update tkinter label from serial data whenever the

Question

I have encounter this problem where i could not display any value on the label which i wanted to constantly update it whenever there's new data coming in from the serial port. I'm new to python, really need the help.

import tkinter
import tkinter.messagebox
import serial
import time

ser = serial.Serial(
    port='COM5',\
    baudrate=9600,\
    parity=serial.PARITY_NONE,\
    stopbits=serial.STOPBITS_ONE,\
    bytesize=serial.EIGHTBITS,\
        timeout=4)

class Menu:

    def __init__(self):    

        self.main_window = tkinter.Tk()
        self.main_window.title("Room Light System")
        self.main_window.geometry("1200x600")


        #Frames
        self.frame_2 = tkinter.Frame(self.main_window, bg='Orange') # Receiving DATAs



        #ReceiveLabel
        self.ReceiveLabel = tkinter.Label(self.frame_2,\
                                       text = 'Received DATAs',\
                                       bg = 'White',\
                                       height = 2, width = 20)


        #Temperature
        self.GetTempLabel = tkinter.Label(self.frame_2,\
                                       text='Temperature :')
        self.TempValue = tkinter.StringVar()

        self.GetTempValueLabel = tkinter.Label(self.frame_2,bg = 'Green',\
                                               textvariable = self.TempValue
                                               )



        #PACKING!!! F2

        self.frame_2.pack()
        self.frame_2.place(x=410, y=0, height=300, width=400)
        #ReceiveLabel
        self.ReceiveLabel.pack()
        self.ReceiveLabel.place(x=100, y=10)
        #Temperature
        self.GetTempLabel.pack()
        self.GetTempLabel.place(x=50, y=80, height=20, width=120)
        self.GetTempValueLabel.pack()
        self.GetTempValueLabel.place(x=200, y=80, height=20, width=50)


        #main loop and quit
        self.quitButton = tkinter.Button(self.main_window,\
                                          text = 'Quit',
                                          command = self.main_window.destroy,\
                                          height = 2, width = 6)
        self.quitButton.pack() 

        self.quitButton.place(x=200, y=500)


        tkinter.mainloop()

    def GetTemp(self):

        data = bytearray()
        while(1):
            readline = ser.read(size=10)
            if len(readline) > 0 : 
                data = readline
                v = memoryview(data)                
                P = v.tobytes() 
                P = P.decode(encoding='UTF-8')
                self.TempValue.set(P)

gui = Menu()
ser.close()

Answer 1

You can run your GetTemp() method in a seperated thread from _thread module. The thread is called with the Tkinter method after(). In following example I substituted your GetTemp() with a randomn number generated.

import tkinter
import tkinter.messagebox
import time
import random
import _thread

class Menu:

    def __init__(self):    

        self.main_window = tkinter.Tk()
        self.main_window.title("Room Light System")
        self.main_window.geometry("1200x600")


        #Frames
        self.frame_2 = tkinter.Frame(self.main_window, bg='Orange') # Receiving DATAs



        #ReceiveLabel
        self.ReceiveLabel = tkinter.Label(self.frame_2,\
                                       text = 'Received DATAs',\
                                       bg = 'White',\
                                       height = 2, width = 20)


        #Temperature
        self.GetTempLabel = tkinter.Label(self.frame_2,\
                                       text='Temperature :')
        self.TempValue = tkinter.StringVar()

        self.GetTempValueLabel = tkinter.Label(self.frame_2,bg = 'Green',\
                                               textvariable = self.TempValue
                                               )



        #PACKING!!! F2

        self.frame_2.pack()
        self.frame_2.place(x=410, y=0, height=300, width=400)
        #ReceiveLabel
        self.ReceiveLabel.pack()
        self.ReceiveLabel.place(x=100, y=10)
        #Temperature
        self.GetTempLabel.pack()
        self.GetTempLabel.place(x=50, y=80, height=20, width=120)
        self.GetTempValueLabel.pack()
        self.GetTempValueLabel.place(x=200, y=80, height=20, width=50)


        #main loop and quit
        self.quitButton = tkinter.Button(self.main_window,\
                                          text = 'Quit',
                                          command = self.main_window.destroy,\
                                          height = 2, width = 6)
        self.quitButton.pack() 

        self.quitButton.place(x=200, y=500)


        self.main_window.after(2000, _thread.start_new_thread, self.GetTemp, ())
        tkinter.mainloop()

    def GetTemp(self):

        while(1):
            value = random.random()
            self.TempValue.set(str(value))
            time.sleep(0.5)

gui = Menu()