Develop Reference

How to properly initialize a QWizard page?

I am having problems with sending data from one QWizard page to the next. I'm using a variable my_name of QWizard object as a container.
My approach is: whenever I change text of QLineEdit on Page1, the variable my_name of my QWizard object changes. And whenever I click Next button on Page1, Page2 is initialized using the method QWizard.initializePage(2). But the QLabel object on Page2 is not update based on the my_name variable of QWizard object. Even though I have initialized the Page2 also. What is wrong with my approach?
My code is:
import sys
from PyQt5.QtWidgets import *
class Window(QWizard):
def __init__(self):
super(Window, self).__init__()
self.firstPage = MainPage(parent=self)
self.my_name = 'Random'
self.secondPage = Page2(parent=self)
self.addPage(self.firstPage)
self.button(QWizard.NextButton).clicked.connect(lambda: self.initializePage(2))
self.addPage(self.secondPage)
class MainPage(QWizardPage):
def __init__(self, parent=None):
self.Parent = parent
super(MainPage, self).__init__(parent)
self.setTitle("Plz input your name?")
self.NameLabel = QLabel("&Name:")
self.NameLineEdit = QLineEdit()
self.NameLineEdit.textChanged.connect(self.assign)
self.NameLabel.setBuddy(self.NameLineEdit)
layout = QHBoxLayout()
layout.addWidget(self.NameLabel)
layout.addWidget(self.NameLineEdit)
self.setLayout(layout)
def assign(self):
self.Parent.my_name = self.NameLineEdit.text()
print(f'Parent text is: {self.Parent.my_name}')
class Page2(QWizardPage):
def __init__(self, parent=None):
super(Page2, self).__init__()
self.Parent = parent
vbox = QVBoxLayout()
label = QLabel()
label.setText(f'My name is : {self.Parent.my_name}')
vbox.addWidget(label)
self.setLayout(vbox)
def main():
app = QApplication(sys.argv)
app.setStyle('plastique')
window = Window()
window.setWizardStyle(1)
window.show()
app.exec_()
if __name__ == "__main__":
sys.exit(main())

Changing the value of the variable "my_name" does not change what the QLabel shows since QLabel copies the text. On the other hand you should not call initializePage(2) since it is a protected method that is called internally. The solution is to override the initializePage method of the QWizardPage:
class Page2(QWizardPage):
def __init__(self, parent=None):
super(Page2, self).__init__()
self.Parent = parent
vbox = QVBoxLayout(self)
self.label = QLabel()
self.label.setText(f'My name is : {self.Parent.my_name}')
vbox.addWidget(self.label)
def initializePage(self):
self.label.setText(f'My name is : {self.Parent.my_name}')
Although I see that you are reinventing the wheel since there is already that characteristic registering the fields:
class Window(QWizard):
def __init__(self, parent=None):
super(Window, self).__init__(parent)
self.firstPage = MainPage()
self.secondPage = Page2()
self.addPage(self.firstPage)
self.addPage(self.secondPage)
class MainPage(QWizardPage):
def __init__(self, parent=None):
super(MainPage, self).__init__(parent)
self.setTitle("Plz input your name?")
self.NameLabel = QLabel("&Name:")
self.NameLineEdit = QLineEdit()
self.NameLabel.setBuddy(self.NameLineEdit)
layout = QHBoxLayout(self)
layout.addWidget(self.NameLabel)
layout.addWidget(self.NameLineEdit)
self.registerField("my_name", self.NameLineEdit)
class Page2(QWizardPage):
def __init__(self, parent=None):
super(Page2, self).__init__(parent)
vbox = QVBoxLayout(self)
self.label = QLabel()
vbox.addWidget(self.label)
def initializePage(self):
self.label.setText(f'My name is : {self.field("my_name")}')
super(Page2, self).initializePage()

Python PyQt button click won't fire a event

i am new in PyQt but i have a problem i can't solve. I am trying to get text from second window and set it to field, so when i close second window i can print it form first main window, but my "AnotherWindow" button won't fire event and i really don't know why? Here is code. Can anyone guide me?
Thanks
class AnotherWindow(QMainWindow):
def __init__(self):
super().__init__()
self.resize(1200, 600)
self.text = "basetext"
self.layoutf = QFormLayout()
self.buttonf = QPushButton("get text")
self.buttonf.clicked.connect(lambda: self.getText)
self.line = QLineEdit()
self.layoutf.addRow(self.buttonf,self.line)
self.widgetf = QWidget()
self.widgetf.setLayout(self.layoutf)
self.setCentralWidget(self.widgetf)
def getText(self):
print(self.line.text)
self.text = self.line.text
self.close()
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.w = None # No external window yet.
self.mainLayout = QGridLayout()
self.button = QPushButton("Push for Window")
self.button.clicked.connect(self.show_new_window)
self.button1 = QPushButton("Push ")
self.button1.clicked.connect(self.printFromSecondWindow)
self.mainLayout.addWidget(self.button,0,0)
self.mainLayout.addWidget(self.button1, 0, 1)
self.widget = QWidget()
self.widget.setLayout(self.mainLayout)
self.setCentralWidget(self.widget)
def show_new_window(self):
if self.w is None:
self.w = AnotherWindow()
self.w.show()
else:
self.w.close() # Close window.
self.w = None # Discard reference.
def printFromSecondWindow(self):
print(self.w.text)
app = QApplication(sys.argv)
w = MainWindow()
w.show()
app.exec_()

