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Qaction Shortcut in extended contextmenu not triggered

I try to extend the contextmenu of a QLineEdit with an additional entry for replacing text. I can extend the contextmenu with .createStandardContextMenu(), which works fine. But when I try to add a shortcut with .setShortcut(QKeySequence(Qt.CTRL + Qt.Key_R)) it will not react on the key. Same with different keys, which I tried. In addition the shortcut made with QAction('&Replace', self) doesn't work too.
Some examples here in SO and other sources are constructed in the same way, so I'm wondering that nobody else has got the same problem. Seems that I'm missing anything. But what? I can't figure out, checked the docs multiple times.
Working Example:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys
class ECM(QWidget):
def __init__(self):
super(ECM, self).__init__()
self.setWindowTitle("Extended Context Menu")
self.lineEdit = QLineEdit()
self.lineEdit.setContextMenuPolicy(Qt.CustomContextMenu)
self.lineEdit.customContextMenuRequested.connect(self.my_contextMenuEvent)
layout = QVBoxLayout()
layout.addWidget(self.lineEdit)
self.setLayout(layout)
self.setFixedSize(800,200)
self.show()
def replace(self):
print("replace")
def my_contextMenuEvent(self):
print("my_contextMenuEvent")
menu = self.lineEdit.createStandardContextMenu()
action = QAction('&Replace', self)
action.setStatusTip('Replace values')
action.setShortcut(QKeySequence(Qt.CTRL + Qt.Key_R))
action.triggered.connect(self.replace)
menu.addAction(action)
menu.exec_()
if __name__ == '__main__':
app = QApplication(sys.argv)
sender = ECM()
app.exec_()

Based on musicamante's comment I came to the following solution:
Extract from the docs:
If you want to extend the standard context menu, reimplement this
function, call createStandardContextMenu() and extend the menu
returned.
The default use of the QAction list (as returned by actions()) is to
create a context QMenu.
It's not totally logically to me, not for the 1st time ;-)
Final code:
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
import sys
class ECM(QWidget):
def __init__(self):
super(ECM, self).__init__()
self.setWindowTitle("Extended Context Menu")
self.lineEdit = QLineEdit()
self.lineEdit.setContextMenuPolicy(Qt.CustomContextMenu)
self.lineEdit.customContextMenuRequested.connect(self.my_contextMenuEvent)
layout = QVBoxLayout()
layout.addWidget(self.lineEdit)
self.setLayout(layout)
self.setFixedSize(800,200)
action = QAction('&Replace', self)
action.setStatusTip('Replace values')
action.setShortcut(QKeySequence(Qt.CTRL + Qt.Key_R))
action.triggered.connect(self.replace)
self.lineEdit.addAction(action)
self.show()
def replace(self):
print("replace")
def my_contextMenuEvent(self):
menu = self.lineEdit.createStandardContextMenu()
menu.addActions(self.lineEdit.actions())
menu.exec_()
if __name__ == '__main__':
app = QApplication(sys.argv)
sender = ECM()
app.exec_()

