我正在使用 tkinter 根据我正在读取的电压显示一些标签。但是，它会在一次读取后停止执行。我发现这是由于 root.mainloop()。但我无法修复它。我已经包含了我的代码。 root.mainloop() 正好位于 while True 的末尾。
from Tkinter import *
import spidev
import time
import os
import RPi.GPIO as GPIO
import numpy
GPIO.cleanup()
GPIO.setmode(GPIO.BOARD)
GPIO.setup(7, GPIO.OUT)
GPIO.setup(11, GPIO.OUT)
GPIO.setup(13, GPIO.OUT)
GPIO.setup(15, GPIO.OUT)
GPIO.setup(12, GPIO.OUT)
adcvolt = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
batvolt = [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
root = Tk() #Makes the window
w,h = root.winfo_screenwidth(), root.winfo_screenheight()
root.overrideredirect(1)
root.geometry("%dx%d+0+0"%(w,h))
labelFont = ("times",15 ,"bold", "italic")
labelText1 = StringVar()
labelText2 = StringVar()
labelText3 = StringVar()
labelText4 = StringVar()
labelText5 = StringVar()
labelText6 = StringVar()
labelText1.set("Battery Management System")
label1 = Label(root, textvariable=labelText1, height=3, anchor="center")
label1.config(font=labelFont)
label1.pack()
labelText2.set("Wait")
label2 = Label(root, textvariable=labelText2, height=3, anchor="center")
label2.config(font=labelFont)
label2.pack()
labelText3.set("Wait")
label3 = Label(root, textvariable=labelText3, height=3, anchor="center")
label3.config(font=labelFont)
label3.pack()
labelText4.set("Wait")
label4 = Label(root, textvariable=labelText4, height=3, anchor="center")
label4.config(font=labelFont)
label4.pack()
labelText5.set("Wait")
label5 = Label(root, textvariable=labelText5, height=3, anchor="center")
label5.config(font=labelFont)
label5.pack()
labelText6.set("Wait")
label6 = Label(root, textvariable=labelText6, height=3, anchor="center")
label6.config(font=labelFont)
label6.pack()
#root.wm_title("Window Title") #Makes the title that will appear in the top left
#root.config(background = "#FFFFFF") #sets background color to white
# Open SPI bus
spi = spidev.SpiDev()
spi.open(0,0)
# Function to read SPI data from MCP3008 chip
# Channel must be an integer 0-7
def ReadChannel(channel):
adc = spi.xfer2([1,(8+channel)<<4,0])
data = ((adc[1]&3) << 8) + adc[2]
return data
#Function to select multiplexer channel on 74HCT4067 chip
#Channel must be an integer 0-15
def MuxSelect(muxchannel):
if muxchannel == 0:
GPIO.output(7,0)
GPIO.output(11,0)
GPIO.output(13,0)
GPIO.output(15,0)
elif muxchannel == 1:
GPIO.output(7,0)
GPIO.output(11,0)
GPIO.output(13,0)
GPIO.output(15,1)
elif muxchannel == 2:
GPIO.output(7,0)
GPIO.output(11,0)
GPIO.output(13,1)
GPIO.output(15,0)
elif muxchannel == 3:
GPIO.output(7,0)
GPIO.output(11,0)
GPIO.output(13,1)
GPIO.output(15,1)
elif muxchannel == 4:
GPIO.output(7,0)
GPIO.output(11,1)
GPIO.output(13,0)
GPIO.output(15,0)
elif muxchannel == 5:
GPIO.output(7,0)
GPIO.output(11,1)
GPIO.output(13,0)
GPIO.output(15,1)
elif muxchannel == 6:
GPIO.output(7,0)
GPIO.output(11,1)
GPIO.output(13,1)
GPIO.output(15,0)
elif muxchannel == 7:
GPIO.output(7,0)
GPIO.output(11,1)
GPIO.output(13,1)
GPIO.output(15,1)
elif muxchannel == 8:
GPIO.output(7,1)
GPIO.output(11,0)
GPIO.output(13,0)
GPIO.output(15,0)
elif muxchannel == 9:
GPIO.output(7,1)
GPIO.output(11,0)
GPIO.output(13,0)
GPIO.output(15,1)
elif muxchannel == 10:
GPIO.output(7,1)
GPIO.output(11,0)
GPIO.output(13,1)
GPIO.output(15,0)
elif muxchannel == 11:
GPIO.output(7,1)
GPIO.output(11,0)
GPIO.output(13,1)
GPIO.output(15,1)
elif muxchannel == 12:
GPIO.output(7,1)
GPIO.output(11,1)
GPIO.output(13,0)
GPIO.output(15,0)
elif muxchannel == 13:
GPIO.output(7,1)
GPIO.output(11,1)
GPIO.output(13,0)
GPIO.output(15,1)
elif muxchannel == 14:
GPIO.output(7,1)
GPIO.output(11,1)
GPIO.output(13,1)
GPIO.output(15,0)
elif muxchannel == 15:
GPIO.output(7,1)
GPIO.output(11,1)
GPIO.output(13,1)
GPIO.output(15,1)
