關閉我的 tkinter 串行應用程序，給了我一個例外

Question

我有這個程序可以從串行中獲取數據並將它們顯示在 tkinter 框架上。

這是代碼：

import tkinter as tk
import tkinter.ttk as ttk
import serial.tools.list_ports
from tkinter import scrolledtext 
#new stuff from vid
import time
import serial
import threading
import continuous_threading


#to be used on our canvas
HEIGHT = 700
WIDTH = 800

#hardcoded baud rate
baudRate = 9600



ser = serial.Serial('COM16', baudRate)
val1 = 0
index = []
def readSerial():
    global val1
    ser_bytes = ser.readline()
    ser_bytes = ser_bytes.decode("utf-8")
    val1 = ser_bytes
    scrollbar.insert("end", val1)
    
t1 = continuous_threading.PeriodicThread(0.1, readSerial)
#----------------------------------------------------------------------

# --- functions ---

#the following two functtions are for the seria port selection, on frame 1
def serial_ports():    
    return serial.tools.list_ports.comports()

def on_select(event=None):

    global COMPort
    COMPort = cb.get()
    print(COMPort)



# --- functions ---


#--------------------------------------------------------------------------------------------------------------
# --- main ---
root = tk.Tk() #here we create our tkinter window
root.title("Sensor Interface")

#we use canvas as a placeholder, to get our initial screen size (we have defined HEIGHT and WIDTH)
canvas = tk.Canvas(root, height=HEIGHT, width=WIDTH)
canvas.pack()

#we use frames to organize all the widgets in the screen
# --- frame 1 ---
frame1 = tk.Frame(root)
frame1.place(relx=0, rely=0.05, relheight=0.03, relwidth=1, anchor='nw') #we use relheight and relwidth to fill whatever the parent is - in this case- root

label0 = tk.Label(frame1, text="Select the COM port that the device is plugged in: ")
label0.config(font=("TkDefaultFont", 8))
label0.place(relx = 0.1, rely=0.3, relwidth=0.3, relheight=0.5)


cb = ttk.Combobox(frame1, values=serial_ports())
cb.place(relx=0.5, rely=0.5, anchor='center')
# assign function to cmbobox
cb.bind('<<ComboboxSelected>>', on_select)
# --- frame 1 ---




# --- frame 2 ---
frame2 = tk.Frame(root, bg='#80c1ff') #remove color later
frame2.place(relx=0, rely=0.1, relheight=1, relwidth=1, anchor='nw')

# make a scrollbar
scrollbar = scrolledtext.ScrolledText(frame2)
scrollbar.place(relx=0, rely=0, relheight=1, relwidth=1, anchor='nw')
# --- frame 2 ---
#--------------------------------------------------------------------------------------------------------
t1.start() 

root.mainloop() #here we run our app

當我終止生成的 GUI 時，我在終端上得到這個異常：

Exception in thread Thread-1:
Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stderr
>'> at interpreter shutdown, possibly due to daemon threads
Python runtime state: finalizing (tstate=005C8F38)

Thread 0x00001a30 (most recent call first):
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 1202 in invoke_excepthook
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 934 in _bootstrap_inner
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 890 in _bootstrap

Current thread 0x00001918 (most recent call first):
<no Python frame>

當我用 control+C 從終端終止它時，我得到：

Traceback (most recent call last):
  File "mySerial.py", line 110, in <module>
    root.mainloop() #here we run our app
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\tkinter\__i
nit__.py", line 1420, in mainloop
    self.tk.mainloop(n)
KeyboardInterrupt
Exception in thread Thread-1:
Fatal Python error: could not acquire lock for <_io.BufferedWriter name='<stderr
>'> at interpreter shutdown, possibly due to daemon threads
Python runtime state: finalizing (tstate=00578F38)

Thread 0x00001ad0 (most recent call first):
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 1202 in invoke_excepthook
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 934 in _bootstrap_inner
  File "C:\Users\User1\AppData\Local\Programs\Python\Python38-32\lib\threading.p
y", line 890 in _bootstrap

Current thread 0x000013d8 (most recent call first):
<no Python frame>

為什么會這樣？

編輯：這是我的代碼和錯誤消息，嘗試 AST 的建議：

import tkinter as tk
import tkinter.ttk as ttk
import serial.tools.list_ports
from tkinter import scrolledtext 
import time
import serial
import threading
import continuous_threading