Switch widget in QStackWidget from a button in another file

I got two py files. One has the main window with a QStackedWidget inside, the setCurrentWidget is set according to a condition. The other file has a widget which is dynamically added into the stacked widget and set as current widget when a button in the main window is clicked.
The widget in the second file has a dialog with a button in it. What I'm trying to do is, on clicking the button inside the dialog, the dialog should be closed and the setCurrentWidget is set according to the condition and the widget is removed from the stacked widget.
Here is what I've tried:
mainwindow.py
import sys
import os
import pathlib
from PySide2.QtWidgets import *
from PySide2 import *
from PySide2.QtCore import *
from PySide2.QtGui import *
list1 = ["item1", "item2", "item3"]
class MainWindow(QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.resize(400, 300)
self.toolbar = QWidget()
self.toolbar.setFixedHeight(30)
self.toolbar.setStyleSheet("background: grey;")
self.button = QPushButton("Click here!")
t_layout = QHBoxLayout()
t_layout.setMargin(0)
t_layout.addWidget(self.button)
self.toolbar.setLayout(t_layout)
self.p1_label = QLabel("Such empty!")
self.p1_label.setStyleSheet("font-size: 30px;")
self.p1_label.setAlignment(Qt.AlignCenter)
self.p2_widget = QWidget()
self.p2_widget.setStyleSheet("background: orange;")
self.sw = QStackedWidget()
self.sw.addWidget(self.p1_label)
self.sw.addWidget(self.p2_widget)
if not list1:
self.sw.setCurrentWidget(self.p1_label)
else:
self.sw.setCurrentWidget(self.p2_widget)
self.mw_layout = QVBoxLayout()
self.mw_layout.addWidget(self.toolbar)
self.mw_layout.addWidget(self.sw)
self.setLayout(self.mw_layout)
def switch_widget():
import widget_test
p3 = widget_test.widget()
self.sw.addWidget(p3)
self.sw.setCurrentWidget(p3)
self.button.clicked.connect(switch_widget)
def switch_back(self):
import widget_test
p3 = widget_test.widget()
mwin = MainWindow()
sw_ = mwin.sw
sw_.removeWidget(p3)
p1 = mwin.p1_label
p2 = mwin.p2_widget
if not list1:
sw_.setCurrentWidget(p1)
else:
sw_.setCurrentWidget(p2)
if __name__ == '__main__':
app = QApplication(sys.argv)
mw = MainWindow()
mw.show()
sys.exit(app.exec_())
widget.py
import sys
import os
import pathlib
import datetime
from PySide2.QtWidgets import *
from PySide2 import *
from PySide2.QtCore import *
from PySide2.QtGui import *
class widget(QWidget):
def __init__(self):
super(widget, self).__init__()
self.setStyleSheet("background: teal;")
widget_label = QLabel("fluid dynamics is cool")
show_pop_up = QPushButton("show pop up")
pop_up = QDialog(self)
pop_up_label = QLabel("click below to, hopefully, get outta here")
get_outta_here = QPushButton("get outta here")
pop_up_layout = QVBoxLayout()
pop_up_layout.addWidget(pop_up_label)
pop_up_layout.addWidget(get_outta_here)
pop_up.setLayout(pop_up_layout)
def show_popup():
pop_up.show()
def get_out():
from main_test import MainWindow
MainWindow.switch_back(self)
pop_up.reject()
get_outta_here.clicked.connect(get_out)
show_pop_up.clicked.connect(show_popup)
widget_layout = QVBoxLayout()
widget_layout.addWidget(widget_label)
widget_layout.addWidget(show_pop_up)
self.setLayout(widget_layout)
I could merge the code together and make it work but I'm trying to keep the directory clean.

