I am a new Ubuntu user and want to do my coding using Python and incorporating Qt designer for my forms (interface). I open the designer and put up some controls on the forms or widgets but I get problems on how to include the form I made in my Python codes. I try using the Import style for my .ui but to no avail. Please help on how I should go about this issue. Here is what I have: Mwakenya is the .ui file I created on Qt designer.
from pyQt import *
from mwakenya.ui import *
class at(mwakenya):
def __init__(self, parent=None, name=None, fl=0):
mwakenya.__init__(self,parent,name,fl)
if __name__ == "__main__":
import sys
a = QApplication(sys.argv)
QObject.connect(a,SIGNAL("lastWindowClosed()"),a,SLOT("quit()"))
w = at()
a.setMainWidget(w)
w.show()
a.exec_loop()
You need to compile your .ui files, into python code.
You can do this with the pyuic command.
eg.
pyuic mwakenya.ui -o mwakenya_ui.py
You then import mwakenya_ui.py
See here for more information:
http://manpages.ubuntu.com/manpages/hardy/man1/pyuic4.1.html
Users of KDE should look for pykdeuic, which performs the same job.
Related
I have created a program to read certain data from files on a drive, display results on a PyQt5 ui and accept corrections if any from user.
The program worked fine when run as a python file. However, when i converted it into a standalone exe using PyInstaller, it works fine upto the point where the pyqt5 gui needs to be launched. At this point, it stops throwing the following error :
qt.qpa.plugin: Could not load the Qt platform plugin "windows" in "" even though it was found. This application failed to start because no Qt platform plugin could be initialized. Reinstalling the application may fix this problem. Available platform plugins are: minimal, offscreen, windows.
I have read this, this and this but they dont resolve my issue.
The code of the gui is very big but here is the structure :
from PyQt5 import uic, QtWidgets
import sys
import os
#baseUIClass, baseUIWidget = uic.loadUiType('gui.ui')
baseUIClass, baseUIWidget = uic.loadUiType(r'C:\mypath\gui.ui')
class Ui(baseUIClass, baseUIWidget ):
def __init__(self, *args, **kwargs):
baseUIWidget.__init__(self, *args, **kwargs)
self.setupUi(self)
# More code to perform the desired actions
def run(input_variables):
app = QtWidgets.QApplication(sys.argv)
ui = Ui()
ui.show()
# More code to make the Ui perform desired actions
app.exec_()
return(output_variables)
The code was converted to a standalone exe with the following arguments :
pyinstaller --hiddenimport <hidden import> --onefile <python filename>
Would you know how to troubleshoot this please?
Thanks
I ran into the same error message with my compiled application.
To track down the issue, I first stripped down the app to its skeleton with minimal imports, which worked flawlessly when compiled. I then partially added back all imports of my "big" application until the error reappeared.
In the end (for me at least) pandas is the culprit:
Minimal reproducibale examples, this works:
from PyQt5 import QtWidgets
app = QtWidgets.QApplication([])
window = QtWidgets.QMainWindow()
window.show()
app.exec()
This (added pandas import in line 2) throws the error you describe:
from PyQt5 import QtWidgets
import pandas as pd # import after pyqt5
app = QtWidgets.QApplication([])
window = QtWidgets.QMainWindow()
window.show()
app.exec()
However, when first importing pandas and then importing PyQt 5, my compiled version works again:
import pandas as pd # import before pyqt5
from PyQt5 import QtWidgets
app = QtWidgets.QApplication([])
window = QtWidgets.QMainWindow()
window.show()
app.exec()
So, in my case the solution was to track down the "erroneous import", fiddle with the import order and get lucky (I am far too unexperienced to even try to understand why the import order leads to this error)
If you are not using pandas, maybe the whole "strip down to skeleton and start importing piece by piece"-approach will help you to further clarify the root cause of the error.
If you are using pandas and the order switch-up did not help, there is another thread which describes which tries to deal with pandas compiling issues.
I am building a Gui in QtDesigner but i do not understand how i add a "dynamical property":
I try to add a QTable Widget but the Header of the Columns are to large (The Text is just 2 letter in the Columns).
For Space reasons in my Gui i just need them to be as big as the text is (or let us say 4 letters)
i found the
QHeaderView::ResizeToContents method but i do not know how to use it- is there a way to do this in QtDesigner?
