New Demo - Threaded Progress Meter

DemoPrograms/Demo_Multithreaded_ProgressBar.py

@@ -0,0 +1,71 @@
+import PySimpleGUI as sg
+import threading
+import random
+import time
+
+"""
+    Demo - Multi-threaded downloader with one_line_progress_meter
+
+    Sometimes you don't have a choice in how your data is downloaded.  In some programs
+    the download happens in another thread which means you cannot call PySimpleGUI directly
+    from the thread.
+
+    Maybe you're still interested in using the one_line_progress_meter feature or perhaps
+    have implemented your own progress meter in your window.
+
+    Using the write_event_value method enables you to easily do either of these.
+
+    Copyright 2021 PySimpleGUI
+"""
+
+DL_START_KEY = '-START DOWNLOAD-'
+DL_COUNT_KEY = '-COUNT-'
+DL_END_KEY = '-END DOWNLOAD-'
+
+
+def the_thread(window:sg.Window):
+    """
+    The thread that communicates with the application through the window's events.
+
+    Once a second wakes and sends a new event and associated value to the window
+    """
+    max_value = random.randint(50, 100)
+    window.write_event_value(DL_START_KEY, max_value)  # Data sent is a tuple of thread name and counter
+    for i in range(max_value):
+        time.sleep(.1)
+        window.write_event_value(DL_COUNT_KEY, i)  # Data sent is a tuple of thread name and counter
+    window.write_event_value(DL_END_KEY, max_value)  # Data sent is a tuple of thread name and counter
+
+
+def main():
+    layout = [  [sg.Text('My Window')],
+                [sg.ProgressBar(100, 'h', size=(30,20), k='-PROGRESS-')],
+                [sg.Button('Go'), sg.Button('Exit')]  ]
+
+    window = sg.Window('Window Title', layout, finalize=True)
+    window.read(timeout=0)
+    window.move(window.current_location()[0], window.current_location()[1]-300)
+    downloading, max_value = False, 0
+
+    while True:             # Event Loop
+        event, values = window.read()
+        # print(event, values)
+        if event == sg.WIN_CLOSED or event == 'Exit':
+            break
+        if event == 'Go' and not downloading:
+            threading.Thread(target=the_thread, args=(window,), daemon=True).start()
+        elif event == DL_START_KEY:
+            max_value = values[event]
+            downloading = True
+            sg.one_line_progress_meter(f'Downloading {max_value} segments', 0, max_value, 1, f'Downloading {max_value} segments', )
+            window['-PROGRESS-'].update(0, max_value)
+        elif event == DL_COUNT_KEY:
+            sg.one_line_progress_meter(f'Downloading {max_value} segments', values[event]+1, max_value, 1, f'Downloading {max_value} segments')
+            window['-PROGRESS-'].update(values[event]+1, max_value)
+        elif event == DL_END_KEY:
+            downloading = False
+
+    window.close()
+
+if __name__ == '__main__':
+    main()