There is a lot going on here, but let's break it down.
The main problem seems to be juggling between modules. Eventhough it might seem appealing to import the modules back and forth, it doesn't really work. What you need to look for, is the built-in Signals module that you can utilize.
Another bigger problem is that you are re-assigning some attributes eventhough you really shouldn't. You also should revisit the condition you are using to assign the .setCurrentWidget. Currently the condition reads as if list1 doesn't exist, do this. Else, do the other. Also, switch_widget should be outside of the def __init__(self):.
I rewrote some parts of the code to make it work with signals as an example for you.
mainwindow.py
import sys
import os
import pathlib
from PySide2.QtWidgets import *
from PySide2 import *
from PySide2.QtCore import *
from PySide2.QtGui import *
from widget_test import widget
list1 = ["item1", "item2", "item3"]
class MainWindow(QWidget):
def __init__(self):
super(MainWindow, self).__init__()
self.resize(400, 300)
self.toolbar = QWidget()
self.toolbar.setFixedHeight(30)
self.toolbar.setStyleSheet("background: grey;")
self.button = QPushButton("Click here!")
t_layout = QHBoxLayout()
t_layout.setMargin(0)
t_layout.addWidget(self.button)
self.toolbar.setLayout(t_layout)
self.p1_label = QLabel("Such empty!")
self.p1_label.setStyleSheet("font-size: 30px;")
self.p1_label.setAlignment(Qt.AlignCenter)
self.p2_widget = QWidget()
self.p2_widget.setStyleSheet("background: orange;")
self.p3 = None
self.sw = QStackedWidget()
self.sw.addWidget(self.p1_label)
self.sw.addWidget(self.p2_widget)
if not list1:
self.sw.setCurrentWidget(self.p1_label)
else:
self.sw.setCurrentWidget(self.p2_widget)
self.mw_layout = QVBoxLayout()
self.mw_layout.addWidget(self.toolbar)
self.mw_layout.addWidget(self.sw)
self.setLayout(self.mw_layout)
self.button.clicked.connect(self.switch_widget)
def switch_widget(self):
self.p3 = widget()
self.p3.update_signal.connect(self.switch_back)
self.sw.addWidget(self.p3)
self.sw.setCurrentWidget(self.p3)
def switch_back(self):
self.sw.removeWidget(self.p3)
if list1:
self.sw.setCurrentWidget(self.p1_label)
else:
self.sw.setCurrentWidget(self.p2_widget)
if __name__ == '__main__':
app = QApplication(sys.argv)
mw = MainWindow()
mw.show()
sys.exit(app.exec_())
widget.py
import sys
import os
import pathlib
import datetime
from PySide2.QtWidgets import *
from PySide2 import *
from PySide2.QtCore import *
from PySide2.QtGui import *
from PySide2.QtCore import Signal
class widget(QWidget):
update_signal = Signal()
def __init__(self):
super(widget, self).__init__()
self.setStyleSheet("background: teal;")
widget_label = QLabel("fluid dynamics is cool")
show_pop_up = QPushButton("show pop up")
pop_up = QDialog(self)
pop_up_label = QLabel("click below to, hopefully, get outta here")
get_outta_here = QPushButton("get outta here")
pop_up_layout = QVBoxLayout()
pop_up_layout.addWidget(pop_up_label)
pop_up_layout.addWidget(get_outta_here)
pop_up.setLayout(pop_up_layout)
def show_popup():
pop_up.show()
def get_out():
self.update_signal.emit()
pop_up.reject()
get_outta_here.clicked.connect(get_out)
show_pop_up.clicked.connect(show_popup)
widget_layout = QVBoxLayout()
widget_layout.addWidget(widget_label)
widget_layout.addWidget(show_pop_up)
self.setLayout(widget_layout)
Finally, check Python coding conventions for naming and other "minor" details.

How to change languages(translations) dynamically on PyQt5?

I wonder if it is possible to change the languages(translations) dynamically without using qt designer to make the UI? That means I don't want to use the function retranslateUi() to update the program interface.
Here is my code, but I'm stuck on lines marked #1 #2 #3. Don't know what I should use to update the interface.
import sys
from PyQt5.QtCore import Qt, QTranslator
from PyQt5.QtWidgets import QApplication, QWidget, QPushButton, QLabel,
QComboBox, QVBoxLayout
class Demo(QWidget):
def __init__(self):
super(Demo, self).__init__()
self.button = QPushButton(self.tr('Start'), self)
self.label = QLabel(self.tr('Hello, World'), self)
self.label.setAlignment(Qt.AlignCenter)
self.combo = QComboBox(self)
self.combo.addItem('English')
self.combo.addItem('中文')
self.combo.addItem('français')
self.combo.currentTextChanged.connect(self.change_func)
self.trans = QTranslator(self)
self.v_layout = QVBoxLayout()
self.v_layout.addWidget(self.combo)
self.v_layout.addWidget(self.button)
self.v_layout.addWidget(self.label)
self.setLayout(self.v_layout)
def change_func(self):
print(self.combo.currentText())
if self.combo.currentText() == '中文':
self.trans.load('eng-chs')
_app = QApplication.instance()
_app.installTranslator(self.trans)
# 1
elif self.combo.currentText() == 'français':
self.trans.load('eng-fr')
_app = QApplication.instance()
_app.installTranslator(self.trans)
# 2
else:
_app = QApplication.instance()
_app.removeTranslator(self.trans)
# 3
if __name__ == '__main__':
app = QApplication(sys.argv)
demo = Demo()
demo.show()
sys.exit(app.exec_())
Any help would be appreciated.

