tkinter

Author: furas

tkinter/progressbar/progressbar-threading-global-variable/main.py

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+
+# author: Bartlomiej "furas" Burek (https://blog.furas.pl)
+# date: 2021.07.30
+#
+# title: Initializing tkinter gui leads to main thread not in main loop
+# url: https://stackoverflow.com/questions/68577245/initializing-tkinter-gui-leads-to-main-thread-not-in-main-loop/
+
+import threading
+import time
+import tkinter as tk
+import tkinter.ttk as ttk
+
+# --- functions ---
+
+def long_script():
+    global progress_value
+    
+    for i in range(20):
+        print('loop:', i)
+        
+        # update global variable
+        progress_value += 5
+        
+        time.sleep(.5)
+
+def run_long_script():
+    global progress_value
+    global t
+    
+    if t is None: # run only one thread
+        # set start value
+        progress_value = 0
+        # start updating progressbar
+        update_progressbar()
+        # start thread
+        t = threading.Thread(target=long_script)
+        t.start()
+    else:
+        print('Already running')
+        
+def update_progressbar():
+    global t
+    
+    # update progressbar
+    pb['value'] = progress_value
+    
+    if progress_value < 100:
+        # run it again after 100ms
+        root.after(100, update_progressbar)
+    else:
+        # set None to run again
+        t = None
+        
+# --- main ---
+
+# default value at start
+progress_value = 0  
+t = None
+
+# - gui -
+
+root = tk.Tk()
+
+pb = ttk.Progressbar(root, mode="determinate")
+pb.pack()
+
+b = tk.Button(root, text="start", command=run_long_script)
+b.pack()
+
+root.mainloop()
+