I’m building a tkinter GUI to retrieve incoming data from a device (through request) and appending them into a csv file, while having a preview of these data.
I use thread but struggle to understand it properly, especially how to pause and restart it.
When I click on the start button, my threads are working properly. Once I try to click the stop streaming button, my stop_threads variable change to 0, however, the while loop in my thread do not see this change. Do you know why?
Thanks a lot!
JavaScript
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import tkinter as tk2
import threading3
from tkinter import ttk4
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def init_csv():7
pass8
# create my csv file here9
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def clear_data():11
tv1.delete(*tv1.get_children())12
init_csv()13
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def stream_data():16
global stop_threads17
IP_Machine = IP_entry.get()18
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while True:20
if stop_threads == 1:21
print('Stream')22
# retrieve incoming data from my device (through request)23
# appending them into a csv file24
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if stop_threads == 0:26
print('Pause')27
# I want to pause this thread here28
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def start_stream():31
t1_stream.start()32
stream_label['text'] = 'Streaming...'33
button_start.destroy()34
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# Create stop streaming button36
button_stop = tk.Button(main_frame, text="Stop Streaming", bg=Blue, fg=Bg_color, font='BOLD 12',37
command=stop_stream)38
button_stop.place(relx=0.2, rely=0.14, relwidth=0.15, relheight=0.07)39
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def stop_stream():42
stop_threads = 043
stream_label['text'] = ''44
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# Create ReStart streaming button46
button_restart = tk.Button(main_frame, text="Start Streaming", bg=Blue, fg=Bg_color, font='BOLD 12',47
command=restart)48
button_restart.place(relx=0, rely=0.14, relwidth=0.15, relheight=0.07)49
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def restart():52
stop_threads = 153
stream_label['text'] = 'Streaming...'54
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def curve():57
# show live plot data with matplot Funcanimation58
pass59
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def refresch_treeview():62
tv1.delete(*tv1.get_children())63
# define content of the treeview and refrech64
tv1.after(500, refresch_treeview)65
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csv_path = 'C:/Users/b/Desktop/testfile.csv'68
init_csv()69
global stop_threads70
stop_threads = 171
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# Multitasking definition73
t1_stream = threading.Thread(target=stream_data)74
t2_refresch = threading.Thread(target=refresch_treeview)75
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# My Tkinter interface bellow77
root = tk.Tk()78
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# Variables80
Bg_color = '#F2F2F2'81
Blue = '#045FB4'82
c_width = 140083
c_height = 70084
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# Template86
canvas = tk.Canvas(root, height=c_height, width=c_width, bg=Bg_color)87
canvas.pack()88
left_frame = tk.Frame(root, bg=Blue)89
left_frame.place(anchor='center', relx=0.05, rely=0.5, relwidth=0.002, relheight=0.9)90
right_frame = tk.Frame(root, bg=Blue)91
right_frame.place(anchor='center', relx=0.95, rely=0.5, relwidth=0.002, relheight=0.9)92
top_frame = tk.Frame(root, bg=Blue)93
top_frame.place(anchor='center', relx=0.5, rely=0.05, relwidth=0.9, relheight=0.004)94
bottom_frame = tk.Frame(root, bg=Blue)95
bottom_frame.place(anchor='center', relx=0.5, rely=0.95, relwidth=0.9, relheight=0.004)96
main_frame = tk.Frame(root, bg=Bg_color)97
main_frame.place(anchor='center', relx=0.5, rely=0.5, relwidth=0.8, relheight=0.8)98
# Title99
title = tk.Label(root, text='Data analysis', height=2, width=20, font='bold 18')100
title.place(anchor='center', relx=0.50, rely=0.05)101
