Small QWorker example

example_qworker.py

"""

    Small example for running a QWorker that sets a list 
    on completion.

"""

import time
import random
import sys
import os

from PySide import QtCore
from PySide import QtGui

# Shorthand to get a number 3..9
size = lambda: random.randint(3, 9)

class Worker(QtCore.QThread):
    signal = QtCore.Signal()
    def __init__(self, parent=None):
        super(Worker, self).__init__(parent)

    def run(self):
        # Perform long task, for now let's imitate one,
        time.sleep(5) # wait 5 seconds, before setting result to a list of random integers
        self.result = [random.randint(0, 256) for _ in range(size())]
        self.signal.emit()

class Window(QtGui.QDialog):
    def __init__(self):
        super(Window, self).__init__()

        self.worker = Worker()
        self.worker.started.connect(self.on_worker_starting)
        self.worker.finished.connect(self.on_worker_finish)
        self.worker.signal.connect(self.sync)

        # QTimer to have it run the worker every interval in miliseconds,
        self.INTERVAL = 30000 
        self.timer = QtCore.QTimer()
        self.timer.setSingleShot(False)
        self.timer.timeout.connect(self.worker.start)
        self.timer.start(self.INTERVAL)

    def on_worker_starting(self):
        print("Getting to work...")

    def on_worker_finish(self):
        print("Work is finished!")

    def sync(self):
        sender = self.sender()
        print("Printing results...")
        for x in sender.result:
            print(x)
        print("... That is all.")

def main():
    app = QtGui.QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())

if __name__ == '__main__':
    main()