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PyQt5: How to 'communicate' between QThread and some sub-class?

To this question I am referring to the answer from #eyllanesc in PyQt5: How to scroll text in QTextEdit automatically (animational effect)?
There #eyllanesc shows how to make the text auto scrolls smoothly using verticalScrollBar(). It works great.
For this question, I have added some extra lines, to use QThread to get the text.
What I want to achieve here: to let the QThread class 'communicate' with the AnimationTextEdit class, so that the scrolling time can be determined by the text-length. So that the programm stops, when the scrolling process ends.
I must say it is very very tricky task for me. I would like to show the programm flow first, as I imagined.
UPDATE: My code is as follows. It works, but...
Problem with the code: when the text stops to scroll, the time.sleep() still works. The App wait there till time.sleep() stops.
What I want to get: When the text stops to scroll, the time.sleep() runs to its end value.
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
from PyQt5.QtCore import *
import sys
import time
import sqlite3
class AnimationTextEdit(QTextEdit):
# signal_HowLongIsTheText = pyqtSignal(int) # signal to tell the QThread, how long the text is
def __init__(self, *args, **kwargs):
QTextEdit.__init__(self, *args, **kwargs)
self.animation = QVariantAnimation(self)
self.animation.valueChanged.connect(self.moveToLine)
# def sent_Info_to_Thread(self):
# self.obj_Thread = Worker()
# self.signal_HowLongIsTheText.connect(self.obj_Thread.getText_HowLongIsIt)
# self.signal_HowLongIsTheText.emit(self.textLength)
# self.signal_HowLongIsTheText.disconnect(self.obj_Thread.getText_HowLongIsIt)
#pyqtSlot()
def startAnimation(self):
self.animation.stop()
self.animation.setStartValue(0)
self.textLength = self.verticalScrollBar().maximum()
# self.sent_Info_to_Thread()
self.animation.setEndValue(self.textLength)
self.animation.setDuration(self.animation.endValue()*4)
self.animation.start()
#pyqtSlot(QVariant)
def moveToLine(self, i):
self.verticalScrollBar().setValue(i)
class Worker(QObject):
finished = pyqtSignal()
textSignal = pyqtSignal(str)
# #pyqtSlot(int)
# def getText_HowLongIsIt(self, textLength):
# self.textLength = textLength
#pyqtSlot()
def getText(self):
longText = "\n".join(["{}: long text - auto scrolling ".format(i) for i in range(100)])
self.textSignal.emit(longText)
time.sleep(10)
# time.sleep(int(self.textLength / 100))
# My question is about the above line: time.sleep(self.textLength)
# Instead of giving a fixed sleep time value here,
# I want let the Worker Class know,
# how long it will take to scroll all the text to the end.
self.finished.emit()
class MyApp(QWidget):
def __init__(self):
super(MyApp, self).__init__()
self.setFixedSize(600, 400)
self.initUI()
self.startThread()
def initUI(self):
self.txt = AnimationTextEdit(self)
self.btn = QPushButton("Start", self)
self.layout = QHBoxLayout(self)
self.layout.addWidget(self.txt)
self.layout.addWidget(self.btn)
self.btn.clicked.connect(self.txt.startAnimation)
def startThread(self):
self.obj = Worker()
self.thread = QThread()
self.obj.textSignal.connect(self.textUpdate)
self.obj.moveToThread(self.thread)
self.obj.finished.connect(self.thread.quit)
self.thread.started.connect(self.obj.getText)
self.thread.finished.connect(app.exit)
self.thread.start()
def textUpdate(self, longText):
self.txt.append(longText)
self.txt.moveToLine(0)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())
Thanks for the help and hint. What have I done wrong?

Although in the animation the duration is established it is necessary to understand that this is not exact, this could vary for several reasons, so calculating using the sleep to wait for it to end in a certain time and just closing the application may fail.
If your main objective is that when the animation is finished the program execution is finished then you must use the finished QVariantAnimation signal to finish the execution of the thread, this signal is emited when it finishes executing.
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.textLength = self.verticalScrollBar().maximum()
self.animation.setEndValue(self.textLength)
self.animation.setDuration(self.animation.endValue()*4)
self.animation.start()
#pyqtSlot(QVariant)
def moveToLine(self, i):
self.verticalScrollBar().setValue(i)
class Worker(QObject):
textSignal = pyqtSignal(str)
#pyqtSlot()
def getText(self):
longText = "\n".join(["{}: long text - auto scrolling ".format(i) for i in range(100)])
self.textSignal.emit(longText)
class MyApp(QWidget):
def __init__(self):
super(MyApp, self).__init__()
self.setFixedSize(600, 400)
self.initUI()
self.startThread()
def initUI(self):
self.txt = AnimationTextEdit(self)
self.btn = QPushButton("Start", self)
self.layout = QHBoxLayout(self)
self.layout.addWidget(self.txt)
self.layout.addWidget(self.btn)
self.btn.clicked.connect(self.txt.startAnimation)
def startThread(self):
self.obj = Worker()
self.thread = QThread()
self.obj.textSignal.connect(self.textUpdate)
self.obj.moveToThread(self.thread)
self.txt.animation.finished.connect(self.thread.quit)
self.thread.started.connect(self.obj.getText)
self.thread.finished.connect(app.exit)
self.thread.start()
def textUpdate(self, longText):
self.txt.append(longText)
self.txt.moveToLine(0)
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())

