[PyQt] Using ui files in PyQt

[Hans-Peter Jansen]

Hi Mike,

On Donnerstag, 27. April 2017 12:46:31 Mike Driscoll wrote:
> Hi,
> 
> At my current job, one of our major applications in written using Qt (the
> C++ version). Most of the UI is done in Qt Creator so we have a lot of *.ui
> files. Our company supports having our engineers do hack-a-thons and I was
> thinking it would be cool if I could create a little prototyping framework
> using PyQt around the ui files.

Shameless ad for the "framework": https://pypi.python.org/pypi/distutils_ui

This is a distutils extension, exactly targeted on handling the auxiliary 
resources, that need to be dealed with in PyQt.

Here's an example run (with comments):
$ python3 setup.py build_ui --force
running build_ui

# create a project file

running gentrpro
gentrpro.gentrpro: "main.pro" generated

# extract translations

running pylupdate
pylupdate.command: pylupdate5 -verbose {infiles}
pylupdate.run_command: "pylupdate5 -verbose main.pro"
Updating 'main_de.ts'...
    Found 65 source texts (0 new and 65 already existing)

# generate binary translation file(s)

running lrelease
lrelease.run_command: "lrelease-qt5 main.pro"
Info: creating stash file 
/home/hp/src/GIT/kde_color_scheme_editor/src/i18n/.qmake.stash
Updating '/home/hp/src/GIT/kde_color_scheme_editor/src/i18n/main_de.qm'...
    Generated 65 translation(s) (65 finished and 0 unfinished)

# generate python modules from ui files

running pyuic
pyuic.run_command: "pyuic5 -x -o src/ui/ui_mainwin.py src/ui/mainwin.ui"
pyuic.run_command: "pyuic5 -x -o src/ui/ui_complementdialog.py 
src/ui/complementdialog.ui"
pyuic.run_command: "pyuic5 -x -o src/ui/ui_aboutdialog.py 
src/ui/aboutdialog.ui"

# generate resource description

running genqrc
genqrc.genqrc: "main.qrc" generated

# generate resource module

running pyrcc
pyrcc.run_command: "pyrcc5 -o src/main_rc.py src/main.qrc"


Now, you have a main_rc.py file containing images, translations and auxiliary 
files, and a couple of ui python modules.

You import the main_rc module once (early in your process):

import main_rc  # __IGNORE_WARNING__

Now, all included files are available the usual way:

E.g.:

    locale = QLocale()
    if locale.name() != "C":
        translator = QTranslator()
        if translator.load(locale, ':/i18n/main', '_', 'i18n'):
            app.installTranslator(translator)
            log.info('translation %s installed', locale.name())

> I am having trouble finding good examples of doing this though. One recent
> example that we did was where we created a wizard using over 15 ui files.
> How does one load up a series ffof ui files for this sort of thing in PyQt?
> What do you need to do if the ui files need to be nested?

Here's a very simple module, that constitutes a Qt dialog, based on designer:


from PyQt5.QtCore import QUrl
from PyQt5.QtGui import QDesktopServices
from PyQt5.QtWidgets import QDialog

from ui.ui_aboutdialog import Ui_AboutDialog
from __init__ import (
    __author__, __author_email__, __version__, __homepage__, __license__,
)


class AboutDialog(QDialog, Ui_AboutDialog):
    def __init__(self, parent = None):
        super(AboutDialog, self).__init__(parent)
        self.setupUi(self)
        self.aboutText.setText(self.aboutText.text().format(
             __version__, __author__, __author_email__,
             __homepage__, __license__))
        self.aboutText.linkActivated.connect(self.openUrl)

    def openUrl(self, url):
        QDesktopServices.openUrl(QUrl(url))


As you can see, ui modules typically are instantiated by multiple inheritance, 
but you're free to deal with these objects however you like.

In short, it all works _very_ similar to C++, but keeps the fun, that working 
with python is (compared to C++). 

If you're a little careful about bytes and encodings, your scripts might even 
keep being python version agnostic. All the generated stuff is (for PyQt5).

Hope, this get you started.

Cheers,
Pete