TL; DR; It is not necessary to use Qt Designer
You should not use Qt Designer necessarily but you should use the same technique, that is, create a method that could be called retranslateUi() and in it set the texts using translate() instead of tr() (for more details read the docs). Calling that method when you change language for it must use the changeEvent() event. For example in your case the code is as follows:
import sys
from PyQt5 import QtCore, QtGui, QtWidgets
class Demo(QtWidgets.QWidget):
def __init__(self):
super(Demo, self).__init__()
self.button = QtWidgets.QPushButton()
self.label = QtWidgets.QLabel(alignment=QtCore.Qt.AlignCenter)
self.combo = QtWidgets.QComboBox(self)
self.combo.currentIndexChanged.connect(self.change_func)
self.trans = QtCore.QTranslator(self)
self.v_layout = QtWidgets.QVBoxLayout(self)
self.v_layout.addWidget(self.combo)
self.v_layout.addWidget(self.button)
self.v_layout.addWidget(self.label)
options = ([('English', ''), ('français', 'eng-fr' ), ('中文', 'eng-chs'), ])
for i, (text, lang) in enumerate(options):
self.combo.addItem(text)
self.combo.setItemData(i, lang)
self.retranslateUi()
#QtCore.pyqtSlot(int)
def change_func(self, index):
data = self.combo.itemData(index)
if data:
self.trans.load(data)
QtWidgets.QApplication.instance().installTranslator(self.trans)
else:
QtWidgets.QApplication.instance().removeTranslator(self.trans)
def changeEvent(self, event):
if event.type() == QtCore.QEvent.LanguageChange:
self.retranslateUi()
super(Demo, self).changeEvent(event)
def retranslateUi(self):
self.button.setText(QtWidgets.QApplication.translate('Demo', 'Start'))
self.label.setText(QtWidgets.QApplication.translate('Demo', 'Hello, World'))
if __name__ == '__main__':
app = QtWidgets.QApplication(sys.argv)
demo = Demo()
demo.show()
sys.exit(app.exec_())
Then generate the .ts:
pylupdate5 main.py -ts eng-chs.ts
pylupdate5 main.py -ts eng-fr.ts
Then use Qt Linguist to do the translations.
And finally the .qm:
lrelease eng-fr.ts eng-chs.qm
The complete project you find here.

No you will have to use a technique like Qt Designer does with retranslateUi because the Qt widget system does not have a way to redo the translation on it's own (otherwise QT Designer would be using that to).
Building such a system would require a fundamental change to the widgets as for each string property you would need to know that it contains a translatable string (not a data value) and knowing the original string for looking up the new translation would be best (reversing translations could be ambiguous).

How do I make a shortcut using arrow key with PySide2?