Using the QWizard next slot in pyside

I've created a wizard with Pyside.
On one page, I create a new thread, which starts an installer.
When the installer is ready, the Wizard should go forward automatically, without clicking the next button.
I've read the pyside documentation, and now my understanding is, that QWizard has a next function. But how can I use this function?
My test is working fine:
from PySide.QtGui import *
from PySide.QtCore import *
...
...
class Install(QWizardPage):
def __init__(self, parent=None):
super(Install, self).__init__(parent)
def initializePage(self):
self.setTitle("Install")
label = QLabel("Install")
label.setWordWrap(True)
layout = QVBoxLayout()
self.progressBar = QProgressBar(self)
self.progressBar.setRange(0,1)
self.progressBar.setRange(0,0)
layout.addWidget(self.progressBar)
layout.addWidget(label)
self.setLayout(layout)
self.myTask = TaskThread()
self.myTask.start()
self.myTask.taskFinished.connect(self.Finished)
def Finished(self):
print("finish")
def isComplete(self):
return False
class TaskThread(QThread):
taskFinished = Signal()
def run(self):
a = 0
while a != 10000:
print("test")
a += 1
self.taskFinished.emit()
And when I try to use the next function I try:
self.CallNext = QWizard().next
self.myTask.taskFinished.connect(self.CallNext)
And also:
self.myTask.taskFinished.connect(QWizard().next)
But this is not working

This connection should be done in the context where the QWizard and QWizardPage exist, but before that we must move the creation of the QThread to the constructor, for example in the following example I do in the main:
class Install(QWizardPage):
def __init__(self, parent=None):
super(Install, self).__init__(parent)
self.myTask = TaskThread()
def initializePage(self):
[...]
self.setLayout(layout)
self.myTask.start()
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
wizard = QWizard()
install = Install()
install.setTitle("installer")
install.myTask.taskFinished.connect(wizard.next)
wizard.addPage(install)
page = QWizardPage()
page.setTitle("next Page")
wizard.addPage(page)
wizard.show()
sys.exit(wizard.exec_())

"QStackedWidget.setCurrentIndex": It does not work or error mark

I'm doing a program with graphical interface using PyQt5 . I want to do is that when the user presses certain button, this change widget and show other options.
For this I decided to use QStackedWidget, and all my interface build it from the QT5 designer.
However, in my code, wanting to determine that my name button "btfr" show me "page_2" of my stackedWidget when pressed, using the QStackedWidget.setCurrentIndex method, this does nothing or make any error.
the code is as follows:
import sys
from PyQt5 import uic
from PyQt5.QtCore import QTimeLine
from PyQt5.QtWidgets import *
from PyQt5.QtGui import *
infz = uic.loadUiType("main.ui")[0]
class FaderWidget(QWidget):
def __init__(self, old_widget, new_widget):
QWidget.__init__(self, new_widget)
self.old_pixmap = QPixmap(new_widget.size())
old_widget.render(self.old_pixmap)
self.pixmap_opacity = 1.0
self.timeline = QTimeLine()
self.timeline.valueChanged.connect(self.animate)
self.timeline.finished.connect(self.close)
self.timeline.setDuration(333)
self.timeline.start()
self.resize(new_widget.size())
self.show()
def paintEvent(self, event):
painter = QPainter()
painter.begin(self)
painter.setOpacity(self.pixmap_opacity)
painter.drawPixmap(0, 0, self.old_pixmap)
painter.end()
def animate(self, value):
self.pixmap_opacity = 1.0 - value
self.repaint()
class StackedWidget(QStackedWidget):
def __init__(self, parent=None):
QStackedWidget.__init__(self, parent)
def setCurrentIndex(self, index):
self.stack = MyWindowClass()
self.a = self.stack.stackedWidget.currentWidget()
self.b = self.stack.stackedWidget.widget(index)
self.fader_widget = FaderWidget(self.a, self.b)
QStackedWidget.setCurrentIndex(self, index)
print(self, index)
def setPage1(self):
self.setCurrentIndex(0)
def setPage2(self):
self.setCurrentIndex(1)
class MyWindowClass(QStackedWidget, infz):
def __init__(self, parent=None):
global pos, c, f
self.pos = 0
self.c = []
self.f = False
QStackedWidget.__init__(self, parent)
self.setupUi(self)
self.setWindowTitle('SkR')
if __name__ == "__main__":
app = QApplication(sys.argv)
window = MyWindowClass()
window.resize(788, 518)
stack = StackedWidget()
window.btfr.clicked.connect(stack.setPage2)
window.btnpx.clicked.connect(stack.setPage1)
window.show()
sys.exit(app.exec_())
What I intend with this code is that the change of widget does so with an effect: "fade out".
If I print the "self " and the "index " receiving QStackedWidget.setCurrentIndex shows the following:
<__main__.StackedWidget object at 0x7fc2eb6b5c18> 0
The number zero is index, and the other element is self
Thank you for your attention, I hope someone can help.