# Function to convert data to voltage level,
# rounded to specified number of decimal places.
def ConvertVolts(data,places):
volts = (data * 3.3) / 1023
volts = round(volts,places)
return volts
# Define sensor channels
voltage_channel = 0
# Define delay between readings
delay = 2
while True:
count = 0
while count<15:
MuxSelect(count)
# Read the voltage sensor data
voltage_level = ReadChannel(voltage_channel)
voltage_volts = ConvertVolts(voltage_level,2)
adcvolt[count] = voltage_volts
batvolt[count] = adcvolt[count] * 2.842
#print adcvolt[count]
#print batvolt[count]
#print count
count = count + 1
#time.sleep(delay)
labelText2.set('Cell1= '+str(batvolt[0])+'V Cell2= ' +str(batvolt[1])+'V Cell3= '+str(batvolt[2]))
#root.update()
labelText3.set('Cell4= '+str(batvolt[3])+'V Cell5= ' +str(batvolt[4])+'V Cell6= '+str(batvolt[5]))
# root.update()
labelText4.set('Cell7= '+str(batvolt[6])+'V Cell8= ' +str(batvolt[7])+'V Cell9= '+str(batvolt[8]))
# root.update()
labelText5.set('Cell10= '+str(batvolt[9])+'V Cell11= ' +str(batvolt[10])+'V Cell12= '+str(batvolt[11]))
# root.update()
labelText6.set('Cell13= '+str(batvolt[12])+'V Cell14= ' +str(batvolt[13])+'V Cell15= '+str(batvolt[14]))
root.update()
print "shit"
medianvolt = numpy.median(batvolt)
maxvolt = max(batvolt)
minvolt = min(batvolt)
diff1 = maxvolt-medianvolt
diff2 = medianvolt-minvolt
if diff1>0.02 or diff2>0.02:
GPIO.output (12,1)
time.sleep(120)
GPIO.output (12,0)
# Wait before repeating loop
time.sleep(delay)
root.update()
root.mainloop() #start monitoring and updating the GUI. Nothing below here runs.
请您参考如下方法:
tkinter 需要 mainloop() 才能正常工作 - 它使用它一次又一次地调用所有需要的函数 - 即。从系统获取键/鼠标事件，将它们发送到小部件，更新值，并在窗口中(重新)绘制小部件。
在 tkinter 中不要使用永远运行(或运行更长时间)的 while True 因为它会阻塞 mainloop() 在 tkinter 并且它无法更新窗口中的项目，看起来像卡住了。
同样的问题使 sleep() - 它可以阻止 tkinter 中的 mainloop()。
您可以使用 root.after(time_ms, function_name_without_brackets )(在 mainloop() 之前)
延迟运行一些函数 - 所以它可以像 sleep() 一样使用。如果函数将运行相同的 after(...) 那么它将像循环一样工作。这样 tkinter 将有时间更新窗口中的小部件。
因此，将 while True 中的所有代码(mainloop() 除外)放入函数中，并使用 after() 调用它。
并使用第二个 after() 代替 sleep()。
import tkinter as tk
master = tk.Tk()
def my_mainloop():
print "Hello World!"
master.after(1000, my_mainloop) # run again after 1000ms (1s)
master.after(1000, my_mainloop) # run first time after 1000ms (1s)
master.mainloop()
如果您不能转换 while 循环并使用 after()，那么您可能必须在单独的线程中运行循环。但是 tkinter(与许多其他 GUI 一样)` 不喜欢在第二个线程中工作，并且 GUI 中的所有更改都必须在主线程中进行。
