqt5* packages but I cannot list some of them using

$ ls /usr/lib/x86_64-linux-gnu/libQt5Gui.so.5
ls: cannot access '/usr/lib/x86_64-linux-gnu/libQt5Gui.so.5': No such file or directory

How can I fix this?

ODA Drawings Explorer (formerly Teigha Viewer) is a free (not libre) viewer for proprietary DWG files, developed by Open Design Alliance.

The developing company provides RPM and DEB packages for easy installation at their site.

I download the 64 bit DEB package, and install it using:

sudo dpkg -i TeighaViewer_QT5_lnxX64_4.7dll.deb

After that, the software is easily installed and I can run the software from Dash (windows key + typing Teigha) or from bash with the command

TeighaViewer

The software loads quickly and automatically prompts to open a file. This is where the trouble beings... and ends: the moment I select any DWG, TeighaViewer consistently crashes every time.

• Regardless if I select big or small DWGs
• Regardless of the location of the files I select or permissions.
• Regardless if the DWG file was generated with a new or old version of AutoCAD
• Regardless if I install the Windows version of Teigha with wine and run it

In all of these cases, Teigha systematically crashes.

I have even tried to open the DWG file directly from command line by issuing:

TeighaViewer myTestFile.dwg

But it still crashes. Note there are no spaces in the name of test DWG file being opened.

When running Teigha from command line, there is a hint of the problem though:

~$ TeighaViewer myTestFile.dwg 
QString::arg: Argument missing: Property Dialog, Teigha Viewer
QString::arg: Argument missing: Property Dialog, Teigha Viewer
terminate called after throwing an instance of 'OdError'
Aborted (core dumped)

I have googled everywhere for these errors, and came empty handed.

Could the be related to missing QT libraries?

My setup:

$ lsb_release -a
Description:    Ubuntu 17.10

$ gnome-shell --version
GNOME Shell 3.26.2

$ uname -a
Linux 4.13.0-36-generic #40-Ubuntu SMP Fri Feb 16 20:07:48 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

$ cat /proc/cpuinfo | grep model
model       : 142
model name  : Intel(R) Core(TM) i7-8550U CPU @ 1.80GHz

If anyone was able to make TeighaViewer run on Ubuntu, I would like to know their setup (Ubuntu version, 32 or 64 bit, graphics card in use)