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# ENTRIES Definition103
# Machine IP104
IP_frame = tk.Frame(main_frame, bg=Bg_color)105
IP_frame.place(relx=0, rely=0.05, relwidth=0.35, relheight=0.05)106
IP_label = tk.Label(IP_frame, text='2000Xc IP address : ', font='12')107
IP_label.pack(side='left', fill='y')108
IP_entry = tk.Entry(IP_frame, width=22, font='12')109
IP_entry.pack(side='right', fill='y')110
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# Streaming runing label112
stream_label = tk.Label(main_frame, font='10', text='')113
stream_label.place(anchor='w', relx=0, rely=0.45, relwidth=0.1, relheight=0.06)114
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# BUTTONS Definition116
# Start streaming button117
button_start = tk.Button(main_frame, text="Start Streaming", bg=Blue, fg=Bg_color, font='BOLD 12', command=start_stream)118
button_start.place(relx=0, rely=0.14, relwidth=0.15, relheight=0.07)119
120
# Clear data121
button_clear = tk.Button(main_frame, text="Clear data", bg=Blue, fg=Bg_color, font='BOLD 10', command=clear_data)122
button_clear.place(relx=0.92, rely=0.9, relwidth=0.08, relheight=0.06)123
# Show graph button124
button_graph = tk.Button(main_frame, text="Show curves", bg=Blue, fg=Bg_color, font='BOLD 10', command=curve)125
button_graph.place(relx=0.6, rely=0.35, relwidth=0.1, relheight=0.05)126
127
# csv preview128
preview_frame = tk.Frame(main_frame, bg=Bg_color)129
preview_frame.place(relx=0, rely=0.5, relwidth=1, relheight=0.4)130
tv1 = ttk.Treeview(preview_frame)131
tv1.place(relheight=0.95, relwidth=1) # set the height and width of the widget to 100% of its container (frame1).132
# scroll preview133
treescrolly = tk.Scrollbar(preview_frame, orient="vertical",134
command=tv1.yview) # command means update the yaxis view of the widget135
treescrollx = tk.Scrollbar(preview_frame, orient="horizontal",136
command=tv1.xview) # command means update the xaxis view of the widget137
tv1.configure(xscrollcommand=treescrollx.set,138
yscrollcommand=treescrolly.set) # assign the scrollbars to the Treeview Widget139
treescrollx.pack(side="bottom", fill="x") # make the scrollbar fill the x axis of the Treeview widget140
treescrolly.pack(side="right", fill="y") # make the scrollbar fill the y axis of the Treeview widget141
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t2_refresch.start()143
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root.mainloop()145
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Answer
You have to change only one thing. You need to define stop_threads as global inside the functions. Python then knows that you are referring to the global variable instead of creating a new variable inside the local function scope.
JavaScript
1
147
147
1
import tkinter as tk2
import threading3
from tkinter import ttk4
5
6
def init_csv():7
pass8
# create my csv file here9
10
def clear_data():11
tv1.delete(*tv1.get_children())12
init_csv()13
14
15
def stream_data():16
global stop_threads17
IP_Machine = IP_entry.get()18
19
while True:20
if stop_threads == 1:21
print('Stream')22
# retrieve incoming data from my device (through request)23
# appending them into a csv file24
25
if stop_threads == 0:26
print('Pause')27
# I want to pause this thread here28
29
30
def start_stream():31
t1_stream.start()32
stream_label['text'] = 'Streaming...'33
button_start.destroy()34
35
# Create stop streaming button36
button_stop = tk.Button(main_frame, text="Stop Streaming", bg=Blue, fg=Bg_color, font='BOLD 12',37
command=stop_stream)38
button_stop.place(relx=0.2, rely=0.14, relwidth=0.15, relheight=0.07)39
40
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def stop_stream():42
global stop_threads43
stop_threads = 044
stream_label['text'] = ''45
46
# Create ReStart streaming button47
button_restart = tk.Button(main_frame, text="Start Streaming", bg=Blue, fg=Bg_color, font='BOLD 12',48
command=restart)49
button_restart.place(relx=0, rely=0.14, relwidth=0.15, relheight=0.07)50
51
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def restart():53
global stop_threads54
stop_threads = 155