I want to add a keyboard shortcut to a button with Qt5 + Python (Pyside2). Code for making a shortcut with a regular key:
import sys
import random
from PySide2 import QtCore, QtWidgets, QtGui
class MyWidget(QtWidgets.QWidget):
def __init__(self):
super().__init__()
self.hello = ["Hallo Welt", "你好，世界", "Hei maailma",\
"Hola Mundo", "Привет мир"]
self.button = QtWidgets.QPushButton("Click me!")
self.text = QtWidgets.QLabel("Hello World")
self.text.setAlignment(QtCore.Qt.AlignCenter)
self.text.setFont(QtGui.QFont("Titillium", 30))
self.button.setFont(QtGui.QFont("Titillium", 20))
self.layout = QtWidgets.QVBoxLayout()
self.layout.addWidget(self.text)
self.layout.addWidget(self.button)
self.setLayout(self.layout)
shortcut = QtWidgets.QShortcut(QtGui.QKeySequence('o'), self.button)
shortcut.activated.connect(self.magic)
self.button.clicked.connect(self.magic)
def magic(self):
self.text.setText(random.choice(self.hello))
if __name__ == "__main__":
app = QtWidgets.QApplication([])
widget = MyWidget()
widget.resize(800, 600)
widget.show()
sys.exit(app.exec_())
If I replace that shortcut = ... line with this:
shortcut = QtWidgets.QShortcut(QtGui.QKeySequence(QtCore.Qt.LeftArrow), self.button)
Nothing happens. What am I missing?
I also tried converting the QtCore.Qt.LeftArrow value to string (nothing happens), and tried making the QShortcut directly with the Qt.LeftArrow (complains about nullptr). Using QtCore.Qt.Key_Left as parameter for QShortcut gave me nullptr too.

I found out:
shortcut = QtWidgets.QShortcut(QtGui.QKeySequence.MoveToPreviousChar, self.button)
The list of actions are here:
http://doc.qt.io/qt-5/qkeysequence.html#StandardKey-enum

With PySide2 something like the following should works:
QtWidgets.QShortcut(QtGui.QKeySequence("right"), self.button, self.magic)
which will directly connect the button with callback function.

Printing button toolbar PySide Python

I have a browser application written in python with PySide Qt. But now I want to add a button in the toolbar to print the website. How do I do this? Because CTRL + P is not working in the application.
Here is the code:
import sys
from PySide import QtCore, QtGui, QtWebKit, QtHelp, QtNetwork
class MainWindow(QtGui.QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
Action1 = QtGui.QAction('Google', self)
Action1.setShortcut('Ctrl+M')
Action1.triggered.connect(self.load_message)
self.toolbar1 = self.addToolBar('Google')
self.toolbar1.addAction(Action1)
Action2 = QtGui.QAction('Yahoo', self)
Action2.setShortcut('Ctrl+H')
Action2.triggered.connect(self.load_list)
self.toolbar2 = self.addToolBar('Yahoo')
self.toolbar2.addAction(Action2)
exitAction = QtGui.QAction('Exit', self)
exitAction.setShortcut('Ctrl+Q')
exitAction.triggered.connect(self.on_exit)
self.toolbar3 = self.addToolBar('Exit')
self.toolbar3.addAction(exitAction)
self.resize(750, 750)
self.setWindowTitle('Browser')
self.web = QtWebKit.QWebView(self)
self.web.load(QtCore.QUrl('http://www.google.com'))
self.setCentralWidget(self.web)
def on_exit(self):
QtGui.qApp.quit
def load_message(self):
self.web.load(QtCore.QUrl('http://www.google.com'))
def load_list(self):
self.web.load(QtCore.QUrl('http://www.yahoo.com'))
app = QtGui.QApplication(sys.argv)
app.setWindowIcon(QtGui.QIcon('myicon.ico'))
main_window = MainWindow()
main_window.show()
sys.exit(app.exec_())

In your __init__ method add a Print action:
printAction = QtGui.QAction('Print', self)
printAction.setShortcut('Ctrl+P')
printAction.triggered.connect(self.do_print)
self.toolbar4 = self.addToolBar('Print')
self.toolbar4.addAction(printAction)
And create a do_print method:
def do_print(self):
p = QtGui.QPrinter()
p.setPaperSize(QtGui.QPrinter.A4)
p.setFullPage(True)
p.setResolution(300)
p.setOrientation(QtGui.QPrinter.Portrait)
p.setOutputFileName('D:\\test.pdf')
self.web.print_(p)
This will print to a file D:\test.pdf.
To configure your printer differently see the QPrinter documentation. Also if you want a print preview dialog see the QPrintPreviewDialog docs.
If you want a standard print dialog the use:
def do_print(self):
p = QtGui.QPrinter()
dialog = QtGui.QPrintDialog(p)
dialog.exec_()
self.web.print_(p)