I am new to this and i do not know how to change the code behind the Gui...
For PyQt, the main purpose of Qt Designer is to create the main GUI structure of your application. It only allows a subset of the available properties to be modified for any given widget, and it cannot be used to write the application's main logic.
Instead, the idea is to generate a python module from the ui file created by Qt Designer, and then import it into your application where you can do the remaining setup code, connect signals, write all the event handlers, etc.
Let's say you've created a ui file with Qt Designer and named it mainwindow.ui.
You would then generate the python module like this:
pyuic4 -o mainwindow_ui.py mainwindow.ui
Next, you would write a separate main.py script that imports the GUI classes from the generated module, and creates instances of them as needed.
So your main.py would look something like this:
from PyQt4 import QtCore, QtGui
from mainwindow_ui import Ui_MainWindow
class MainWindow(QtGui.QMainWindow, Ui_MainWindow):
def __init__(self, parent=None):
QtGui.QMainWindow.__init__(self, parent)
self.setupUi(self)
header = self.tableWidget.horizontalHeader()
header.setResizeMode(QtGui.QHeaderView.ResizeToContents)
...
if __name__ == '__main__':
import sys
app = QtGui.QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())
The base-class here must be same as the top-level widget in Qt Designer (i.e. usually either QMainWindow, QDialog, or QWidget). Also, the objectName property of the top-level widget is used to generate the classname of the imported GUI class (with "Ui_" prepended to it). The example above assumes this was set to "MainWindow".
The objectName properties of all the other widgets will become attributes of the MainWindow class, so that they can be accessed easily in the rest of your code. Because of this, it's important that you always set the objectName properties to descriptive names (i.e. not "pushButton_1", "pushButton_2", etc).
I have created a GUI with Qt Designer and accessed it via
def loadUiWidget(uifilename, parent=None):
loader = QtUiTools.QUiLoader()
uifile = QtCore.QFile(uifilename)
uifile.open(QtCore.QFile.ReadOnly)
ui = loader.load(uifile, parent)
uifile.close()
return ui
MainWindow = loadUiWidget("form.ui")
MainWindow.show()
children = MainWindow.children()
button1 = MainWindow.QPushButton1
"children" does already contain the widgets "QPushButton1", "QTextBrowser1" created in the UI but shouldn't the be accessed by the recoursive findChildren() method?
What is an elegant way to access the widgets of the .ui File?
References:
Find correct instance,
Load .ui file
Since widget names in Qt Designer must be unique, the hierarchy (at least for getting references to the widgets) is flattened (with no risk of conflict), and so the best way is just to access them via:
loader = QtUiTools.QUiLoader()
ui = loader.load('filename.ui', parent)
my_widget = ui.my_widget_name
This would place a reference to the widget called 'my_widget_name' in Qt Designer in the variable my_widget.
I would say the above is the most pythonic way of accessing the widgets created when you load the .ui file.
There are two disadvantages of loading UI at run time:
overhead each time the program is run (actually, each time the loader is used)
lack of support of code completion and checking, since IDE doesn't know the code behind ui until the uifile has been loaded.
An alternative, assuming you are using the modern version of PySide called "Qt for Python", is to "compile" the .ui file to a Python class (see docs). For this, after saving filename.ui, execute
pyside2-uic filename.ui -o ui_mainwindow.py
while within your virtual environment, if any. The new class will be called Ui_MainWindow. Assuming you have a text_box widget in your UI, you can now access its properties and methods. Here is a full working example:
import sys
from PySide2.QtWidgets import QApplication, QMainWindow
from ui_mainwindow import Ui_MainWindow
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.ui.text_box.setPlainText('test') # here we are addressing widget
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MainWindow()
window.show()
sys.exit(app.exec_())
Notes:
pyside2-uic should be called after every change of the .ui file. This is a disadvantage of this approach in comparison to OP. It also means that you should either version-control both .ui and .py files for your UI, or somehow call uic during deployment.
The big advantage is that IDE like PyCharm has access to all widget methods and properties for autocompletion and code checking.
As of today, pyside2-uic creates non-PEP8 compliant code. However, as long as you give your widgets PEP8-compliant names, your own code will be OK.