Your question isn't completely clear, but don't you just want:
def setIndex(self, index):
self.setCurrentIndex(index)
However, this is a little redundant as you should able to link the button directly to the setCurrentIndex method and use lambda to pass the index value:
btfr.clicked.connect(lambda: self.setCurrentIndex(2))

PyQt Make Custom PushButton / inheritance from class which has arguments

I'm new at PyQt I want to build my own Check Box which inheritance from QCheckBox.
class Valve(QtGui.QCheckBox):
def __init__(self, x, y, inputs=[], outputs=[]):
QtGui.QCheckBox.__init__(self)
self.sources = inputs
self.outputs = outputs
self.move(x, y)
def is_fillable(self):
for source in self.sources:
if source.value == 100:
return 1
return 0
def stateChanged():
if isChecked():
for output in self.outputs:
if self.is_fillable():
output.fill(1)
else:
for output in self.outputs:
if self.is_fillable:
output.fill(-1)
class MainWindow(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.initUI()
def initUI(self):
self.button1 = Valve('', self, 5, 6)
self.setGeometry(0, 0, 500, 500)
self.show()
def main():
app = QtGui.QApplication(sys.argv)
ex = MainWindow()
sys.exit(app.exec_())
if __name__ == '__main__':
main()
Description what I did here:
I want to build water system. I will use progress bars as pipe so in my code inputs and outputs will be QProgressBar and I will fill them with their values.
However my Valve(CheckBox) is not show up at my Window Because I couldn't figure how to inheritance from QCheckButton out since it has argument.
Thanks for answers

You'd want to pass MainWindow as the parent of your checkbox:
class Valve(QtGui.QCheckBox):
def __init__(self, parent, x, y, inputs=[], outputs=[]):
QtGui.QCheckBox.__init__(self, parent)
class MainWindow(QtGui.QWidget):
def initUI(self):
self.button1 = Valve(self, 5, 6)

Calling QMainWindow From Second QDialog

My PyQt application starts with Login screen. If password OK, a module-screen (with icons) appears. When user click some button, a QMainWindow will appears. But I can't do this because of qmainwindow object has no attribute '_exec' error. This is my code:
from PyQt4.QtGui import *
from PyQt4.QtCore import *
class Main(QMainWindow):
def __init__(self, parent=None):
super(Main, self).__init__(parent)
...
...
class Login(QDialog):
def __init__(self, parent=None):
super(Login, self).__init__(parent)
...
...
uyg=QApplication(sys.argv)
class icons(QDialog):
def __init__(self, parent=None):
super(icons, self).__init__(parent)
...
self.buton = QPushButton()
self.buton.pressed.connect(self.open)
...
def open(self):
dialogmain = Main()
dialogmain._exec() #or dialogmain.show() ???
self.accept()
self.close()
uyg.exec_()
if Login().exec_() == QDialog.Accepted:
dialog = icons()
dialog.exec_()
else:
uyg.quit()
What am I doing wrong? Thank you.

Lately i have done the similar work:I have a loging window and a main window ,and I used something like a FSM to switch between the loging and main window.
Let's say we have 3 state:loging,main,quit.
STATE_LOGING = 0
STATE_MAIN = 1
STATE_QUIT = 2
STATE_DESTROY = 3 #this is a flag
class CState():
sigSwitchState = pyqtSignal(int)
def __init__(self):
super(CState,self).__init__()
def start(self):
pass
def sendQuit(self,nextstate):
self.sigSwitch.emit(nextstate)
class CLoginState(CState):
def __init__(self):
super(CLoginState,self).__init__()
def start(self):
w = Loging()
w.show()
def whenPasswdOk(self):
self.sendQuit(STATE_MAIN)
class CMainState(CState):
def __init__(self):
super(CMainState,self).__init__()
def start(self):
w = MainWindow()
w.show()
def whenMainWindowQuit(self):
self.sendQuit(STATE_QUIT)
class CQuitState(CState):
def __init__(self):
super(CQuitState,self).__init__()
def start(self):
#do some clean stuff...
pass
def whenCleanDone(self):
self.sendQuit(STATE_DESTROY)
class CMainApp():
def __init__(self):
self.app = QApplication(sys.argv)
def __CreateState(state):
if state == STATE_LOGING:
s = CLoginState()
if state == STATE_MAIN:
s = CMainState()
#... same as other state
s.sigSwitchState.connect(self.procNextState)
def procNextState(self,state):
if state == STATE_DESTROY:
QApplication().exit()
s = self.__CreateState(state)
s.start()
def run(self):
self.procNextState(STATE_LOGING)
sys.exit(self.app.exec_())
if __name__ == "__main__":
app = CMainApp()
app.run()

Apart from the application object and QDrag, please pretend that exec() doesn't exist. It is an utterly confusing method that essentially never has to be used. Especially not by anyone new to Qt.
If you want to display any widget, simply show() it. If you want to be notified when a dialog was accepted, connect some code to its accepted() signal. That's all.