[英]Python Tkinter Variable label not updating
我試圖在我的標簽更新上制作我的變量,但是遇到了一個問題,按鈕的功能通過將溫度設置向上和向下改變0.5攝氏度來工作,但是溫度和所需溫度上的標簽不會隨之改變。
我在python3.6工作
這是我的代碼,我想知道是否有人可以幫助我嗎?
import os
import glob
import time
import RPi.GPIO as GPIO
from datetime import datetime
#Set gpio's
GPIO.setmode(GPIO.BCM)
GPIO.setwarnings(False)
GPIO.setup(17,GPIO.OUT)#RED
GPIO.setup(22,GPIO.OUT)#GREEN
GPIO.setup(27,GPIO.OUT)#BLUE
#grab temp probe information
os.system('modprobe w1-gpio')
os.system('modprobe w1-therm')
base_dir = '/sys/bus/w1/devices/'
device_folder = glob.glob(base_dir + '28*')[0]
device_file = device_folder + '/w1_slave'
# Read temperature from device
def read_temp_raw():
f = open(device_file, 'r')
lines = f.readlines()
f.close()
return lines
def read_temp():
lines=read_temp_raw()
while lines[0].strip()[-3:] != 'YES':
time.sleep(0.1)
lines = read_temp_raw()
equals_pos = lines[1].find('t=')
if equals_pos != -1:
temp_string = lines[1][equals_pos+2:]
temp_c = float(temp_string) / 1000
#temp_f = temp_c * 9.0 / 5.0 + 32.0
return temp_c#, temp_f
temp = read_temp()
desiredtemp = 17
deg = u'\xb0'#utf code for degree
def increase():
global desiredtemp
desiredtemp = desiredtemp + 0.5
print(desiredtemp)
def decrease():
global desiredtemp
desiredtemp = desiredtemp - 0.5
print(desiredtemp)
#Tkinter start
from tkinter import *
root = Tk()
#code to add widgets will go here....
topFrame = Frame(root)
topFrame.pack(side=TOP)
middleFrame = Frame(root)
middleFrame.pack()
bottomFrame = Frame(root)
bottomFrame.pack(side=BOTTOM)
#Set buttons
button1 = Button(bottomFrame, text="Increase (0.5"+ deg +"C)", fg="black", command=increase)
button2 = Button(bottomFrame, text="Decrease (0.5"+ deg +"C)", fg="black", command=decrease)
#use to put buttons on screen
button1.pack(side=LEFT)
button2.pack(side=LEFT)
#Set labels
label1 = Label(topFrame, text="Desired Temp = ", fg="black")
label2 = Label(middleFrame, text="Actual Temp = ", fg="black")
label3 = Label(topFrame, text=desiredtemp, fg="black")
label4 = Label(middleFrame, text=temp, fg="black")
#use to put labels on screen
label1.pack(side=LEFT)
label2.pack(side=LEFT)
label3.pack(side=LEFT)
label4.pack(side=LEFT)
root.mainloop()
#Tkinter End
# Open file to be logged
file = open("/home/pi/Desktop/Templog.csv", "a")
if os.stat("/home/pi/Desktop/Templog.csv").st_size == 0:
file.write("Date, Time, TemperatureSensor1\n")
# Continuous print loop
while True:
print(read_temp())
if(read_temp()<desiredtemp):
GPIO.output(17,GPIO.LOW)
GPIO.output(22,GPIO.HIGH)
else:
GPIO.output(17,GPIO.HIGH)
GPIO.output(22,GPIO.LOW)
now = datetime.now()
file.write(str(now.day)+"-"+str(now.month)+"-"+str(now.year)+","+str(now.hour)+":"+str(now.minute)+":"+str(now.second)+","+str(read_temp())+"\n")
file.flush()
time.sleep(1)
您可以使用StringVar
將字符串變量與Label
小部件相關聯。 您將StringVar
作為textvariable
關鍵字參數傳遞給Label
,並且在每個按鈕回調中,只需使用其set
方法更新溫度值和StringVar
。
擴展自己的代碼的示例:
import os
import glob
import time
from datetime import datetime
from tkinter import *
temp = 18
desiredtemp = 17
deg = u'\xb0' # utf code for degree
def increase():
global desiredtemp
desiredtemp += 0.5
tmpstr.set("%s" % desiredtemp)
def decrease():
global desiredtemp
desiredtemp -= 0.5
tmpstr.set("%s" % desiredtemp)
root = Tk()
topFrame = Frame(root)
topFrame.pack(side=TOP)
middleFrame = Frame(root)
middleFrame.pack()
bottomFrame = Frame(root)
bottomFrame.pack(side=BOTTOM)
button1 = Button(bottomFrame, text="Increase (0.5"+ deg +"C)", fg="black", command=increase)
button2 = Button(bottomFrame, text="Decrease (0.5"+ deg +"C)", fg="black", command=decrease)
button1.pack(side=LEFT)
button2.pack(side=LEFT)
tmpstr = StringVar(value="%s" % desiredtemp)
label1 = Label(topFrame, text="Desired Temp = ", fg="black")
label2 = Label(middleFrame, text="Actual Temp = ", fg="black")
label3 = Label(topFrame, textvariable=tmpstr, fg="black")
label4 = Label(middleFrame, text=temp, fg="black")
label1.pack(side=LEFT)
label2.pack(side=LEFT)
label3.pack(side=LEFT)
label4.pack(side=LEFT)
root.mainloop()
請注意,使用global
關鍵字通常被認為是代碼氣味 ,應該考慮將所有這些元素放入類中。
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