Is there a way to make qtimer wait until a function is done?

Question

I have an application in which I would like to do the following thing:

1. optimize a problem
2. wait for a certain amount of time, e.g. one minute
3. measure a certain property
4. repeat steps two and three several times
5. start again at 1.)

I want to start the entire process when clicking on a QPushButton. It is necessary that the step 2.) only starts when step 1.) is completely terminated. I dont know how long the optimzation process takes, therefre I cant just use QTimer.sleep().

I have solved this problem the following way:

from PyQt5.QtCore import QTimer
from PyQt5.QtWidgets import QApplication, QDialog
from PyQt5 import QtWidgets
import sys



class MyForm():
    def __init__(self):
        self.ui = QDialog()
        self.button = QtWidgets.QPushButton(self.ui)
        self.button.clicked.connect(self.start_timer)
        self.waiting_interval = 10000
        self.ui.show()

    def start_timer(self):
        self.optimize()
        self.counter = 0
        self.timer = QTimer()
        self.timer.timeout.connect(self.tick)
        self.timer.setSingleShot(True)
        self.timer.start(self.waiting_interval)



    def tick(self):


        self.timer = QTimer()
        if self.counter == 9:
            self.timer.timeout.connect(self.start_timer)
        else:
            self.measure_property()
            self.timer.timeout.connect(self.tick)
        self.timer.setSingleShot(True)
        self.timer.start(self.waiting_interval)
        self.counter += 1


    def optimize(self):
        pass


    def measure_property(self):
        pass



if __name__ == '__main__':
    app = QApplication(sys.argv)
    w=MyForm()
    app.exec_()

It produces the results that I want but I am looking for a smarter way to do this, maybe using signals and slots. Any help would be appreciated!

Answer 1

The tasks that take a long time are heavy and tend to freeze the GUI giving a bad experience to the user, in these cases those tasks must be executed in another thread:

import sys
from PyQt5 import QtCore, QtWidgets


class ProcessThread(QtCore.QThread):
    def run(self):
        while True:
            self.optimize()
            for _ in range(3):
                QtCore.QThread.sleep(60)
                self.measure_property()

    def optimize(self):
        print("optimize")

    def measure_property(self):
        print("measure_property")


class MyForm():
    def __init__(self):
        self.ui = QtWidgets.QDialog()
        self.thread = ProcessThread(self.ui)
        self.button = QtWidgets.QPushButton("Press me")
        self.button.clicked.connect(self.thread.start)
        self.waiting_interval = 10000
        lay = QtWidgets.QVBoxLayout(self.ui)
        lay.addWidget(self.button)
        self.ui.show()


if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    w=MyForm()
    sys.exit(app.exec_())