Report progress to QProgressBar using variable from an imported module

Question

I have a PyQT GUI application progress_bar.pywith a single progressbar and an external module worker.py with a process_files() function wh

Answer 1

Make the process_files function a generator function that yields a value (the progress value) and pass it as a callback to a method in your Window class that updates the progress bar value. I have added a time.sleep call in your function so you can observe the progress:

import time
from worker import process_files

class Window(QtGui.QMainWindow):
    def __init__(self):
        ...

    def observe_process(self, func=None):
        try:
            for prog in func():
                self.progress.setValue(prog)
        except TypeError:
            print('callback function must be a generator function that yields integer values')
            raise


app = QtGui.QApplication(sys.argv)
GUI = Window()
# process files and report progress using .setValue(percent)
GUI.observe_process(process_files)
sys.exit(app.exec_())

worker.py

def process_files():
    file_list = ['file1', 'file2', 'file3']
    counter = 0
    for file in file_list:
        counter += 1
        percent = 100 * counter / len(file_list)
        time.sleep(1)
        yield percent

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Result:

After processing file2