76 lines
3.1 KiB
Python
76 lines
3.1 KiB
Python
#!/usr/bin/python3
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import threading
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import time
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import PySimpleGUI as sg
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"""
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DESIGN PATTERN - Multithreaded Long Tasks GUI
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Presents one method for running long-running operations in a PySimpleGUI environment.
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The PySimpleGUI code, and thus the underlying GUI framework, runs as the primary, main thread
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The "long work" is contained in the thread that is being started.
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July 2020 - Note that this program has been updated to use the new Window.write_event_value method.
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This method has not yet been ported to the other PySimpleGUI ports and is thus limited to the tkinter ports for now.
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Internally to PySimpleGUI, a queue.Queue is used by the threads to communicate with main GUI code
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The PySimpleGUI code is structured just like a typical PySimpleGUI program. A layout defined,
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a Window is created, and an event loop is executed.
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This design pattern works for all of the flavors of PySimpleGUI including the Web and also repl.it
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You'll find a repl.it version here: https://repl.it/@PySimpleGUI/Async-With-Queue-Communicationspy
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"""
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def long_operation_thread(seconds, window):
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"""
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A worker thread that communicates with the GUI through a queue
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This thread can block for as long as it wants and the GUI will not be affected
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:param seconds: (int) How long to sleep, the ultimate blocking call
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:param gui_queue: (queue.Queue) Queue to communicate back to GUI that task is completed
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:return:
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"""
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print('Starting thread - will sleep for {} seconds'.format(seconds))
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time.sleep(seconds) # sleep for a while
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window.write_event_value('-THREAD-', '** DONE **') # put a message into queue for GUI
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def the_gui():
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"""
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Starts and executes the GUI
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Reads data from a Queue and displays the data to the window
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Returns when the user exits / closes the window
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"""
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sg.theme('Light Brown 3')
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layout = [[sg.Text('Long task to perform example')],
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[sg.Output(size=(70, 12))],
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[sg.Text('Number of seconds your task will take'),
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sg.Input(key='-SECONDS-', size=(5, 1)),
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sg.Button('Do Long Task', bind_return_key=True)],
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[sg.Button('Click Me'), sg.Button('Exit')], ]
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window = sg.Window('Multithreaded Window', layout)
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# --------------------- EVENT LOOP ---------------------
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while True:
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event, values = window.read()
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if event in (sg.WIN_CLOSED, 'Exit'):
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break
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elif event.startswith('Do'):
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seconds = int(values['-SECONDS-'])
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print('Thread ALIVE! Long work....sending value of {} seconds'.format(seconds))
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threading.Thread(target=long_operation_thread, args=(seconds, window,), daemon=True).start()
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elif event == 'Click Me':
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print('Your GUI is alive and well')
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elif event == '-THREAD-':
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print('Got a message back from the thread: ', values[event])
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# if user exits the window, then close the window and exit the GUI func
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window.close()
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if __name__ == '__main__':
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the_gui()
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print('Exiting Program')
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