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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_()

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).

I want to know how to use pyqt5 to load the created widget at once

Sorry. I will modify the contents. I would like to load a widget inside def test by pressing Qbutton. Can not you use QStackedWidget to load the widget's configured functions? I've compiled the class and called it, but only a = QLineEdit ('Qline', self). I wonder what should be done to switch widgets.
You can also create a table like html using pyqt5.
import sys
from PyQt5.QtWidgets import *
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.stacked = QStackedWidget(self)
self.FirstpUI()
def FirstpUI(self):
self.btn1 = QPushButton('test1', self)
self.btn1.move(50,50)
self.btn1.clicked.connect(self.btn1_click)
def test(self):
a = QLineEdit('Qline', self)
b = QLineEdit('Qline2', self)
c = QPushButton('button', self)
a.move(0, 0)
b.move(100, 0)
c.move(50,50)
c.clicked.connect(self.btn2_click)
def btn1_click(self):
self.btn1.deleteLater()
self.stacked.addWidget(self.test())
self.stacked.setCurrentIndex(self.stacked.currentIndex()+1)
def btn2_click(self):
QMessageBox.about(self,'hello','hello2')
if __name__ == "__main__":
app = QApplication(sys.argv)
fream = MainWindow()
fream.show()
app.exec_()

May be I don't know what you real want,because I know that little, I think You can use QtDesigner,it's very useful

How can I add a submit, output and input box using PyQt4?

I never tried creating a GUI with a language other than Java(kinda left it aside not long ago)
and started using Python.
made a simple program that calculates Pi to a certain digit as the user wishes.
Now, I created a window with PyQt4, made a button and got everything in place.
How can I add a input box so that the user could enter a number into it, make the button "Enter" the information and at the end of all that output it to the window instead of the terminal?
That's what I've got for now:
import sys
from PyQt4 import QtGui
from PyQt4 import QtCore
from decimal import *
class Window(QtGui.QMainWindow):
def __init__(self):
super(Window, self).__init__()
self.setGeometry(50, 50, 800, 600)
self.setWindowTitle("Pi's Nth Digit")
self.setWindowIcon(QtGui.QIcon('icon.jpg'))
self.buttons()
def buttons(self):
btn = QtGui.QPushButton("Quit",self)
btn1 = QtGui.QPushButton("Get Pi",self)
btn.clicked.connect(QtCore.QCoreApplication.instance().quit)
btn1.clicked.connect(self.getpi())
btn1.resize(btn1.sizeHint())
btn.resize(btn.sizeHint())
btn1.move(350,500)
btn.move(450,500)
self.show()
def start():
app = QtGui.QApplication(sys.argv)
GUI = Window()
sys.exit(app.exec_())
start()
don't mind the getpi function.
Thanks! :)

You would want to use a QLineEdit or a QSpinBox for a number. If you want multiple things in a widget you would use a layout. A QMainWindow typically has one central widget and toolbars and dock widgets.
class Window(QtGui.QMainWindow):
def __init__(self):
super().__init__()
self.container = QtGui.QWidget()
self.setCentralWidget(self.container)
self.container_lay = QtGui.QVBoxLayout()
self.container.setLayout(self.container_lay)
# Input
self.le = QtGui.QLineEdit()
self.container_lay.addWidget(self.le)
# enter button
self.enter_btn = QtGui.QPushButton("Enter")
self.container_lay.addWidget(self.enter_btn)
self.enter_btn.clicked.connect(self.run) # No '()' on run you want to reference the method.
# display
self.container_lay.addWidget(QtGui.QLabel("Answer:"))
self.ans = QtGui.QLabel()
self.container_lay.addWidget(self.ans)
def run(self):
precision = self.le.text()
pi = str(round(math.pi, precision)) # probably different formatting
self.ans.setText(pi)
if __name__ == "__main__":
app = QtGui.QApplication(sys.argv)
window = Window()
window.show()
sys.exit(app.exec_())

You have almost everything, just add a QLineEdit to get the input and a QLabel where to show the result (with QLabel.setText).

TreeWidget setItemWidget Issue Qt

I am adding a Qwidget(QPushButton) into a QTreeWidget through setItemWidget method, but Button is not appearing as expected.
Need some help in this case.
Code:
import sys
from PyQt4 import QtGui, QtCore
class Test_Ui(QtGui.QMainWindow):
def __init__(self):
super(Test_Ui, self).__init__()
self.setMainWidget()
self.setTree()
self.show()
def setMainWidget(self):
self.QwCentral = QtGui.QWidget()
self.setCentralWidget(self.QwCentral)
self.QglCentral = QtGui.QGridLayout()
self.QwCentral.setLayout(self.QglCentral)
def setTree(self):
self.QtwExp = QtGui.QTreeWidget()
self.QtwExp.headerItem().setText(0, 'First')
self.QtwExp.headerItem().setText(1, 'Second')
self.QglCentral.addWidget(self.QtwExp, 0,0)
Qcategory = QtGui.QTreeWidgetItem()
Qcategory.setText(0, 'TEST')
self.QtwExp.addTopLevelItem(Qcategory)
Qbutton = QtGui.QPushButton()
Qbutton.setText('BUTTON')
# setItem Widget Command
self.QtwExp.setItemWidget(Qcategory, 1, Qbutton)
def main():
global wapp
app = QtGui.QApplication(sys.argv)
wapp = Test_Ui()
sys.exit(app.exec_())

Simple typo:
Replace following
self.QtwExp.addToplevelItem(Qcategory)
with
self.QtwExp.addTopLevelItem(Qcategory)
# ^

Its the PyQt4 version issue.
when i use PyQt4 version 4.7.x it works fine.