I want to convert the langauge of pyqt application from english to finnish . I saw that pyqt has some methods for it and i try to use it but it didnt help me
app = QtGui.QApplication(sys.argv)
translator = QtCore.QTranslator()
translator.load("qt_fr.qm")
app.installTranslator(translator)
.qm file is present at right path (right now its taking french i guess) and on button i use this text
name = "File"
button.setText(self.tr(QtCore.QString(name)))
It seems you are mixing two things: the translations of Qt itself (which are provided via qt_xx.qm files and distributed along with Qt) and your own translations.
Here you have an example using the russian translation file of Qt itself:
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class MyWindow(QWidget):
def __init__(self, parent=None):
super(QWidget, self).__init__(parent)
self.hbox = QHBoxLayout(self)
self.myButtons = QDialogButtonBox(self)
self.hbox.addWidget(self.myButtons)
button = self.myButtons.addButton(QDialogButtonBox.Open)
if __name__ == "__main__":
import sys
app = QApplication(sys.argv)
translator = QTranslator()
print translator.load("qt_ru", QLibraryInfo.location(QLibraryInfo.TranslationsPath))
app.installTranslator(translator)
ui = MyWindow()
ui.show()
sys.exit(app.exec_())
If you need your own translations then the Produce translations section of the i18n with Qt can be of help to you. You will need to provide a project file, your translation files (.ts) and use the Qt Linguist tool.
You can mix both the Qt itself translation and your own app translation by installing multiple translators.
Please note that when loading the translator you don't have to add the .qm extension to the filename.
Please read the Qt Manual on Translation or just have a look at a very basic yet illustrative example here: http://doc.qt.digia.com/qt/linguist-hellotr.html. Please note: you may need to provide the translation files yourself using f.i. Qt Linguist.
If you're doing this inside your window's __init__(), you must save (retain a reference to) your translator:
self.translator = translator
Otherwise your translator will get garbage-collected, even after installation. In that case, self.tr() will stop working (fails silently).
I am trying to get a minimal example for an application designed by the qt designer with pyqt involving a QTreeView to work
1) i can start the app this way but if i push the butten, no entry in the TreeView widget is shown, i do not get any error message, and the layout looks fine, is there some kind of update method?
if you answer, please be specific, as i am still a beginner with qt and much of the documentation is written with c++ examples, and i only have some experience with basic c and python
from PyQt4 import uic, QtGui, QtCore
(Ui_MainWindow, QMainWindow) = uic.loadUiType('main_window.ui')
class MainWindow(QtGui.QMainWindow):
def __init__(self, parent=None):
super().__init__(parent)
self.ui = Ui_MainWindow()
self.ui.setupUi(self)
self.model = QtGui.QStandardItemModel()
self.connect(self.ui.pushButton_NeuesMoebel, QtCore.SIGNAL('clicked()'), self.add_item)
def add_item(self):
t = self.ui.lineEdit_Moebel.text()
if len(t) > 0:
item = QtGui.QStandardItem(t)
self.model.appendRow(item)
self.ui.lineEdit_Moebel.clear()
else:
self.ui.statusBar.showMessage('error: no text in Moebel')
if __name__ == "__main__":
import sys
app = QtGui.QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())
2) additionally, is there a cleaner way to directly use the *.ui file than this, to sort of directly subclass the MainWindow of the that file? the ui stuff seems a bit messy
3) for example it would be nicer to have the add_item method in a subclass of the window created by the *.ui file, are we supposed to use the intermediate step of translating the *.ui file to a *.py file?
You just forgot to set the model on your QTreeView. Right now the tree view has no model so it never sees the data update:
def __init__(self, parent=None):
....
self.ui.treeView.setModel(self.model)
Also as a suggestion, save yourself some typing and use the new-style signal/slot connections that are more pythonic and don't make you type out signatures:
self.ui.pushButton_NeuesMoebel.clicked.connect(self.add_item)
I just came across this question and am really glad I did. It caused me to look into using the uic module, which I've been ignoring. In all the years that I've used pyqt I've always generated a .py file from the designer .ui file, and then importing the generated file as a module.
Using uic instead to directly load the .ui file saves a step and simplifies things quite a bit. It's easy to do.
So yes, in answer to question #2 there's a simpler way than calling the ui stuff:
from PyQt4 import uic, QtGui, QtCore
class MainWindow(QtGui.QMainWindow):
def __init__(self, parent=None):
QtGui.QWidget.__init__(self,parent)
uic.loadUi('main_window.ui',self)
....