#to be used on our canvas
HEIGHT = 700
WIDTH = 800

#hardcoded baud rate
baudRate = 9600

# flag to be notified when application is terminated
stop=False


ser = serial.Serial('COM16', baudRate)
val1 = 0

def readSerial():
    global val1, stop
    if not stop:
       ser_bytes = ser.readline()
       ser_bytes = ser_bytes.decode("utf-8")
       val1 = ser_bytes
       scrollbar.insert("end", val1)
    else:
        return

t1 = continuous_threading.PeriodicThread(0.1, readSerial)
#----------------------------------------------------------------------

# --- functions ---

#the following two functions are for the seria port selection, on frame 1
def serial_ports():    
    return serial.tools.list_ports.comports()

def on_select(event=None):

    global COMPort
    COMPort = cb.get()
    print(COMPort)

def on_close():
    global stop
    stop=True
    root.destroy()



# --- functions ---


#--------------------------------------------------------------------------------
# --- main ---
root = tk.Tk() #here we create our tkinter window
root.title("Sensor Interface")
root.protocol('WM_DELETE_WINDOW', on_close)

#we use canvas as a placeholder, to get our initial screen size (we have defined HEIGHT and WIDTH)
canvas = tk.Canvas(root, height=HEIGHT, width=WIDTH)
canvas.pack()

#we use frames to organize all the widgets in the screen
# --- frame 1 ---
frame1 = tk.Frame(root)
frame1.place(relx=0, rely=0.05, relheight=0.03, relwidth=1, anchor='nw') #we use relheight and relwidth to fill whatever the parent is - in this case- root

label0 = tk.Label(frame1, text="Select the COM port that the device is plugged in: ")
label0.config(font=("TkDefaultFont", 8))
label0.place(relx = 0.1, rely=0.3, relwidth=0.3, relheight=0.5)


cb = ttk.Combobox(frame1, values=serial_ports())
cb.place(relx=0.5, rely=0.5, anchor='center')
# assign function to cmbobox
cb.bind('<<ComboboxSelected>>', on_select)
# --- frame 1 ---




# --- frame 2 ---
frame2 = tk.Frame(root, bg='#80c1ff') #remove color later
frame2.place(relx=0, rely=0.1, relheight=1, relwidth=1, anchor='nw')

# make a scrollbar
scrollbar = scrolledtext.ScrolledText(frame2)
scrollbar.place(relx=0, rely=0, relheight=1, relwidth=1, anchor='nw')
# --- frame 2 ---
#--------------------------------------------------------------------------------
t1.start() 
root.mainloop() #here we run our app

我得到的錯誤是我列為代碼的第一個錯誤。

編輯2：當我做AST的第二種方法時：

如果我關閉 GUI（按 X），它會在沒有任何錯誤的情況下關閉，但提示卡在終端上 - 我無法輸入任何內容，甚至鍵盤退出 (Control+C) 也不起作用。

如果程序運行並且我在終端中使用鍵盤退出（Control+C）退出，我會收到鍵盤中斷錯誤（我已列為代碼的第二個錯誤）

Answer 1

據我說，這是因為可能有一個計划線程在應用程序被銷毀后執行，因此無法找到它必須更新的 GUI 元素。

我沒有嘗試運行您的代碼，但我認為這可能會有所幫助

將 window 刪除與更新標志的 function 相關聯（ stop ）

def on_close():
    global stop
    stop=True
    root.destroy()

root.protocol('WM_DELETE_WINDOW', on_close)
stop=False

並修改readSerial function 以檢查是否相同

def readSerial():
    global val1,stop
    if not stop:
        ser_bytes = ser.readline()
        ser_bytes = ser_bytes.decode("utf-8")
        val1 = ser_bytes
        scrollbar.insert("end", val1)
    else:
        return

編輯

這是threading.py中的 function 引發異常。

def _bootstrap(self):
    # Wrapper around the real bootstrap code that ignores
    # exceptions during interpreter cleanup.  Those typically
    # happen when a daemon thread wakes up at an unfortunate
    # moment, finds the world around it destroyed, and raises some
    # random exception *** while trying to report the exception in
    # _bootstrap_inner() below ***.  Those random exceptions
    # don't help anybody, and they confuse users, so we suppress
    # them.  We suppress them only when it appears that the world
    # indeed has already been destroyed, so that exceptions in
    # _bootstrap_inner() during normal business hours are properly
    # reported.  Also, we only suppress them for daemonic threads;
    # if a non-daemonic encounters this, something else is wrong.
    try:
        self._bootstrap_inner()
    except:
        if self._daemonic and _sys is None:
            return
        raise

在這種情況下，可以在所有non-daemonic線程都被殺死時殺死線程，您可以嘗試將線程設置為daemonic線程，以便自動處理異常。 我認為這種方法不需要標志。

t1.daemon=True
t1.start()