The problem is with self.buttonf.clicked.connect(...). This call attaches a function to the "clicked" action on the button. The function is called without parameters and the return is simply discarded. In your case, lambda: self.get_text is a function that does nothing but return the address of the self.get_text method. Since get_text doesn't need any additional parameters, you can bind it directly to this slot.
self.buttonf.clicked.connect(self.get_text)
You also have a bug later on where you need to call the text method. With these two changes, the working program is
import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5.Qt import *
class AnotherWindow(QMainWindow):
def __init__(self):
super().__init__()
self.resize(1200, 600)
self.text = "basetext"
self.layoutf = QFormLayout()
self.buttonf = QPushButton("get text")
self.buttonf.clicked.connect(self.getText)
self.line = QLineEdit()
self.layoutf.addRow(self.buttonf,self.line)
self.widgetf = QWidget()
self.widgetf.setLayout(self.layoutf)
self.setCentralWidget(self.widgetf)
def getText(self):
print("the info", self.line.text())
self.text = self.line.text()
self.close()
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.w = None # No external window yet.
self.mainLayout = QGridLayout()
self.button = QPushButton("Push for Window")
self.button.clicked.connect(self.show_new_window)
self.button1 = QPushButton("Push ")
self.button1.clicked.connect(self.printFromSecondWindow)
self.mainLayout.addWidget(self.button,0,0)
self.mainLayout.addWidget(self.button1, 0, 1)
self.widget = QWidget()
self.widget.setLayout(self.mainLayout)
self.setCentralWidget(self.widget)
def show_new_window(self):
if self.w is None:
self.w = AnotherWindow()
self.w.show()
else:
self.w.close() # Close window.
self.w = None # Discard reference.
def printFromSecondWindow(self):
print(self.w.text)
app = QApplication(sys.argv)
w = MainWindow()
w.show()
app.exec_()

Instantiate the second window once in the main window constructor. self.w = AnotherWindow (self)
When creating an instance of the second window, self.w = AnotherWindow (self) - self is passed as a parent, so that when the main window is closed, the second window also closes.
To get text from a QLineEdit widget - apply QString text() const, more https://doc.qt.io/qt-5/qlineedit.html#text-prop
You did not show the method printFromSecondWindow in which, as I understand it, you wanted to show what you intended.
Try it:
import sys
from PyQt5 import QtWidgets, QtCore, QtGui
from PyQt5.Qt import *
class AnotherWindow(QMainWindow):
def __init__(self, parent=None):
super(AnotherWindow, self).__init__(parent)
self.widgetf = QWidget()
self.setCentralWidget(self.widgetf)
# self.resize(1200, 600)
self.text = "basetext"
self.layoutf = QFormLayout(self.widgetf)
self.buttonf = QPushButton("get text")
# self.buttonf.clicked.connect(lambda: self.getText) # ??? lambda
self.buttonf.clicked.connect(self.getText)
self.line = QLineEdit()
self.layoutf.addRow(self.buttonf,self.line)
def getText(self):
print(self.line.text()) # ! .text()
self.text = self.line.text() # ! .text()
self.close()
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.widget = QWidget()
self.setCentralWidget(self.widget)
# ? self.w = None # No external window yet.
self.button = QPushButton("Push for Window")
self.button.clicked.connect(self.show_new_window)
self.button1 = QPushButton("Push ")
self.button1.clicked.connect(self.printFromSecondWindow)
self.mainLayout = QGridLayout(self.widget)
self.mainLayout.addWidget(self.button, 0, 0)
self.mainLayout.addWidget(self.button1, 0, 1)
self.w = AnotherWindow(self) # +++
def show_new_window(self):
# if self.w is None:
# self.w = AnotherWindow()
self.w.show() # !
# else:
# self.w.close() # Close window.
# self.w = None # Discard reference.
def printFromSecondWindow(self): # +++
print(self.w.text)
if __name__ == '__main__':
app = QApplication(sys.argv)
w = MainWindow()
w.show()
sys.exit(app.exec_())

