How can i stop the progressbar while loop with the pushbutton? (Pyqt5 Gui)

caca91

This is a basic progress bar.

i just tried this code. the progress bar is loading but not stopping when i push the stop button it just contiues.

and whenever i push the stop button the application is locking until progress bar finish.

import sys
import time

from PyQt5.QtWidgets import (QApplication, QDialog,
                             QProgressBar, QPushButton)

TIME_LIMIT = 100

class Actions(QDialog):
    """
    Simple dialog that consists of a Progress Bar and a Button.
    Clicking on the button results in the start of a timer and
    updates the progress bar.
    """
    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Progress Bar')
        self.progress = QProgressBar(self)
        self.progress.setGeometry(0, 0, 300, 100)
        self.progress.setMaximum(100)
        self.button = QPushButton('Start', self)
        self.button.move(0, 30)
        self.button2 = QPushButton('Stop', self)
        self.button2.move(30, 60)
        self.show()
        self.show()

        self.button.clicked.connect(self.onButtonClick)
        self.button2.clicked.connect(self.onButtonClick2)

    def onButtonClick(self):
        count = 0
        while count < TIME_LIMIT:
            count += 1
            time.sleep(1)
            self.progress.setValue(count)
            print(count)
            stop = 0
            if stop == 1:
                break

    def onButtonClick2(self):
            stop = 1

if __name__ == "__main__":
    app = QApplication(sys.argv)
    window = Actions()
    sys.exit(app.exec_())

jsulm

@caca91 said in How can i stop the progressbar while loop with the pushbutton? (Pyqt5 Gui):

while count < TIME_LIMIT:
count += 1
time.sleep(1)

Such code should never be in the main thread of an event driven application! This is a no go.
It blocks the main thread, so the event loop is blocked until the loop terminates.
Remove the while loop and use a QTimer to update the progress dialog.

JonB

@caca91
As @jsulm has written, your main issue is that you must not use sleep() and you must start using Qt/PySide2 signals/slots, like a QTimer.

However, additionally:

            stop = 0
            if stop == 1:
                break

    def onButtonClick2(self):
            stop = 1

How do you expect stop to ever == 1 so as to break out of your loop? Conceptually, onButtonClick2() would have to get called immediately after stop = 0 and before if stop == 1, which ain't going to happen. Your stop = 0 needs to be moved outside the loop which tests its value.

Plus, in Python those two occurrences of a stop variable in two separate functions (onButtonClick & onButtonClick2) are two separate local variables, and one does not refer to the other. You would need to make them self.stop for it to begin to work. Just saying....