stream_label['text'] = 'Streaming...'56
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def curve():59
# show live plot data with matplot Funcanimation60
pass61
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def refresch_treeview():64
tv1.delete(*tv1.get_children())65
# define content of the treeview and refrech66
tv1.after(500, refresch_treeview)67
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csv_path = 'C:/Users/b/Desktop/testfile.csv'70
init_csv()71
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stop_threads = 173
74
# Multitasking definition75
t1_stream = threading.Thread(target=stream_data)76
t2_refresch = threading.Thread(target=refresch_treeview)77
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# My Tkinter interface bellow79
root = tk.Tk()80
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# Variables82
Bg_color = '#F2F2F2'83
Blue = '#045FB4'84
c_width = 140085
c_height = 70086
87
# Template88
canvas = tk.Canvas(root, height=c_height, width=c_width, bg=Bg_color)89
canvas.pack()90
left_frame = tk.Frame(root, bg=Blue)91
left_frame.place(anchor='center', relx=0.05, rely=0.5, relwidth=0.002, relheight=0.9)92
right_frame = tk.Frame(root, bg=Blue)93
right_frame.place(anchor='center', relx=0.95, rely=0.5, relwidth=0.002, relheight=0.9)94
top_frame = tk.Frame(root, bg=Blue)95
top_frame.place(anchor='center', relx=0.5, rely=0.05, relwidth=0.9, relheight=0.004)96
bottom_frame = tk.Frame(root, bg=Blue)97
bottom_frame.place(anchor='center', relx=0.5, rely=0.95, relwidth=0.9, relheight=0.004)98
main_frame = tk.Frame(root, bg=Bg_color)99
main_frame.place(anchor='center', relx=0.5, rely=0.5, relwidth=0.8, relheight=0.8)100
# Title101
title = tk.Label(root, text='Data analysis', height=2, width=20, font='bold 18')102
title.place(anchor='center', relx=0.50, rely=0.05)103
104
# ENTRIES Definition105
# Machine IP106
IP_frame = tk.Frame(main_frame, bg=Bg_color)107
IP_frame.place(relx=0, rely=0.05, relwidth=0.35, relheight=0.05)108
IP_label = tk.Label(IP_frame, text='2000Xc IP address : ', font='12')109
IP_label.pack(side='left', fill='y')110
IP_entry = tk.Entry(IP_frame, width=22, font='12')111
IP_entry.pack(side='right', fill='y')112
113
# Streaming runing label114
stream_label = tk.Label(main_frame, font='10', text='')115
stream_label.place(anchor='w', relx=0, rely=0.45, relwidth=0.1, relheight=0.06)116
117
# BUTTONS Definition118
# Start streaming button119
button_start = tk.Button(main_frame, text="Start Streaming", bg=Blue, fg=Bg_color, font='BOLD 12', command=start_stream)120
button_start.place(relx=0, rely=0.14, relwidth=0.15, relheight=0.07)121
122
# Clear data123
button_clear = tk.Button(main_frame, text="Clear data", bg=Blue, fg=Bg_color, font='BOLD 10', command=clear_data)124
button_clear.place(relx=0.92, rely=0.9, relwidth=0.08, relheight=0.06)125
# Show graph button126
button_graph = tk.Button(main_frame, text="Show curves", bg=Blue, fg=Bg_color, font='BOLD 10', command=curve)127
button_graph.place(relx=0.6, rely=0.35, relwidth=0.1, relheight=0.05)128
129
# csv preview130
preview_frame = tk.Frame(main_frame, bg=Bg_color)131
preview_frame.place(relx=0, rely=0.5, relwidth=1, relheight=0.4)132
tv1 = ttk.Treeview(preview_frame)133
tv1.place(relheight=0.95, relwidth=1) # set the height and width of the widget to 100% of its container (frame1).134
# scroll preview135
treescrolly = tk.Scrollbar(preview_frame, orient="vertical",136
command=tv1.yview) # command means update the yaxis view of the widget137
treescrollx = tk.Scrollbar(preview_frame, orient="horizontal",138
command=tv1.xview) # command means update the xaxis view of the widget139
tv1.configure(xscrollcommand=treescrollx.set,140
yscrollcommand=treescrolly.set) # assign the scrollbars to the Treeview Widget141
treescrollx.pack(side="bottom", fill="x") # make the scrollbar fill the x axis of the Treeview widget142
treescrolly.pack(side="right", fill="y") # make the scrollbar fill the y axis of the Treeview widget143
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t2_refresch.start()145
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root.mainloop()147