Can't open gui class window with specified options

I'm new to python and pyqt. I'm trying to open a new window after the first screen. My second window opens but without the options I specified, label and pushbutton.
from PyQt5 import QtWidgets
import sys
class secondwindow(QtWidgets.QMainWindow):
def __init__(self):
super(secondwindow, self).__init__()
self.label1 = QtWidgets.QLabel("Second Window");
self.button1 = QtWidgets.QPushButton("Click Me");
hbox = QtWidgets.QHBoxLayout()
hbox.addWidget(self.label1)
hbox.addWidget(self.button1)
self.setLayout(hbox)
class Window(QtWidgets.QWidget):
def btnclicked(self):
sender = self.sender()
if sender.text() == "OK":
self.secwin.show()
def __init__(self, parent=None):
super(Window, self).__init__(parent)
self.button1 = QtWidgets.QPushButton("OK");
vbox = QtWidgets.QVBoxLayout()
vbox.addWidget(self.button1)
self.setLayout(vbox)
self.button1.clicked.connect(self.btnclicked)
self.secwin = secondwindow()
self.show()
def main():
app = QtWidgets.QApplication(sys.argv)
main = Window()
main.show
sys.exit(app.exec())
if __name__ == '__main__':
main()

QMainWindow is a special widget because it has a defined structure, http://doc.qt.io/qt-5/qmainwindow.html#qt-main-window-framework:
As shown in the image there is already an area destined to place the widgets called Central Widget, in it you must place the widgets that you want to be displayed for it, you use setCentralWidget().
In your case the solution is:
class secondwindow(QtWidgets.QMainWindow):
def __init__(self):
super(secondwindow, self).__init__()
central_widget = QtWidgets.QWidget()
self.label1 = QtWidgets.QLabel("Second Window")
self.button1 = QtWidgets.QPushButton("Click Me")
hbox = QtWidgets.QHBoxLayout(central_widget)
hbox.addWidget(self.label1)
hbox.addWidget(self.button1)
self.setCentralWidget(central_widget)

How to scroll text in QTextEdit automatically (animational effect)?

I would like to ask how to make the text in QTextEdit scoll, to achieve an animational effect. The animational effect should be something like what in the video shows: https://www.youtube.com/watch?v=MyeuGdXv4XM
With PyQt I want to get this effect:
The text should be scolled automatically at a speed of 2 lines/second downwards, till it reaches the end and stops.
In my code below, when the button is clicked, the text is shown in QTextEdit-Widget. The text is very long, so that the scroll bar is shown.
My Problem:
I dont know how to make the animation effect. Thus I would like to ask your help to correct my code.
# -*- coding: utf-8 -*-
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys
import time
list_longText = [" long text 1 - auto scrolling " * 1000, " long text 2 - auto scrolling " * 2000]
class Worker(QObject):
finished = pyqtSignal()
strTxt = pyqtSignal(str)
def __init__(self, parent=None):
super(Worker, self).__init__(parent)
#pyqtSlot()
def onJob(self):
for i in range(2):
self.strTxt.emit(list_longText[i])
time.sleep(2)
class MyApp(QWidget):
def __init__(self):
super(MyApp, self).__init__()
self.setFixedSize(600, 400)
self.setObjectName("window")
self.initUI()
def initUI(self):
self.txt = QTextEdit("", self)
self.btn = QPushButton("Button", self)
self.btn.clicked.connect(self.start)
self.layout = QHBoxLayout(self)
self.layout.addWidget(self.txt)
self.layout.addWidget(self.btn)
self.setLayout(self.layout)
self.show()
def start(self):
self.thread = QThread()
self.obj = Worker()
self.obj.strTxt.connect(self.showText)
self.obj.moveToThread(self.thread)
self.obj.finished.connect(self.thread.quit)
self.thread.started.connect(self.obj.onJob)
self.thread.start()
def showText(self, str):
self.txt.setText("{}".format(str))
self.autoScroll()
def autoScroll(self):
vsb = self.txt.verticalScrollBar()
if vsb.value() <= vsb.maximum():
vsb.setValue(vsb.value() + 2)
time.sleep(1)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
sys.exit(app.exec_())
Thanks very much for the help!

The task you want is not heavy, it is periodic so using a thread is inappropriate, for this task we can use QVariantAnimation.
The other part is to create a method that moves to a certain line of text for it we use QTextCursor next to findBlockByLineNumber() of QTextDocument.
And for the last one we must start moving to the last initial visible for it we use the cursorForPosition() method through the size of the viewport().
longText = "\n".join(["{}: long text - auto scrolling ".format(i) for i in range(100)])
class AnimationTextEdit(QTextEdit):
def __init__(self, *args, **kwargs):
QTextEdit.__init__(self, *args, **kwargs)
self.animation = QVariantAnimation(self)
self.animation.valueChanged.connect(self.move)
#pyqtSlot()
def startAnimation(self):
self.animation.stop()
lines_per_second = 2
self.moveToLine(0)
p = QPoint(self.viewport().width() - 1, self.viewport().height() - 1)
cursor = self.cursorForPosition(p)
self.animation.setStartValue(cursor.blockNumber())
self.animation.setEndValue(self.document().blockCount()-1)
self.animation.setDuration(self.animation.endValue()*1000/lines_per_second)
self.animation.start()
#pyqtSlot(QVariant)
def move(self, i):
cursor = QTextCursor(self.document().findBlockByLineNumber(i))
self.setTextCursor(cursor)
class MyApp(QWidget):
def __init__(self):
super(MyApp, self).__init__()
self.setFixedSize(600, 400)
self.txt = AnimationTextEdit(self)
self.btn = QPushButton("Start", self)
self.layout = QHBoxLayout(self)
self.layout.addWidget(self.txt)
self.layout.addWidget(self.btn)
self.txt.append(longText)
self.txt.move(0)
self.btn.clicked.connect(self.txt.startAnimation)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
Update:
if you want a continuous movement you must use verticalScrollBar():
longText = "\n".join(["{}: long text - auto scrolling ".format(i) for i in range(100)])
class AnimationTextEdit(QTextEdit):
def __init__(self, *args, **kwargs):
QTextEdit.__init__(self, *args, **kwargs)
self.animation = QVariantAnimation(self)
self.animation.valueChanged.connect(self.moveToLine)
#pyqtSlot()
def startAnimation(self):
self.animation.stop()
self.animation.setStartValue(0)
self.animation.setEndValue(self.verticalScrollBar().maximum())
self.animation.setDuration(self.animation.endValue()*4)
self.animation.start()
#pyqtSlot(QVariant)
def moveToLine(self, i):
self.verticalScrollBar().setValue(i)
class MyApp(QWidget):
def __init__(self):
super(MyApp, self).__init__()
self.setFixedSize(600, 400)
self.txt = AnimationTextEdit(self)
self.btn = QPushButton("Start", self)
self.layout = QHBoxLayout(self)
self.layout.addWidget(self.txt)
self.layout.addWidget(self.btn)
self.txt.append(longText)
self.txt.moveToLine(0)
self.btn.clicked.connect(self.txt.startAnimation)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())

Passing variables from login form

I'm trying to pass two variables from a login form.Not sure is it the right way. My login form and main one created on QstackedWidget. However, as result I'm getting an empty list. Where is my mistake? Code below:
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class MainWindow(QMainWindow):
def __init__(self, parent=None):
QMainWindow.__init__(self, parent)
self.central_widget = QStackedWidget()
self.setCentralWidget(self.central_widget)
self.start_screen = Start(self)
self.second_screen = Second(self)
self.central_widget.addWidget(self.start_screen)
self.central_widget.addWidget(self.second_screen)
self.central_widget.setCurrentWidget(self.start_screen)
self.start_screen.clicked.connect(lambda: self.myshort(self.second_screen))
self.second_screen.clicked.connect(lambda: self.central_widget.setCurrentWidget(self.start_screen))
def myshort(self, your_function):
print(self.my_notes[0], self.my_notes[1]) #empty list
return self.central_widget.setCurrentWidget(your_function)
class Start(QWidget):
clicked = pyqtSignal()
def __init__(self, parent=None):
super(Start, self).__init__(parent)
self.textName = QLineEdit(self)
self.textPass = QLineEdit(self)
self.buttonSave = QPushButton('Save Details', self)
layout = QVBoxLayout(self)
layout.addWidget(self.textName)
layout.addWidget(self.textPass)
layout.addWidget(self.buttonSave)
self.buttonSave.clicked.connect(self.my_notes())
def my_notes(self):
MainWindow.my_notes = []
MainWindow.my_notes.append(str(self.textName.text()))
MainWindow.my_notes.append(str(self.textPass.text()))
return self.clicked.emit
class Second(QWidget):
clicked = pyqtSignal()
def __init__(self, parent=None):
super(Second, self).__init__(parent)
layout = QHBoxLayout()
button = QPushButton(text=QString('Back to Start!'))
layout.addWidget(button)
self.setLayout(layout)
button.clicked.connect(self.clicked.emit)
app = QApplication(sys.argv)
myWindow = MainWindow(None)
myWindow.show()
app.exec_()

Try following:
in class Start, method __init__
self.buttonSave.clicked.connect(self.my_notes())
remove bracelets:
self.buttonSave.clicked.connect(self.my_notes)
and in class Start, method my_notes change:
return self.clicked.emit
to:
self.clicked.emit()